(19)
(11)EP 3 641 299 A1

(12)EUROPEAN PATENT APPLICATION
published in accordance with Art. 153(4) EPC

(43)Date of publication:
22.04.2020 Bulletin 2020/17

(21)Application number: 18818235.6

(22)Date of filing:  30.05.2018
(51)International Patent Classification (IPC): 
H04N 5/232(2006.01)
(86)International application number:
PCT/CN2018/088936
(87)International publication number:
WO 2018/228186 (20.12.2018 Gazette  2018/51)
(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR
Designated Extension States:
BA ME
Designated Validation States:
KH MA MD TN

(30)Priority: 16.06.2017 CN 201710458995

(71)Applicant: GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP., LTD.
Wusha, Chang'an Dongguan, Guangdong 523860 (CN)

(72)Inventor:
  • LI, Xiaopeng
    Dongguan Guangdong 523860 (CN)

(74)Representative: Penza, Giancarlo 
Bugnion S.p.A. Viale Lancetti, 17
20158 Milano
20158 Milano (IT)

  


(54)FOCUSING METHOD AND APPARATUS, COMPUTER READABLE STORAGE MEDIUM, AND MOBILE TERMINAL


(57) The present application relates to a focusing method and apparatus, a computer readable storage medium, and a mobile terminal. The method comprises: acquiring a focal length corresponding to the lens position when a first camera is in focus; acquiring the lens position when a second camera corresponding to the focal length is in focus; and driving the lens of the second camera to reach the lens position of the second camera when in focus, and performing focusing. In the present method, after focusing of the primary camera is complete, the focal length of the primary camera is acquired, the lens position of a corresponding secondary camera when in focus is found on the basis of the focal length of the primary camera, and the secondary camera is driven to reach the corresponding lens position and complete focusing, thus improving the accuracy of dual camera focusing, and making dual camera focusing more convenient.




Description

CROSS-REFERENCE TO RELATED APPLICATION



[0001] This application claims priority to a Chinese application No. 201710458995.X filed on June 16, 2017, titled "FOCUSING METHOD AND APPARATUS, COMPUTER READABLE STORAGE MEDIUM, AND MOBILE TERMINAL". The entirety of the above-mentioned application is hereby incorporated by reference herein.

TECHNICAL FIELD



[0002] The present disclosure relates to a technical field of mobile terminal in general. More particularly, and without limitation, the disclosed embodiments relate to a focusing method, a apparatus, a computer readable storage medium, and a mobile terminal.

BACKGROUND



[0003] With a development of smart mobile terminals, a smart mobile terminal is widely used for taking photos and videos. Requirements for a shooting effect of smart mobile terminals are getting stricter. When shooting an object with a camera, the camera needs to determine an in-focus distance that ensures to capture a clear image, and then the camera may capture images of the object basing on the in-focus distance, so that the images are clear enough.

SUMMARY



[0004] A focusing method, apparatus, computer readable storage medium, and mobile terminal are provided , in accordance with embodiments of the present disclosure, which can ensure that the dual-camera module focuses more conveniently.

[0005] In a first aspect, a focusing method is provided. In the focusing method, .an in-focus distance, corresponding to an in-focus lens position of a first camera that is in focus, is obtained. An in-focus lens position of a second camera is obtained, the in-focus lens position is corresponding to the in-focus distance. The lens of the second camera are driven to move to the in-focus lens position of the second camera and to focus.

[0006] In a second aspect, a focusing apparatus is provided. The focusing apparatus includes an obtaining module, and a driving module. The obtaining module is configured to obtain an in-focus distance corresponding to an in-focus lens position of a first camera that is in focus, and obtain an in-focus lens position of a second camera corresponding to the in-focus distance. The driving module is configured to move the lens of the second camera to the in-focus lens position of the second camera and focuses when driving the second camera to focus.

[0007] In a third aspect, a mobile terminal is provided. The mobile terminal includes a memory and a processor. The memory stores a computer program, and the processor is configured to execute the computer program to perform the following operations including: obtaining an in-focus distance corresponding to an in-focus lens position of a first camera that is in focus; obtaining an in-focus lens position of a second camera corresponding to the in-focus distance; and moving the lens of the second camera to the in-focus lens position of the second camera and focuses when driving the second camera to focus.

[0008] In a fourth aspect, a computer readable storage medium is provided. The computer readable storage medium has a computer program, the computer program is executed by a processor to perform the following operations including: obtaining an in-focus distance corresponding to an in-focus lens position of a first camera that is in focus; obtaining an in-focus lens position of a second camera corresponding to the in-focus distance; and moving the lens of the second camera to the in-focus lens position of the second camera and focuses when driving the second camera to focus.

BRIEF DESCRIPTION OF THE DRAWINGS



[0009] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the present disclosure, and together with the description, serve to explain the principles of the disclosure.

FIG. 1 illustrates a schematic flowchart of a focusing method, in accordance with an embodiment of the present disclosure.

FIG. 2 illustrates a schematic view of functional blocks of a focusing apparatus, in accordance with an embodiment of the present disclosure.

FIG. 3 illustrates a schematic view of functional blocks of a focusing apparatus, in accordance with another embodiment of the present disclosure.

FIG. 4 illustrates a schematic view of functional blocks of a focusing apparatus, in accordance with still another embodiment of the present disclosure.

FIG. 5 illustrates a schematic view of an image processing circuit, in accordance with still another embodiment of the present disclosure.


DETAILED DESCRIPTION OF EMBODIMENTS



[0010] The technical solutions in the embodiments of the present disclosure will be clearly and completely described in the following with reference to the accompanying drawings. It is understood that the specific embodiments described herein are merely illustrative of the disclosure and are not intended to limit the disclosure. It should also be noted that, for ease of description, only some but not all of the structures related to the present disclosure are illustrated in the drawings. All other embodiments obtained by those skilled in the art based on the embodiments of the present disclosure without any creative efforts are fall in the scope claimed by the present disclosure.

