JP2008187402A - Correction information creating device and its method, imaging apparatus, and imaging system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology capable of quickly correcting defective pixels. <P>SOLUTION: This correction information creating device is provided with a storage control part 123 for making a memory 116 store the number of pixels from defective pixels 602 included in an imaging element 107 existing just before in the reading direction (y direction) of the imaging element 107 and pixels read first in the reading direction (y direction) and information indicating the necessity/non-necessity of correction while associated with each other. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a correction information creation apparatus and method, an imaging apparatus and an imaging system, and more particularly to a defective pixel correction technique for an imaging element.

  In recent years, in an electronic still camera and a video camera, the number of pixels of an image sensor has been increased, and accordingly, it is important to correct defective pixels in the image sensor.

  Under such circumstances, a technique for correcting image quality deterioration due to defective pixels has been proposed. For example, there is a technique in which defect correction data including the position and defect level of a defective pixel in an image sensor is stored in advance in a memory, and the defective pixel is corrected based on the defect correction data.

  However, if defect correction data is stored in the memory for each pixel in the image sensor, defect correction data corresponding to all the pixels in the image sensor must be stored in the memory, which increases the amount of data. There's a problem. Therefore, techniques for reducing the data amount of defect correction data have been proposed.

Patent Document 1 discloses a technique for reducing the amount of defect correction data by expressing the position of a defective pixel using a relative address between defective pixels. In Patent Document 1, when the value of the relative address is large, the maximum value of the relative address is decreased by setting a dummy defective pixel.
JP-A-1-103376

  However, in the technique of Patent Document 1, since the position of the dummy defective pixel changes depending on the position of the defective pixel, the position of the defective pixel cannot be obtained using the relative address as it is. Therefore, it takes time to convert the relative address to the position of the defective pixel, and there is a problem that high-speed operation is hindered particularly in moving image shooting.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a technique capable of correcting a defective pixel at high speed.

  A first aspect of the present invention relates to a correction information generation apparatus, and for each defective pixel included in an image sensor, the defective pixel existing immediately before in the readout direction of the image sensor and the first readout in the readout direction are read out. A storage control unit is provided that associates the number of pixels from the pixel with information indicating whether correction is necessary, and stores the information in a storage unit.

  According to a second aspect of the present invention, the number of pixels stored in the storage unit and the necessity of the correction are calculated based on the image sensor, the correction information generation device, and the pixels read from the image sensor. And a correction unit that performs correction based on the information shown.

  A third aspect of the present invention relates to an imaging system, and includes an optical system and the imaging device described above.

  According to a fourth aspect of the present invention, there is provided an imaging apparatus, in which information indicating the positions of a plurality of defective pixels included in an imaging device is recorded as the number of pixels from a pixel that is first read in the readout direction of the imaging device. And a correction unit that corrects the pixels read from the image sensor based on information stored in the storage unit.

  According to a fifth aspect of the present invention, there is provided the imaging apparatus, wherein the last pixel read in the readout direction of the imaging device is a dummy defective pixel, and information indicating the positions of a plurality of defective pixels included in the imaging device is stored in the dummy device. And a correction unit that corrects the pixels read out from the image sensor based on information stored in the storage unit.

  A sixth aspect of the present invention relates to a correction information generation method, and for each defective pixel included in the imaging device, the defective pixel existing immediately before in the readout direction of the imaging device and first read out in the readout direction. The number of pixels from the pixels and information indicating whether correction is necessary are associated with each other and stored in the storage unit.

  According to the present invention, it is possible to provide a technique capable of correcting a defective pixel at high speed.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram illustrating an imaging system such as a digital camera. The imaging system in FIG. 1 includes an imaging device having an imaging element 107 and an optical system 101 that forms an optical image of a subject on the imaging element 107. The imaging system is connected to a correction information creation device 121 that generates defect correction data 118 for correcting a defect of a pixel in the image sensor 107.

  An optical system 101 composed of a lens or the like includes a diaphragm mechanism and forms an optical image of a subject on the image sensor 107. The optical system driving device 102 controls the focus of the optical system 101 and the diaphragm mechanism.

