(19)
(11)EP 2 015 566 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
03.10.2018 Bulletin 2018/40

(21)Application number: 08012428.2

(22)Date of filing:  09.07.2008
(51)International Patent Classification (IPC): 
H04N 5/232(2006.01)

(54)

Method and apparatus for compensating handtrembling of camera

Verfahren und Vorrichtung zur Kompensation des Handwackelns bei einer Kamera

Procédé et appareil de compensation des tremblements de la main avec une caméra


(84)Designated Contracting States:
DE FR GB

(30)Priority: 09.07.2007 KR 20070068615

(43)Date of publication of application:
14.01.2009 Bulletin 2009/03

(73)Proprietor: Samsung Electronics Co., Ltd.
Suwon-si, Gyeonggi-do, 443-742 (KR)

(72)Inventors:
  • Yoon, Young-Kwon
    Suwon-si Gyeonggi-do 443-742 (KR)
  • Lee, Yong-Gu
    Suwon-si Gyeonggi-do 443-742 (KR)
  • Kang, Byung-Kwon
    Suwon-si Gyeonggi-do 443-742 (KR)

(74)Representative: Grünecker Patent- und Rechtsanwälte PartG mbB 
Leopoldstraße 4
80802 München
80802 München (DE)


(56)References cited: : 
WO-A1-92/11727
JP-A- 2003 101 862
US-A1- 2004 239 771
US-A1- 2006 158 532
JP-A- 2002 112 100
JP-A- 2004 279 514
US-A1- 2006 132 623
US-A1- 2007 122 130
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    BACKGROUND OF THE INVENTION


    1. Field of the Invention



    [0001] The present invention relates to a digital camera based on an image sensor, such as a CCD (Charge Coupled Device) or a CIS (CMOS Image Sensor). More particularly, the present invention relates to a method and apparatus for minimizing deterioration of a photographed image caused by user's hand-trembling when photographing using such a digital camera.

    2. Description of the Related Art



    [0002] When a user photographs an image using a digital camera, a hand-trembling phenomenon may occur in the photographed image by user's hand-trembling or unintended movement. There has been research previously conducted on various methods for compensating such a trembling phenomenon. Technologies for compensating such a hand-trembling phenomenon generally employed in the prior art are classified into three technologies, i.e., DIS (Digital Image Stabilization), EIS (Electronic Image Stabilization), and OIS (Optical Image Stabilization). The features of these conventional methods are summarized in Table 1.
    Table 1
    TechDetection of Hand-TremblingImage CompensatingAdvantageDisadvantageRelated KR Unexamined Patent Publication Nos.
    DIS Comparing two Image processing - Small size - Large amount of calculation 1996-0036545
    continued images - Low cost -Long photographing time
            - Deterioration of image quality  
    EIS Employing movement detection means, such as gyro-sensor Image processing -Medium or small size -Short photographing time as compared to DIS -Deterioration of image quality 1996-0020371
    2004-0082645
    OIS Employing movement detection means, such as gyro-sensor Optical System Compensating - High image quality - Large size Lens movement technology: 2006-0071224 Sensor movement technology: 2006-004003
    - Applicable to still image - High cost
    - Small amount of calculation  


    [0003] As indicated in Table 1, the OIS technology is advantageous in that it is also applicable to still image compensation and is expected to provide a high image quality after compensation. With the OIS technology, however, it is essential to add movement detection means, such as gyro-sensor for detecting the amount of hand-trembling, and an optical correction means for compensating the hand trembling detected by the movement detection means. Therefore, high costs and increased size are inevitable with the OIS technology. Examples of such a technology include Korean Un-examined Patent Publication No. 2006-0071224 entitled "Image Stabilizer for Camera" of Hong-Seok Lee et al., which was filed in the name of Samsung Electronic Co., Ltd. on December 21, 2004, and Korean Un-examined Patent Publication No. 2006-004003 entitled "Apparatus for Compensating Hand-Trembling in Camera Lens Assembly" of Jun-Mo Koo, which was filed in the name of Samsung Electronic Co., Ltd. on November 4, 2004.

    [0004] Compared to the OIS technology, the DIS technology can assure low H/W cost and small size since detection and compensation of hand-trembling are both achieved by image processing. However, the DIS technology has a problem in that the time the camera requires for photographing the image is relatively long due to the increased amount of calculation, which results from the employment of an image processing S/W for detecting the amount of hand-trembling and for compensating an image. Thus, there is difficulty in capturing an image that quickly changes, as well as having person posing for the additional time required.

    [0005] Currently available hand-trembling compensating technologies employing an image processing S/W include pixel data movement, a synthesis of multiple short-time exposure images, synthesis of a long-time exposure image with a short time exposure image, application of an image-trembling compensating filter, etc.

    [0006] However, due to shortcomings of software technologies developed up to now, deterioration of image quality is inevitable. An example of such a technology is disclosed in Korean Un-examined Patent Publication No. 1996-0036545 entitled "Apparatus for Compensating Hand-Trembling of Camcorder" of Young-Cheol Park, which was filed in the name of Samsung Electronic Co., Ltd. on March 30, 1995.

