JP2009124524A - Imaging apparatus, and captured pixel data correcting method and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus capable of appropriately correcting captured pixel data of pixels for the same color light of a solid-state imaging device to which a pixel-shaped-pixel technology is applied. <P>SOLUTION: An imaging apparatus includes a solid-state imaging device in which a plurality of pixels arrayed in a two-dimensional array shape are collected into sets each constituted of a plurality of predetermined pixels having the same array patterns of pixels and an imaging plane is provided to share a circuit required for pixel constitution for the plurality of predetermined pixel constituting each one set. The imaging apparatus further includes: a correction means for performing predetermined correction based on a correction control signal upon captured pixel data for each of the same color light made incident on pixels through an optical system; and a correction control signal calculation means which calculates the correction control signal for each of the same color light, respectively, in accordance with the difference of pixel positions within the array patterns for the plurality of predetermined pixels within the array pattern, and supplies the correction control signal to the correction means. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an imaging device including a solid-state imaging device such as a CMOS image sensor, a correction method for imaged pixel data from the imaging device, and a program for executing the correction method.

  For example, a solid-state image sensor such as a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor includes a color filter above a pixel cell including a photoelectric conversion element, and a condensing microlens thereon. Has a laminated structure. In an imaging device such as a digital video camera or a digital still camera, an imaging surface of a solid-state imaging device in which a lens system such as a photographing lens is provided in front of a microlens and a plurality of pixels are arranged in a two-dimensional array A subject image is formed on the screen.

  By the way, in general, in the imaging device, the incident light amount to the imaging surface of the solid-state imaging device is caused by the lens system, the peripheral portion of the imaging surface is lower than the central portion of the imaging surface of the solid-state imaging device, It is known that a phenomenon of non-uniformity of sensitivity (non-uniformity) called shading occurs in which the peripheral part of the image becomes darker than the central part of the image.

  This shading occurs mainly due to the optical relationship between the microlens provided on the front side of the imaging surface of the solid-state imaging device and the photographing lens. For example, the light beam that has passed through the photographic lens is incident obliquely toward the periphery of the imaging surface. Therefore, in the region of the peripheral portion away from the optical axis of the photographic lens on the imaging surface, the photosensitive portion (pixel cell) of the pixel. On the other hand, only a part of the original incident light is incident, the amount of light is reduced, and shading occurs. The shading phenomenon occurs in proportion to the distance from the position of the pixel position on the imaging surface of the solid-state imaging device to the position where the imaging surface and the optical axis of the photographing lens intersect (usually the center position of the imaging surface). That is, shading occurs in which the amount of light decreases according to the deviation of the photographing lens from the optical axis center position.

  In order to correct such shading, in general, the pixel value is multiplied by the correction coefficient obtained according to the distance from the center of the optical axis, or the gain is adjusted from the correction coefficient, for the image pickup pixel signal from the image pickup device. For example, Japanese Patent Application Laid-Open No. 2007-36696 discloses that electrical correction is performed.

  As an example of a shading correction method, Patent Document 1 discloses a method of reading correction data stored in a storage device in accordance with a distance from the optical axis center, performing gain adjustment, and performing correction. In addition, the imaging plane is divided into four areas, upper, lower, left, and right. Each area is weighted, coordinate-shifted, and further rotated so that it does not face the optical axis but has an angle. There is also a method capable of correcting the shading characteristics of the rotational shape.

  In recent years, solid-state imaging devices such as CCD image sensors and CMOS image sensors used for video cameras and digital still cameras are required to have higher pixel counts and smaller sizes at the same time. If the number of pixels is increased while maintaining the size reduction, the area per pixel is naturally reduced, and there is a concern that the pixel sensitivity may decrease.

  In order to solve this problem, in the past, in a pixel configuration of a solid-state imaging device (consisting of a photodiode, a peripheral circuit including an amplification transistor, a reset transistor, etc.) by devising a circuit / wiring layout or an evolution of a manufacturing process, etc. By increasing the proportion of the photodiode portion as much as possible, we have attempted to achieve both high pixel count and miniaturization.

  However, the recent demand for higher pixel count and smaller size for solid-state imaging devices has increased, and at the same time, higher image quality at low illuminance has attracted attention. It has become virtually impossible to provide a solid-state imaging device.

