JP2009267593A - Imaging device, defective pixel detecting method, and defective pixel detection program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique of an imaging device which accurately detects a subsequent defective pixel regarding all pixels of an imaging element. <P>SOLUTION: The imaging device detects a defective pixel per pixel group belonging to each of a plurality of divided areas obtained by dividing an imaging surface of an imaging element into areas. When the imaging device is started up, an elapse period from a completion of an immediate detection regarding a defective pixel detection per divided area to a present time is firstly calculated (step S1). Then, while in the presence of a divided area where a fixed period (for example one week) has elapsed, the divided area is set in a detection object area, in the absence of the divided area where the fixed period has elapsed, a divided area where a detection completion date and time is the oldest is set in the detection object area (steps S2 to S4). The defective pixel detection is performed to the detection object area (step S7). Thus, a detection of a subsequent defective pixel regarding all pixels of the imaging element is accurately performed by the operation of the imaging device. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technique of an imaging device provided with an imaging element.

  In recent years, the number of pixels of an image sensor provided in an image pickup apparatus such as a digital camera has been increasing. Here, it is generally difficult to manufacture an image sensor having a higher pixel with a defect that is completely uniform in characteristics of each pixel. Then, in an image acquired by an image sensor having a defective pixel, a portion where a pixel signal larger than the original level is recorded (white defect), or a portion where a pixel signal smaller than the original level is recorded (black defect). Will occur.

  As countermeasures for defective pixels as described above, based on defective pixel data (defective pixel position data, etc.) acquired in advance in an inspection before product shipment for all pixels of the image sensor, for example, around the defective pixels There is a technique for performing pixel interpolation using pixel signals to eliminate abnormal pixel signals generated in defective pixels.

  On the other hand, even after the product is shipped, the image pickup device may be deteriorated or damaged due to the environment in which the image pickup device is used even if the image pickup device is at the user's control. Defective pixels that are generated automatically (hereinafter also referred to as “subsequent defective pixels”) cannot be grasped by the above-described inspection before product shipment. If inspection similar to that before product shipment is performed after product shipment, subsequent defective pixels can be detected. However, if all pixels of the image sensor are inspected, the processing time is long and the user needs to There is a risk of missing a chance.

  As a technique for improving the detection process of such a subsequent defective pixel, there is one disclosed in Patent Document 1. According to this technique, the imaging surface of the imaging device is divided into regions, and defective pixels are detected in the randomly selected divided regions, so that subsequent defective pixels can be detected quickly.

JP 2003-8998 A

  However, in the technique of Patent Document 1 described above, each defective area defined on the imaging surface is randomly selected to detect a defective pixel later, so that reliable defective pixel detection is guaranteed for all the pixels of the imaging device. There may be late defective pixels that are not detected over a long period of time.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a technique of an imaging apparatus that can accurately detect subsequent defective pixels regarding all the pixels of the imaging element.

  One aspect of the present invention is an imaging apparatus, an imaging element that generates an image signal based on an optical image received on an imaging surface, and pixels that belong to each of a plurality of regions obtained by dividing the imaging surface into regions. A defective pixel detection means capable of detecting a defective pixel for each group; a recording control means for recording information on the latest execution time when the defective pixel was most recently detected for each of the plurality of regions in a predetermined recording means; A detection control unit configured to detect the defective pixel with respect to a selected region selected from the plurality of regions when the imaging device is started up, and the detection control unit includes the detection control unit in the plurality of regions. A first selection control unit configured to select a part of the plurality of regions as the selection region when there is no region in which a predetermined period has elapsed from the execution time; If there is a region in which the predetermined period of time has elapsed since the last execution time, a second selection control means for selecting a region in which the predetermined period of time as the selected area.

  According to the present invention, in a plurality of regions obtained by dividing the imaging surface of the image sensor, when there is no region in which a predetermined period has elapsed since the most recent execution time when the defective pixel was detected most recently, A part of the plurality of regions is selected as a selected region, and defective pixels are detected in the selected region. In addition, when there is an area in which a predetermined period has elapsed since the most recent execution time in a plurality of areas, an area in which the predetermined period has elapsed is selected as a selection area, and defective pixels are detected in this selection area To do. As a result, subsequent defective pixels can be accurately detected for all the pixels of the image sensor.