    [0007] The EIS technology combines the above-mentioned DIS technology and OIS technology in such a manner that the detection of an amount of hand-trembling is performed using a movement detection means, such as a gyro-sensor, and the compensation of an image is performed using an image processing S/W. As a result, with the EIS technology, it is possible to expect that a result of a middle level between the DIS technology and the OIS technology can be obtained in terms of the length of time and costs for image-capturing, the size of H/W, etc.

    [0008] However, EIS technology has a disadvantage in that a substantially degraded image is obtained as compared to the OIS because it employs an image processing S/W like the DIS technology. Examples of such a technology includes Korean Un-examined Patent Publication No. 1996-0020371 entitled "Method and Apparatus for Compensating Hand-Trembling of Camcorder" of Nam-Soo Lee, which was filed in the name of LG EI on November 21, 1994, and Korean Un-examined Patent Publication No. 2004-0082645 entitled "An Image Acquisition System Capable of Obtaining Stabilized Image and Method of Stabilizing Image" of Yong-Cheol Cho, which was filed in the name of Samsung Electronic Co., Ltd. on March 19, 2003.

    [0009] Beyond the above-mentioned hand-trembling compensating technologies, also known is an increasing sensitivity of an image sensor (e.g., change ISO 100 into ISO 400 with regard to the sensitivity of an image sensor) so as to reduce exposure time, thereby avoiding hand-trembling problems, and a remote exposure button technology employing a remote controller for exposing a shutter so as to reduce the hand-trembling effect. However, the increasing sensitivity of an image sensor has a problem in that image quality is deteriorated due to noise, and the remote exposure button technology has a problem in that user's convenience is made worse, and it is impossible to avoid hand-trembling caused by an action beyond shutter pressing.

    [0010] In addition, the best picture function, which provides a number of pictured images so as to allow a user to choose one or more desired pictures, may be considered as conducting a role of reducing hand-trembling problems. However, with this technology, a user's inconvenience is caused because the user must select the image from one or more photographs. Furthermore, it is difficult for the user to determine a hand-trembling level and to choose images pictured without hand-trembling from high-pixel images displayed through a small LCD window.

    [0011] Consequently, there is a need in the art to provide a technology of minimizing deterioration of image quality caused by hand-trembling without deteriorating a user's convenience.

    SUMMARY OF THE INVENTION



    [0012] Accordingly, the present invention provides a method and apparatus for minimizing deterioration of photographed images caused by hand-trembling in a digital camera utilizing an image sensor, such as a CCD (Charge Coupled Device)

    [0013] According to an exemplary aspect of the present invention, there is provided a method according to claim 1. The proper exposure time for preventing hand-trembling may be, for example in the range of about 1/10 sec to 1/30 sec. If the calculated exposure time is not the proper exposure time, the exposure time is calculated again after the ISO is increased. If the image-capturing is performed multiple times, a number of times of image-capturing is set in such a manner that the total photographing time does not exceed, for example, about 1 sec. In the step of detecting the amount of hand-trembling for each captured image, the amount of blur may be additionally detected for each captured image.

    [0014] According to another exemplary aspect of the present invention, there is provided an apparatus for compensating hand-trembling of a camera according to claim 7. The hand-trembling detector may comprise of a gyro-sensor. In addition, the hand-trembling detector may be implemented in a digital type employing an image process. The number of times of image-capturing may be set in such a manner that the total photographing time does not exceed 1 sec. The image-capturing controller stores, for example, 2 to 8 images with a relatively lower amount of hand-trembling in the image storage unit as resultant images.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0015] The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

    FIG. 1 is a block diagram showing a construction of an apparatus for compensating hand-trembling of a camera according to an example not forming part of the invention as claimed;

    FIG. 2 is a flowchart of a method for compensating hand-trembling of a camera according to another example not forming part of the invention as claimed;

    FIG. 3 is a block diagram showing a construction for compensating hand-trembling of a camera according to an exemplary embodiment of the present invention; and

    FIG. 4 is a flowchart of a method of compensating hand-trembling of a camera according to another exemplary embodiment of the present invention.


    DETAILED DESCRIPTION



    [0016] Hereinafter, the exemplary embodiments of the present invention and examples not forming part of the invention as claimed will be described with reference to the accompanying drawings. It should be noted that in the following description, the same elements will be designated by the same reference numerals even though they are shown in different drawings. In addition, in the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may obscure appreciation of the subject matter of the present invention by a person of ordinary skill in the art.

    [0017] The present invention provides a method and apparatus for reducing hand-trembling of a digital camera at the time of photographing. The present invention also provides a method using a proper exposure time for reducing hand-trembling in a digital camera at the time of photographing, rendering multiple image-capturing operations to be continuously performed in the camera through a single inputting operation through a photographing button, inspecting the amount of hand-trembling at the time of each image-capturing operation, and providing a captured image with the lowest amount of hand-trembling as a resultant image, whereby an image with reduced hand-trembling can be obtained.

    [0018] An example not forming part of the invention as claimed is described in detail with reference to FIG. 1.