  The mirror 103 is a mirror for guiding an optical image that has passed through the optical system 101 to a finder (not shown), and is generally called a quick return (QR) mirror. The mirror 103 guides light to a finder (not shown) except during shooting, but operates so that the optical image reaches the image sensor 107 by moving up when shooting. The mirror driving device 104 drives the mirror 103 as described above. The shutter 105 has a shutter curtain corresponding to a front curtain and a rear curtain of a focal plane type shutter. The shutter driving device 106 controls the exposure time and light shielding of the optical image that has passed through the optical system 101. The photometric device 113 measures the luminance of the subject. The distance measuring device 114 measures the distance to the subject. The focus and exposure amount are controlled by controlling the optical system driving device 102 and the shutter driving device 106 based on the output signals of the photometry device 113 and the distance measurement device 114. The image sensor 107 captures the subject imaged by the optical system 101 as an image signal. The imaging signal processing circuit 108 performs various corrections such as reading of the image signal of the imaging element 107, amplification of the read image signal, analog-digital conversion (A / D conversion), and defect correction for the image data after A / D conversion. , Data compression and so on. The imaging signal processing circuit 108 includes a defect correction circuit 117 as a correction unit that corrects the pixels read from the imaging element 107 based on the defect correction data 118. The timing generation unit 109 outputs various timing signals to the image sensor 107 and the image signal processing circuit 108. The control unit 115 performs various calculations and controls the entire imaging apparatus. The memory 116 functions as a storage unit that is used for temporarily storing image data or permanently storing adjustment values and the like, and includes a data area for storing defect correction data 118 for flaw correction. . The interface (recording medium control I / F unit) 110 records data on the recording medium 111 and reads data from the recording medium 111. The recording medium 111 can be configured to be detachable. As the recording medium 111, for example, a semiconductor memory can be used. An interface (external I / F unit) 112 communicates with an external computer or the like. The display device 120 displays captured still images, moving images, and the like. The SW interface (SWI / F) 119 controls switches (not shown) such as SW1 and SW2.

  The correction information creation apparatus 121 includes a setting unit 122 for setting defective pixels. The setting unit 122 sets a pixel having a defect among a plurality of pixels included in the image sensor 107 as a defective pixel, and a pixel read out last in the reading direction of the image sensor 107 among the plurality of pixels included in the image sensor 107. Are set as dummy defective pixels. Further, the correction information creation device 121 associates the number of pixels from the defective pixel and the dummy defective pixel with information indicating whether correction is necessary for each of the defective pixel and the dummy defective pixel set by the setting unit 122. And a storage control unit 123 that stores the data in the memory 116. At this time, the storage control unit 123 stores the number of pixels from the defective pixel and the dummy defective pixel existing immediately before in the reading direction and the information indicating the necessity of the correction in the memory 116 in association with each other. In the present embodiment, the correction information creation device 121 is disposed outside the imaging system, but may be disposed within the imaging system.

  Next, the operation at the time of shooting of the imaging system shown in FIG. 1 will be described.

  When a main power supply (not shown) is turned on, the power supply of each driving device is turned on, and the power supply of an imaging system circuit such as the imaging signal processing circuit 108 is turned on. When a release button (not shown) is half-pressed, the control unit 115 measures the subject brightness with the photometric device 113 and the subject distance with the distance measuring device 114 to control the exposure amount. In accordance with the result, the optical system driving apparatus 102 performs the focusing operation of the optical system 101. When a release button (not shown) is fully pressed, the control unit 115 controls the aperture of the optical system 101 through the optical system driving device 102 based on the photometric value of the photometric device 113.

  In order to capture an image, the control unit 115 controls the timing generation unit 109 and the imaging signal processing circuit 108, initializes the imaging element 107, and controls the imaging element 107 to accumulate image signals. The mirror driving device 104 raises the mirror 103, and the shutter driving device 106 controls to open the shutter 105 for a predetermined time based on the photometric value of the photometric device 113. After a predetermined time has elapsed, the shutter driving device 106 controls to close the shutter 105 and the mirror driving device 104 to lower the mirror 103.

  Thereafter, the control unit 115 controls the timing generation unit 109 and the imaging signal processing circuit 108 and reads out the image signal for the still image from the imaging element 107 in order to read out the image signal. At the same time, the defect correction circuit 117 corrects the defective pixel using the defect correction data 118. The memory 116 temporarily stores the read image signal as image data. The interface 110 records the image data stored in the memory 116 on the recording medium 111.

  As described above, a series of imaging sequences is completed and returned to the original.