<Appearance configuration of imaging device>
1 and 2 are diagrams showing an external configuration of an imaging apparatus 1 according to the embodiment of the present invention. Here, FIGS. 1 and 2 show a front view and a rear view, respectively.

  The imaging device 1 is configured as, for example, a single-lens reflex digital still camera, and includes a camera body 10 and an interchangeable lens 2 as a photographic lens that can be attached to and detached from the camera body 10.

  In FIG. 1, on the front side of the camera body 10, a mount portion 301 to which the interchangeable lens 2 is mounted at the center of the front surface, a lens exchange button 302 disposed on the right side of the mount portion 301, and a gripper. The grip part 303 is provided. In addition, the camera body 10 includes a mode setting dial 305 disposed at the upper left portion of the front surface, a control value setting dial 306 disposed at the upper right portion of the front surface, and a shutter button 307 disposed on the upper surface of the grip portion 303. Is provided.

  In FIG. 2, on the rear side of the camera body 10, there are an LCD (Liquid Crystal Display) 311, a setting button group 312 arranged on the left side of the LCD 311, and a cross key 314 arranged on the right side of the LCD 311. And a push button 315 disposed in the center of the cross key 314. On the back side of the camera body 10, an optical finder 316 disposed above the LCD 311, an eye cup 321 surrounding the optical finder 316, and a main switch 317 disposed on the left side of the optical finder 316. And are provided. Further, on the back side of the camera body 10, an exposure correction button 323 and an AE lock button 324 disposed on the right side of the optical finder 316, a flash unit 318 disposed above the optical finder 316, and a connection terminal unit. 319.

  The mount 301 is provided with a connector (not shown) for electrical connection with the mounted interchangeable lens 2 and a coupler (not shown) for mechanical connection.

  The lens exchange button 302 is a button that is pressed when the interchangeable lens 2 attached to the mount unit 301 is removed.

  The grip part 303 is a part where the user grips the imaging device 1 at the time of photographing, and is provided with surface irregularities that match the finger shape in order to improve fitting properties. Note that a battery storage chamber and a card storage chamber (not shown) are provided inside the grip portion 303. A battery is housed in the battery compartment as a power source for the camera, and a memory card 90 (see FIG. 5) for recording image data of a photographed image is detachably housed in the card compartment. Yes. The grip unit 303 may be provided with a grip sensor for detecting whether or not the user has gripped the grip unit 303.

  The mode setting dial 305 and the control value setting dial 306 are made of a substantially disk-shaped member that can rotate in a plane substantially parallel to the upper surface of the camera body 10. The mode setting dial 305 is used for various shootings such as an automatic exposure (AE) control mode, an autofocus (AF) control mode, a still image shooting mode for shooting a single still image, and a continuous shooting mode for continuous shooting. This mode is used to selectively select a mode and a function installed in the imaging apparatus 1, such as a mode and a reproduction mode for reproducing a recorded image. On the other hand, the control value setting dial 306 is for setting control values for various functions installed in the imaging apparatus 1.

  The shutter button 307 is a push switch that can be operated in a “half-pressed state” that is pressed halfway and further operated in a “full-pressed state”. When the shutter button 307 is half-pressed in the still image shooting mode, a preparatory operation (preparation operation for setting an exposure control value, focus detection, etc.) for capturing a still image of the subject is executed, and the shutter button 307 is fully pressed. Then, a photographing operation (exposure of the image sensor 101 (see FIG. 3) is performed, and a series of operations for performing predetermined image processing on the image signal obtained by the exposure and recording the image signal on a memory card or the like) is executed. The

  The LCD 311 includes a color liquid crystal panel capable of displaying an image. The LCD 311 displays an image picked up by the image pickup device 101 (see FIG. 3), reproduces and displays a recorded image, and is mounted on the image pickup apparatus 1. Function and mode setting screen. Note that an organic EL or a plasma display device may be used instead of the LCD 311.