[0011] FIG. 1 illustrates a schematic flowchart of a focusing method, in accordance with an embodiment of the present disclosure. As illustrated in FIG. 1, the focusing method may begin from block S 102 to block S 106.

[0012] At the block S 102, an in-focus distance, which is corresponding to an in-focus lens position of a first camera that is in focus, may be obtained when the first camera has been in focus.

[0013] In some embodiments, when a rear camera module of a mobile terminal is a dual-camera module including two cameras, the dual-camera module can be used for focusing. In general, a dual-camera module may include a common camera and a depth camera. In some embodiments, the dual-camera module may include a color camera and a black-and-white camera. In other embodiments, the dual-camera module may include a wide camera and a telephoto camera. Different shooting effects may be achieved by different dual-cameral module. The first camera refers to a main camera of the rear camera module of the mobile terminal. When the rear camera module of the mobile terminal is a dual-camera module having a main camera and a secondary camera, the main camera and the secondary camera of the dual-camera module can be distinguished according to camera identifications (IDs) thereof. For example, in the mobile terminal, a camera ID may be determined as 0 for indicating the main camera, and a camera ID may be determined as 1 for indicating the secondary camera, and a camera ID may be determined as 2 for a front camera of the mobile terminal. When a camera application in the mobile terminal is activated and starts to focus, the mobile terminal may search for the main camera according to the camera ID thereof, and move a lens of the main camera to focus. In an operation of moving the lens of the main camera to focus, the main camera may perform a first scanning operation to obtain a location range of an in-focus lens position of the first camera that is in focus; then the main camera may perform a second scanning operation to obtain the in-focus lens position that is in focus, after the location range of the in-focus lens position is obtained. After obtaining the in-focus lens position, the mobile terminal may obtain an in-focus distance corresponding to the in-focus lens position. When the lens of the main camera are moved, by the mobile terminal, to arrive at the in-focus lens position, an image captured by the main camera, is in focus. In other words, the image captured by the mobile terminal is clear. The in-focus distance indicates a straight-line distance between the lens of the main camera and a point at which an image is focused.

[0014] At the block S104, an in-focus lens position of a second camera, which is corresponding to the in-focus distance, is obtained.

[0015] The second camera refers to the secondary camera of the rear camera module of the mobile terminal. The main camera and the secondary camera are distinguished according to the camera IDs thereof. The main camera and the secondary camera may have different numbers of pixels, or may have the same numbers of pixels. The mobile terminal pre-stores a correspondence between the in-focus distance and the lens position of each of the cameras. When specifications of the cameras are different, the correspondences, between the in-focus distance and the lens position of each of the cameras, may be different. A correspondence of the camera ID of every camera, the in-focus lens position of every camera, and the in-focus distance may be pre-stored in the mobile terminal. After obtaining the in-focus distance corresponding to the in-focus lens position of the main camera that is in focus, the in-focus lens position of the secondary camera, which is corresponding to the in-focus distance, can be obtained by searching correspondingly up in the correspondence. As illustrated in Table 1, a correspondence of the in-focus lens position and the in-focus distance is illustrated.
Table 1 correspondence of the in-focus lens position of every camera and the in-focus distance
In-focus lens position of lens (mm)In-focus distance (cm)
0.1 20
0.2 40
0.3 60
0.6 120
2.5 500


[0016] At the block S 106, the second camera is focusing, by moving the lens of the second camera to the in-focus lens position that indicates the second camera has been in focus.

[0017] The mobile terminal may move the lens of the secondary camera to the in-focus lens position by activating a motor, when the in-focus lens position, that indicates the second camera is in focus, is obtained by the mobile terminal. And the mobile terminal may obtain an in-focus area when moving the secondary camera to focus. In some embodiments, operations of moving the lens of the secondary camera to focus is the same as the operations of moving the lens of the main camera to focus.

[0018] In the prior art, a main camera and a secondary camera of a dual-camera module is focusing independently when the dual-camera module of a prior mobile terminal focus. The dual-camera module then capture an image after the main camera and the secondary camera are in focus, which results in that an in-focus distance of the main camera and an in-focus distance of the secondary camera is different because of the operation of focusing independently. Therefore, a focus of an image capture by the main camera and a focus of an image captured by the secondary camera is different, and a processed image based on the two images may have a poor quality. In the focusing method according to the embodiments of the present disclosure, the main camera and the secondary camera are focusing on substantially identical focus area according to the correspondence of the in-focus lens position of every camera and the in-focus distance. Thereby a quality of a processed image based on two images respectively captured by the main camera and the secondary camera is improved.

[0019] In one embodiment, before the in-focus distance corresponding to the in-focus distance of the lens of the first camera is obtained, the focusing method further includes the following operations: driving the first camera to focus; obtaining a current position of the first camera at the time when a current frame of image is in focus, and determining the in-focus lens position of the first camera as the current position corresponding the current frame of image that is in-focus.

[0020] Before the mobile terminal obtains the in-focus distance corresponding to the in-focus lens position of the main camera, the main camera is driven to focus by the mobile terminal, and the mobile terminal is configured to determine whether or not the current frame of image is in focus. The operation of determining whether or not the current frame of image is in focus may include the operations of: driving the lens of the main camera to perform a pre-scanning, and obtaining every focus value corresponding to every frame of image when the lens of the main camera is scanning; and the pre-scanning is stopped and an accurate scanning is performed at the time when the focus value corresponding to the current frame of image is smaller than that of a previous frame. In the pre-scanning process, a movement of the main camera is relatively large at each time of approaching. After the pre-scanning is finished, the mobile terminal drives the lens of the main camera to perform the accurate scanning. In the accurate scanning process, the main camera is moved and retreated, and the movement of the main camera is relatively smaller than that in the pre-scanning process. When a focus value of an intermediate frame of three consecutive frames of images is greater than the focus value of each of a previous and a consecutive frames of the intermediate frame, the accurate scanning is stopped. A fitted parabola is forming according to the focus values corresponding to the three consecutive frames of images. The main camera is determined as in focus at the time when the lens arrives at a position corresponding to a vertex of the fitted parabola. When the mobile terminal determines that the main camera has been in focus and the current frame of image is in focus, the lens position corresponding to the current frame of image is recorded as the in-focus lens position when the main camera has been in focus.