    [0019] FIG. 1 is a block diagram showing an exemplary construction of an apparatus for compensating hand-trembling of a camera according to the example. Referring to FIG. 1, the apparatus for compensating hand-trembling of a camera according to the present example includes: a camera optical system 110 for copying image information of an object to an image sensor 120, the image sensor 120 for converting the copied image information into an electronic signal; an image signal processor 130 for restoring the converted electronic signal to the image information; an image storage unit 160 for storing temporary information data during the restoration of the converted electronic signal to the image information, and the final image data; a hand-trembling detector 140 for detecting the hand-trembling level of a camera system; and an image-capturing controller 150 for controlling the operation of each of the above-mentioned components at the time of image-capturing of the camera.

    [0020] The hand-trembling detector 140 may be implemented in an electronic type employing, for example, a gyro-sensor, or in a digital type employing, for example, an image process. FIG. 2 is a flowchart of an exemplary method for compensating hand-trembling of a camera according to another example not forming part of the invention as claimed. As shown in FIG. 2, the method according to the present example includes a digital camera starting at step 205, and initiating a preview operation at a photographing stand-by mode at step 210. At step 215, exposure time is calculated using an Automatic Exposure (AE) algorithm.

    [0021] The AE algorithm used is known in the art such that an exposure value (EV) specifies the relationship between the f-number, F, and exposure duration, T:

    The exposure value [1] becomes smaller as the exposure duration increases, and it becomes larger as the f-number grows.

    [0022] At step 220, it is determined whether the exposure time calculated by the AE algorithm at step 215 is the proper exposure time for preventing hand-trembling effects on image quality or not.

    [0023] The proper exposure time for preventing hand-trembling effects on image quality means a length of time not exceeding the critical exposure time calculated through a preliminary test in the present invention. The critical exposure time is a condition which renders probability of obtaining images free of hand-trembling statistically not less than several tens percent (%) when image-capturing is performed with the critical exposure time. The preferred critical exposure time in this example is varied within the range of about 1/10 to 1/30 sec depending on camera H/W, such as an image sensor, a camera optical system, and a camera circuit. Beyond this, the critical exposure time may also be varied depending on a target hand-trembling reducing specification, and the number of times of repeating image-capturing for reducing hand-trembling.

    [0024] If it is determined that the exposure time is the proper exposure time for preventing hand-trembling effects at step 220, the process proceeds to step 230. However, if it is determined that the exposure time is not the proper exposure time for preventing hand-trembling effects at step 220, the process proceeds to step 225, at which step the ISO is increased by one step, and returns to step 215, at which step the exposure time is calculated again with the AE algorithm.

    [0025] Typically, under a photographing condition with high illumination, the exposure time calculated by the AE algorithm is sufficiently short, so that it will be the proper exposure time for preventing hand-trembling. However, under a photographing condition with low illumination, the calculated exposure time is extended, so that it may be determined as the improper exposure time. In such a case, an operation for increasing the ISO of the camera is performed so that the exposure time calculated by the AE algorithm can be reduced, and the above-mentioned procedure is repeated from the AE calculation until the exposure time arrives at the value proper for reducing hand-trembling effects.

    [0026] If the above-mentioned procedure is terminated, a condition enabling image-capturing is obtained, and the image-capturing is prepared at step 230. Next, if there is detection of a shutter activation at step 235 typically via an image capturing button, an image-capturing sensor executes exposure and composes an image at step 240. At step 250, the hand-trembling detector 140 detects the amount of hand-trembling occurring during image-capturing.

    [0027] Next, it is determined whether a captured image is an initial image or not at step 250. If it is determined that the captured image is the initial image, the process proceeds to step 255, at which step the initially captured image and the amount of the corresponding image detected at step 245 are stored in the image storage unit 160, and the process proceeds to step 245.

    [0028] If it is determined that the captured image is not the initial image at step 250, the process proceeds to step 260, at which step the amount of hand-trembling of the image stored in the image storage unit 160 and the amount of hand trembling effects of a currently captured image are compared with each other. If the amount of hand trembling effects of the currently captured image is lower than the amount of hand-trembling effects of the image stored in the image storage unit 160, the process proceeds to step 265, at which step the newly captured image and the amount of hand-trembling thereof are stored in the image storage unit 160, thereby updating the image storage unit 160.

    [0029] At step 260, if it is determined that the amount of hand-trembling effects of the currently captured image is higher than the amount of hand-trembling effects of the image previously stored in the image storage unit, the process proceeds to step 270, at which step it is determined whether the number of times of image-capturing is equal to the preset number of times of required image-capturing or not. If the number of times of current image-capturing is lower than the number of times of required image-capturing, the process returns to step 245 again, and the above-mentioned procedure is repeated. The number of times of required image-capturing is set to the number of times that is sufficient for statistically ensuring the possibility for user to obtain an image with reduced hand-trembling in consideration of probability capable of obtaining an image free of hand-trembling when the user photographs using the critical exposure time determined at a preliminary test, and that does not make the user feel inconvenience due to excessively long total photographing time.

    [0030] For example, with a camera operating at 15 fps, if the number of times of required image-capturing is set to 10, the total photographing time may be equal to or less than 1 sec. Therefore, the set number of times of required image-capturing may be considered desirable.

    [0031] If it is determined that the number of times of current image-capturing is equal to the number of the preset number of times of required image-capturing at step 270, the process proceeds to step 275, at which step it is determined whether the final image stored in the image storage unit 160 is stored or not, and the image-capturing operation is terminated. The image stored in the image storage unit 160 after the preset number of times of required image-capturing has been completed will be the final image captured with the minimum hand-trembling among the images repeatedly captured over the number of times of required image-capturing.