  FIG. 2 is a flowchart showing imaging control of the imaging system according to the preferred embodiment of the present invention.

  In step S201, the control unit 115 creates index data for moving image display, particularly for moving image partial enlarged display, from the still image defect correction data 118 before the start of shooting. A method for creating the index data will be described later.

  In step S202, the control unit 115 confirms the state of SW1 of the imaging system and waits for SW1 to be turned on. Here, SW1 is a SW (switch) that is turned on when the release button is pressed halfway, and is used by the photographer to instruct the imaging system to start photographing preparation. SW1 is connected to the SW interface 119.

  In step S202, when the control unit 115 confirms that SW1 is turned on, the control unit 115 proceeds to step S203.

  In step S <b> 203, the control unit 115 starts supplying power to each block necessary for photographing such as each driving device, timing generation device, imaging signal processing circuit, imaging device, and photometric distance measuring device. Other than this, supply of power to each block that is used other than shooting such as the memory 116, the external interface unit, and the recording medium control interface unit is started when the main SW is turned on before the main shooting control. And

  In step S204, the control unit 115 determines the currently set shooting mode. If the still image shooting mode is selected, the process proceeds to step S205. If the moving image shooting mode is selected, the process proceeds to step S206. As the photographing mode switching means, for example, a means such as a mode dial or a menu screen configured to perform the photographing mode setting operation other than the main photographing control can be considered.

  The shooting control in the still image shooting in step S205 and the moving image shooting in step S206 will be described later.

  When the shooting control in the still image shooting in step S205 or the moving image shooting in step S206 ends, the control unit 115 proceeds to step S207.

  In step S207, the control unit 115 stops power supply to each block for which power supply has been started in step S204.

  Thereafter, the control unit 115 ends the series of shooting control, but if shooting continues, the process returns to step S201.

  FIG. 3 is a flowchart showing the shooting control in step S205 of FIG. 2 in more detail.

  In step S301, the control unit 115 detects the brightness of external light (photometric information) and the distance to the subject (distance information) using the photometric device 113 and the distance measuring device 114.

  In step S302, the optical system driving apparatus 102 drives the optical system 101 so that the subject is in focus based on the distance measurement information detected in step S301.

  In step S303, the control unit 115 confirms the state of SW2 of the imaging system and waits for SW2 to be turned on. Here, SW2 is a SW (switch) that is turned on when the release button is fully pressed, and is used by the photographer to instruct the imaging system to start the actual photographing. SW2 is connected to the SW interface 119.

  In step S <b> 304, the control unit 115 controls the timing generation unit 109 and the imaging signal processing circuit 108. The control unit 115 also initializes the image sensor 107 and controls the image sensor 107 to accumulate image signals.

  In step S305, the optical system driving apparatus 102 drives the aperture of the optical system 101 to a predetermined opening position based on the photometric information detected in step S301.

  In step S306, the mirror driving device 104 raises the mirror 103, and the shutter driving device 106 opens the shutter 105.

  In step S307, the control unit 115 waits for the exposure time of the shutter to elapse based on the photometric information detected in step S301. When the exposure time of the shutter has elapsed in step S307, the control unit 115 proceeds to step S308.

  In step S308, the control unit 115 performs control to close the shutter 105 and lower the mirror 103.

  In step S309, the control unit 115 performs control so that the diaphragm that has been throttled based on the photometric information in step S305 is opened to the open position.

  In step S <b> 310, the control unit 115 controls the timing generation unit 109 and the imaging signal processing circuit 108 to read out the image signal accumulated in the imaging element 107. At this time, the imaging signal processing circuit 108 performs A / D conversion on the analog image signal, and temporarily stores the read image signal in the memory 116. The imaging signal processing circuit 108 preferably develops and compresses the image signal in advance during the accumulation. As a result, the amount of memory consumed for one image can be reduced. The defective pixel according to the preferred embodiment of the present invention is corrected based on the defect correction data 118 created in advance at the time of reading, and the detailed description thereof will be described later.