[0021] In the focusing method according to the embodiments of the present disclosure, the in-focus lens position of the first camera is determined as the current position corresponding to the current frame of image, only at the time when the current frame of image is in focus. Thereby a system resource and the power consumption of the mobile terminal is reduced.

[0022] In one embodiment, before the in-focus distance corresponding to the in-focus lens position of the first camera is obtained, the focusing method further includes the following operations: driving the first camera to focus; obtaining every position corresponding to every frame of image; determining the lens position corresponding to a frame of image that is in focus as the in-focus lens position of the first camera.

[0023] Before the mobile terminal obtains the in-focus distance corresponding to the in-focus lens position of the main camera, the main camera is driven to focus by the mobile terminal, and the terminal is configured to records a current position corresponding to the current frame of image. At the time when the current frame of image is determined as in focus, an in-focus lens position, corresponding to an in-focus frame of image, is obtained; and the mobile terminal may search for the in-focus distance corresponding to the in-focus lens position.

[0024] In one embodiment, correspondences of a device identification number of every camera, the lens position of every camera, and the in-focus distance are pre-stored in the mobile terminal. The operation, of obtaining an in-focus distance corresponding to the in-focus lens position of a first camera that is in focus, may include the following operations: obtaining the device identification number of the first camera; searching for the in-focus distance corresponding to the in-focus lens position of the first camera that is in focus, according to the device identification number of the first camera. The operation, of obtaining an in-focus lens position of a second camera, which is corresponding to the in-focus distance, may include the following operations: obtaining the device identification number of the second camera; and searching for, according to the device identification number of the second camera, the in-focus lens position of the second camera, which is corresponding to the in-focus distance.

[0025] Correspondences of the device identification number of every camera, the lens positions of every camera, and the in-focus distance are pre-stored in the mobile terminal.

[0026] Different cameras with different device identification numbers may have different in-focus distances that is corresponding to the in-focus lens positions of the cameras. When the main camera has been in focus, the mobile terminal may obtain the in-focus lens position of lens of the main camera, and configured to search for, according to the device identification numbers and the lens position of the main camera, the in-focus distance corresponding to the in-focus lens position of the main camera. After obtaining the in-focus distance, the mobile terminal may search for the lens position of the secondary camera, which is corresponding to the in-focus distance. The device identification number of the camera is a string for uniquely identifying the corresponding camera, such as a camera ID. As illustrated in Table 2, Table 2 illustrates a correspondence of the device identification number of the camera, the lens position of the camera, and the in-focus distance.
Table 2 correspondence of the device identification number of every camera, the lens position of every camera, and the in-focus distance.
device identification numberLens position (mm)In-focus distance (cm)
0 0.2 40
0 0.3 60
0 0.6 120
0 2.5 500
1 0.1 40
1 0.15 60
1 0.3 120
1 1.25 500


[0027] In the focusing method according to the embodiments of the present disclosure, the in-focus distance is determined according to the lens position of the main camera, and the in-focus lens position of the secondary camera is determined according to the in-focus distance. Such that a focus area of the secondary camera is the same as that of main first camera. Thereby the mobile terminal with the dual-camera module may focus conveniently, and a quality of images capture by the dual-camera module is improved.

[0028] In one embodiment, the focusing method further include an operation of capturing images via the first camera and the second camera simultaneously when the second camera has been in focus.

[0029] When the second camera has been in focus, the mobile terminal is configured to capture images with the first camera and the second camera simultaneously. In the focusing method according to the embodiments of the present disclosure, both of the first camera and the second camera are simultaneously used for capturing images when the dual-camera module is in focus, which ensures a better consistency of the images and improves a quality of a processed image that is processed according to the images captured by the first camera and the second camera.

[0030] The steps in the flowchart of the focusing method according to the embodiments of the present disclosure are sequentially illustrated in accordance with the indication of the arrow, but the steps are not necessarily performed in the order indicated by the arrow. Except as explicitly stated herein, the execution of these steps is not strictly limited, and may be performed in other order. Furthermore, at least some of the steps in the flowchart of the focusing method according to the embodiments of the present disclosure may include multiple sub-steps or multiple stages, which are not necessarily performed at the same time, but may be executed at different times. The order of execution is not necessarily performed sequentially, but may be performed alternately or alternately with at least a portion of other steps or sub-steps or stages of other steps.

[0031] FIG. 2 illustrates a schematic view of functional blocks of a focusing apparatus, in accordance with an embodiment of the present disclosure. As illustrated in FIG. 2, the focusing apparatus includes an obtaining module 202 and a driving module 204.

[0032] The obtaining module 202 is configured to obtain an in-focus distance corresponding to an in-focus lens position of a first camera that is in focus, when the first camera has been in focus; and configured to obtain an in-focus lens position of a second camera that is in focus, which is corresponding to the in-focus distance.

[0033] The driving module 204 is configured to drive the lens of the second camera to arrive the in-focus lens position of the second camera and to focus.

[0034] FIG. 3 illustrates a schematic view of functional blocks of a focusing apparatus, in accordance with another embodiment of the present disclosure. As illustrated in FIG. 3, the focusing apparatus includes an obtaining module 302, a driving module 304, and a detection module 306. The obtaining module 302 and the driving module 304 in FIG. 3 have the same functions as those in FIG. 2.

[0035] The driving module 304 is further configured to drive the first camera to focus before obtaining the in-focus distance corresponding to the in-focus lens position of the first camera that is in focus.

[0036] The detecting module 306 is configured to determine where or not a current frame of image is in focus, obtain a current position of the first camera at the time when the current frame of image is in focus, and determine the in-focus lens position of the first camera as the current position of the lens that is in focus.