    [0032] The method of compensating hand-trembling according to the present example can produce a final image with reduced hand-trembling effects according to the above-mentioned operating flow because the exposure time and the number of times of repeating are set to a condition that statistically enables an image to be obtained with reduced hand-trembling.

    [0033] It is possible to add an image compensating process employing an image synthesizing technology to the method of compensating hand-trembling described above.

    [0034] Now, an exemplary embodiment of the present invention employing an image synthesizing technology will be described with reference to FIG. 3.

    [0035] FIG. 3 is a block diagram showing a construction of a hand-trembling compensating apparatus for a camera according to an exemplary embodiment of the present invention. Referring to FIG. 3, the hand-trembling compensating apparatus of the present exemplary embodiment includes: a camera optical system 310 for copying image information of an object to an image sensor 320, the image sensor 320 converting the copied image information into an electronic signal; an image signal processor 330 for restoring the converted electronic signal to the image information; an image storage unit 360 for storing temporary information during the restoration of the image information and the final image data; a hand-trembling detector 340 for detecting the level of hand-trembling of a camera system; an image correction unit 370 for synthesizing the image data stored in the image storage unit 360 after the image-capturing operation so as to produce a final resultant image; and an image-capturing controller 150 for controlling the operation of each of the above-mentioned components at the time of image-capturing of the camera.

    [0036] The hand-trembling detector 140 may be implemented either in an electronic type employing a gyro-sensor, or in a digital type employing an image process.

    [0037] In the prior art, it was impossible for a hand-trembling image processing S/W based on image synthesis to avoid deterioration of an image after synthesis because blur in the original image caused by hand-trembling effects prior to the synthesis is partially included in the synthesized image. However, according to the present embodiment, images with reduced hand-trembling effects are extracted by a predetermined required number (typically two to eight images) and then the extracted images are synthesized with each other, whereby it is possible to obtain an image which is substantially improved as compared to an image, the hand-trembling of which is corrected by the existing image processing S/W.

    [0038] In another exemplary embodiment of the present invention, a final image is obtained by acquiring a predetermined number of images, the hand-trembling effects of which has been reduced according to the characteristics of the present invention, and then by synthesizing the acquired images with each other. The present invention is advantageous in that deterioration of image quality, which may be caused at the time of high ISO operation, can be suppressed.

    [0039] A method of compensating for hand-trembling according to the present exemplary embodiment will be described with reference to FIG. 4.

    [0040] FIG. 4 is a flowchart of a method of compensating hand-trembling of a camera according to an embodiment of the present invention. As shown in FIG. 4, the present exemplary embodiment includes a digital camera starting at step 405, and initiates a preview operation at a photographing stand-by mode at step 410.

    [0041] At step 415, exposure time is calculated using an AE algorithm. At step 420, it is determined whether the exposure time calculated by the AE algorithm at step 415 is the exposure time proper for preventing hand-trembling or not. The exposure time proper for preventing hand-trembling effects means a length of time not exceeding a critical exposure time determined through a preliminary test in the present invention. The preferred critical exposure time is a condition for rendering the provability of obtaining images free of hand-trembling effects to be statistically not less than several tens of percentage (%) when image-capturing is performed with the critical exposure time, and is varied in the range of about 1/10 sec to 1/30 sec depending on camera H/W, such as an image sensor, a camera optical system, a camera circuitry, etc. In addition, the critical exposure time can be varied according to a target specification for reducing hand-trembling effects, and the number of times of repeating image-capturing for reducing hand-trembling effects.

    [0042] If it is determined that the proper exposure time for preventing hand-trembling effects at step 420, the process proceeds to step 430. However, if it is determined that the proper exposure time for preventing hand-trembling effects has not been reached at step 420, the process proceeds to step 425, at which step the ISO is increased by one step, and returns to step 415, at which step the exposure time is calculated again by the AE algorithm.

    [0043] Under a photographing condition with high illumination, the exposure time calculated by the AE algorithm is typically short enough to be the exposure time proper for reducing hand-trembling. However, under a photographing condition with low illumination, the calculated exposure time is extended, and may be deemed as an improper exposure time. In that event, an operation for increasing the ISO of the camera so that the exposure time is calculated by the AE algorithm, and the above-mentioned procedure is repeated from the AE calculation until the exposure time becomes a value proper for reducing hand-trembling effects on image quality.

    [0044] If the above-mentioned procedure is completed, a condition allowing image-capturing is obtained, so that image-capturing is prepared at step 430. Then, upon detecting activation of the shutter via the image-capturing button at step 435, an image-capturing sensor executes exposure and composes an image. At step 445, a hand-trembling detector detects the amount of hand-trembling occurring during image-capturing.

    [0045] Then, in order to store initially captured images in the image storage unit 360 by a predetermined required number (n), it is determined whether a currently captured image is included in the predetermined required number (n) of the initially captured images or not. If it is determined that the currently captured image is included in n initially captured images, the process proceeds to step 455, at which step the currently captured image and the amount of hand-trembling of the currently captured image detected at step 445 are stored in the image storage unit 360, and then the process returns to step 445.