  In step S311, the control unit 115 records the image signal temporarily stored in the memory 116 in step S310 on the external recording medium 111. In the present embodiment, the shooting control for single shooting is taken as an example, but the case of continuous shooting is also described below. In the case of continuous shooting, since the continuous shooting speed is set in accordance with the reading speed of the image signal, the reading from the reading of the image signal to the temporary storage in the memory 116 is continuously performed. Since the speed from reading to storage to reading from the memory 116 and recording to the external recording medium 111 is much slower than this speed from reading to accumulation, this portion becomes a bottleneck. Therefore, when image signals are temporarily stored in the memory 116 and recorded in the order of shooting, continuous shooting can be performed as long as recording is delayed as long as the memory 116 is free. When all of the image data in the memory 116 has been recorded on the external recording medium 111, the still image shooting control ends.

  Thereafter, the control unit 115 ends the shooting control of the still image shooting, and proceeds to step S207 in FIG.

  FIG. 4 is a flowchart showing the shooting control in step S206 of FIG. 2 in more detail.

  In step S401, the control unit 115 controls the timing generation unit 109 and the image signal processing circuit 108 to initialize the image sensor 107 so that the image sensor 107 can accumulate image signals.

  In step S402, the mirror driving device 104 raises the mirror 103, and the shutter driving device 106 opens the shutter 105.

  In step S403, the control unit 115 determines the currently set moving image shooting mode. If the mode is a mode for displaying a full screen (hereinafter referred to as “full screen display”), the control unit 115 proceeds to step S404, and partially displays the screen. If it is a mode for displaying in an enlarged manner (hereinafter referred to as “partial enlarged display”), the process proceeds to step S406. Here, description of the moving image shooting mode switching means is omitted, but if the system can be switched by operating a SW (switch) (not shown) during the moving image shooting control, the photographer can easily take the moving image shooting. You can switch to mode.

  In step S <b> 404, the control unit 115 controls the timing generation unit 109 and the imaging signal processing circuit 108 to read out the image signal accumulated in the imaging element 107. At this time, the imaging signal processing circuit 108 performs A / D conversion on the analog image signal, and temporarily stores the read image signal in the memory 116. The imaging signal processing circuit 108 develops the image signal during the accumulation. In addition, the amount of image data required for the display device is much smaller than the amount of image data at the time of still image shooting, and it takes time to read out the image signal at the time of still image reading from the image sensor 107. It will not become a moving image. Therefore, when full screen display is performed, necessary image signals are thinned out from the image sensor 107 and read out. In the correction of the defective pixel according to the present embodiment, the defective pixel is corrected based on the defect correction data 118 created in advance at the time of reading. Detailed description thereof will be described later.

  In step S405, the imaging signal processing circuit 108 corrects the image data read in step S404 so as to be the display size of the display device 120. This is because when the entire screen is read by thinning, it does not match the display size of the display device 120. Then, the imaging signal processing circuit 108 causes the display device 120 to display the corrected image data. In step S406, the imaging signal processing circuit 108 reads out an image signal from the imaging element 107 and performs development processing in the same manner as in step S404. However, the reading method in step S406 is different from that in step S404. When performing full-screen display, reading is performed by thinning out the entire screen, whereas when performing partial enlargement display, a necessary area is read out and displayed. In the correction of the defective pixel according to the present embodiment, the defective pixel is corrected based on the defect correction data 118 created in advance at the time of reading. Detailed description thereof will be described later.

  In step S407, the imaging signal processing circuit 108 cuts out an area corresponding to the display area from the image signal of the area read in step S406. This is because the display area is a part of the read area, so that the area necessary for display is cut out and this image data is displayed on the display device 120.

  In step S408, the control unit 115 detects the brightness of external light (photometry information) and the distance to the subject (distance measurement information). However, here, the photometry information and the distance measurement information are detected based on the image signal read out in step S404 or S406 without using the photometry device 113 and the distance measurement device 114. This is because in the imaging system according to the present embodiment, when the mirror 103 is raised, the light cannot be guided to the photometry device 113 and the distance measurement device 114, and neither device can be used.

  In step S409, the optical system driving apparatus 102 drives the optical system 101 so that the subject is in focus based on the distance measurement information detected in step S408.

  In step S410, the optical system driving apparatus 102 drives the aperture of the optical system 101 to a predetermined opening position based on the photometric information detected in step S408.

  In step S411, the control unit 115 confirms the state of SW2, and determines whether SW2 is on. If SW2 is not turned on, control unit 115 proceeds to step S413. In this case, no image is recorded, and only a moving image is displayed on the display device 120. If SW2 is on, the process proceeds to step S412.