[0037] In one embodiment, before the in-focus distance corresponding to the in-focus lens position of the first camera is obtained, the driving module 304 is further configured to drive the first camera to focus, and obtain every position corresponding to every frame of image.

[0038] The detection module 306 is further configured to determine the lens position corresponding to a frame of image that is in focus as the in-focus lens position of the first camera..

[0039] In one embodiment, correspondences of device identification number of every camera, the lens positions of every camera, and the in-focus distances are pre-stored in the mobile terminal. The obtaining module 202 is further configured to:

obtaining the device identification number of the first camera; and searching for the in-focus distance corresponding to the in-focus lens position of the first camera that is in focus, according to the device identification number of the first camera; and

obtaining the device identification number of the second camera; and searching for, according to the device identification number of the second camera, the in-focus lens position of the second camera, which is corresponding to the in-focus distance.



[0040] FIG. 4 illustrates a schematic view of functional blocks of a focusing apparatus, in accordance with still another embodiment of the present disclosure. As illustrated in FIG. 4, the focusing apparatus includes an obtaining module 402, a driving module 404, and a shooting module 406. The obtaining module 402 and the driving module 404 in FIG. 4 have the same functions as those in FIG. 2.

[0041] The shooting module 406 is configured to configured to capture images with the first camera and the second camera simultaneously when the second camera has been in focus.

[0042] The division of each module in the above focusing apparatus is for illustrative purposes only. In other embodiments, the focusing apparatus may be divided into different modules as needed to perform all or part of the functions of the focusing apparatus.

[0043] Each of the above-described focusing apparatus may be implemented in whole or in part by software, hardware, and combinations thereof. The above modules may be embedded in the hardware, in the processor, or in the memory in the server, or may be stored in the memory of the server, so that the processor can involve the above modules to perform corresponding operations of. As used in this disclosure, the terms "component", "module" and "system" and the like are intended to mean a computer-related entity, which may be hardware, a combination of hardware and software, software, or software in execution. For example, a component can be, but is not limited to, a process running on a processor, a processor, an object, an executable, a thread of execution, a program, and/or a computer. By way of illustration, both an application running on a server and a server can be a type of a component. One or more components can reside in a process and/or executed thread, and the components can be located within one computer and/or distributed in two or more computers.

[0044] A computer readable storage medium is provided, in accordance with the embodiments of the present disclosure. The computer readable storage medium stores a plurality of instructions, and the instructions are adapted to be executed by a processor to perform the following operations (1) to (3):
At the operation (1), an in-focus distance, corresponding to a lens position of a first camera that is in focus, may be obtained when the first camera has been in focus.

[0045] In some embodiment, when a rear camera module of a mobile terminal is a dual-camera module including two cameras, the dual-camera module can be used for focusing. In general, a dual-camera module may include a common camera and a depth camera. In some embodiments, the dual-camera module may include a color camera and a black-and-white camera. In other embodiments, the dual-camera module may include a wide camera and a telephoto camera. Different shooting effects may be achieved by different dual-cameral module. The first camera refers to a main camera of the rear camera module of the mobile terminal. When the rear camera module of the mobile terminal is a dual-camera module having a main camera and a secondary camera, the main camera and the secondary camera of the dual-camera module can be distinguished according to camera IDs thereof. For example, in the mobile terminal, a camera ID may be determined as 0 for indicating the main camera, and a camera ID may be determined as 1 for indicating the secondary camera, and a camera ID may be determined as 2 for a front camera of the mobile terminal. When a camera application in the mobile terminal is activated and starts to focus, the mobile terminal may search for the main camera according to the camera ID thereof, and move a lens of the main camera to focus. In an operation of moving the lens of the main camera to focus, the main camera may perform a first scanning operation to obtain a location range of an in-focus lens position of the first camera that is in focus; then the main camera may perform a second scanning operation to obtain the in-focus lens position that is in focus, after the location range of the in-focus lens position is obtained. After obtaining the in-focus lens position, the mobile terminal may obtain an in-focus distance corresponding to the in-focus lens position. When the lens of the main camera are moved, by the mobile terminal, to arrive at the in-focus lens position, an image captured by the main camera, is in focus. In other words, the image captured by the mobile terminal is clear. The in-focus distance indicates a straight-line distance between a focus of the image and the lens of the main camera.

[0046] At the operation (2), an in-focus lens position of a second camera, which is corresponding to the in-focus distance, is obtained.

[0047] In some embodiment, the second camera refers to the secondary camera of the rear camera module of the mobile terminal. The main camera and the secondary camera are distinguished according to the camera IDs thereof. The main camera and the secondary camera may have different numbers of pixels, or may have the same numbers of pixels. The mobile terminal pre-stores correspondences between the in-focus distance and the in-focus lens position of each of the cameras. When specifications of the lenses are different from each other, the correspondences, between the in-focus distance and the in-focus lens position of each of the cameras, may be different. A correspondence of the camera ID, the in-focus lens position, and the in-focus distance may be pre-stored in the mobile terminal. After obtaining the in-focus distance corresponding to the in-focus lens position of the main camera that is in focus, the in-focus lens position of the secondary camera, which is corresponding to the in-focus distance, can be obtained by searching correspondingly up in the correspondence. As illustrated in Table 1, a correspondence of the in-focus lens position of every camera and the in-focus distance is illustrated.

[0048] At the operation (3), the second camera is moved to the in-focus lens position that indicates the second camera is in focus, and the second camera is focusing during the movement.

[0049] In some embodiment, the mobile terminal may move the lens of the secondary camera to the in-focus lens position by activating a motor, when the in-focus lens position, that indicates the second camera is in focus, is obtained by the mobile terminal. And the mobile terminal may obtain an in-focus area when moving the secondary camera to focus. In some embodiments, operations of moving the lens of the secondary camera to focus is the same as the operations of moving the lens of the main camera to focus.

