Technical Field
[0001] This invention relates to a privacy cover for a camera. The camera may find particular
application in the field of security in domestic and commercial premises, but this
is not a limitation. The invention may also relate to a method of operating a camera
with a privacy cover and determining when the privacy cover is in use.
Background
[0002] The use of privacy covers on cameras are known. Privacy covers provide an option
for a user to block the camera lens to prevent the viewing or recording of images.
Such privacy covers may be employed during predetermined times or events, such as
when a resident is at home or during normal office hours, for example.
[0003] A privacy cover will typically comprise a removable cover or cap which can be placed
over the lens of a camera to block the camera lens/aperture. The cap or cover may
be attached to the camera housing and moved from an open position to a closed (i.e.
covering position) using a hinged or sliding connection, for example.
[0004] An issue can arise with some privacy covers in that they are capable of being placed
in an open state but believed to be fully closed by the user. For example, the user
may forget the state of the cover, or another person may have changed the state of
the cover, unbeknownst to that user. A further issue may arise when a user forgets
to remove a privacy cover, for example, when leaving a premises that has the camera.
[0005] Such issues may be especially problematic in the cases where the camera is part of
a security system.
[0006] The present invention seeks to address disadvantages or problems associated with
known privacy covers or provide useful alternatives.
Summary of the Invention
[0007] The present invention provides a method of determining the cover position of a camera
unit according to the appended claims. Disclosed herein are various examples and embodiments
of camera units and methods of operating the camera units.
[0008] According to a first aspect of the disclosure a method of determining the cover position
of a camera unit comprising: a camera having a lens for receiving light from a field
of view, FOV; a cover which is movable from an open position in which the lens is
exposed, to a closed position in which the lens is covered. The method may comprise:
receiving a cover position status request at the camera unit from a central controller;
and, determining the cover position status in response to receiving the cover position
status request.
[0009] The camera unit may be in a security system comprising one or more control hubs which
receive data from and/or transmit commands to the camera unit.
[0010] The cover position status request may comprise an arm command. The camera unit may
be configured to be placed in an armed state in which the camera is responsive to
a motion detection signal from a motion detector in response to the arm command. The
motion detector may be an integral motion detector within the camera unit.
[0011] The method may further comprise determining that the cover position status is either
open or closed and transmitting the cover position status from the camera unit to
the central controller. The transmission may only occur when the cover position status
is closed. Transmitting the cover position status when the cover is closed may save
power.
[0012] When the cover is determined to be closed a cover status notification may be transmitted
to a user. The transmission may be provided by the central controller or a server.
[0013] The method may further comprise: receiving a second cover position status request
at the camera unit in response to a re-arming command received by the central controller
associated with the camera unit.
[0014] The method may further comprise: obtaining one or more images with the camera in
response to a security sensor or upon receiving an image capture command from a central
controller. The security sensor may comprise at least one: of a motion detector or
an entry sensor.
[0015] The method may further comprise determining the cover position status in response
to connecting the camera unit to a power source.
[0016] The connection to a power source may follow an installation of the camera unit, a
change of the power source or re-connection of the power source following a disconnection.
The disconnection may be due to a power failure or change of power source.
[0017] The determination of the cover position status may be carried out prior to or during
the camera being activated for image capture.
[0018] The determination of the cover position status may be executed whilst the camera
is being powered-up following a powered-down period. The powered-down period may be
a stand-by mode or being off. The powered-down period may relate to either the camera
unit or the camera alone.
[0019] The cover position status may be transmitted as part of another transmission.
[0020] Determining the cover position status may comprise obtaining the cover position status
from a position sensor. The position sensor may comprise: a light sensor which is
covered by the cover when in the closed position and exposed when the cover is in
the open position, or, an actuator position sensor configured to provide positional
information to an actuator.
[0021] In a second aspect, the method of determining the cover position of a camera unit
may comprise: a camera having a lens for receiving light from a field of view, FOV;
a cover which is movable from an open position in which the lens is exposed, to a
closed position in which the lens is covered. The method may comprise: transmitting
a cover position status request from a central controller to the camera unit; and,
in the event of receiving a closed cover position status from the camera unit in response
to the request, determining that the camera is ineffective.
[0022] The camera unit may be in a security system comprising one or more control hubs which
receive data from and/or transmit commands to the camera unit.
[0023] In the event of not receiving a cover position status from the camera unit in response
to the request, determining that the cover is in the open position.
[0024] The cover position status may be transmitted in response to an arm command.
[0025] When the cover position status is closed, the method may further comprise sending
a notification to a user or server to inform the user or server of the cover position
status.
[0026] The notification may comprise one or more selectable response options for the user
to select in response to the cover position status.
[0027] In a third aspect, the present disclosure provides a method of confirming a security
system configuration, comprising: receiving, by a user device, a cover position status
of a camera cover when the cover is in a closed position; displaying a notification
for a user on the user device in response to receiving the cover position status,
wherein the notification comprises an indication that the cover position is closed.
[0028] The receiving of the cover position status may be in response to an arm request transmitted
from the user device and, optionally, further comprising providing one or more user
selectable options for a user to select in response to the notification of the cover
position status, wherein, optionally, the user selectable options comprise one or
more of: a disarm command for disarming the security system; an accept command for
accepting the cover position status; or an open application command for opening an
application for interfacing with the security system on the user device.
[0029] In a fourth aspect, the present disclosure may comprise: a camera comprising a lens
for receiving light from a field of view, FOV; a cover which is movable from an open
position in which the lens is exposed, to a closed position in which the lens is covered,
and, at least one processor configured to carry out the method according to of the
first to third aspects.
[0030] In a fourth aspect of the present disclosure, a camera unit may comprise an actuator
for moving the cover from an open position to a closed position. The actuator may
comprise a position sensor for determining the position of the cover.
[0031] In a fifth aspect, the present disclosure provides a security system controller comprising
at least one processor and at least one memory, wherein the processor is configured
to carry out the method according to the second aspect or any combination of features
associated with the second aspect.
[0032] In a sixth aspect, the present disclosure may provide a user device comprising at
least one processor and at least one memory, wherein the processor is configured to
carry out the method according to the third aspect or any combination features associated
with the third aspect.
[0033] In a seventh aspect, the present disclosure may provide a non-transitory storage
medium comprising electronic-processor readable code that, when read by one or more
electronic processors, cause performance of the method according to any combination
of the first aspect of the disclosure.
[0034] In an eight aspect, the present disclosure may provide a non-transitory storage medium
comprising electronic-processor readable code that, when read one or more electronic
processors of a user device, configure the user device to carry out the method according
to the second aspect or any combination of features relating to the second aspect.
[0035] In a ninth aspect, the present disclosure provides a camera unit comprising: a camera
comprising a lens for receiving light from a field of view, FOV; a cover which is
movable from an open position in which the lens is exposed, to a closed position in
which the lens is covered; and, an actuator for moving the cover between the closed
position to the open position.
[0036] The actuator may comprise an electromagnetic actuator.
[0037] The actuator may comprise a position sensor configured to provide an indication of
the cover position.
[0038] The position sensor may be configured to provide a position signal for controlling
the actuator. The position sensor may be an encoder.
[0039] The actuator may comprise one or more of a linear drive or rotary drive.
[0040] The actuator may comprise at least one electrical solenoid or an electric motor.
The electric motor is a DC motor.
[0041] The camera unit may further comprise: at least one memory, wherein the memory is
configured to store the cover position status.
The camera unit may be configured to transmit the cover position status to a central
controller upon receipt of a request for the cover position status.
[0042] The request for the cover position status may comprise an arm command in response
to which the camera unit is placed in an armed state.
[0043] The camera unit may be configured to open the cover in response to a determination
that the cover position is closed.
[0044] The may be configured to open the cover in response to receiving a signal from a
central controller. The signal may be an arm command.
[0045] Disclosed herein in a tenth aspect is a camera unit comprising: a light source; a
light sensor; a camera comprising a lens for receiving light from a field of view,
FOV, and an image sensor for capturing of images of the FOV; a cover which is movable
from an open position in which the light source, the light sensor and the lens are
exposed, to a closed position in which the light source, the light sensor and the
lens are covered.
[0046] Providing a cover which is movable between an open position and a closed position
in which the light sensor, light source and lens are covered in the closed position,
provides an improved camera unit which can be used in various ways to determine whether
the cover is open or closed, thereby improving the utility and reliability of the
system.
[0047] The cover may be slidably movable from the open position to the closed position.
A sliding cover provides a convenient way of actuating the cover between position.
Further, the linear action of the cover can be usefully employed in combination with
the positioning of the light source, lens and light sensor to aid the detection process
of the cover.
[0048] Either or both of the light source and the light sensor may be located on an opposing
side of the lens to the cover when the cover is in the open position, such that either
or both of the light source and light sensor are covered by the cover only when the
lens is covered. If both the light source and light sensor are covered only once the
lens is covered, any effects the cover has on the light received by the light sensor
from the light source when in the closed position can be determined to be occurring
when the cover is closed so as to obscure the lens. Thus, the determination of the
lens being covered or uncovered can be made more readily.
[0049] The light sensor and light source may be located on opposing sides of the lens. By
placing the light sensor and light source on opposing sides of the lens, the amount
of light received by the light sensor from the light source can be more accurately
controlled by the position of the cover. That is, when the light source and light
sensor are located adjacent one another, light may be received by the light sensor
from the light source when the cover is open by virtue of the proximity, which reduces
the accuracy of the positional determination.
[0050] The light sensor may be located proximal to the cover when the cover is in the open
position.
[0051] The cover may be movable sequentially from the open position through a first intermediate
position in which the light sensor is covered, through a second intermediate position
in which the lens is covered, to the closed position in which the light source, the
light sensor and the lens are all covered. A sequential closing further defines the
relative positions of the lens, light sensor and light source and aids the determination
of the cover position by ensuring that the lens is covered prior to both the light
source and light sensor both being covered.