  In step S412, the imaging signal processing circuit 108 corrects the image signal temporarily stored in the memory 116 in step S404 or S406 to the size of the recorded image. Alternatively, a part of the image signal is cut out and corrected to the size of the recording image, the image is compressed for recording, and then recorded on the external recording medium 111. The compression rate in this case is adjusted according to the writing speed to the external recording medium 111.

  In step S413, the control unit 115 confirms the state of SW1, and if SW1 is on, the control unit 115 returns to step S403 and repeats the series of imaging operations described above. If SW1 is not turned on, the process proceeds to step S414.

  In step S414, the control unit 115 performs control to close the shutter 105 and lower the mirror 103.

  In step S415, the control unit 115 performs control so that the diaphragm that has been throttled based on the photometric information in step S410 is opened to the open position.

  Thereafter, the control unit 115 ends the moving image shooting sequence, and proceeds to step S207 in FIG.

  Next, the defect correction data 118 for correcting the defective pixel in step S310 in FIG. 3 will be described in more detail with reference to FIGS.

  FIG. 5 is a diagram illustrating the position of the defective pixel in the image sensor 107. FIG. 6 is a diagram illustrating the position of the defective pixel in the image sensor 107 and the format of the defect correction data 118 stored in the imaging system. Each square shown in FIG. 5 represents a pixel 601, and a pixel hatched with a cross diagonal line is a defective pixel 602 having a defect. Here, the entire image sensor 107 is a 12 × 8 pixel 601 and a defective pixel 602 is shown therein, but the present invention is not limited to this. In addition, although a large number of defective pixels 602 are shown as examples, in reality, it is considered that such defective pixels 602 are hardly present in this number of pixels.

  In the defect correction data 118 shown on the left side of FIG. 6, the position information of the defective pixel 602 is represented by xy coordinates, but the data amount increases as it is. Therefore, as shown on the right side of FIG. 6, the data of the absolute address represented by the xy coordinates is converted into the offset data represented by the relative address between the pixels and stored in the imaging system. This offset data represents the number of pixels (movement amount) from the position of a certain defective pixel to the position of the next defective pixel. Then, the image sensor 107 is configured to sequentially read out from the upper left pixel in the right direction, and when proceeding to the right end pixel, the y coordinate is advanced by one and read out again in order from the left to the right. Therefore, by converting into such an offset data format, the position of the defective pixel can be specified based on the number of pixels between the defective pixels. Further, it is preferable to store a defect level detected in advance in association with each defective pixel. This defect level corresponds to information indicating whether or not correction is necessary, and thus it is possible to switch to which defect level correction is performed for each shooting scene.

  Such defective pixel correction is performed based on the defect correction data 118 at the time of still image shooting by obtaining offset data and defect level data in advance in still image shooting and storing them in the imaging system. Is called. Using the defect correction data 118 created in this way, it is determined one by one whether the image data read from the image sensor 107 is at the position of the defective pixel, and if it is determined that it is a defective pixel, this defective pixel Is corrected using surrounding normal pixels.

  Next, the correction of the defective pixel in step S404 in FIG. 4 will be described in more detail with reference to FIGS.

  FIG. 7 is a diagram illustrating the position of the defective pixel 602 in the image sensor 107 as in FIG. 5. However, when displaying the entire screen as a moving image, if the same number of pixels as the still image is read out from the image sensor 107, it takes time to read out, and smooth moving image display is not achieved. Therefore, in general, the readout time is shortened by performing thinning when the pixels are read out. In this case, although the number of pixels is reduced as compared with a still image, smooth moving image display can be performed. In FIG. 7, a pixel 1011 surrounded by a thick line indicates a pixel that is read without being thinned out. In FIG. 7, half thinning is performed in the y direction and half thinning is performed in the x direction. As a result, the number of pixels to be read is a quarter of the total number of pixels (for example, 24 pixels in FIG. 7).

  FIG. 8 is a diagram showing defect correction data 118 corresponding to the thinning readout of FIG. When the thinning is performed, the offset amount between the defective pixel and the defective pixel is different from that in the still image shooting. Therefore, the defect correction data 118 shown in FIG. 8 needs to be created in advance and stored in the imaging system for moving image shooting in the case of full screen display. However, in the case of a moving image, since the time that can be used for one image is limited, the maximum accumulation time (exposure time) for a still image is significantly shortened. For this reason, the defect correction data 118 for long-second shooting is no longer necessary, and the number of data becomes even smaller than the number reduced by thinning. Therefore, the capacity of the defect correction data 118 of the imaging system is not so large. Using the defect correction data 118 created in this way, it is determined one by one whether the image data read from the image sensor 107 is at the position of the defective pixel, and if it is determined that it is a defective pixel, this defective pixel Is corrected using surrounding normal pixels.