[0050] In one embodiment, before the in-focus distance corresponding to the in-focus distance of the lens of the first camera is obtained, the focusing method further includes the following operations: driving the first camera to focus; obtaining a current position of the first camera at the time when a current frame of image is in focus, and determining the in-focus lens position of the first camera as the current position corresponding the current frame of image.

[0051] Before the mobile terminal obtains the in-focus distance corresponding to the in-focus lens position of the main camera, the main camera is driven to focus by the mobile terminal, and the mobile terminal is configured to determine whether or not the current frame of image is in focus. The operation of determining whether or not the current frame of image is in focus may include the following operations: driving the lens of the main camera to perform a pre-scanning, and obtaining every focus value corresponding to every frame of image when the lens of the main camera is scanning; and the pre-scanning is stopped and an accurate scanning is performed at the time when the focus value corresponding to the current frame of image is smaller than that of a previous frame. In the pre-scanning process, a movement of the main camera is relatively large at each time of approaching. After the pre-scanning is finished, the mobile terminal drives the lens of the main camera to perform the accurate scanning. In the accurate scanning process, the main camera is moved and retreated, and the movement of the main camera is relatively smaller than that in the pre-scanning process. When a focus value of an intermediate frame of three consecutive frames of images is greater than the focus value of each of a previous and a consecutive frames of the intermediate frame, the accurate scanning is stopped. A fitted parabola is forming according to the focus values corresponding to the three consecutive frames of images. The main camera is determined as in focus at the time when the lens arrives at a position corresponding to the vertex of the fitted parabola. When the mobile terminal determines that the main camera has been in focus and the current frame of image is in focus, the lens position corresponding to the current frame of image is recorded as the in-focus lens position when the main camera has been in focus.

[0052] In one embodiment, before the in-focus distance corresponding to the in-focus lens position of the first camera is obtained, the focusing method further includes the following operations: driving the first camera to focus; obtaining every position corresponding to every frame of image; determining the lens position corresponding to a frame of image that is in focus as the in-focus lens position of the first camera.

[0053] Before the mobile terminal obtains the in-focus distance corresponding to the in-focus lens position of the main camera, the main camera is driven to focus by the mobile terminal, and the terminal is configured to records a current position corresponding to the current frame of image. At the time when the current frame of image is determined as in focus, an in-focus lens position, corresponding to an in-focus frame of image, is obtained; and the mobile terminal may search for the in-focus distance corresponding to the in-focus lens position.

[0054] In one embodiment, correspondences of device identification numbers of every cameras, the lens position of every camera, and the in-focus distances are pre-stored in the mobile terminal. The operation, of obtaining an in-focus distance corresponding to the in-focus lens position of a first camera that is in focus, may include the following operations: obtaining the device identification number of the first camera; searching for the in-focus distance corresponding to the in-focus lens position of the first camera that is in focus, according to the device identification number of the first camera. The operation, of obtaining an in-focus lens position of the second camera, which is corresponding to the in-focus distance, may include the following operations: obtaining the device identification number of the second camera; and searching for, according to the device identification number of the second camera, the in-focus lens position of the second camera, which is corresponding to the in-focus distance.

[0055] Correspondences of device identification number of every cameras, the lens positions of every camera, and the in-focus distance are pre-stored in the mobile terminal.

[0056] Different cameras with different device identification numbers may have different in-focus distances that is corresponding to the in-focus lens positions of the cameras. When the main camera has been in focus, the mobile terminal may obtain the in-focus lens position of lens of the main camera, and configured to search for, according to the device identification numbers and the lens position of the main camera, the in-focus distance corresponding to the in-focus lens position of the main camera. After obtaining the in-focus distance, the mobile terminal may search for the lens position of the secondary camera, which is corresponding to the in-focus distance. The device identification number of the camera is a string for uniquely identifying the corresponding camera, such as a camera ID.

[0057] In one embodiment, the focusing method further include an operation of capturing images via the first camera and the second camera simultaneously when the second camera has been in focus.

[0058] When the second camera has been in focus, the mobile terminal is configured to capture images with the first camera and the second camera simultaneously. In the focusing method according to the embodiments of the present disclosure, both of the first camera and the second camera are simultaneously used for capturing images when the dual-camera module is in focus, which ensures a better consistency of the images and improves a quality of a processed image that is processed according to the images captured by the first camera and the second camera.

[0059] A mobile terminal is also provided, in accordance with the embodiments of the present disclosure. he mobile terminal includes an image processing circuit, and the image processing circuit can be implemented by hardware and/or software components, and can include various processing units defining an Image Signal Processing (ISP) pipeline. FIG.5 illustrates a schematic view of an image processing circuit, in accordance with still another embodiment of the present disclosure. As illustrated in FIG. 5, for convenience of explanation, only various aspects of the image processing technique related to the embodiment of the present disclosure are illustrated.

[0060] As illustrated in FIG. 5, the image processing circuit 540 includes an ISP pre-processing logical module 542, an ISP pipeline processing logical module 544, and a controlling logical module 546. An image data captured by an imaging device 510 is processed by the ISP pre-processing logical module 542. The ISP pre-processing logical module 542 may analyze the image data to capture image statistics for determining one or more controlling parameters of the ISP pipeline processing logical module 544 and/or the imaging device 510. The imaging device 510 can include a camera having one or more lenses 512 and image sensors 514. The image sensor 514 may include a color filter array (such as a Bayer filter). The image sensor 514 may be configured to capture light intensity and wavelength information via each imaging pixel of image sensor 514, and configured to provide a group of raw image data that may be processed by the ISP pre-processing logical module 542. For example, an interface of a sensor 520 may receive an output data of the imaging device 510 and transmits, according to a type of the interface of the sensor 520, the raw image data to the ISP pre-processing logical module 542. The interface of the sensor 520 may include any one of a Standard Mobile Imaging Architecture (SMIA) interface, other serial or parallel camera interfaces, or any combination of the above.