[0052] The cover may comprise an inner side which is located opposite the light source and
the light sensor when the cover is in the closed position. The inner side may comprise
a light reflecting surface for directing light from the light source to the light
sensor when the light source and light sensor are covered by the cover.
[0053] The camera unit may further comprise an inner side which has a channel therein. The
channel may oppose the light sensor and light source when the cover is in the closed
position. The channel may help receive and guide light from the light source to the
light sensor, thereby improving the amount of light which is received. This may in
turn aid with the setting of one or more threshold values for determining whether
the cover is open or closed. The channel may provide the light reflecting surface.
[0054] The inner side may comprise a light blocking layer on a body of the cover. The light
blocking layer may reduce a transmissibility of ambient light to the light sensor
from outside of the cover when the light sensor is covered by the cover. Thus, the
light blocking layer may reduce the amount of light which is received within the cover
from the exterior of the camera unit.
[0055] The camera may further comprise a processor configured to: measure the output from
the light sensor when the light source is deactivated. Additionally, or alternatively,
the processor may be configured to: measure the output from the light sensor when
the light source is activated. Controlling the activation of the light source and
corresponding measurements can aid with the determination of the cover position.
[0056] Thus, the processor may be further configured to determine the cover position on
the basis of either or both of the measured outputs from when the light is activated
and when the light is deactivated.
[0057] The determination of the cover position may comprise a comparison of either or both
measured outputs with a predetermined threshold. The thresholds may be set at levels
which correspond to expected levels of light which are received when the cover is
open or closed, and the light source is activated (on), or deactivated (off).
[0058] The measured output when the light source is activated may be compared with a higher
threshold than the measured output when the light source is deactivated. The setting
of the second threshold at a higher level corresponds to the higher light level which
would be expected to be received by the light sensor when the cover is closed, due
to light being reflected of the inner side of the cover.
[0059] The processor may be configured to activate and deactivate the light source. The
processor may be further configured to determine whether an ambient light level is
below a predetermined level. By determining the level of the ambient light with respect
to a predetermined threshold or level, it is possible to determine whether the cover
is open, particularly when the ambient light level is above the predetermined level.
The ambient light may be taken to be the light level in the field of view. The ambient
light may correspond to the level of light when the light source is off.
[0060] The image sensor and the light sensor may be independent of one another so as to
comprise different/discrete components having separate light transducers. As such,
the image sensor may be deactivated during the measuring of the outputs from the light
sensor for said determining of the cover position, thereby making the camera unit
more energy efficient.
[0061] Also described herein in a eleventh aspect is a camera unit comprising: a camera
lens for receiving light from a field of view; a cover which is movable from an open
position in which the camera lens can capture the full field of view, FOV, and a closed
position in which the cover obscures the FOV; a light source; a light sensor; a processor
configured to: measure the amount of light received by the light sensor when the light
source is deactivated; and, compare the measured light with a predetermined value
to determine whether the cover is in an open or closed position. Measuring the amount
of light when the light source is deactivated allows a determination of the ambient
light which can indicate whether the cover is open under certain circumstances, for
example, when the cover is open in daylight hours or when the FOV of otherwise illuminated.
[0062] The predetermined value may be selected on the basis of an attributed maximum detectable
ambient light level when the cover is in a closed position. By attributed maximum
detectable ambient light, it is meant the amount of light which can be attributed
to the ambient light conditions which can be received by the sensor when the cover
is closed and the light source is off. Setting the predetermined value on the basis
of the attributed maximum detectable ambient light when the camera is closed provides
a sensible lower limit which is indicative of whether the cover is open.
[0063] When the measured light is below the predetermined value the processor may be further
configured to: activate the light source; measure a second amount of light received
by the light sensor; and, compare the measurement of the second amount of light with
a second predetermined value to determine whether the cover is in the open or closed
position.
[0064] When the light received by the sensor is less than the predetermined level, it may
be indicative that the FOV external to the camera unit is too low, that is, too dark,
or the cover is closed. By activating the light source and taking a second measurement,
it is possible to determine whether the light sensor is receiving light from the light
source, for example as reflected off the inner side of the cover so as to determine
that the cover is closed.
[0065] The camera unit may be further configured to instruct transmission of an open signal
to a controller based on a determination that the cover is open. The camera unit is
further configured to instruct the transmission of a closed signal to a controller
based on a determination that the cover is closed. The camera unit may be configured
to pass the determination of the cover positional status to a control system such
that the status may be used for determining an associated action. The action may,
for example, be providing a notification to a user indicating the status of the cover,
or an action, such as configuring the camera unit for image capture.
[0066] The light sensor may be an image sensor or part thereof, wherein the image sensor
is configured for capturing images of the FOV. The disclosure does not necessarily
require a separate light sensor, or may, in some examples, use the image sensor as
a secondary light sensor, for example to verify the operation of the independent light
sensor or position of the cover. Equally, the camera unit may further comprise an
image sensor configured for capturing images from the FOV, wherein the light sensor
is distinct from the image sensor. The image sensor may be deactivated when the light
source is activated and the measurement of light is taken. Providing a distinct light
sensor allows the camera unit to be more power efficient.
[0067] Where two predetermined values are used for determining the position of the cover,
the first predetermined value may be less than the second predetermined value. The
first predetermined value may correspond to the measurement taken when the light source
is deactivated (off).
[0068] Also disclosed herein, in a twelfth aspect, is a camera unit comprising: a camera
lens for receiving light from a field of view; a cover which is movable from an open
position in which the camera lens can capture the full field of view, FOV, and a closed
position in which the cover obscures the FOV; a light source; a light sensor; a processor
configured to: measure the amount of light received by the light sensor when the light
source is activated; and, compare the measured light with a predetermined value to
determine whether the cover is in an open or closed position.
[0069] As noted above, providing a measurement when the light source is activated may be
useful when the cover is closed as the light received by the light sensor as reflected
(or not reflected) off the inner side of the light source can be determinative of
the cover position. Hence, the predetermined value may be selected on the basis of
an expected level of light redirected from the light source to the light sensor by
an inner side of the cover.
[0070] The comparison of the measured light with a predetermined value may result in a determination
that the cover is closed if the measured light is above the predetermined value. The
comparison of the measured light with a predetermined value may result in a determination
that the cover is open if the measured light is below the predetermined value.
[0071] The processor may be configured to instruct a transmission of an open signal to a
controller based on a determination that the cover is open. Alternatively or additionally,
the processor may be configured to instruct transmission of a closed signal to a controller
based on a determination that the cover is closed.
[0072] The light sensor may be an image sensor or part thereof, the image sensor may be
configured for capturing images said FOV.
[0073] The camera unit may further comprise an image sensor for sensing images from the
FOV, said light sensor being distinct from said image sensor.
[0074] The camera units disclosed herein may comprise a motion sensor. The camera unit may
be configured to capture one or more images of the FOV in response to a detected motion
based on the motion sensor. The camera unit may be battery powered. The camera unit
may be configured to store the one or more images and upon receiving a request for
said images wirelessly transmit said images to a controller.
[0075] A further aspect disclosed herein is a cover for a camera unit. The camera unit may
comprise a light source, a light sensor and a camera lens. The cover may have sides
shaped for sliding along rails on the camera unit to move between an open position
in which the camera lens, light sensor and light source are uncovered and a closed
position in which the camera lens, light sensor and light source are covered. The
cover may comprise a side for facing the camera unit, wherein the side for facing
the camera unit has a reflective surface for directing light from the light source
to the light sensor. As noted above, the reflective surface may comprise a recessed
region of the inner side of the cover. The reflective surface may be metallic. The
reflective surface may be on a plastic body. The reflective surface is provided in
an open channel in said side.
[0076] Also disclosed herein are methods pertaining to the use of the disclosed camera units
and the detection of the cover position. Thus, in a thirteenth aspect there may be
a method of determining the cover position of a camera unit, the method comprising:
measuring the light detected by a light sensor when the light source is deactivated;
compare the measured light level with a predetermined value to determine whether the
cover is in the open position or closed position.
[0077] The method may further comprise: selecting the predetermined value on the basis of
a minimum expected ambient light level for the FOV when the cover is in the open position.
Setting the value on the basis of a minimum expected ambient light level for the field
of view may be useful for particular times of day, particularly if the camera unit
is located outside.
[0078] The method may further comprise: selecting the predetermined value on the basis of
a maximum expected noise level in the light level measurement. Setting the predetermined
level on the basis of a maximum amount of noise may allow the system to account for
a minimum level of ambient light which is detectable over a noise floor of the system.
This provides the effective detectable minimum ambient light level.
[0079] The predetermined value may be selected on the basis of an attributed maximum detectable
ambient light level when the cover is in a closed position. Setting the predetermined
value on the basis of the attributed maximum detectable ambient light when the camera
is closed provides a sensible lower limit which is indicative of whether the cover
is open or potentially closed. By attributed maximum detectable ambient light, it
is meant the amount of light which can be attributed to the ambient light conditions
which can be received by the sensor when the cover is closed and the light source
is off.
[0080] The method may further comprise, when the measured light is below the predetermined
value, activating the light source; measuring the second amount of light received
by the light sensor; and, comparing the measurement of the second amount of light
with a second predetermined value to determine whether the cover is open or closed.
[0081] Upon a determination that the cover is open, the camera unit may transmit an open
signal to a controller. Additionally, or alternatively, upon a determination that
the cover is closed, the camera unit may be configured to transmit a closed signal
to the controller.
[0082] The method may further comprise, using an image sensor of the camera unit as the
light sensor. The image sensor may be configured for capturing images of the FOV.
The method may further comprise when the light source is activated and the measurement
of light is taken, the image sensor is in a deactivated state.
[0083] The first predetermined value may be less than the second predetermined value.
A fifth aspect may disclose a method comprising: measuring the amount of light received
by the light sensor when the light source is activated; and, comparing the measured
light with a predetermined value to determine whether the cover is in an open position
or closed position.
[0084] The predetermined value may be selected on the basis of an expected light level redirected
from the light source to the light sensor by a reflective surface of the cover. The
comparison of the measured light with the predetermined value may result in a determination
that the cover is open if the measured light is above the predetermined value.