  In the partial enlargement display at the time of moving image shooting according to the present embodiment, a part of the image sensor 107 is read without thinning, and the read part of the image is displayed on the entire screen of the display device 120. As a result, the display is enlarged with respect to the full screen display. This will be described with reference to FIG. 9. In the case of full screen display, the entire image sensor 107 is read out and displayed in the size of the display device 120 to display full screen. In the case of partial enlargement display, partial enlargement display is achieved by reading a part of the image sensor 107 without thinning out and displaying the display area in the size of the display device 120. In this case, unlike the case where the thinned image is enlarged, the image quality does not deteriorate.

  When reading and displaying such an image of partial enlargement display, if only the central portion of the image sensor 107 is enlarged and displayed, the central portion of the image sensor 107 is read as shown in FIG. 10, and as shown in FIG. In addition, defect correction data 118 corresponding to this reading may be created. Thereby, the defective pixel can be corrected. Further, if there is only one enlarged display position, for example, the defect correction data 118 does not increase greatly.

  However, with such a method, every time the position for partial enlarged display changes, defect correction data 118 corresponding to that position is required. As a result, there are a large number of movable positions in the image sensor 107 of the millions of pixels, which is currently mainstream, and a huge amount of defect correction data 118 is required to correct this.

  Next, the correction of the defective pixel in step S406 in FIG. 4 will be described in more detail with reference to FIGS. The creation of index data for correcting defective pixels in step S201 in FIG. 2 will also be described.

  FIG. 12 is a diagram showing the position of the defective pixel 602 in the image sensor 107 as in FIG. In FIG. 12, pixels with horizontal lines are dummy defective pixels 801 added to perform partial enlargement display during moving image shooting. In the present embodiment, the last pixel (rightmost pixel) in the reading direction of the image sensor 107 is set as a dummy defective pixel 801, and the defect correction data 118 is associated with the dummy defective pixel 801. Thus, the last pixel in the reading direction of the image sensor 107 can be set as a dummy defective pixel, and the offset data from the dummy defective pixel can be used as the number of pixels (address) from the beginning of the reading start line. . Therefore, the offset data can be used as it is without performing the process of converting the offset data at the time of reading, which is particularly advantageous in the processing of moving images. The dummy defective pixel 801 is handled in the same manner as a defective pixel having a defect when calculating the number of pixels between defective pixels, but is different in that correction processing is not performed. In FIG. 12, pixels 801 with a horizontal line correspond to dummy defective pixels, and in FIG. 13, numbers 2, 4, 6, 8, 10, and 11 correspond to dummy defective pixels. In FIG. 13, the defect level of the dummy defective pixel is set to “0” indicating that no correction is necessary to distinguish the defective pixel from the defective pixel. If the last pixel in the readout row of the image sensor 107 is a defective pixel as indicated by number 13, defect correction data 118 is set as a defective pixel, and defect correction is performed as a dummy defective pixel. Data 118 is not set.

  Next, a partial enlarged display when the defect correction data 118 is used will be described.

  As shown in FIG. 9, in the case of partial enlargement display, the area from which the image signal is read with respect to the entire image sensor 107 has a length including the display area in the vertical direction, and in the horizontal direction. It is assumed that the image sensor 107 has a length. In FIG. 9, for the convenience of illustration, the length in the vertical direction of the readout area is more than half of the entire image sensor 107, but is actually about one fifth of the entire image sensor 107. Then, of the image signals read out horizontally in this way, only the display area is displayed in the size of the display device 120, and partial enlarged display is performed. For example, when an image signal is read out from the pixel (x, y) = (1, 3) in the third row in FIG. 12, the previous pixel (x, y) = (12, 2) is used as the defect correction data 118. Offset data of pixel No. 4 in FIG. 13 is used. Similarly, when an image signal is read out from the pixel (x, y) = (1, 5) in the fifth row in FIG. 12, the previous pixel (x, y) = (12, 4) as the defect correction data 118. ) Offset data, that is, the offset data of pixel number 8 in FIG. In this case, as described above, the processing for converting the offset data is unnecessary, and high-speed operation is possible.