[0061] The ISP pre-processing logical module 542 processes the raw image data pixel by pixel in a variety of formats. For example, each of image pixels can have a bit depth of 8, 10, 12, or 14 bits, and the ISP pre-processing logical module 542 can perform one or more image processing operations on the raw image data, for collecting statistical information about the image data. The image processing operations can be performed according to the same or different bit depth precision.

[0062] The ISP pre-processing logical module 542 can also receive pixel data from an image memory 530. For example, the interface of the sensor 520 may transmit the raw pixel data to the image memory 530, which is then provided to the ISP pre-processing logical module 542 for further processing. The image memory 530 can be part of a memory device, a storage device, or an independent dedicated memory of an electronic device. The image memory 530 can include a direct memory access (DMA) features.

[0063] When receiving the raw image data from the interface of the sensor 520 or from the image memory 530, the ISP pre-processing logical module 542 can perform one or more image processing operations, such as a time domain filtering. A processed image data is generated and can be sent to the ISP pipeline processing logical module 544 or the image memory 530 for further processing before being displayed. The ISP pipeline processing logical module 544 can also receive a pre-processing image data directly from the ISP pre-processing logical module 542, or receive a pre-processing image data from the image memory 530, and process the pre-processing image data in the original domain as well as in color space of RGB and YCbCr. A processed image data is generated after being processed by the ISP pipeline processing logical module 544, and can be transmitted to a displayer for displaying. Thereby a user can see the processed image, and/or the processed image may be further processed by a graphics engine or a Graphics Processing Unit (GPU). Additionally, the processed image from the ISP pipeline processing logical module 544 can also be transmitted to the image memory 530. The displayer can read image data, from image memory 530, of the processed image. In one embodiment, image memory 530 can be configured to implement one or more frame buffers. Furthermore, the processed image from the ISP pipeline processing logical module 544 can be transmitted to an encoder/decoder 560 to encode/decode image data. An encoded image data can be saved and decompressed before being displayed on the displayer device.

[0064] The image statistics determined by the ISP pre-processing logical module 542 can be transmitted to the controlling logical module 546 unit. For example, the image statistics may include statistics of the image sensor 514, such as an auto exposure, an auto white balance, an auto focus, a flicker detection, a black level compensation, a shading correction for the lens 512, and the like. The controlling logical module 546 can include a processor and/or a microcontroller configured to execute one or more routines, such as firmware. The one or more routines can determine a controlling parameters for controlling the imaging device 510 and the controlling parameters for controlling the ISP pipelines, based on the image statistics. For example, the controlling parameters may include controlling parameters (e.g., gain, integration time for exposure control) for controlling the sensor 520, controlling parameters for controlling a camera flash, controlling parameters (e.g., focus or zoom in-focus distance) for controlling the lens 512, or any combination of these parameters. The controlling parameters for ISP may include a gain levels and color correction matrices for automatic white balance and color adjustment (e.g., during RGB processing), as well as shading correction parameters for the lens 512.

[0065] The following operations are performed to achieve the focusing method, by applying the image processing technique of FIG. 5.

[0066] At an operation (1), an in-focus distance, which is corresponding to an in-focus lens position of the first camera that is in focus, may be obtained when the first camera has been in focus.

[0067] In some embodiment, when a rear camera module of a mobile terminal is a dual-camera module including two cameras, the dual-camera module can be used for focusing. In general, a dual-camera module may include a common camera and a depth camera. In some embodiments, the dual-camera module may include a color camera and a black-and-white camera. In other embodiments, the dual-camera module may include a wide camera and a telephoto camera. Different shooting effects may be achieved by different dual-cameral module. The first camera refers to a main camera of the rear camera module of the mobile terminal. When the rear camera module of the mobile terminal is a dual-camera module having a main camera and a secondary camera, the main camera and the secondary camera of the dual-camera module can be distinguished according to camera IDs thereof. For example, in the mobile terminal, a camera ID may be determined as 0 for indicating the main camera, and a camera ID may be determined as 1 for indicating the secondary camera, and a camera ID may be determined as 2 for a front camera of the mobile terminal. When a camera application in the mobile terminal is activated and starts to focus, the mobile terminal may search for the main camera according to the camera ID thereof, and move a lens of the main camera to focus. In an operation of moving the lens of the main camera to focus, the main camera may perform a first scanning operation to obtain a location range of an in-focus lens position of the first camera that is in focus; then the main camera may perform a second scanning operation to obtain the in-focus lens position that is in focus, after the location range of the in-focus lens position is obtained. After obtaining the in-focus lens position, the mobile terminal may obtain an in-focus distance corresponding to the in-focus lens position. When the lens of the main camera are moved, by the mobile terminal, to arrive at the in-focus lens position, an image captured by the main camera, is in focus. In other words, the image captured by the mobile terminal is clear. The in-focus distance indicates a straight-line distance between a focus of the image and the lens of the main camera.

[0068] At an operation (2), an in-focus lens position of a second camera, which is corresponding to the in-focus distance, is obtained.

[0069] In some embodiment, the second camera refers to the secondary camera of the rear camera module of the mobile terminal. The main camera and the secondary camera are distinguished according to the camera IDs thereof. The main camera and the secondary camera may have different numbers of pixels, or may have the same numbers of pixels. The mobile terminal pre-stores correspondences between the in-focus distance and the in-focus lens position of every camera. When specifications of the lenses are different from each other, the correspondences, between the in-focus distance and the in-focus lens position of each of the cameras, may be different. A correspondence of the camera ID, the in-focus lens position, and the in-focus distance may be pre-stored in the mobile terminal. After obtaining the in-focus distance corresponding to the in-focus lens position of the main camera that is in focus, the in-focus lens position of the secondary camera, which is corresponding to the in-focus distance, can be obtained by searching correspondingly up in the correspondence. As illustrated in Table 1, a correspondence of the in-focus lens position of every camera, and the in-focus distance is illustrated.

[0070] At an operation (103), the second camera is moved to the in-focus lens position that indicates the second camera is in focus, and the second camera is focusing during the movement.