    [0046] However, if it is determined that the currently captured image is not included in the predetermined required number (n) of images at step 450, the process proceeds to step 460, at which step the image with the highest amount of hand-trembling among the number of required images stored in the image storage unit 360 (shown in FIG. 3)is compared with the currently captured image in terms of the amount of hand-trembling.

    [0047] If the amount of hand-trembling effects of the currently captured image is lower than the amount of hand-trembling effects of the image with the highest amount of hand-trembling, the process proceeds to step 465, at which step the image with the highest amount of hand-trembling among the images stored in the image storage unit 360 is deleted, and then the newly captured current image and the amount of hand-trembling thereof are stored in the image storage unit 360, thereby updating the information.

    [0048] If it is determined that the amount of hand-trembling effects of the currently captured image is higher than the amount of hand-trembling of the image with the highest amount of hand-trembling among the images previously stored in the image storage unit 360 at step 460, the process proceeds to step 470, at which step it is determined whether the number of times of current image-capturing is equal to the predetermined number of times of required image-capturing. If the number of times of current image-capturing is less than the number of times of required image-capturing, the process returns to step 445, and the above-mentioned procedure is repeatedly performed. The number of times of required image-capturing is set to the number of times that is sufficient for statistically ensuring the possibility for user to obtain an image with reduced hand-trembling effects in consideration of probability capable of obtaining an image free of hand-trembling effects when the user photographs using a critical exposure time determined at a preliminary test according to the present invention, and that does not make the user feel inconvenience due to an excessively long total photographing time.

    [0049] For example, with a camera operating at 15 fps, if the number of times of required image-capturing is set to 10, the total photographing time may be equal to or less than 1 sec. Therefore, the preset number of times of required image-capturing may be considered as being desirable.

    [0050] If it is determined that the number of times of current image-capturing is equal to the preset number of times of required image-capturing at step 470, the process proceeds to step 475, at which step the images stored in the image storage unit are synthesized with each other, thereby composing the final image.

    [0051] Next, the process proceeds to step 480, at which step it is determined whether the final image stored in the image storage unit 360 is stored or not, and the image-capturing operation is terminated.

    [0052] After the preset number of times of required image-capturing is completed, the images stored in the image storage unit 360 are n images stored sequentially from an image with a relatively lower amount of hand-trembling among the repeatedly captured images during the number of times of required image-capturing. At step 475, the n images are synthesized with each other, and the final image is produced. The method of compensating hand-trembling according to the present embodiment can produce the final image with reduced hand-trembling according to the above-mentioned operating flow because the exposure time and the number of times of repeating are set to a condition that statistically enables an image to be obtained with reduced hand-trembling.

    [0053] In the above-mentioned exemplary embodiments, whether to store a captured image is determined on the basis of the amount of hand-trembling measured while the corresponding image is being captured. However, it is possible to determine whether to store a captured image on the basis of one or more characteristics of the image itself, such as the amount of blur in the image or the like.

    [0054] In other words, it is possible to use the amount of blur as the basis for determining whether to store a captured image through the quantification of blur in the image. The quantification of blur may be made by comparing the signal magnitudes of components of frequencies similar to a pixel space frequency. For example, if two images are obtained by photographing the same object, the image with a higher high frequency signal magnitude can be determined as having a lower amount of blur. If desired, it is also possible to determine whether to store an image in consideration of both of the amount of blur and the amount of hand-trembling effects.

    [0055] According to the present invention, it is possible to obtain an image free of hand-trembling effects with minimized degradation of image quality without deteriorating the user's convenience by changing an image-capturing algorithm in a digital camera based on an image sensor, such as a CCD (Charge Coupled Device) or a CIS (CMOS Image Sensor).

    [0056] While the invention has been shown and described with reference to certain preferred exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention as defined by the appended claims.

    [0057] For example the term "proper exposure" which is used in the art, may be varied outside a preferred range and still within the scope of the presently claimed invention. In addition, while the images can be stored in a predetermined order, typically starting with the image having the lowest amount of hand-trembling effects, the predetermined order could be in any logical order (reverse order, for example) or the images could be labeled in memory with an identifier that, for example, starts with the image having the least amount of hand-trembling effects and sequentially increases the identification number with increased hand-trembling effects.


    Claims

    1. A method of compensating for hand-trembling effect of a camera comprising the steps of:

    calculating (415) a proper exposure time for preventing hand-trembling using an Automatic Exposure algorithm during an image-capturing standby mode;

    executing (440) image-capturing for a plurality of instances, corresponding to a preset number of times, within the calculated exposure time in response to detecting actuation of a photographing button, and

    detecting (445) an amount of hand-trembling effect at each instance of image-capturing;

    storing (455) initially captured images by predetermined required numbers and amount of hand-trembling effect detected corresponding to the initially captured images;

    comparing (460) the amount of hand-trembling of a currently captured image with the amount of hand-trembling of an image with the highest amount of hand-trembling effect among the initially captured images, if it is determined(450) that the number of times of current image-capturing is not included in the predetermined required numbers;

    storing (465) the currently captured image and the amount of hand-trembling effect of the currently captured image after deleting the image with the highest amount of hand-trembling effect among the initially captured images, if it is determined (460) that the amount of hand-trembling effect of the currently captured image is lower than the amount of hand-trembling effect of the image with the highest amount of hand-trembling effect among the initially captured images;

    determining (470) whether the number of times of current image-capturing is equal to the preset number of times of image-capturing;

    synthesizing (475) the stored images with each other, thereby producing a final resultant image, if it is determined (470) that the number of times of current image-capturing is equal to the preset number of times of image-capturing.