  The setting button group 312 is a button for performing operations on various functions installed in the imaging apparatus 1. The setting button group 312 includes, for example, a selection confirmation switch for confirming the content selected on the menu screen displayed on the LCD 311, a selection cancel switch, a menu display switch for switching the content of the menu screen, a display on / off switch, A display enlargement switch is included.

  The cross key 314 has an annular member having a plurality of pressing portions (triangle marks in the figure) arranged at regular intervals in the circumferential direction, and is not shown and provided corresponding to each pressing portion. The pressing operation of the pressing portion is detected by the contact (switch). The push button 315 is arranged at the center of the cross key 314. The cross key 314 and the push button 315 are used to change the shooting magnification (movement of the zoom lens in the interchangeable lens 2 in the wide direction or the tele direction), frame advance of the recorded image to be reproduced on the LCD 311 and the like, and shooting conditions (aperture value, For inputting settings such as shutter speed and flash emission.

  The optical viewfinder 316 optically displays a range where a subject is photographed. In other words, the subject image from the interchangeable lens 2 is guided to the optical finder 316, and the user can visually recognize the subject actually captured by the image sensor 101 by looking into the optical finder 316. .

  The main switch 317 is a two-contact slide switch that slides to the left and right. When the switch is set to the left, the power of the imaging apparatus 1 is turned on, and when the switch is set to the right, the power is turned off.

  The flash unit 318 is configured as a pop-up built-in flash. On the other hand, when attaching an external flash or the like to the camera body 10, the connection is made using the connection terminal portion 319.

  The eye cup 321 is a “U” -shaped light shielding member that has light shielding properties and suppresses intrusion of external light into the optical viewfinder 316.

  The exposure correction button 323 is a button for manually adjusting an exposure value (aperture value or shutter speed), and the AE lock button 324 is a button for fixing exposure.

  The interchangeable lens 2 functions as a lens window that captures light (light image) from a subject, and also functions as a photographing optical system that guides the subject light to the image sensor 101 disposed inside the camera body 10. It is. The interchangeable lens 2 can be detached from the camera body 10 by depressing the lens interchange button 302 described above.

  The interchangeable lens 2 includes a lens group including a plurality of lenses arranged in series along the optical axis LT (see FIG. 3). This lens group includes a focus lens for adjusting the focus and a zoom lens for zooming, and each lens group is driven in the direction of the optical axis LT (see FIG. 3) to change the focus. Double and focus adjustment is performed. The interchangeable lens 2 is provided with an operation ring that can rotate along the outer peripheral surface of the lens barrel at an appropriate position on the outer periphery of the lens barrel. The zoom lens can be operated by manual operation or automatic operation. It moves in the optical axis direction according to the rotation direction and rotation amount, and is set to a zoom magnification (imaging magnification) according to the position of the movement destination.

<Internal Configuration of Imaging Device 1>
Next, the internal configuration of the imaging apparatus 1 will be described. FIG. 3 is a longitudinal sectional view of the imaging apparatus 1. As shown in FIG. 3, the camera body 10 includes an image sensor 101, a finder unit 102 (finder optical system), a mirror unit 103, a phase difference AF module 107, and the like.

  The imaging element 101 is arranged in a direction perpendicular to the optical axis LT on the optical axis LT of the lens group included in the interchangeable lens 2 when the interchangeable lens 2 is attached to the camera body 10. . As the imaging device 101, for example, a CMOS color area sensor (CMOS type imaging device) including an imaging surface 101f (see FIG. 4) in which a plurality of pixels configured with photodiodes are two-dimensionally arranged in a matrix. Is used. The image sensor 101 is provided with three primary color filters for R (red), G (green), and B (blue) in a Bayer arrangement, and analog RGB components of RGB color components related to the subject luminous flux received through the interchangeable lens 2. Electric signals (image signals) are generated and output as RGB color image signals.