[0071] In some embodiment, the mobile terminal may move the lens of the secondary camera to the in-focus lens position by activating a motor, when the in-focus lens position, that indicates the second camera is in focus, is obtained by the mobile terminal. And the mobile terminal may obtain an in-focus area when moving the secondary camera to focus. In some embodiments, operations of moving the lens of the secondary camera to focus is the same as the operations of moving the lens of the main camera to focus.

[0072] In one embodiment, before the in-focus distance corresponding to the in-focus distance of the lens of the first camera is obtained, the focusing method further includes the following operations: driving the first camera to focus; obtaining a current position of the first camera at the time when a current frame of image is in focus, and determining the in-focus lens position of the first camera as the current position corresponding the current frame of image that is in-focus.

[0073] Before the mobile terminal obtains the in-focus distance corresponding to the in-focus lens position of the main camera, the main camera is driven to focus by the mobile terminal, and the mobile terminal is configured to determine whether or not the current frame of image is in focus. The operation of determining whether or not the current frame of image is in focus may include the following operations: driving the lens of the main camera to perform a pre-scanning, and obtaining every focus value corresponding to every frame of image when the lens of the main camera is scanning; and the pre-scanning is stopped and an accurate scanning is performed at the time when the focus value corresponding to the current frame of image is smaller than that of a previous frame. In the pre-scanning process, a movement of the main camera is relatively large at each time of approaching. After the pre-scanning is finished, the mobile terminal drives the lens of the main camera to perform the accurate scanning. In the accurate scanning process, the main camera is moved and retreated, and the movement of the main camera is relatively smaller than that in the pre-scanning process. When a focus value of an intermediate frame of three consecutive frames of images is greater than the focus value of each of a previous and a consecutive frames of the intermediate frame, the accurate scanning is stopped. A fitted parabola is forming according to the focus values corresponding to the three consecutive frames of images. The main camera is determined as in focus at the time when the lens arrives at a position corresponding to the vertex of the fitted parabola. When the mobile terminal determines that the main camera has been in focus and the current frame of image is in focus, the lens position corresponding to the current frame of image is recorded as the in-focus lens position when the main camera has been in focus.

[0074] In one embodiment, before the in-focus distance corresponding to the in-focus lens position of the first camera is obtained, the focusing method further includes the following operations: driving the first camera to focus; obtaining every position corresponding to every frame of image; determining the lens position corresponding to a frame of image that is in focus as the in-focus lens position of the first camera.

[0075] Before the mobile terminal obtains the in-focus distance corresponding to the in-focus lens position of the main camera, the main camera is driven to focus by the mobile terminal, and the terminal is configured to records a current position corresponding to the current frame of image. At the time when the current frame of image is determined as in focus, an in-focus lens position, corresponding to an in-focus frame of image, is obtained; and the mobile terminal may search for the in-focus distance corresponding to the in-focus lens position.

[0076] In one embodiment, correspondences of device identification number of every camera, the lens positions of every camera, and the in-focus distance are pre-stored in the mobile terminal. The operation, of obtaining an in-focus distance corresponding to the in-focus lens position of a first camera that is in focus, may include the following operations: obtaining the device identification number of the first camera; searching for the in-focus distance corresponding to the in-focus lens position of the first camera that is in focus, according to the device identification number of the first camera. The operation, of obtaining an in-focus lens position of the second camera, which is corresponding to the in-focus distance, may include the following operations: obtaining the device identification number of the second camera; and searching for, according to the device identification number of the second camera, the in-focus lens position of the second camera, which is corresponding to the in-focus distance.

[0077] Correspondences of device identification numbers of every camera, the lens positions of every camera, and the in-focus distance are pre-stored in the mobile terminal.

[0078] Different cameras with different device identification numbers may have different in-focus distances that is corresponding to the in-focus lens positions of the cameras. When the main camera has been in focus, the mobile terminal may obtain the in-focus lens position of lens of the main camera, and configured to search for, according to the device identification numbers and the lens position of the main camera, the in-focus distance corresponding to the in-focus lens position of the main camera. After obtaining the in-focus distance, the mobile terminal may search for the lens position of the secondary camera, which is corresponding to the in-focus distance. The device identification number of the camera is a string for uniquely identifying the corresponding camera, such as a camera ID.

[0079] In one embodiment, the focusing method further include an operation of capturing images via the first camera and the second camera simultaneously when the second camera has been in focus.

[0080] When the second camera has been in focus, the mobile terminal is configured to capture images with the first camera and the second camera simultaneously. In the focusing method according to the embodiments of the present disclosure, both of the first camera and the second camera are simultaneously used for capturing images when the dual-camera module is in focus, which ensures a better consistency of the images and improves a quality of a processed image that is processed according to the images captured by the first camera and the second camera.

[0081] One of ordinary skill in the art can understand that all or part of the process of implementing the above embodiments can be completed by a computer program to instruct related hardware, and the program can be stored in a non-volatile computer readable storage medium. The program, when executed, may include the flow of any embodiment of the methods as described above. The storage medium may be a magnetic disk, an optical disk, a read-only memory (ROM), or the like.

[0082] The principles and embodiments of the present disclosure are described in the above examples. The description is only used for helping to understand the technical solution of the present disclosure and its core idea. Those of ordinary skill in the art should understand that it can still modify the technical solutions described in foregoing embodiments, or replace some of the technical features. The modifications or substitutions do not depart from the scope of the technical solutions of the embodiments of the present disclosure.


Claims

1. A focusing method comprising:

obtaining an in-focus distance corresponding to an in-focus lens position of a first camera that is in focus;

obtaining an in-focus lens position of a second camera corresponding to the in-focus distance; and

driving the lens of the second camera to move to the in-focus lens position of the second camera and to focus.


 
2. The focusing method according to claim 1, wherein before the operation of obtaining an in-focus distance corresponding to an in-focus lens position of a first camera that is in focus, the focusing method further comprised:

driving the first camera to focus;

obtaining a current position of a first camera at the time when a current frame of image is in focus; and

determining an in-focus lens position of the first camera as the current position that is in focus.