[0085] Upon a determination that the cover is open, the camera unit may transmit an open
signal to a controller. Additionally or alternatively, upon a determination that the
cover is closed, transmitting a closed signal to a controller.
[0086] The method may further comprise using the image sensor of the camera unit as the
light sensor.
[0087] The above disclosed camera units and features thereof may be used in any combination,
where possible. Thus, a camera unit according to the tenth aspect, and any combination
of its optional features, may be combined with the camera unit according to the eleventh
aspect, and any combination of its optional features. The camera unit of the eleventh
aspect, and any combination of its optional features, may be combined with the camera
unit of the twelfth aspect and any combination of its optional features. Similarly,
the camera unit of the tenth aspect and any combination of its optional features may
be used with the camera unit of the twelfth aspect and any combination of its optional
features. Finally, the camera units of the tenth, eleventh and twelfth aspects may
be used in combination with any combination of the respective optional features. Similar
combinations are also possible within the combination of first to third aspects of
the disclosed methods.
[0088] Also described herein is a camera unit or controller comprising: at least one processor;
at least one memory comprising computer readable instructions; the at least one processor
being configured to read the computer readable instructions to cause performance of
one or more of the methods described herein.
[0089] Also disclosed herein is a computer program that, when read by a computer or camera
unit, causes performance of the method as described herein.
[0090] Also disclosed is non-transitory computer readable storage medium comprising computer
readable instructions that, when read by a computer or camera unit, cause performance
of the method as claimed in any of claims.
[0091] The skilled person will appreciate that except where mutually exclusive, a feature
described in relation to any one of the aspects, examples or embodiments described
herein may be applied to any other aspect, example, embodiment or feature. Further,
the description of any aspect, example or feature may form part of or the entirety
of an embodiment of the invention as defined by the claims. Any of the examples described
herein may be an example which embodies the invention defined by the claims and thus
an embodiment of the invention.
Brief Description of the Drawings
[0092] The invention will now be described, by way of example only, with reference to the
accompanying drawings, in which:
Figures 1a and 1b show schematic representations of a camera unit with a cover in
open and closed positions respectively;
Figures 2a and 2b show schematic representations of an alternative camera unit which
include a light sensor that is independent of an image sensor;
Figures 3a and 3b respectively show schematic representations of the inner side and
a section of a cover for a camera unit;
Figures 4a and 4b respectively show schematic representations of the inner side and
a section of an alternative cover for a camera unit;
Figure 5 shows a method of detecting the status of a cover;
Figure 6 shows a further method of detecting the status of a cover;
Figure 7 shows a yet further method of detecting the status of a cover;
Figure 8 shows a schematic representation of a camera unit and a central controller
showing a processor and memory parts thereof;
Figure 9 shows a flow diagram for a method of operating an arm aware camera unit;
Figure 10 shows a flow diagram for a method of operating an arm unaware camera unit;
Figures 11a,b and 12a,b show two example actuation mechanisms for a cover.
Detailed description of the embodiments
[0093] The present invention may provide a camera lens cover, a camera comprising a camera
lens cover and method of detecting the position of the cover. The present invention
may also provide a method of determining (that is, identifying) when a camera is operable.
[0094] Some aspects of the present disclosure are concerned with improving the energy efficiency
of a camera comprising a cover. The camera in question may be resource constrained.
For example, instead of having a connection to a mains supply, the camera may be powered
by a local power source such as a battery or solar panel.
[0095] Figures 1a and 1b show a schematic representation of a camera unit 10. The camera
unit 10 may comprise a camera shown generally by reference numeral 12 and a cover
14. The cover 14 is movable from an open or stowed configuration in which the camera
lens is exposed (Figure 1a), to a closed position 14' in which the camera lens is
covered so as to prevent viewing or recording (Figure 1b). The prime in reference
numeral 14' is used to denote the cover in the closed configuration. This is also
the case for the other components which are effected by the closure of the covers,
such as the camera lens 16, 16' and the light sensor 24, 24', as described below.
This described prime notation is used throughout the drawings.
[0096] The camera 12 may be conventional in many respects and include a lens 16 which is
arranged to receive light from a field of view, FOV, and one or more image sensors
(behind the lens and therefore not shown) which receive light from the FOV to generate
an electrical signal which is representative of the image provided in the FOV. This
image data may be processed locally, or transmitted via a suitable transmission medium
for handling by a remote signal processor. The transmission, particularly in embodiments
not powered by a mains supply, may be wireless, and may, in some embodiments use a
short range network, for example as ZigBee (or other IEEE802.12.4 based network) or
WiFi, to a wide area network (WAN) connected hub, as opposed to a cellular network.
[0097] The camera unit 10 may comprise a housing 18 to provide containment and support for
the camera 12 and any associated electronics. The camera unit 10 may be hardwired
or operate wirelessly with respect to power supply and data transmission. Hence, the
camera may comprise one or more local power sources such as a battery (not shown)
or solar generator, for example. Further the camera unit 10 may comprise one or more
antennas for transmitting image data to, and receiving commands from, a remote device.
The camera and/or remote device may comprise one or more processing devices, memory,
controllers, signal processing equipment. The remote device may comprise a control
hub of a system that provides at least premises security monitoring functions. The
hub may be a WAN connected hub as described above. In another example, the remote
device may be a server.
[0098] The cover 14 may be generally referred to as a privacy cover and enable a user to
obscure the camera lens and FOV to prevent unwanted viewing or recording of a location.
The cover 14 comprise a cap, door, panel, shutter or other object which can be positioned
on the device so as to obstruct the camera lens.
[0099] The cover 14 may be configured to be removably locatable in front of the camera lens.
In the example shown in Figure 1a, the camera lens 16 is located above the cover 14
such that the cover 14 may be moved upwards from a stowed position below the camera
12 to a closed position 14' in which the camera lens 16' is covered (Figure 1b).
[0100] The cover 14 may be attached to the camera unit 10 via any suitable arrangement such
as one or more hinges or a sliding arrangement, for example. In a linear sliding arrangement
the cover 14 and/or camera unit housing 18 comprises one or more runners 20 along
which the cover 14 can slide relative to the camera lens 16. The runners 20 may, for
example, be provided by the lateral edges 15 of the cover 14 which, are vertically
extending as shown in Figure 1, and corresponding rails in the form of grooves provided
in the camera unit housing 18, into which the lateral edges 15 have a sliding fit.
In other examples, the cover 14 may be located above or to the side of the camera
lens 16 and may pivot into place by way of one or more hinges. Other arrangements
for providing a displaceable cover 14 may be possible.
[0101] During use, the cover 14 may be moved from the open position to the closed position
14' by a user and vice-versa, as desired.
[0102] The camera unit 10 may be installed at a premises, typically for security purposes.
The camera unit 10 may be mounted on a wall or other vertical or horizontal surface
which is capable of providing the necessary support to locate the camera unit in a
desired viewing location. The location may be internal or external. The premises may
be any premises but will typically be a domestic premises such as a dwelling or an
associated outbuilding building of a dwelling such as a garage or shed, or a commercial
building such as a restaurant, shop or other facility. Thus, for a dwelling, the privacy
cover 14 may be employed when a resident is home and does not feel comfortable with
the camera being operable. For a commercial property, such as a restaurant, the camera
may be covered during opening hours and exposed only for out of hours security.
[0103] An image capturing function of the camera 12 may be triggered automatically using
one or more local sensors, such as a motion sensor (in some embodiments, a passive
infrared, PIR, detector) or other activity sensor (a microphone or other acoustic
wave sensor, for example), and/or may be responsive to an external signal provided
from a remote controller.
[0104] As such, in some embodiments, such as in those presently exemplified, the camera
unit 10 may further comprise a passive infrared, PIR sensor 22 which may be used to
determine the presence of a person (or other infrared source, such as an animal) in
at least part of the FOV of the camera lens 16. The PIR sensor 22 may be used to trigger
the operation of the camera 12 and the beginning of capturing and recording one or
more images. The camera unit 10 may also (or in other embodiments, instead) initiate
image capturing based indication of a detected motion received wirelessly from another
device that may be located remotely from the camera unit 10, or on command.
[0105] As noted above, a possible issue with a privacy cover 14 may arise in a situation
when a user forgets to open the cover 14 making the camera unit effectively inoperable.
[0106] A possible solution for reducing the likelihood of this is for the camera unit 10
to identify the position of the cover 14 upon being prompted to do so. The camera
unit 10 may, in some embodiments, determine light at one or more levels within an
image recorded by the camera 12 to determine whether the camera lens 16 is uncovered.
Thus, in one example, the camera 12 may be configured to undertake image recordings
on a periodic basis such that the light levels can be determined. In this way, the
camera image sensor can be used to establish whether the cover 14 is open or closed.
[0107] However, this method requires the camera 12 to be powered, recording and some image
processing or transmission of image data to allow the images to be analysed and determine
whether the camera 12 is viewing the correct FOV. This clearly requires an amount
of power and reduces the energy efficiency of the system. Further, it is possible
that a room may be photographed or filmed during night hours or when the room is otherwise
dark. Under such conditions, it would be difficult to determine whether the cover
is in place or whether the dark image is merely a result of dark environmental conditions.
[0108] To help ameliorate these issues, it may be desirable to use a light source in tandem
with the camera 12. The light source may be selectively operable and used to illuminate
the FOV of the camera 12 such that the captured image data can be assessed and a determination
made as to whether the cover 14 is open or closed on the basis of a threshold value
which is set on the basis of an expected level or intensity of light, rather than
determining whether a FOV is being viewed.
[0109] The inside of the lens cover 14 may be reflective such that, if the cover 14 is open
but the ambient conditions are dark, the camera 12 will detect no reflected light
from the cover when the light is on. If the cover 14' is closed, there will be light
from the light source that is reflected by the cover to the image sensor of the camera,
so the camera will detect light as being above a certain level. The determination
of the cover 14 position using this method may comprise determining a level of illumination
in a captured image, for example. The method may further comprise capturing an image
with the light source on, and the light source off, and comparing the 'light on' image
with the 'light off image to determine whether the comparison, that is, the contrasting
light levels, are above or below a threshold value which is indicative of the cover
14 position.