     
    2. The method of claim 1, wherein the predetermined required numbers are set between 2 to 8.
     
    3. The method of claim 1, wherein the proper exposure time for preventing hand-trembling effect is substantially in the range of 1/10 sec to 1/30 sec.
     
    4. The method of claim 1, wherein, if the calculated exposure time is not the proper exposure time, the exposure time is recalculated after an increasing sensitivity of an image sensor.
     
    5. The method of claim 1, wherein a total number of the image-capturing is set so a total photographing time does not exceed about 1 sec.
     
    6. The method of claim 1, wherein, in the step of detecting the amount of hand-trembling effect for the initially captured images, an amount of blur is additionally detected for the initially captured images.
     
    7. An apparatus for compensating for hand-trembling of a camera comprising:

    a camera optical system (310) for copying image information of an object;

    an image sensor (320) for converting the image information copied by the camera optical system into an electronic signal;

    a signal processor (330) for restoring the electronic signal into the image information;

    an image storage unit (360) for storing temporary information during the restoration into the image information, and final image data;

    a hand-trembling detector (340) for detecting a hand-trembling level in the camera system at the time of image-capturing;

    an image-capturing controller (350) for controlling the operation of each of the above-mentioned components at the time of compensating for hand-trembling in the camera, wherein the image-capturing controller is adapted to control execution of the following steps:

    detect (445) an amount of hand-trembling effect at each instance of image-capturing,

    store (455) initially captured images by predetermined required numbers and amount of hand-trembling effect detected corresponding to of the initially captured images,

    compare (460) the amount of hand-trembling effect of a currently captured image with the amount of hand-trembling effect of an image with the highest amount of hand-trembling effect among the initially captured images, if it is determined(450) that the number of times of current image-capturing is not included in the predetermined required numbers,

    store (465) the currently captured image and the amount of hand-trembling effect of the currently captured image after deleting the image with the highest amount of hand-trembling effect among the initially captured images, if it is determined (460) that the amount of hand-trembling effect of the currently captured image is lower than the amount of hand-trembling effect of the image with the highest amount of hand-trembling effect among the initially captured images,

    determining(470) whether the number of times of current image-capturing is equal to a preset number of times of image-capturing, and

    synthesize (475) the stored images with each other, thereby producing the final resultant image, if it is determined (470) that the number of times of current image-capturing is equal to the preset number of times of image-capturing.


     
    8. The apparatus of claim 7, wherein the stored images are identified sequentially starting from an image with the lowest amount of hand-trembling level upon storage into the storage unit.
     
    9. The apparatus of claim 7, wherein the predetermined required numbers are set between 2 to 8.
     


    Ansprüche

    1. Verfahren zur Kompensation einer Wirkung des Handwackelns einer Kamera, mit den Schritten:

    Berechnen (415) einer geeigneten Belichtungszeit zur Verhinderung des Handwackelns unter Anwendung eines automatischen Belichtungsalgorithmus während eines Bildaufnahmebereitschaftsmodus;

    Ausführen (440) einer Bildaufnahme für mehrere Fälle entsprechend einer vorgegebenen Häufigkeit mit der berechneten Belichtungszeit in Reaktion auf das Erfassen einer Betätigung eines fotografieauslösenden Knopfes, und

    Erfassen (445) eines Betrags der Wirkung des Handwackelns bei jedem Fall einer Bildaufnahme;

    Speichern (455) anfänglich aufgenommener Bilder entsprechend einer vorbestimmten erforderlichen Häufigkeit und des Betrags der Wirkung des Handwackelns, der entsprechend den anfänglich aufgenommenen Bildern erfasst wird;

    Vergleichen (460) des Betrags an Handwackeln eines aktuell aufgenommenen Bildes mit dem Betrag des Handwackelns eines Bildes mit dem höchsten Betrag der Wirkung des Handwackelns aus den anfänglich aufgenommenen Bildern, wenn ermittelt wird (450), dass die Häufigkeit der aktuellen Bildaufnahme nicht in den vorbestimmten erforderlichen Häufigkeiten enthalten ist;

    Speichern (465) des aktuell aufgenommenen Bildes und des Betrags der Wirkung des Handwackelns des aktuell aufgenommenen Bildes nach dem Löschen des Bildes mit dem höchsten Betrag der Wirkung des Handwackelns aus den anfänglich aufgenommenen Bildern, wenn ermittelt wird (460), dass der Betrag der Wirkung des Handwackelns des aktuell aufgenommenen Bildes kleiner ist als der Betrag der Wirkung des Handwackelns des Bildes mit dem höchsten Betrag der Wirkung des Handwackelns der anfänglich aufgenommenen Bilder;

    Ermitteln (470), ob die Häufigkeit der aktuellen Bildaufnahme gleich der vorgegebenen Häufigkeit für die Bildaufnahme ist;

    Zusammensetzen (475) der gespeicherten Bilder, wodurch ein endgültiges resultierendes Bild erzeugt wird, wenn ermittelt wird (470), dass die Häufigkeit der aktuellen Bildaufnahme gleich der vorgegebenen Häufigkeit für die Bildaufnahme ist.