  However, only the defect correction data 118 of FIG. 13 is stored in the imaging system. For this reason, it is necessary to search from the top of the defect correction data 118 as to which number of data in FIG.

  In order to eliminate this, the defect correction data 118 is searched from the top at the timing of step S202 in FIG. Next, it is only necessary to create index data in which a row from which an image signal is read as shown in FIG. 14 and a number of defect correction data 118 that starts use corresponding to the row are paired. By creating the index data for the defect correction data 118 as shown in FIG. 14 in advance, it is not necessary to search from the top of the defect correction data 118 every time the read line of the image signal changes.

  In this embodiment, the imaging system creates index data before shooting. However, if you want to further shorten the time until the shooting operation starts, create index data in advance by factory adjustment and store it in the imaging system. Also good. As a result, the time for creating the index data can be shortened by the time until the start of the photographing operation.

  Further, comparing FIG. 5 with FIG. 12, the defect correction data 118 corresponding to the dummy defective pixel 602 is the same except for the defect correction data 118 corresponding to the dummy defective pixel 602, and correction processing is applied to the defect correction data 118 corresponding to the dummy defective pixel 602. Not performed. For this reason, the defect correction data 118 for partial enlargement display of the moving image shown in FIG. 12 can be used as the defect correction data 118 for the still image instead of the one shown in FIG. As a result, the total number of defect correction data 118 can be reduced.

  The format of the defect correction data 118 will be described with reference to FIG.

  In the format of the defect correction data 118 described above, dummy defect correction data 118 is added as shown in FIG. 13 so that the line switching can be understood with respect to the defect correction data 118 for still image shooting as shown in FIG. It was. On the other hand, in order to perform defective pixel correction using the defect correction data 118 as shown in FIG. 6, defect correction data 118 in the format as shown in FIG. 15 is generated in advance. This data format is data for one row of the image sensor 107 in one row. From the left, the number of rows of data, the number of defective pixels for the row, the number of pixels from the first pixel of the row to the defective pixel (the first pixel is included in the number of pixels), and the defects present in the row Correction data 118 are arranged. When used as the defect correction data 118 for still image shooting, since the image sensor 107 reads sequentially from the beginning, the defect correction data 118 is used correspondingly from the beginning. Further, for example, when reading from the third row instead of from the beginning of the image sensor 107 for partial enlarged display, the defect pixel correction is performed by using the defect correction data 118 corresponding to the third row. It can be carried out. When the correction of defective pixels for one row is completed, the data is moved to the next row and correction is performed again from the beginning of the row.

  The format of the defect correction data 118 will be described with reference to FIG.

  In the same manner as described with reference to FIG. 15, this is a data format for performing defective pixel correction using the defect correction data 118 as shown in FIG. This data format is data for one row of the image sensor 107 in one row. From the left, the number of rows of data, the number of pixels from the first pixel of the row to the defective pixel (including the first pixel in the number of pixels), the number of pixels of the image sensor 107 in the row, and the presence in the row The defect correction data 118 to be arranged are arranged. When reading from the third row instead of from the beginning of the image sensor 107 for partial enlarged display, the defect pixel can be corrected by using the defect correction data 118 corresponding to the third row. Then, the number of offsets is added, and when the number of pixels of the image sensor 107 for one row becomes larger, the data moves to the next row and correction is performed again from the beginning of the row.

  As described with reference to FIGS. 15 and 16, the data format of the defect correction data 118 is set to a format completed for each row. In this case, the defect correction data 118 for still image shooting can be used for full-screen display when only the rows are read out for full-screen reading.

  As described above, according to a preferred embodiment of the present invention, the position of a defective pixel can be obtained at high speed using the number of pixels from the pixel that is first read in the reading direction of the image sensor. As a result, it is possible to provide a technique capable of correcting a defective pixel at high speed.

  Further, it is possible to share a single piece of defect correction data for enlarging an arbitrary area in the image sensor at the time of moving image shooting, which required a plurality of images. As a result, the ROM capacity required for storing defect correction data can be greatly reduced.

  Further, the ROM capacity can be further reduced by sharing the defect correction data for still image shooting and the defect correction data for expanding an arbitrary area in the sensor at the time of moving image shooting, which were separate in the past. Can do.