  On the optical axis LT, a mirror unit 103 is disposed at a position where subject light is reflected toward the viewfinder unit 102. The subject light that has passed through the interchangeable lens 2 is reflected upward by a mirror unit 103 (a main mirror 1031 described later). Part of the subject light that has passed through the interchangeable lens 2 passes through the mirror unit 103.

  The viewfinder unit 102 includes a pentaprism 105, an eyepiece lens 106, and an optical viewfinder 316. The pentaprism 105 has a pentagonal cross section, and is a prism for converting an object light image incident from the lower surface thereof into an upright image by changing the top and bottom of the light image by internal reflection. The eyepiece 106 guides the subject image that has been made upright by the pentaprism 105 to the outside of the optical viewfinder 316. With such a configuration, the finder unit 102 functions as a finder for confirming the object scene at the time of shooting standby before actual shooting.

  The mirror unit 103 includes a main mirror 1031 and a sub mirror 1032, and is provided on the back side of the main mirror 1031 so that the sub mirror 1032 is tilted toward the back of the main mirror 1031. Part of the subject light transmitted through the main mirror 1031 is reflected by the sub mirror 1032, and the reflected subject light enters the phase difference AF module 107.

  The mirror unit 103 is configured as a so-called quick return mirror, and during exposure (main photographing), as shown in FIG. 4, the mirror unit 103 jumps upward with a rotating shaft 1033 as a rotation fulcrum. At this time, the sub mirror 1032 is folded so as to be substantially parallel to the main mirror 1031 when the mirror unit 103 stops at a position below the pentaprism 105. As a result, the subject light from the interchangeable lens 2 reaches the image sensor 101 without being blocked by the mirror 103, and the image sensor 101 is exposed. When the imaging operation with the imaging element 101 is completed, the mirror unit 103 returns to the original position (position shown in FIG. 3).

  In addition, by setting the mirror unit 103 in the mirror-up state shown in FIG. 4 before the main shooting (shooting for image recording), the imaging device 1 can perform moving image processing based on image signals sequentially generated by the imaging device 101. Live view (preview) display in which the subject is displayed on the LCD 311 in a manner is possible. That is, in the imaging apparatus 1 before the actual photographing, the composition of the subject can be determined by selecting the electronic viewfinder (live view mode) in which the live view display is performed or the optical viewfinder. Note that switching between the electronic viewfinder and the optical viewfinder is performed by operating the changeover switch 85 shown in FIG.

  The phase difference AF module 107 is configured as a so-called AF sensor including a distance measuring element that detects focus information of a subject. The phase difference AF module 107 is disposed at the bottom of the mirror unit 103 and detects a focus position by phase difference detection type focus detection (hereinafter also referred to as “phase difference AF”). That is, when the user checks the subject with the optical viewfinder 316 during shooting standby, the light from the subject is guided to the phase difference AF module 107 with the main mirror 1031 and the sub mirror 1032 down as shown in FIG. It is burned. Based on the output from the phase difference AF module 107, the focus lens in the interchangeable lens 2 is driven to perform focusing.

  A shutter unit 40 is disposed in front of the image sensor 101 in the optical axis direction. The shutter unit 40 includes a curtain body that moves in the vertical direction, and a mechanical focal plane that performs an optical path opening operation and an optical path blocking operation of subject light guided to the image sensor 101 along the optical axis LT by the opening operation and the closing operation. It is configured as a shutter. The shutter unit 40 can be omitted when the image sensor 101 is an image sensor capable of complete electronic shutter.

<Functional Configuration of Imaging Device 1>
FIG. 5 is a block diagram illustrating a functional configuration of the imaging apparatus 1.

  As shown in FIG. 5, the imaging apparatus 1 includes the above-described interchangeable lens 2 and the LCD 311, and includes an image sensor 101 on which a subject light image that has passed through the interchangeable lens 2 is formed.

  The imaging element 101 generates an image signal (recording image signal) related to the actual captured image by photoelectric conversion based on the optical image of the subject received by the imaging surface 101f as described above. The image signal generated by the image sensor 101 is output to an analog front end (AFE) 51 including an A / D conversion circuit.