 
3. The focusing method according to claim 1, wherein before the operation of obtaining an in-focus distance corresponding to an in-focus lens position of a first camera that is in focus, the focusing method further comprises:

driving the first camera to focus;

obtaining current position of the first camera, the lens position corresponding to every frame of image; and

determining the lens position corresponding to a frame of image that is in focus as the in-focus lens position of the first camera.


 
4. The focusing method according to claim 1, wherein, correspondences of device identification number of every camera, the lens position of every camera, and the in-focus distance of every camera are pre-stored in a mobile terminal;
the operation of obtaining an in-focus distance corresponding to an in-focus lens position of a first camera that is in focus, comprises:

obtaining the device identification number of the first camera; and

searching for an in-focus distance corresponding to the in-focus lens position of the first camera, according to the device identification number of the first camera;

the operation of obtaining an in-focus lens position of the second camera, which is corresponding to the in-focus distance, comprises:

obtaining the device identification number of the second camera; and

searching for, according to the device identification number of the second camera, the in-focus lens position of the second camera, which is corresponding to the in-focus distance.


 
5. The focusing method according to claim 1, further comprising:
capturing images via the first camera and the second camera simultaneously when the second camera has been in focus.
 
6. A focusing apparatus comprising:

an obtaining module, configured to obtain an in-focus distance corresponding to an in-focus lens position of a first camera that is in focus, and obtain an in-focus lens position of a second camera corresponding to the in-focus distance; and

a driving module, configured to drive the lens of the second camera to move to the in-focus lens position of the second camera and to focus.


 
7. A mobile terminal comprising a memory and a processor, wherein the memory stores a computer program, and the processor is configured to execute the computer program to perform the following operations comprising:

obtaining an in-focus distance corresponding to an in-focus lens position of a first camera that is in focus;

obtaining an in-focus lens position of a second camera corresponding to the in-focus distance; and

driving the lens of the second camera to move to the in-focus lens position of the second camera and to focus.


 
8. The mobile terminal according to claim 7, wherein before obtaining an in-focus distance corresponding to an in-focus lens position of a first camera that is in focus, the processor is further configured to execute the computer program to perform the following operations comprising:

driving the first camera to focus;

obtaining a current position of the first camera at the time when a current frame of image is in focus; and

determining an in-focus lens position of the first camera as the current position that is in focus.


 
9. The mobile terminal according to claim 7, wherein before obtaining an in-focus distance corresponding to an in-focus lens position of a first camera that is in focus, the processor is further configured to execute the computer program to perform the following operations comprising:

driving the first camera to focus;

obtaining current position of the first camera, the lens position corresponding to every frame of image; and

determining the lens position corresponding to a frame of image that is in focus as the in-focus lens position of the first camera.


 
10. The mobile terminal of claim 7, wherein, correspondences of device identification number of every camera, the lens position of every camera, and the in-focus distance of every camera are pre-stored in a mobile terminal;
when obtaining an in-focus distance corresponding to an in-focus lens position of a first camera that is in focus, the processor is configured to execute the computer program to perform the following operations comprising:

obtaining the device identification number of the first camera; and

searching for an in-focus distance corresponding to the in-focus lens position of the first camera, according to the device identification number of the first camera;

when obtaining an in-focus distance corresponding to an in-focus lens position of a second camera that is in focus, the processor is configured to execute the computer program to perform the following operations comprising:

obtaining the device identification number of the second camera; and

searching for, according to the device identification number of the second camera, the in-focus lens position of the second camera, which is corresponding to the in-focus distance.


 
11. The mobile terminal according to claim 7, wherein the processor is further configured to execute the computer program to capture images via the first camera and the second camera simultaneously when the second camera has been in focus.
 
12. A computer readable storage medium having a computer program, the computer program being executed by a processor to perform the following operations comprising:

obtaining an in-focus distance corresponding to an in-focus lens position of a first camera that is in focus;

obtaining an in-focus lens position of a second camera corresponding to the in-focus distance; and

moving the lens of the second camera to the in-focus lens position of the second camera and focuses when driving the second camera to focus.


 
13. The computer readable storage medium according to claim 12, wherein before obtaining an in-focus distance corresponding to an in-focus lens position of a first camera that is in focus, the computer program is executed to perform the following operations comprising:

driving the first camera to focus;

obtaining a current position of the first camera at the time when a current frame of image is in focus; and

determining an in-focus lens position of the first camera as the current position that is in focus.


 
14. The computer readable storage medium according to claim 12, wherein before obtaining an in-focus distance corresponding to an in-focus lens position of a first camera that is in focus, the computer program is executed to perform the following operations comprising:

driving a first camera to focus;

obtaining current position of the camera, the lens position corresponding to each frame of image; and

determining the lens position corresponding to a frame of image that is in focus as the in-focus lens position of the first camera.


 
15. The computer readable storage medium of claim 12,
wherein, correspondences of device identification number of every camera, the in-focus lens position of every camera, and the in-focus distance are pre-stored in a mobile terminal;
when obtaining an in-focus distance corresponding to an in-focus lens position of a first camera that is in focus, the processor is configured to execute the computer program to perform the following operations comprising:

obtaining the device identification number of the first camera; and

searching for an in-focus distance corresponding to the in-focus lens position of the first camera, according to the device identification number of the first camera;

when obtaining an in-focus distance corresponding to an in-focus lens position of a second camera that is in focus, the processor is configured to execute the computer program to perform the following operations comprising:

obtaining the device identification number of the second camera; and

searching for, according to the device identification number of the second camera, the in-focus lens position of the second camera, which is corresponding to the in-focus distance.


 
16. The computer readable storage medium of claim 12, wherein the processor is further configured to execute the computer program to capture images via the first camera and the second camera simultaneously when the second camera has been in focus.
 




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Cited references

REFERENCES CITED IN THE DESCRIPTION



This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

Patent documents cited in the description