  In addition, index data for sharing defect correction data for enlargement of an arbitrary area in the image sensor at the time of moving image shooting with one data is scanned from the top when the camera is started, and the index data corresponding to the data Create As a result, the ROM capacity is not consumed excessively. The index data is created together with the defect correction data and stored in the camera. As a result, it is necessary to create index data at the time of startup, and the problem that the startup time becomes longer can be solved.

1 is a block diagram of an imaging system according to a preferred embodiment of the present invention. It is a figure which shows the flowchart which shows imaging | photography control of the imaging system which concerns on suitable embodiment of this invention. It is a figure which shows the flowchart which shows the imaging | photography control in step S205 of FIG. 2 in detail. It is a figure which shows the flowchart which shows the imaging | photography control in step S206 of FIG. 2 in detail. It is a figure which shows the position of the defective pixel in an image pick-up element. It is a figure which shows the position of the defective pixel in an image pick-up element, and the format of the defect correction data memorize | stored in an imaging system. It is a figure which shows the position of the defective pixel in an image pick-up element. It is a figure which shows the defect correction data corresponding to the thinning-out reading shown in FIG. It is a figure which shows the relationship between the read-out area | region and display area in the whole image pick-up element. It is a figure which shows the correction position of the defective pixel in partial expansion display. It is a figure which shows the defect correction data in a partial expansion display. It is a figure which shows the position of the defective pixel in the image pick-up element which concerns on suitable embodiment of this invention. It is a figure which shows the defect correction data based on suitable embodiment of this invention. It is a figure which shows the index data which concerns on suitable embodiment of this invention. It is a figure which shows the other format of the defect correction data based on suitable embodiment of this invention. It is a figure which shows the further another format of the defect correction data based on suitable embodiment of this invention.

Explanation of symbols

107 Image sensor 116 Memory 123 Storage control unit 602 Defective pixel

Claims (10)

  For each defective pixel included in the image sensor, the number of pixels from the defective pixel and the pixel that is read first in the readout direction, which is present immediately before in the readout direction of the image sensor, and information indicating whether correction is necessary, A correction information creating apparatus comprising a storage control unit that associates and stores the information in a storage unit. A setting unit that sets a pixel read last in the reading direction of the image sensor as a dummy defective pixel;
The storage control unit, for each of the defective pixel and the dummy defective pixel, information indicating the number of pixels from the defective pixel and the dummy defective pixel that exist immediately before in the readout direction, and whether correction is necessary. The correction information creating apparatus according to claim 1, wherein the correction information is stored in a storage unit.   The correction information creating apparatus according to claim 2, wherein when the dummy defective pixel has a defect, the setting unit performs setting as the defective pixel.   The storage control unit uses information indicating that correction is necessary for the defective pixel and information indicating that correction is not necessary for the dummy defective pixel as information indicating whether correction is necessary. The correction information creating apparatus according to claim 2 or 3, wherein the correction information is stored in the storage unit. The imaging element;
The correction information creation device according to any one of claims 1 to 4,
An image pickup apparatus comprising: a correction unit that corrects the pixels read from the image pickup device based on the number of pixels stored in the storage unit and information indicating the necessity of the correction.   The correction unit identifies the position of the defective pixel in the imaging element based on the number of pixels stored in the storage unit, and according to information indicating whether or not the correction of the defective pixel stored in the storage unit is necessary. The imaging apparatus according to claim 5, wherein the identified defective pixel is corrected. Optical system,
The imaging device according to claim 5 or 6,
An imaging system comprising: A storage unit that records information representing the positions of a plurality of defective pixels included in the image sensor as the number of pixels from a pixel that is first read in the reading direction of the image sensor;
A correction unit that corrects the pixels read from the image sensor based on information stored in the storage unit;
An imaging apparatus comprising: A storage unit that records, as a dummy defective pixel, a pixel that is read last in the reading direction of the imaging element, and information indicating the positions of a plurality of defective pixels included in the imaging element as the number of pixels from the dummy defective pixel;
A correction unit that corrects the pixels read from the image sensor based on information stored in the storage unit;
An imaging apparatus comprising:   For each defective pixel included in the image sensor, the number of pixels from the defective pixel and the pixel that is read first in the readout direction, which is present immediately before in the readout direction of the image sensor, and information indicating whether correction is necessary, Is stored in the storage unit in association with each other.

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