  The charge signal (pixel signal) accumulated in each pixel of the image sensor 101 can be read out by an interlace method. Specifically, as shown in FIG. 6, after reading out the first field Fa (parallel hatched portion) for reading out the charge signal of the odd-numbered rows on the imaging surface 101 f, after reading out the first field Fa is completed, Reading of the second field Fb for reading the charge signal of the even-numbered row is performed.

  For the image sensor 101, charge signals can be read from four output channels. Specifically, as shown in FIG. 7, the charge signal can be read for each of the first channel Ha, the second channel Hb, the third channel Hc, and the fourth channel Hd divided in the horizontal direction on the imaging surface 101f. It has become.

  An image signal output as an analog electrical signal from the image sensor 101 is converted into digital image data (image data) by the AFE 51. The image data is input to a signal processing unit 6 configured with a CPU, for example.

  The signal processing unit 6 performs digital signal processing on the image data output from the AFE 51 to generate image data related to the captured image. The signal processing unit 6 performs various kinds of image processing such as pixel interpolation processing, correcting the black level of each pixel data constituting the image data to a reference black level, and adjusting the white balance of the image. A RAM 52 for temporarily storing image data generated by each image processing is provided so as to be able to transmit data with the signal processing unit 6.

  The image data that has been subjected to the digital signal processing by the signal processing unit 6 can be displayed on the LCD 311. By this image display, confirmation display (after view) for confirming the captured image, reproduction display for reproducing the captured image, and the like are realized. Further, the image data temporarily subjected to digital signal processing in the signal processing unit 6 and temporarily stored in the RAM 52 is subjected to JPEG data compression processing or the like in the signal processing unit 6 and then stored in a memory card 90 as a recording medium. It is also possible to memorize. Further, the signal processing unit 6 has a timekeeping function, and can acquire the current date and time.

  A flash ROM 53 is connected to the signal processing unit 6 so that data can be transmitted. The flash ROM 53 stores a defect detection program PG that functions as a defect detection control unit 61 described later by being executed by the CPU of the signal processing unit 6. In addition, by installing program data such as the defect detection program PG recorded in the memory card 90 in the flash ROM 53, the program can be reflected in the operation of the imaging apparatus 1.

  The signal processing unit 6 executes and controls detection of abnormal defective pixels (later defective pixels) that occur later on the image sensor 101 (for example, after the user purchases the imaging device after shipment from the factory). A control unit 60 and a defective pixel correction unit 65 that corrects a defective pixel with respect to an image signal acquired by the image sensor 101 are provided. In this defective pixel correction unit 65, based on the position data of the defective pixel stored in the defective data storage area 530 in the flash ROM 53, which will be described later, for example, the defective pixel to be interpolated with the pixel signal output from the peripheral pixel of the defective pixel. Correction processing is performed. The defect detection control unit 60 and the defective pixel correction unit 65 are functionally realized by the above-described CPU.

  The defect detection control unit 60 includes a detection processing management unit 61 that manages detection processing of defective pixels, a pixel signal reading unit 62 that reads out pixel signals necessary for detection processing of defective pixels from the image sensor 101, and detection processing of defective pixels. And a data recording control unit 64 for recording the detected defective pixel position data and the like in the defect data storage area 530. The pixel signal read from the image sensor 101 by the pixel signal reading unit 62 is stored in the pixel signal storage area 520 in the RAM 52, and defective pixel detection is performed by the defective pixel detection unit 63 on the stored pixel signal. Is done. In the defective pixel detection unit 63, for example, pixels with a level higher than a certain level with respect to the average level of each pixel signal generated by the image sensor 101 with the shutter unit 40 closed are defective pixels (white defect pixels). Will be detected. The defective pixel detection unit 63 can detect a defective pixel for each pixel group belonging to each of the eight divided regions Eaa to Ebd (see FIG. 8) obtained by dividing the imaging surface 101f. Details).

  A defective pixel detection process performed by the defect detection control unit 6 having the above-described configuration will be described in detail below.