[0110] As shown in the example of Figures 1a and 1b, the camera unit 10 comprises the light
source 24. The light source 24' is at a location where it is behind the cover 14'
when the cover 14' is in the closed position and the camera lens 16' is fully obscured.
More specifically, the light source 24 may be located on an opposing side of the camera
lens 16 with respect to the stowed position of the cover 14. Hence, the cover 14 may
be movable from an open position to an intermediate position to a closed position
14'. In the open position, the camera lens 16 and light source 24 may be exposed.
In the intermediate position the camera lens 16' may be obscured and the light source
24 may be exposed. In the closed position 14', the camera lens 16' and light source
24' may both be covered. For the sliding cover 14 shown in Figure 1, this results
in the light source 24 being proximal to the terminal end of the throw of the cover
14 (relative to the camera lens 16), and the camera lens 16 being proximal to the
cover 14 when the cover 14 is in the open position.
[0111] With this arrangement, when the cover 14' is closed, the light from the light source
24' may be reflect off the inner side (i.e. the camera lens 16' and light source 24
facing surface) of the cover 14 and provide a distinct light signal to an image sensor
behind the lens 16 that senses the light. When ambient light is low and the cover
14 is open, the camera 12 will receive a light signal that is lower than that which
would be received when the cover 14 is fully closed. When there is appreciable ambient
light and the cover 14 is open the measured light level may be relatively high. The
measured light level may also be relatively high if the cover 14 is closed and the
light source 24 is on. It can be determined which of the two possible scenarios exists
by analyzing the images (by a person or automatically by imaging processing) to determine
whether the content of the image depicts a scene.
[0112] The above described example in which the light source 24' is provided behind the
cover 14' in the closed position addresses several problems in determining if the
cover 14 is open and/or closed. However, the methods which use the camera image sensor
as a light sensor require power for the camera 12 and any transmission of image data
and/or signal processing. Hence, for remotely powered cameras this is less than ideal.
Further, as noted immediately above, there is potential for situations where the camera
cannot differentiate between ambient light and that issued from the light source 24
and requires either human intervention or image analysis.
[0113] Figures 2a and 2b show a schematic representation of a camera unit 110 which is similar
in many respects to that described in connection with Figures 1a and 1b and shares
corresponding reference numerals incremented by 100. As with Figures 1a and 1b, the
primed references denote the items of the camera unit when the cover is in a closed
position. Thus, there may be provided a camera unit 110 comprising a camera 112 having
a camera lens 116, a cover 114 and a light source 124. The cover 114 may be movable
from an open position in which the camera lens 116 is exposed and operable to capture
images from the scene surrounding the camera unit 110, to a closed position 114' in
which the camera lens 116' is obscured.
[0114] The camera unit 110 shown in Figures 2a and 2b includes a light sensor 126. The light
sensor is separate from the camera 12 and may be any suitable light sensor known in
the art, but is preferably a solid state light sensor. The light sensor is independent
of the image sensor of the camera 12, both physically and operatively. In some examples,
the image sensor and/or camera more generally, may be deactivated whilst a light level
is measured using the light sensor 126 to determine the position of the cover 114.
The light sensor 126 may be configured to provide an output on the level of light
only. The light sensor 126 may be used to determine the level of light and associated
position of the cover 114.
[0115] Optionally, the light sensor 126 may also be used to determine ambient light levels
before an image is captured, for adjusting a camera setting(s), e.g. aperture size,
so that the settings used to capture the first image are at or approximate an appropriate
setting(s).
[0116] Likewise the light source 124 may double as a flash for illuminating the field of
view in dark conditions. Further the need for the flash can be determined based on
ambient light conditions measured by the light sensor 126.
[0117] The light sensor 126 may be located anywhere on the camera unit 110 but in the described
embodiment is located behind the cover 114' when the cover 114' is closed such that
it can detect light which is reflected back off the interior of the cover 114' when
there is light emitted from the light source 124', which is also located behind the
cover 114' when closed. In some examples, the light sensor 126 and light source 124
may be located adjacent to one another. Thus, the light source 124 and light sensor
126 may be side-by-side above the camera 112 (or elsewhere). In other examples, the
light source 124 may be located away from the light sensor 126. The light source 124
and light sensor 126 may be separated by the camera 112. Such a separation of the
light source 124 and light sensor 126 may advantageously reduce an amount of stray
light that from the light source 124 that may be detected by the light sensor 126
when the cover 114 is open. The cover 114 and light sensor 126 may be provided in
close fitting relation to one another, such that when the cover 114 is placed over
the light sensor 126, the light entering the light sensor 126 from outside of the
cover 114 and camera unit 110 is significantly reduced. Hence, the cover blocks (for
example, stops all or substantially all) light from entering the sensor 126.
[0118] In the example shown in Figures 2a and 2b, the light sensor 126 and light source
124 are separated by the camera lens 116. The light sensor 126 may be located proximal
to the cover 114 when the cover 114 is in the open position. The light source 124'
may be located proximal to the terminal end of the cover 114' throw when the cover
114' is in the closed position. The cover 114 may move sequentially from an open position
to a first intermediate position to a second intermediate position to a closed position.
In the open position the light sensor 126, camera lens 116 and light source 124 may
all be exposed. In the first intermediate position, the light sensor 126' may be covered
and the camera lens 116 and light source 124 are exposed. In the second intermediate
position, the light sensor 126' and camera lens 116' may be covered, and the light
source 124 may be exposed. In the closed position, the light sensor 126', camera lens
116' and light source 124' maybe covered.
[0119] It will be appreciated that the open position, first intermediate position, second
intermediate position and closed position do not necessarily represent discrete positions.
Rather they are intended to show stages along the throw (i.e. the path of travel from
open to closed) of the cover 114. It will also be appreciated that the positions of
the light sensor 126 and light source 124 may be switched so as to provide the light
sensor 126 above the camera lens 116, and the light source 124 below.
[0120] The camera 112 of the camera unit 110 comprises an image sensor (not shown) that
receives light from the lens 116 to capture images of the FOV. The camera 112 may
comprise processing circuitry (which may comprise one or more processing chip(s))
that the controls the capturing of images from, and compression of data by, the image
sensor. To save power, the image sensor or the processing circuitry (and in some embodiments
both) of the camera 112 are default to a low power or off state and are temporarily
woken to an active state to capture a one or more images (of a predefined number or
for a predefined duration of time) in response to a detected motion.
[0121] Providing a separate light sensor 126 allows the power consumption of the camera
unit 110 to be much reduced as a dedicated light sensor 126 will typically require
less power than the imaging sensor of the camera 112 to detect a light level.
[0122] In use, the light sensor 126 signal may be used to determine whether the cover 114
is open and/or closed. When the cover 114 is determined to be open, the camera 112
may be operated to capture images in response to the detected motion.
[0123] In some embodiments the camera unit 110 may be configured so the function of having
a detected motion trigger the capturing of an image(s) may be disabled. For example
the processor of the camera unit 110 may disable the function in response determining
that the cover 114 is closed. The operation of the camera unit is described in more
detail below.
[0124] Figures 3a and 3b show schematic representations of a cover 214 removed from a camera
unit showing an inside side 228 of the cover 214 as viewed from the inside (Figure
3a) and in section (Figure 3b). The cover may be comprise a plate member having an
inner side 228 and an outer side 234. The plate member may be planar or shaped to
correspond to the opposing surface of the camera unit housing 18, as required. The
runners 20 may be provided by the lateral edges of the cover 214, as described above.
The inner side 228 may face the light sensor 126, camera lens 116 and light source
124 when mounted to the housing 18 and in the closed position. The outer side of cover
214 may face externally and be viewable from the outside of the camera unit 10.
[0125] The inner side 228 may comprise one or more light reflective surfaces. The light
reflective surface(s) are configured to redirect light from the light source 124 to
the light sensor 126 (or to the camera lens 116 in the instances where the image sensor
of the camera 112 is the light sensor).
[0126] The light reflecting surface(s) may take any suitable form and may be provided by
one or more of: a specular reflective layer on the inner side of the cover; a diffusive
reflective layer on the inner side of the cover; and internal surfaces of an optical
waveguide included on the inner side of the cover. Layers may comprise coatings applied
on the cover or may be integrally formed within the thickness of the cover material.
The layers may be provided sequentially. Thus, the inside of the cover 114 may be
provided with a reflective layer which is disposed to reflect light from the light
source 124 to the light sensor 126, which may be on a light blocking coating to prevent
ambient external light reaching the light sensor 126 when the cover 214 is closed
so as to cover the light sensor 126.
[0127] As shown in Figures 3a and 3b, the inner side of the cover 214 comprises a channel
232 having a reflective surface. The channel 232 may comprise an indentation in the
inner side 228 so as to provide a greater separation between the reflective surface
of the inner side 228 and the opposing surface of the housing 18. The channel 228
is provided for the purpose of increasing light transmission between the light sensor
126 and light source 124 to increase the light signal which is received by the sensor
126 when the cover 114 is shut. Hence, the channel 232 may be located opposite the
light source 124' and the light sensor 126' when the cover 114' is in the closed position.
Light from the light source 124 may reflect one or more times on the inner side 228
of the cover 214 before reaching the light sensor 126. In the case of multiple reflections,
the opposing surface of the housing 18, between the light source 124 and the light
sensor 126, may reflect light back to inner side 228 of the cover 214 until the final
reflection from the inner side 228 of the cover 214 reaches the light sensor 126.
Thus, the opposing surface may be involved in the redirection of light from the light
source 124 to the light sensor 126 (or camera lens 116 in the instances where the
image sensor of the camera 112 is the light sensor). As such the inside 228 of the
cover in combination with the opposing surface of the housing 18 may collectively
form a kind of light guide.