     
    2. Verfahren nach Anspruch 1, wobei die vorbestimmten erforderlichen Häufigkeiten auf 2 bis 8 festgelegt werden.
     
    3. Verfahren nach Anspruch 1, wobei die geeignete Belichtungszeit zur Verhinderung der Wirkung des Handwackelns im Wesentlichen im Bereich von 1/10 s bis 1/30 s liegt.
     
    4. Verfahren nach Anspruch 1, wobei, wenn die berechnete Belichtungszeit nicht die geeignete Belichtungszeit ist, die Belichtungszeit nach Erhöhung einer Empfindlichkeit eines Bildsensors neu berechnet wird.
     
    5. Verfahren nach Anspruch 1, wobei eine Gesamtanzahl der Bildaufnahme so festgelegt wird, dass eine gesamte Zeitdauer des Fotografierens ungefähr 1 s nicht übersteigt.
     
    6. Verfahren nach Anspruch 1, wobei in dem Schritt des Erfassens des Betrags der Wirkung des Handwackelns für die anfänglich aufgenommenen Bilder zusätzlich ein Betrag an Verschmierung für die anfänglich aufgenommenen Bilder erfasst wird.
     
    7. Vorrichtung zum Kompensieren des Handwackelns bei einer Kamera, mit:

    einem Kameraoptiksystem (310) zur Aufnahme von Bildinformation eines Objekts;

    einem Bildsensor (320) zur Umwandlung der durch das Kameraoptiksystem aufgenommenen Bildinformation in ein elektronisches Signal;

    einem Signalprozessor (330) zur Wiederherstellung der Bildinformation aus dem elektronischen Signal;

    einer Bildspeichereinheit (360) zur Speicherung temporärer Information während der Wiederherstellung der Bildinformation und zur Speicherung endgültiger Bilddaten;

    einem Handwackel-Detektor (340) zur Erfassung des Grades des Handwackelns in dem Kamerasystem zum Zeitpunkt einer Bildaufnahme;

    einer Bildaufnahmesteuerung (350) zur Steuerung des Betriebs jeder der zuvor genannten Komponenten zum Zeitpunkt des Kompensierens des Handwackelns in der Kamera, wobei die Bildaufnahmesteuerung ausgebildet ist, die Ausführung der folgenden Schritte zu steuern:

    Erfassen (445) eines Betrags der Wirkung des Handwackelns bei jedem Fall einer Bildaufnahme;

    Speichern (455) anfänglich aufgenommener Bilder entsprechend einer vorbestimmten erforderlichen Häufigkeit und des Betrags der Wirkung des Handwackelns, der entsprechend den anfänglich aufgenommenen Bildern erfasst wird;

    Vergleichen (460) des Betrags an Handwackeln eines aktuell aufgenommenen Bildes mit dem Betrag des Handwackelns eines Bildes mit dem höchsten Betrag der Wirkung des Handwackelns aus den anfänglich aufgenommenen Bildern, wenn ermittelt wird (450), dass die Häufigkeit der aktuellen Bildaufnahme nicht in den vorbestimmten erforderlichen Häufigkeiten enthalten ist;

    Speichern (465) des aktuell aufgenommenen Bildes und des Betrags der Wirkung des Handwackelns des aktuell aufgenommenen Bildes nach dem Löschen des Bildes mit dem höchsten Betrag der Wirkung des Handwackelns aus den anfänglich aufgenommenen Bildern, wenn ermittelt wird (460), dass der Betrag der Wirkung des Handwackelns des aktuell aufgenommenen Bildes kleiner ist als der Betrag der Wirkung des Handwackelns des Bildes mit dem höchsten Betrag der Wirkung des Handwackelns der anfänglich aufgenommenen Bilder;

    Ermitteln (470), ob die Häufigkeit der aktuellen Bildaufnahme gleich der vorgegebenen Häufigkeit für die Bildaufnahme ist;

    Zusammensetzen (475) der gespeicherten Bilder, wodurch ein endgültiges resultierendes Bild erzeugt wird, wenn ermittelt wird (470), dass die Häufigkeit der aktuellen Bildaufnahme gleich der vorgegebenen Häufigkeit für die Bildaufnahme ist.


     
    8. Vorrichtung nach Anspruch 7, wobei die gespeicherten Bilder sequentiell gekennzeichnet werden bei der Speicherung in der Speichereinheit beginnend mit einem Bild mit dem kleinsten Betrag des Grades an Handwackelns.
     