<Defect pixel detection processing>
In the imaging apparatus 1, it is possible to detect a defective pixel later using the defect detection control unit 6 as described above. In this defective pixel detection process, the imaging surface 101f of the image sensor 101 is divided and performed for each divided area (hereinafter also referred to as “divided area”), so that defective pixels in each divided area are obtained. While using the image pickup apparatus 1 while distributing the detection time and reducing the processing load, it is assumed that the inspection of defective pixels for all the pixels of the image pickup device 101 is properly completed.

  Specifically, the imaging surface 101f of the imaging device 101 is divided for each of the first and second fields Fa and Fb described above, and is also divided for each of the first to fourth channels Ha to Hd, as shown in FIG. The area is divided into eight divided areas Eaa, Eab, Eac, Ead, Eba, Ebb, Ebc, and Ebd. In this way, if the imaging surface 101f is divided by area division based on each field related to interlace reading of the image pickup element 101 and area division based on each channel of the image pickup element 101, eight divided areas Eaa to Ebd are obtained. Thus, pixel signal readout from each of the divided areas Eaa to Ebd can be easily realized. Then, every time the image pickup apparatus 1 is started up until a period (for example, one week) when it is less likely that a new defective pixel is generated in the image pickup device 101 after the defective pixel detection is performed, the defect is detected at that time. Defective pixel detection is performed on one divided region with the oldest pixel detection completion time. By performing defective pixel detection for each divided region in this way, the memory region of the RAM 52 used as the pixel signal storage region 520 is reduced to 1/8 compared to the collective defective pixel detection for all the pixels of the image sensor 101. It is possible to reduce the pixel signal readout time required for detecting defective pixels to about 1/8. When the inspection of defective pixel detection is completed in each of the divided areas Eaa to Ebd, the position data of the defective pixels detected in the divided areas (hereinafter also abbreviated as “defective pixel data”) and the inspection completion date and time are recorded. The data is stored in the defect data storage area 530 in the flash ROM 53 by the control unit 64. That is, the date / time information related to the time point when the defective pixel detection is most recently executed for each of the eight divided regions Eaa to Ebd (most recent execution time point) is recorded in the defect data storage region 530.

  A specific operation of the imaging apparatus 1 that performs the defective pixel detection process as described above will be described below.

<Operation of Imaging Device 1>
FIG. 9 is a flowchart showing the basic operation of the imaging apparatus 1. This operation particularly shows a defective pixel detection process performed immediately after the imaging apparatus 1 is activated, and is executed by the defect detection program PG being executed by the CPU of the signal processing unit 60.

  First, when the power is turned on by a user operation on the main switch 317 and the imaging apparatus 1 is activated, the inspection completion date and time of defective pixel detection relating to each of the divided areas Eaa to Ebd (FIG. 8) is displayed as defective data in the flash ROM 53. The data is read from the storage area 530 to the detection process management unit 61. And the detection process management part 61 acquires the present date and time using the time measuring function of the signal processing part 60, and calculates the elapsed time from the examination completion date and time to each divided area Eaa to Ebd (step S1). .

  In step S <b> 2, the detection processing management unit 61 determines whether or not there is a divided region in which a certain period (for example, one week) has passed since the completion of the defective pixel detection inspection. Here, if there is a divided area for which a certain period has elapsed, the process proceeds to step S3, and if there is no such divided area, the process proceeds to step S4.

  In step S3, the detection processing management unit 61 sets all the divided areas for which a certain period has elapsed from the time when the defective pixel detection inspection is completed as the inspection target areas. That is, when there is a divided area in which a certain period has elapsed from the time when the defective pixel detection was most recently executed (the latest execution time) in the eight divided areas Eaa to Ebd, all the corresponding divided areas are the inspection target areas (selected areas). ) Is selected. As a result, defective pixel detection can be performed for all the divided regions where a certain period of time has elapsed and a new defective pixel may be generated when the imaging apparatus 1 is activated. As a result, when the activated imaging device 1 is actually used, defective pixel correction can be performed in a state where subsequent defective pixels are accurately detected for all the pixels of the image sensor 101.