[0128] The channel 232 may be an elongate depression in the inner side 228 and have a length
at least as great as the separation between the light source 124 and light sensor
126. The depth and width of the channel 232 may be adjusted to suit a desired arrangement
and provide a required level of light conductance between the light source 124 and
light sensor 126.
[0129] It will be appreciated that the inner side 228 of the cover 214 may comprise reflective
layers without the channel in some embodiments. Further, a channel may be provided
in the outwardly facing of the housing to provide an increased separation between
the light sensor 126 and light source 124 as well as or in place of the channel in
the cover 114.
[0130] As noted above, the inner side 228 may include one or more layers/coatings to enhance,
or inhibit, the conductance of light from the light source 124 to the light sensor
126. The layers/coatings may include or be restricted to the inside of the channel
232. Thus, as per Figure 3b, a cross sectional view of the cover 114 shows an open
channel having a depth into the thickness of the cover 114. At the bottom surface
of the channel 232 (which provides the reflective surface of the channel 232) there
may be one or more coatings. The first coating 234 comprises an opaque or light blocking
coating, for example one or more layers of a black ink, which prevents transmission
of light from the exterior of the cover 114 into the channel 232 and light sensor
126 when the cover 114 is closed. This may be desirable where the reduction in thickness
of the cover 114 due to the presence of the channel 232 may result in parasitic light
transmissions through the cover when using the light source 124 or in light ambient
conditions. Such parasitic transmissions may occur in embodiments in which the cover
has a plastic body, for example. Hence, with such a coating the light being received
by the light sensor 126 can be minimised to aid the detection process and setting
of and adherence to any thresholds.
[0131] The channel may comprise a layer/second coating 236 on the inner side 228, on top
of the first layer/coating. The second coating 236 may be restricted to the channel
232. The second coating 236 may aid the conductance of light from the light source
124 to the light sensor 126. The second coating 236 may comprise coating that provides
diffusive reflection, for example one or more layers of a white ink, which diffusively
reflects the light to provide a more diffuse light field to the light sensor 126.
[0132] In other embodiments, a single layer may provide both blocking of ambient light transmission
and reflection of light from the light source 124. In one example, the layer may comprise
a reflective metal or alloy. In some embodiments the layer provides specular reflection.
The layer and/or coating may for example be a metallic sticker. The metallic sticker
may comprise aluminium, for example.
[0133] In addition to the above layers/coatings, a protective coating may be provided in
some embodiments. The protective coating may include one or more layers to prevent
oxidisation of the reflective surface, for example.
[0134] Figures 4a and 4b show an alternative cover 314 which is provided with an optical
waveguide 338. The optical waveguide 338 is configured to receive light from the light
source 124 and transmit it to the light sensor 126. The optical waveguide 338 may
be embedded into the inner side 328 of the cover 314, for example by being mounted
to a body of the cover 314. The optical waveguide 338 may include an inlet 340 (which
may be referred to an inlet window) which is located opposite the light source 124
when in the closed configuration. The optical waveguide 338 may include an outlet
342 (which may be referred to as an outlet window) which is located opposite the light
sensor 126 when the cover 314 is in the closed configuration. A bridge portion may
extends between the inlet window 340 and outlet window 342 to provide an enclosed
optical pathway for light to travel between the inlet and outlet.
[0135] The separation of the inlet 340 and the outlet 342 may be the same as the separation
between the light source 124 and light sensor 126 so as to provide good alignment
when the cover 314 is in the closed position.
[0136] The optical waveguide 338 can be comprised of any suitable material and include any
suitable coating. In some examples, the optical waveguide 338 may be a clear plastic
material having suitable transmissivity. The optical waveguide 338 may comprise one
or more coatings to aid internal reflections. It will be appreciated that reflectivity
provided by the surface(s) of the waveguide may be dependent on the angle of incidence
of the light from the light source, and as such the reflective surface of the waveguide
need not be reflective for all angles of incidence.
[0137] It will be appreciated that the inlet 340 and outlet 342 are shown nominally and
the role of each will be dictated by the interaction with the light source 124 and
light sensor 126 and the relative locations thereof.
[0138] An advantage of providing a light reflective surface in the cover 114, such as on
a reflective channel and/or in an optical waveguide, is that the light sensor 126
is efficiently directed light from the light source 124, so less power is required
to the light sensor 124 to deliver the prerequisite amount of light to indicate that
the cover is closed.
[0139] An example method of operating the camera units as described above is now provided.
The method is described with the embodiment of Figures 2a and 2b in mind, in which
the camera unit 110 includes a light sensor 126 and light source 124 which are obscured
by the cover 114' when the cover 114' is in a closed position. In some embodiments,
a light sensor 126 which is separate from the camera 112 is not employed, and instead
the image sensor of the camera 112 acts as the light sensor. For such cases, the method
described below may adapted accordingly to the embodiment of Figures 1a and 1b,
[0140] The camera unit 110 may comprise a processor to carry out the instructions in relation
to the measurement, determinations and the activating or deactivating of the light
source 124 and light sensor 126. The processor may be housed within the camera housing,
or may be remote, or may be distributed to be in part in the housing and in part remote.
[0141] The light sensor 126 may be configured to measure the light level received by the
light sensor 126, whilst the light source 124 is off or on. Figure 5, shows a method
500 in which the light sensor 126 is used to measure 510 the amount (e.g. intensity)
of light whilst the light source 124 is off. The measurement with the light source
off may be used to provide an indication as to whether the cover is open by relying
on the detection of ambient light. In particular, if light is detected by the light
sensor 126 when the light source is off 124, it is indicative that the cover is fully
open 514 and the camera lens 116 is operative (uncovered), since detected light must
be ambient light. In this instance, the camera 112 can be configured to capture one
or more images as required and/or to provide a confirmatory notification as to the
open status of the cover to a controller.
[0142] Hence, at step 512, a determination is made as to whether the light received by the
light sensor 126 is sufficient to represent a level of ambient light.
[0143] If no ambient light is detected 516 with the light source 124 off, then there are
two possible outcomes. The first is that the cover is at least partially closed and
no ambient light can be detected by the light sensor 126 due to it being blocked.
The second is that the ambient light levels are too low to be detected. For applications
in which the ambient light is controlled or known to exist (e.g. the camera is used
outside and it is known to be daytime), then if the measured light is below a threshold
it may be concluded by the processor that the cover 114 is at least partially closed.
However for applications in which the ambient light is not known then in the event
that no light is detected, it may be advantageous to carry out further measurements.
The further measurements may comprise measuring an output of the light sensor 126
when the light source 124 is on.
[0144] The determination of whether ambient light is detected 512 may be achieved using
a predefined condition. The predefined condition may comprise a predetermined value,
for example a threshold value, which is representative of a positive indication of
ambient light. The threshold value may be set at a value which is greater than an
expected noise floor for the light sensor 126, for example, such that any amount of
light received above a background noise level may be representative of ambient light.
The background noise may arise as a result of the light sensor, the transmission or
processing of the output signal of the light sensor 126, or any other source which
may affect the determination of whether there is ambient light or not. For example
such noise may also include parasitic light transmissions through and/or around the
cover 114 such that when the cover is closed a non-zero amount of ambient light may
be detected by the light sensor 126. For a light sensor having a maximum noise reading
when the cover is closed at or below 1 Lux, the threshold may be set to 2 Lux, for
example.
[0145] Hence, the threshold value may correspond to a maximum amount of ambient light that
may be detected when the cover is in the closed position and/or a representation of
the light sensor output which there is no ambient light..
[0146] In another example method 600, of Figure 6, the light sensor 126 is configured to
measure 610 the light when the light source 124 is on. The measured output may be
compared to a threshold value 612 to identify if the cover is closed 616 and light
is received from the light source 124 as reflected by the inside of the cover 114.
The cover 114 is configured to efficiently convey light from the light source 124
to the light sensor 126 and the light source 124 is powered such that a first intensity
that is minimum intensity of light that it emits, as detected by the light sensor
126 when the cover is closed, is greater than a second intensity maximum intensity
of light expected from ambient conditions. Thus, if the measured light is below a
threshold that is between the first and second intensity, then the cover is determined
to be open 614.
[0147] The method 600 can be achieved with a relatively low power consumption for the light
source 124 in circumstances in which the ambient light level is known to be low. For
example, the ambient conditions may be measured using a light sensor that is exposed
to ambient light.
[0148] Figure 7 shows another method of determining a position of the cover 114. In this
example, the light sensor 126 is used to measure 710 the ambient light with the light
source 124 deactivated. The measured light is compared with a first threshold 712.
If the light level is above the first threshold, then ambient light may be determined
to be detected and the cover determined to be open 714. If the light is measured as
being below the first threshold then either the cover is closed or the ambient light
level is low.
[0149] To determine which is the case, if the level of measured light is below the first
threshold, the light source 124 is then activated 718, and the light received by the
light sensor 126 is measured 720. The measured light is compared to a second threshold
722 and a determination made as to whether the cover 114 is open or closed. If the
level of the detected light is above the second threshold, the cover is determined
to be closed 726, on the basis a closed cover 114' results in light from the light
source 124 being directed to the light sensor 126. If the light is below the second
threshold, the cover 114 is determined to be open 724.
[0150] It will be appreciated that with method 700 it is possible to determine the status
of the cover 114 at any time and with a relatively low power usage.
[0151] The method described in Figure 7 requires the first measurement to be carried out
when the light source is deactivated, and the second measurement carried out when
the light source is activated. It will be appreciated that the these two stages could
be reversed in some examples. However, the measurement made with the light source
124 switched off may make a positive determination that the cover is open when there
is sufficient ambient light which removes the need for the measurement in which the
light source 124 is powered, and therefore power would be saved in such circumstances.
[0152] As noted above, the methods of Figures 5 to 7 involved the use of a camera unit 110
having a separate light sensor which is independent from the image sensor of the camera
112. However, in some embodiments, the image sensor of the camera 112 may be used
in place of an independent light sensor 124 which may or may not be present in the
camera unit 110. Thus, although determining cover position based on measurements from
a light sensor that is independent of the image sensor advantageously saves power,
the methods of Figures 5 to 7 may in other implementations be performed by using the
image sensor as the light sensor.