    9. Vorrichtung nach Anspruch 7, wobei die vorbestimmten erforderlichen Häufigkeiten auf 2 bis 8 festgelegt sind.
     


    Revendications

    1. Procédé de compensation de l'effet des tremblements de la main avec une caméra comprenant les étapes suivantes:

    calculer (415) un temps d'exposition approprié pour éviter les tremblements de la main en utilisant un algorithme d'exposition automatique (AE) pendant un mode d'attente de capture d'image;

    exécuter (440) une capture d'image pour une pluralité d'instances, correspondant à un nombre prédéterminé de fois, dans le temps d'exposition calculé en réponse à la détection de l'actionnement d'un bouton de photographie, et

    détecter (445) une quantité d'effet des tremblements de la main à chaque instance de capture d'image;

    stocker (455) des images initialement capturées par des nombres requis prédéterminés et une quantité d'effet des tremblements de la main détectés correspondant aux images initialement capturées;

    comparer (460) la quantité d'effet des tremblements de la main d'une image actuellement capturée avec la quantité d'effet des tremblements de la main d'une image avec le plus grand effet des tremblements de la main parmi les images capturées initialement, si l'on détermine (450) que le nombre des temps de capture d'image actuels n'est pas inclus dans les nombres requis prédéterminés;

    mémoriser (465) l'image actuellement capturée et l'effet des tremblements de la main de l'image actuellement capturée après avoir effacé l'image avec le plus grand effet des tremblements de la main parmi les images initialement capturées, si l'on détermine (460) que l'effet des tremblements de la main de l'image actuellement capturée est inférieur à l'effet des tremblements de la main de l'image avec le plus grand effet des tremblements de la main parmi les images capturées initialement;

    déterminer (470) si le nombre de fois de la capture d'image actuelle est égal au nombre de fois prédéfini de capture d'image;

    synthétiser (475) les images stockées les unes avec les autres, produisant ainsi une image résultante finale, si l'on détermine (470) que le nombre de fois de capture d'image actuelle est égal au nombre de fois prédéfini de capture d'image.


     
    2. Procédé selon la revendication 1, dans lequel les nombres requis prédéterminés sont établis entre 2 et 8.
     
    3. Procédé selon la revendication 1, dans lequel le temps d'exposition approprié pour empêcher l'effet des tremblements de la main est sensiblement compris entre 1/10 seconde et 1/30 seconde.
     
    4. Procédé selon la revendication 1, dans lequel, si le temps d'exposition calculé n'est pas le temps d'exposition correct, le temps d'exposition est recalculé après une sensibilité croissante d'un capteur d'image.
     
    5. Procédé selon la revendication 1, dans lequel un nombre total de capture d'image est réglé de manière à ce que la durée totale de la photographie n'excède pas environ 1 seconde.
     
    6. Procédé selon la revendication 1, dans lequel, dans l'étape de détection de la quantité d'effet des tremblements de la main pour les images initialement capturées, une quantité de flou est en outre détectée pour les images initialement capturées.
     
    7. Appareil pour compenser les tremblements de la main avec une caméra comprenant:

    un système optique de caméra (310) pour copier des informations d'image d'un objet;

    un capteur d'image (320) pour convertir les informations d'image copiées par le système optique de caméra en un signal électronique;

    un processeur de signal (330) pour restaurer le signal électronique dans les informations d'image;

    une unité de stockage d'image (360) pour stocker des informations temporaires pendant la restauration dans les informations d'image, et des données d'image finales;

    un détecteur des tremblements de la main (340) pour détecter un niveau des tremblements de la main dans le système de caméra au moment de la capture d'image;

    un contrôleur de capture d'image (350) pour commander le fonctionnement de chacun des composants susmentionnés au moment de la compensation des tremblements de la main avec la caméra,

    dans lequel le contrôleur de capture d'image est prévu pour commander l'exécution des étapes suivantes:

    détecter (445) une quantité d'effet des tremblements de la main à chaque instance de capture d'image;

    stocker (455) des images initialement capturées par des nombres requis prédéterminés et une quantité d'effet des tremblements de la main détectés correspondant aux images initialement capturées,

    comparer (460) la quantité d'effet des tremblements de la main d'une image actuellement capturée avec la quantité d'effet des tremblements de la main d'une image avec le plus grand effet des tremblements de la main parmi les images capturées initialement, si l'on détermine (450) que le nombre des temps de capture d'image actuels n'est pas inclus dans les nombres requis prédéterminés,

    mémoriser (465) l'image actuellement capturée et l'effet des tremblements de la main de l'image actuellement capturée après avoir effacé l'image avec le plus grand effet des tremblements de la main parmi les images initialement capturées, si l'on détermine (460) que l'effet des tremblements de la main de l'image actuellement capturée est inférieur à l'effet des tremblements de la main de l'image avec le plus grand effet des tremblements de la main parmi les images capturées initialement,

    déterminer (470) si le nombre de fois de la capture d'image actuelle est égal au nombre de fois prédéfini de capture d'image, et

    synthétiser (475) les images stockées les unes avec les autres, produisant ainsi une image résultante finale, si l'on détermine (470) que le nombre de fois de capture d'image actuelle est égal au nombre de fois prédéfini de capture d'image.


     
    8. Appareil selon la revendication 7, dans lequel les images stockées sont identifiées de manière séquentielle en commençant par une image avec la plus faible quantité d'effets des tremblements de la main lors du stockage dans l'unité de stockage.
     
    9. Appareil selon la revendication 7, dans lequel les nombres requis prédéterminés sont définis entre 2 et 8.
     




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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