  In step S4, a detection process management is performed by setting the inspection completion date and time of defective pixel detection among the eight divided areas Eaa to Ebd, that is, the divided area having the oldest time when the defective pixel detection was most recently executed (most recent execution time) as the inspection target area. Set in section 61. That is, in the eight divided areas Eaa to Ebd, when there is no divided area for which a certain period has elapsed since the most recent execution time of defective pixel detection, some of the eight divided areas Eaa to Ebd are inspected areas ( Selected area). Thereby, since it becomes possible to gradually advance the defective pixel detection for the image sensor 101 each time the image pickup apparatus 1 is activated, the generation of the divided regions after a certain period of time is suppressed, and the inspection target is detected in step S3. The number of divided areas set in the area can be reduced. In addition, since only one divided region is set as the inspection target region, the inspection time can be shortened, and thereby the delay in the completion of the startup of the imaging apparatus 1 can be minimized. As a result, the probability that the user misses a photo opportunity can be reduced.

  In step S5, in order to read out from the image sensor 101 the pixel signals generated in the pixel group belonging to the inspection target area set in step S3 or step S4, the drive mode and readout mode of the image sensor 101 related to the inspection target area. And set. For example, when the divided area Eab shown in FIG. 8 is set as the inspection target area, the image sensor 101 is read so that the second channel Hb (FIG. 7) of the first field Fa (FIG. 6) is read. Settings for are made.

  In step S6, in accordance with the drive mode and read mode set in step ST5, for example, the pixel signal of the inspection target area generated with the shutter unit 40 closed is read from the image sensor 101 to the pixel signal read unit 62. Here, the pixel signal read by the pixel signal reading unit 62 is stored in the pixel signal storage area 520 in the RAM 52.

  In step S7, based on the pixel signal stored in the pixel signal storage area 520, the defective pixel detection unit 63 performs defective pixel detection for the inspection target area, and updates the defective pixel data in the defect data storage area 530. That is, when the imaging device 1 is activated, the defective pixel detection unit 63 performs defective pixel detection on the inspection target region (selected region) selected from the eight divided regions Eaa to Ebd, and the detection is performed. The result is recorded in the defect data storage area 530 by the data recording control unit 64.

  In step S8, the inspection completion date and time of the divided region that is set as the inspection target region and in which defective pixel detection is performed is updated to the current date and time. Specifically, the inspection completion date and time for each divided area stored in the defect data storage area 530 in the flash ROM 53 is rewritten.

  By performing the operation of the imaging apparatus 1 as described above, the defective pixel detection is performed by setting all the divided areas in which a certain period has elapsed from the completion of the inspection of the defective pixel detection when the imaging apparatus 1 is started as the inspection target area. The subsequent defective pixels can be accurately detected for all the pixels. As a result, when the user uses the imaging apparatus 1, appropriate defective pixel correction can be performed on a pixel signal generated by a subsequent defective pixel of the imaging element 101.

<Modification>
In the operation of step S4 (FIG. 9) in the above embodiment, it is not essential to set the divided area with the oldest inspection completion date as the inspection target area, and one arbitrarily selected divided area is to be inspected. You may make it set as an area | region. Further, two or more divided areas smaller than the number of divisions related to the divided areas may be set as inspection target areas.

  In the above embodiment, it is not essential to divide the imaging surface 101f into the eight divided areas Eaa to Ebd, and even if the imaging surface 101f is divided into two by area division based on each field related to interlace reading. The image pickup surface 101f may be divided into four by area division based on each channel of the image pickup element 101. Further, the imaging surface 101f may be divided into two or more areas without being limited to the area division based on the field or channel.