[0153] The first and second thresholds may be set in accordance with expected values and
accounting for any noise. As noted above, the first threshold value may be set at
a light level which is a noise floor of the sensing system which comprises the light
sensor and associated processing devices. The noise sources may be same as in the
case of method 500, and so the threshold used in the case of method 500 may be used
as the first threshold of the method 700. The second threshold may be set to include
a range of values which are indicative of the light levels which are expected to be
received from light reflected by the inner side of the cover. However, since when
the cover is closed there should be an increase in detected light when the light source
126 is turned on, the second threshold is selected to be greater than the first threshold.
In some embodiments, turning on the light source 126 may result in some parasitic
light from the light source 126 being detected from by the light sensor even when
the cover is open. Such parasitic light may be treated as noise, wherein the second
threshold is greater than the maximum noise when the light source 126 is on. Setting
the second threshold as low as possible/practical advantageously enables minimal power
consumption in determining the cover position according to the described method. The
actual first and second thresholds (or any others disclosed herein) may be determined
empirically or analytically using known techniques, taking into account the considerations
discussed above, and taking into account an expected variance over the lifetime or
the camera unit 110 product, and in some embodiments variance from product to product,
to attribute appropriate thresholds.
[0154] As well as determining the light levels using the sensor 126, there may be other
examples which detect a light signature from the light source 124, such a spectral
content of the light, which can be associated with the output of the light source
24 rather than any ambient light source.
[0155] As shown in Figure 8, the camera unit 810 having the features of camera units 10
or 110 may comprise a processor 812 and a memory 814. The processor 812 and/or memory
814 may be conventional. The processor 812 and/or or the memory 814 may each be comprised
of a single device or a plurality devices. Further, the memory 814 or a part thereof
may be integrated into one or more processing devices.
[0156] The processor, or at least a part thereof, described herein may be implemented hardware
or software and may be implemented as a controller, rather than a processor per se.
The processing devices may comprise, for example: control circuitry; and/or processor
circuitry; and/or at least one application specific integrated circuit (ASIC); and/or
at least one field programmable gate array (FPGA); and/or single or multi-processor
architectures; and/or sequential/parallel architectures; and/or at least one programmable
logic controllers (PLCs); and/or at least one microprocessor; and/or at least one
microcontroller; and/or a central processing unit (CPU); and/or a graphics processing
unit (GPU), and/or transceiver(s) to perform the methods described herein.
[0157] The memory devices may store code/instructions that, when read by the processor,
causes performance of any of the methods described herein, and/or as illustrated in
the drawings. For example, the memory may comprise: volatile memory, for example,
one or more dynamic random access (DRAM) modules and/or static random access memory
(SRAM) modules; and/or non-volatile memory, for example, one or more read only memory
(ROM) modules, which for example may comprise a Flash memory and/or other electrically
erasable programmable read-only memory (EEPROM) device. The code may for example be
software, firmware, or hardware description language (HDL) or may be any combination
of these or any other form of code for one or more processing devices that is known
by a person skilled in the art.
[0158] Further, the present disclosure includes a signal processor comprising readable instructions
that, when read by a processor, cause performance of one or more of the methods described
herein. Such a signal may be generated and transmitted from a central controller to
the camera unit, for example.
[0159] The camera units described herein may form part of a security system. The security
system may include one or more central controllers 816 (e.g. a control hub) which
receive data from and/or transmit commands to the camera unit 810 and in some embodiments
to other peripheral devices (e.g. door locks; door/window entry sensors). Hence, the
camera unit 810 may transmit data including image, video or audio data to the controller
816. Further, the camera unit 810 may transmit a status of the cover position to the
controller 816. The controller 816 may be configured to provide a notification of
the cover position to an operator of the security system, such as an occupant of the
dwelling.
[0160] It will be appreciated that references to a processor within the camera unit 810
in the present disclosure, may be a distributed processor in which some of the steps
are carried out in a processor which is remote to the camera unit 810. For example,
some of the steps described as being carried out by the processor 818 may be executed
by the central controller 816 and data and instructions may be stored in a memory
820 of the central controller 816. Such a step may include, for example, a comparison
of the measured light with a predetermined value.
[0161] The devices comprising camera units, cameras and/or PIRs described herein may be
arm aware or arm unaware devices. An arm aware device may be one in which the cameras
and/or PIR are configured to receive and be responsive to and/or store an arm or disarm
status or command which is issued from the central controller (or other controlling
entity) when the system is armed or disarmed by a user or operator.
[0162] Generally, the camera in a camera unit may reside in a powered down state until one
or more images are required. This is the case in an arm aware or arm unaware camera
unit. Hence, the camera unit and/or a PIR may be in a powered down state when the
system is armed or unarmed. In arm aware device, a processor of the device may be
temporarily woken by and process an arm request using, for example, known beacon techniques.
Once armed, the device may go back to sleep state. A motion detector may be operable
to detect motion on an ongoing basis as a motion detecting transducer, such as a PIR
transducer, and some electronics that process its signal use very little power. Thus,
the camera unit (and/or a separate motion detector of the security system) may be
constantly active to detect motion within a field of view, regardless of whether the
camera unit is considered to be in a sleep state (e.g. by virtue of a CPU of the camera
unit being in a sleep state). A processor (e.g. the CPU of the device) may be woken
from the sleep state if the PIR processing electronics indicate a motion has been
detected.
[0163] In some embodiments the camera may be controlled by a separate processor to that
of the CPU, and may only be woken when the camera needs to capture an image(s). So
more the camera unit may comprise more than one processor with each having sleep states
that are woken as needed.
[0164] When armed, the camera of an arm aware device may receive and be responsive to a
signal or command issued from an integrated security sensor, such as a motion sensor
(e.g. a camera PIR), or door or entry sensor, which signals possible activity and/or
motion in the camera's field of view. This may prompt the camera unit to record an
image (i.e. at least one image), either as one or more stills or video using the camera.
Alternatively, or additionally, the camera may receive an image record command from
the central controller. The image record command from the central controller may,
in some embodiments, also be made in response to a PIR signal that is not in integrated
with the camera and which is received at the central controller, or in response to
a request of an operator, for example, a person or system responsible for monitoring
the security system and premises.
[0165] In the case of an arm unaware device, the camera unit is normally in a sleep state
and woken to be fully power-up and capture an image upon an appropriate signal from
the central controller. Thus, a motion detector may send a motion detection notification
to the controller which is responsive on the basis of whether the device or system
is armed. If armed, the response may be to transmit an image record command to the
camera unit. If unarmed, the response may be null, meaning that no action is taken.
This may be the case, for example, when an occupant of the premises triggers the motion
detector.
[0166] Whether arm aware or arm unaware, a camera in a camera unit may be provided in a
sleep state when the system is in an armed state.
[0167] For either of arm aware and arm unaware camera units, a cover position status may
be determined upon request from the central controller or at predetermined events
or times.
[0168] For example, the camera unit may be configured to determine the cover position upon
request from the central controller when the security system is switched from a disarmed
to armed state, or when the camera unit is otherwise placed in an active state from
an inactive state, such as when it is first installed or commissioned or a power source
is connected following a disconnection (e.g. after a change of batteries or power
cut). Additionally or alternatively, the camera unit may be configured to determine
the cover position status upon receipt of a command to record an image. The command
to record an image may be caused by an output signal of one or more sensors in the
security system or a controlling entity such as the central controller or other remote
device. The one or more sensors may provide an output signal to a processor of the
camera unit or central controller which issues an image record command in response.
[0169] As noted previously, the camera unit may include a camera (which may also be referred
to as a camera module). The camera may include a lens, an image sensor and, optionally,
one or more processors. The camera unit may additionally comprise a PIR The camera
unit may be referred to as a security device and/or a premises security device. It
will be appreciated that placing the camera unit in an active state may not require
the camera to be placed in an active recording state. The active state may be defined
by a processor being configured to be responsive to a motion detection signal issued
from a motion detector. Hence, when the camera unit is in the awake/active state,
the camera of the camera unit may or may not be active. For example, when the camera
unit is in the awake/active state, the camera module may be on stand-by until activated
to be in a state to record one or more images upon receipt of an image record command
from a processor of the camera unit or central controller.
[0170] Figures 9 and 10 show methods of determining a cover position status. Figure 9 shows
a method 900 for an arm aware system. Figure 10 shows a method 1000 for an arm unaware
system.
[0171] With regards to Figure 9, at step 910 an arm command may be received by a controller
which is configured to arm the security system. The request to arm the system may
be received from a user leaving the premises, for example. Upon receipt of the request
from the user, the central controller may be configured to notify the camera unit
that the system has been armed. The camera unit may be configured to receive the arm
command and determine the cover position status. It may be implicit from the arm command
that a cover position status is required, meaning a cover position status request
is received by the camera unit by virtue of receiving a command to arm from the controller.
However, it will be appreciated that a separate command may alternatively be issued
with the arm command as part of the same or a different transmission. As well as determining
the cover position in response to the arm command, it will be appreciated that the
receipt of the arm command may prompt the camera to carry out additional actions such
as preparing a camera for image capture, and/or to configure the camera to automatically
perform image capture in response to a motion detected by a motion detector of the
camera unit.
[0172] Having the camera unit configured to respond to the arm command by determining the
cover position status is advantageous as it reduces the need for a further transmission
to determine the cover position status, and the associated power required to receive
and process that further transmission. Further, having the camera unit determine the
cover position status upon receipt of an arm command allows the cover position status
to be determined whilst the camera unit is preparing for service.
[0173] In some embodiments, the determination of the cover position and the camera activation
may be carried out in parallel. This is particularly advantageous where the cover
position is determined in response to a motion detection where the camera unit may
be configured to activate (e.g. power-up) the camera upon receipt of the motion detection
signal. Carrying out the camera activation and cover position determination in parallel
may shorten the period it takes to acquire an image. Further, where a cover position
status is determined to be closed, the camera unit may be configured to cease activating
the camera to further save power.