1 is a diagram illustrating an external configuration of an imaging apparatus 1 according to an embodiment of the present invention. 1 is a diagram illustrating an external configuration of an imaging apparatus 1. FIG. 1 is a longitudinal sectional view of an imaging apparatus 1. FIG. It is a figure which shows the state of the mirror up in the mirror part. 3 is a block diagram illustrating a functional configuration of the imaging apparatus 1. FIG. It is a figure for demonstrating the 1st field Fa and the 2nd field Fb prescribed | regulated on the imaging surface 101f. It is a figure for demonstrating each channel Ha-Hd prescribed | regulated on the imaging surface 101f. It is a figure for demonstrating eight division area Eaa-Ebd prescribed | regulated on the imaging surface 101f. 3 is a flowchart showing a basic operation of the imaging apparatus 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Imaging device 2 Interchangeable lens 6 Signal processing part 10 Camera body 52 RAM
53 Flash ROM
60 Defect Detection Control Unit 61 Detection Process Management Unit 62 Pixel Signal Reading Unit 63 Defective Pixel Detection Unit 64 Data Recording Control Unit 65 Defective Pixel Correction Unit 90 Memory Card 101 Imaging Element 101f Imaging Surface 520 Pixel Signal Storage Area 530 Defect Data Storage Area Eaa ~ Ebd Divided area Fa First field Fb Second field Ha First channel Hb Second channel Hc Third channel Hd Fourth channel PG Defect detection program

Claims (5)

An image sensor that generates an image signal based on an optical image received on the imaging surface;
A defective pixel detection means capable of detecting a defective pixel for each pixel group belonging to each of a plurality of regions obtained by dividing the imaging surface into regions;
Recording control means for causing a predetermined recording means to record information related to the most recent execution time at which the defective pixel was most recently detected for each of the plurality of areas;
Detection control means for executing detection of the defective pixel with respect to a selected region selected from the plurality of regions when the imaging device is activated;
With
The detection control means includes
A first selection control unit that selects a part of the plurality of regions as the selection region when there is no region in which the predetermined period has elapsed since the most recent execution time point in the plurality of regions;
A second selection control means for selecting, as the selection area, an area in which the predetermined period has elapsed when there is an area in which the predetermined period has elapsed since the most recent execution time in the plurality of areas;
An imaging apparatus having   2. The imaging according to claim 1, wherein the plurality of areas are obtained by dividing the imaging surface by area division based on each field related to interlace reading of the image sensor and / or area division based on each channel of the image sensor. apparatus. The first selection control means includes
Means for setting, as the partial area, an area having the oldest execution time point among the plurality of areas;
The imaging apparatus according to claim 1, comprising: A defective pixel detection step of detecting a defective pixel for each pixel group belonging to each of a plurality of regions obtained by dividing an imaging surface of an imaging element provided in an imaging device;
A recording control step of causing a predetermined recording unit to record information on the latest execution time at which the detection of the defective pixel was executed most recently for each of the plurality of regions;
A detection control step of detecting the defective pixel with respect to a selected region selected from the plurality of regions when the imaging device is activated;
With
The detection control step includes
A first selection control step of selecting a part of the plurality of regions as the selection region when there is no region in which the predetermined period has elapsed since the most recent execution time in the plurality of regions;
A second selection control step of selecting, as the selection area, an area in which the predetermined period has elapsed when there is an area in which the predetermined period has elapsed since the most recent execution time in the plurality of areas;
A defective pixel detection method comprising: In the computer built into the imaging device,
A defective pixel detection step of detecting a defective pixel for each pixel group belonging to each of a plurality of regions obtained by dividing an imaging surface of an imaging element provided in the imaging device;
A recording control step of causing a predetermined recording unit to record information on the latest execution time at which the detection of the defective pixel was executed most recently for each of the plurality of regions;
A detection control step of detecting the defective pixel with respect to a selected region selected from the plurality of regions when the imaging device is activated;
And execute
The detection control step includes
A first selection control step of selecting a part of the plurality of regions as the selection region when there is no region in which the predetermined period has elapsed since the most recent execution time in the plurality of regions;
A second selection control step of selecting, as the selection area, an area in which the predetermined period has elapsed when there is an area in which the predetermined period has elapsed since the most recent execution time in the plurality of areas;
A defective pixel detection program.

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