[0174] The activation of the camera and an associated start-up time for the camera may be
defined by the time it takes to power up the camera electronics, such as the image
sensor, and optically stabilize the camera (e.g. by determining the correct aperture
and for the ambient light conditions, for example, by using a light sensor).
[0175] The camera may be activated from a powered down (e.g. off or stand-by) period. Thus,
in an arm aware or an arm unaware camera unit, the camera may be in a powered down
in which it is unactive and unable to take images. In one embodiment, the determination
of the cover position status is executed whilst the camera is being powered-up following
a powered-down period.
[0176] At step 912, the cover position status is determined. As noted immediately above,
the cover position status may be determined using one of the methods described herein
in which a light sensor and/or camera and/or light emitter is used to determine the
cover position status. Alternatively, a different cover position status technique
may be employed such as using a mechanical sensor. The mechanical sensor may be in
the form of a limit switch for example. In other embodiments an electronic or magnetic
sensor may be used. In some examples, the sensor may form part of an actuating mechanism
which is described further below. It will be appreciated that the camera unit may
not include the light emitting diode 24 and the light sensor 126 as disclosed in connection
with Figures 1a, 1b, 2a and 2b when not required for determining the cover position
status.
[0177] In some examples, the cover position status may be stored in memory and recalled
rather than being determined in every instance. This may occur where the cover position
status is determined and stored on an ongoing basis, for example, where the position
is determined via an actuation system in which the actuation system records the position
either by virtue of operation or otherwise. This is described in more detail below.
[0178] Once the position of the cover is determined (or obtained from memory) 914 as being
open or closed, appropriate actions can follow. Where the cover has an 'open' status,
the camera may be determined to be operable 916 and an image may be obtained at an
appropriate time. The time at which an image is obtained may be triggered by a motion
detection or upon request from the central controller. The motion detection may be
provided by a PIR which may be part of the camera unit, as noted above.
[0179] In the alternative, where the cover position is determined to be 'closed', the status
may be transmitted 918 to the central controller. In response to receiving a 'closed'
status, the central controller may be configured to either deactivate the camera of
the camera unit or flag the camera of the camera unit as being ineffective (e.g. inoperable)
so that it does not form any part of the security surveillance. The motion detector
of the camera unit, however, can still provide useful information for security so
may continue to operate under such conditions. Another option may be to undertake
a confirmatory test to reaffirm the position of the cover. For example, where the
position has been determined using the light sensor, it may be that the central controller
instructs the camera to carry out a further determination using, for example, the
camera output. The use of the camera to determine the cover position may be avoided
in preference of the light sensor in the first instance to avoid the associated increased
power consumption.
[0180] As indicated by the dashed line in Figure 9, an optional step 920 is for the central
controller (or some other entity) to send a notification to a user device to inform
the user of the cover position status and/or camera status. The user may be one or
more of a supervising entity who is responsible for supervising the premises when
the security system is in an armed state, a property owner, or the person who has
set the system from disarm to arm, for example.
[0181] Upon receiving the closed notification, the user may consider taking action 922 in
response to the notification. Where the user requires the camera to be uncovered,
they may disarm the security system (or in other embodiments, the initial arm attempt
may have been aborted as a result of the camera being covered), and they may then
return to open the cover and re-arm the system 924 accordingly. This will result in
the process, 900, restarting at 910 and the cover position status being determined
once again.
[0182] Where the user does not wish for the camera to be opened or it would be inconvenient
for the user to return to open the camera cover, the user may ignore the notification
such that the system remains armed but with the camera unit disabled.
[0183] The notification may take any suitable form and may include one or more predetermined
selectable options. For example, the notification may inform the user of the cover
status and location of the camera. It may also provide selectable options such as
'disarm', 'accept', 'confirm', 'ignore' or 'open app', for example. The 'disarm' command
may result in the security system being disarmed to allow a person to re-enter the
premises to open the cover without trigger an alarm; the 'accept' command may inform
the central controller that the user accepts the camera being covered; 'confirm' may
result in the central controller carrying out a further test to confirm cover position
(for example, where a user believes the cover is open already); 'ignore' may allow
a user to pause the notification and possibly receive a follow-up reminder to check
the cover position at a later time, for example when the security system is disarmed;
and 'open app' may relate to opening an application on the user device to allow the
user to interface with the security system, e.g. the central controller, if required.
It will be appreciated that other actions are possible. Where no response is received
following the notification, the system may default to disabling the camera as noted
above such that it plays no role in the surveillance. In some examples, the notification
may not provide selectable options for response but may simply inform the user that
the camera is inoperable.
[0184] The way the notification is delivered to the user may be user specific and dependant
on the user device in question. For an end user, such as the person who has armed
the system and/or the property owner, the notification may be delivered to a user
device in the form of a mobile phone or other mobile device carried by user and may
be a push notification. The push notification may be presented as a pop-up box or
drop-down menu providing the selectable options. Alternatively, the push notification
may result in an app being started on the mobile device such that the user can fully
interact with the security system, if required. The advantage of using a push notification
is that it allows a quick response time from the user such that they may return to
the property more conveniently, rather than continuing to travel away from the premises
whilst the app opens.
[0185] Where a notification is provided to a central supervisor of the system, it may be
presented on an operator's screen, for example. It will be appreciated, that several
notifications may be issued, for example, to the person arming the system, the property
owner, or the supervising service.
[0186] The push notification may be transmitted from a remote device such as a server which
is responsible for monitoring several premises, or the central controller.
[0187] In the example of Figure 9, the status of the cover position is only requested when
the system is switched from a disarmed status to an armed status and the status update
may only be provided when the cover is closed. Hence, the central controller may be
configured to proceed on the basis of the camera being uncovered in the event of no
response from camera unit.
[0188] The central controller may be configured to additionally (or in other embodiments,
alternatively) determine the cover position status on an ad hoc basis and/or in response
to an operator request. An operator may request a cover position status where one
or more images taken with the camera indicates that the camera lens is obscured in
some way. This may be advantageous, for example, where an infiltrator has managed
to obscure the camera lens.
[0189] The status of the cover may be recorded in the central controller during or shortly
after an installation process. During the installation process the camera may be registered
with the central controller when the cover position is set to a default condition,
such as the cover being open. This may be useful for preventing a cover position status
being required, thereby saving power, or may help with configuring the camera, LED,
light sensor or some other sensor used to determine the position of the cover. The
status of the cover may also be recorded in the central controller when a power supply
for the camera, such as a battery, is replaced. The status of the cover may be recorded
in central controller using an associated piece of software such as an app which is
usable from a user's mobile device or other computing device which is used to configure
or control the system in some way.
[0190] In Figure 10, there is shown a method 1000 for determining the position of a cover
in an arm unaware system. Here, as with Figure 9, the command to arm the security
system 1010 is received by the central controller. The central controller may then,
instead of sending an arm command to the camera, simply send a request 1012 to determine
the cover position status. From thereon, the remaining tasks may be the same as those
described in relation to Figure 9 which share similar reference numerals incremented
by 100.
[0191] As described above, the image capture in an arm unaware camera unit will typically
be carried out following the central controller being notified of a motion detection
from a motion detector, which in some embodiments is integrated into the camera unit.
However, it will be appreciated that, in an arm unaware system, the camera unit may,
in some embodiments, always capture images in response to motion detection. However,
this results in a potential waste of energy when the system is unarmed and occupants
of the premises cause a lot of unnecessary images to be captured. Therefore, in preferred
embodiments, a camera unit in an arm unaware system may only capture an image in response
to a request from the controller. In some embodiments, the camera units may not comprise
an integrated motion detector/sensor or be configured to communicate with an external
motion detector, and so the only option is to capture an image if told to do so by
the controller. Hence, a cover position status may be determined at the request of
the controller at the time of the controller is armed such that the controller knows
whether the camera is covered or uncovered at the time of arming.
[0192] The cover position status updates for an arm aware of arm unaware system may be provided
in response to a request received from the central controller or when the security
system is armed. The status update may be provided as a dedicated transmission, or
maybe part of a multipurpose transmission which conveys other information to the central
controller. Such additional information may include: a status for the camera; information
relating to the operating status of the camera and/or one or more PIR's; a status
for one more sensors used within the camera and/or a battery status; an acknowledgement
of or other communication in response to a request from the controller. The acknowledgment
may be in response of receiving an arm command. Such information may be required by
the central controller in order to determine the operating status of the system at
any particular time. Such transmissions may be sent at regular intervals whilst the
system is armed or at particular events such as a request for an image or when powering
up a camera.
[0193] Returning briefly to Figure 1a, it will be recalled that the cover 14 may be movable
between a closed position, in which the camera lens 16 is obscured, and an open position,
in which the camera lens 16 is unobscured, using various mechanisms such as a linear
sliding mechanism or a hinged mechanism. In Figure 1a, the cover 14 is shown as being
slidable between an open and a closed position on runners 20 which are attached to
the housing 18.
[0194] In some embodiments, cover 14 may be movable between open and closed positions using
an actuator, controlled by processor 812. The actuator may be any suitable device
which is operable to cause a movement of the cover 14 relative to the housing 18.
Thus, the actuator may move the cover 14 from the open position towards the closed
position and, additionally or alternatively, from the closed position to the open
position. The actuator may, for example, be mechanical, electromagnetic, hydraulic
and/or pneumatic. The actuator may comprise a rotary drive or a linear drive.
[0195] In Figures 11a,b and 12a,b there are shown two examples of different actuation mechanisms
for a cover. Figure 11a shows a closed configuration of a cover 1114 from inside the
cover along line A-A facing outwards on the left hand side, and section B-B on the
right hand side. Figure 11b shows the corresponding cover 1114 in an open configuration.
The actuation system includes an electromagnetic actuator 1144 in the form of a rotary
drive which engages with a corresponding linear drive member on the cover 1114. As
shown, the rotary drive may comprise an electric motor 1146 having a rotatable gear
1148 which engages with elongate toothed member 1150 on the cover to form a rack and
pinion drive. The reference numerals are not repeated in Figure 11b, but the various
parts correspond with those of Figure 11a, with the exception that the cover is in
a lower, open position. It will be appreciated that the reference to open and closed
is arbitrary and the actuator can be considered to be moving the cover between a first
position and second position, either of which could be the open or closed positions.
[0196] In more detail, Figure 11a shows a cover 1114 having an outwardly facing external
surface (or outer side) 1134 and an inwardly facing internal surface (or inner side)
1128, in which the internal surface faces the exterior of the camera unit housing
1118. Mounted on the internal surface 1128 is the elongate tooth member 1150 which
engages with the rotatable drive gear 1148 attached to the motor 1146 via a drive
shaft 1152. The motor 1146 is located within the camera unit housing 1118 with the
drive gear 1146 being located on the exterior with a connecting drive shaft 1152 extending
therebetween and passing through an appropriate aperture in a camera housing wall.
[0197] When the electric motor 1146 is energised, the drive gear 1148 engages with and drives
the elongate toothed member 1150 so as to lower the cover 1114 from a closed position
(Fig. 11a) to an open position (Fig. 11b). It will be appreciated that the camera
lens is not shown in Figures 11a and 11b but would be located above the motor 1146
so as to be obscured in Figure 11a and unobscured in Figure 11b.
[0198] When it is desirable to close the cover 1114, the actuator may be controlled to drive
the cover 1114 from the open position to the closed position.
[0199] The actuator may include a sensor for sensing the position of the drive and/or the
cover. In the example shown in Figure 11a the motor 1146 includes a position sensor
1154. The position sensor 1154 may take any suitable form and may be an integral part
of the electric motor 1146 required for controlling the motor 1146.
[0200] The motor 1146 may be any suitable motor which can be controlled to provide the necessary
drive. Examples may include a brushed or brushless DC motor, for example. Where the
motor is a DC motor 1146, it may include an encoder such as a rotary encoder on the
rotor or drive shaft, or a linear encoder on or associated with the slidable cover
1114. The encoder may be used to provide control of the motor with the encoder output
being indicative of, or usable to determine, the cover position. In other examples,
a brushless DC, or stepper motor, may be employed and the position of the rotor may
be acquired from the motor controller to determine the position of the cover 1114.
It will be appreciated that the position sensor 1154 may be provided by other means
which may or may not be connected with the operation of the motor 1146 and may not
form part of the motor 1146.
[0201] The actuator controller may be provided by a processor and memory within the camera
unit or central controller as described in connection with Figure 8. The camera unit
may be configured to receive a command, such as an arm command which prompts the camera
unit to determine the cover position status as described herein. In some examples,
the cover position status may be already stored in memory as a result of a previous
actuation or requirement of the actuator controller. Thus, the determination of the
cover position status may be achieved by obtaining the cover position from a memory
associated with an actuator controller.
[0202] The control of the motor 1146 (or other actuator) may be 'closed-loop' in which the
position of the motor 1146 and or cover 1114 is monitored as part of a feedback signal.
Alternatively, the control of the motor 1146 (or other actuator) may be open-loop
in which the motor 11146 records a cover position status rather than providing a feedback
signal relating to the cover position in any one instance.
[0203] The actuator may additionally be controlled using one or more sensors to determine
the position of the cover 1118. For example, the sensor may be in the form of a limit
switch which has the effect of cutting power to the motor when triggered.
[0204] The memory used to store the position of either the actuator and/or the cover may
be that of the camera unit or the central controller. It will be appreciated that
storing the position within the camera unit memory will generally be more energy efficient
as it will not be necessary to transmit the position back to the central controller
except for predefined events such as the system becoming armed.
[0205] Figures 12a and 12b show an alternative arrangement comprising a linear actuator
1244. Figure 12a shows a closed configuration of a cover 1214 from outside the cover
along line C-C facing inwards, and section D-D. Figure 12b shows the corresponding
cover in an open configuration. The actuation system includes an electromagnetic actuator
1244 in the form of a linear drive which is drivably connected to the cover 1214.
The linear actuator 1244 may comprise an electric solenoid 1246 having an elongate
linearly translatable drive arm 1252 which connects to the inside surface of the cover
1228 such that energising the solenoid causes the drive arm 1252 to move and a corresponding
translation of the cover 1214 between the open and closed positions, or vice versa.
The camera lens 1216 is shown above the actuator, but this is not a limitation.
[0206] The reference numerals used in Figure 12a are not repeated in Figure 12b, but the
various parts correspond with those of Figure 12a, with the exception that the cover
1214 is in a lower, open position. It will be appreciated that the reference to open
and closed is arbitrary and the actuator can be considered to be moving the cover
between a first position and second position, either of which could be the open or
closed positions.
[0207] In more detail, Figure 12 shows a cover 1214 having an outwardly facing external
surface (or outer side) 1234 and an inwardly facing internal surface (or inner side)
1228, in which the internal surface faces the exterior of the camera unit housing
1218. Mounted on the internal surface 1228 is linear drive arm connection 1256 which
extends inwardly from the inner side through an aperture 1258 in the housing wall.
The linear drive arm connection 1256 is attached to the linear drive arm 1252 which
is in turn received by the solenoid.
[0208] The aperture 1258 is in the form of an elongate slot which extends longitudinally
in the direction of motion of the cover 1218. The aperture 1258 is located so as to
be concealed by the cover 1218 when in the open or closed positions, however, this
is not essential.
[0209] Although not shown in Figures 12a and 12b, a second solenoid may be used to drive
movement of the cover 1218 in the opposite direction to that caused by solenoid 1246,
rather than relying on gravity. In such embodiments, to save power, a detent (not
shown) may be included to keep the cover in the elevated position shown in in Figure
12a, wherein the powering of the solenoid 1246 and the other solenoid overcomes a
holding power of the detent. Alternatively the two solenoids may be positioned and
configured to control movement of the cover along a horizontal axis instead of a vertical
axis.
[0210] As with Figures 11a and 11b, the linear actuator shown in Figures 12a and 12b may
incorporate a sensor which can be used to determine the position of the cover 1214.
Such sensors are known in the art and may be used for controlling the actuator. Similarly,
the control of the actuator and storage of the position, where applicable, may be
achieved using the camera unit processor and memory, and/or that of the central controller,
as per the arrangement described for Figures 11a and 11b.
[0211] In both of Figures 11a and 12a the covers 1114, 1214 are shown in isolation of any
of the guide features. However, it will be appreciated that the housing units 1118,1218
and/or cover 1114,1214 may include one or more guide features such as the runners
shown in Figures 1a and 1b.
[0212] It will also be appreciated that other actuation mechanisms may be possible. For
example the rotary actuator may comprise a worm gear as opposed to a rack and pinion.
The solenoid may be replaced by a linear motor or hydraulic or pneumatic ram, for
example.
[0213] In some embodiments, the opening of the cover with the solenoid or other actuation
mechanism may be carried out in parallel to determining the cover status position
and/or powering up the camera of the camera unit.
[0214] As described above, the sensor(s) used to determine the position of the cover and/or
actuator may include a passive sensor such as a discrete limit switch which could
be located at a predetermined position in relation to the cover 1114, 1214 and camera
unit housing. Thus, when the limit switch is engaged by the cover when moving from
an open to a close position, or vice versa, it will be possible to determine the position
of the cover to the extent required. The limit switch may be a mechanical device,
in which a switch is mechanically connected to via the cover. Alternatively, the limit
switch may comprise a non-contact device such as a magnetic switch in which, for example,
a magnet is mounted to the cover and a reed switch is activated at the predetermined
position (or vice versa).
[0215] The covers 1114, 1214 shown in Figures 11a and 12a do not include the light directing
channel and/or waveguide of Figures 3a and 4a. However, it will be appreciated that
such features may be incorporated with the actuation mechanisms described herein.
This may be achieved by moving the position of the cover 1114, 1214 in relation to
the camera and/or drive mechanism features. The location of the actuators relative
to the cover, housing, camera, camera lens, light-emitting diode, and light sensor
may be variably arranged to suit a particular configuration. In some examples, the
covers 1114, 1214 may be mounted asymmetrically in relation to the camera lens, or
the drive mechanism may be mounted to one side of the cover to accommodate a centrally
mounted camera.
[0216] In some embodiments the camera units are PIR cameras. The camera functionality of
the unit need not be its primary function. For example, the unit may operate as a
PIR for the security system, with the camera functionality only being used at select
instances, for example when the unit is security system is armed or if instructed
to capture images by the controller. Further, the unit may have other functionalities
too. Thus, the present disclosure is not limited to devices that, as an entire device,
is necessarily termed a camera unit. For example, it may more generally apply to a
security device, in some embodiments. Thus the term "camera unit" as used herein may
refer to a device, more particularly any security device in some embodiments, which
may comprise additional features, for example other security sensors, and/or perform
additional functions, unrelated to the use of the camera.
[0217] Reference to any prior art in this specification is not an acknowledgement or suggestion
that this prior art forms part of the common general knowledge in any jurisdiction,
or globally, or that this prior art could reasonably be expected to be understood,
regarded as relevant/or combined with other pieces of prior art by a person skilled
in the art.
[0218] As used herein, except where the context requires otherwise, the terms "comprises",
"includes", "has", and grammatical variants of these terms, are not intended to be
exhaustive. They are intended to allow for the possibility of further additives, components,
integers or steps.
[0219] The skilled person will appreciate that except where mutually exclusive, a feature
described in relation to any one of the aspects, examples or embodiments described
herein may be applied to any other aspect, example, embodiment or feature. Further,
the description of any aspect, example or feature may form part of or the entirety
of an embodiment of the invention as defined by the claims. Any of the examples described
herein may be an example which embodies the invention defined by the claims and thus
an embodiment of the invention.
[0220] It will be understood that the invention is not limited to the examples and embodiments
above-described and various modifications and improvements can be made without departing
from the concepts described herein. Except where mutually exclusive, any of the features
may be employed separately or in combination with any other features and the disclosure
extends to and includes all combinations and sub-combinations of one or more features
described herein.