  Therefore, as a technique for avoiding this problem in the solid-state imaging device, a part of a circuit necessary for constituting a pixel, for example, an amplifying transistor and a resetting transistor are adjacent to or adjacent to each other in the horizontal direction and / or the vertical direction. A technology that increases the sensitivity of pixels by reducing the number of circuits (including wiring) per pixel by increasing the area allocated to the light-receiving photodiode by reducing the number of circuits (including wiring) shared by multiple pixels is drawing attention. (Hereinafter, this technology is referred to as pixel sharing technology).

  For example, in Patent Document 2 (Japanese Patent No. 3838665), an amplification transistor and a reset transistor necessary for reading pixel data from a pixel are shared by two adjacent pixels, and the amplification transistor and the reset transistor are shared. By sequentially selecting two pixels connected to each other at different times, pixel data is read out from each pixel, thereby reducing the number of transistors per pixel and turning that amount to the area of the photodiode. Thus, a pixel sharing technique that improves the sensitivity of the pixel is disclosed.

  By the way, in a general solid-state imaging device that does not use the pixel sharing technique, all the pixels are usually configured uniformly. That is, the pixel configuration of a general solid-state imaging device is always the same regardless of the pixel at any position on the screen. For this reason, in a general solid-state image sensor, the peripheral environment on the semiconductor structure of the photodiode for each pixel is the same for all pixels, and basically, except for the factor of manufacturing variation, it is basically optical. The characteristics are common to all pixels.

  However, in the solid-state imaging device to which the “pixel sharing technology” including the above-mentioned Patent Document 2 is applied, in order to share and use a circuit between a plurality of adjacent or adjacent pixels, a plurality of pixels sharing a circuit are combined into one pixel. When considered as a unit, all the units have the same configuration, but the surrounding environment on the semiconductor structure differs for each pixel in the unit depending on the pixel arrangement position in the unit. For this reason, in a solid-state imaging device using a pixel sharing technique, a circuit layout is formed with a repetitive pattern corresponding to an arrangement pattern of a plurality of pixels sharing a circuit.

  That is, when a plurality of pixels sharing a circuit are used as a unit, a plurality of the units are repeatedly arranged in the horizontal direction and the vertical direction on the solid-state imaging device. The pixels at the same position on the arrangement pattern of a plurality of pixels in the unit have the same peripheral environment arrangement on the semiconductor structure of the photodiode, and therefore have the same optical characteristics.

  However, since the circuit and layout are different between pixels at different positions on the arrangement pattern of the pixels in a plurality of pixel units sharing a circuit, that is, between adjacent pixels or adjacent pixels in the unit, The peripheral environment arrangement on the semiconductor structure of the photodiode is also different, and it is inevitable that the pixel characteristics of the pixels are different from each other.

  For this reason, even if a solid-state image sensor to which the “pixel sharing technology” is applied is used to capture an image of a subject that is uniform on the entire screen, the pixel data output value differs between adjacent pixels in the unit, and the quality of the final output image This causes a problem that the remarkably decreases.

In order to avoid the above problems related to the pixel sharing technology as described above,
A. Reduce optical non-uniformity as much as possible by devising pixel layout. Patent Document 3 (Japanese Patent Application Laid-Open No. 2004-172950) discloses a technique for devising the pixel structure on the solid-state imaging device side such that pixels are shared in a combination that does not affect the output image even if optical non-uniformity occurs. Publication No.), Patent Literature 4 (Japanese Patent Laid-Open No. 205-110104), Patent Literature 5 (Japanese Patent Laid-Open No. 2006-73733), Patent Literature 6 (Japanese Patent Laid-Open No. 2006-157953), etc.

The above-mentioned patent documents are as follows.
Japanese Patent Laid-Open No. 2007-142697 Japanese Patent No. 3838665 JP 2004-172950 A Japanese Patent Laid-Open No. 205-110104 JP 2006-73733 A JP 2006-157953 A

  In the shading correction technique disclosed in Patent Document 1 described above, in the case of a monochrome (single color) image, the storage device stores a set of correction data for shading correction. In the case of a color image, a set of correction data for shading correction is stored for each color light (thus, a plurality of sets of correction data for shading correction corresponding to the number of color lights for color).

  Pixels for each color light (including a single color in the case of monochrome. In addition, a single color includes a case of only a luminance value (brightness signal), that is, a so-called black and white case. In accordance with the distance from the optical axis center, the correction data is read out from the correction coefficient calculation table for the color light stored in the storage device (including the case of black and white monochrome; the same applies hereinafter), and gain adjustment is performed. To make corrections.

  In other words, the shading characteristics of the pixels for each color light are established on the premise that they have the same characteristics over the entire screen.

  For this reason, even in a solid-state imaging device to which the above-described pixel sharing technique is applied, it is necessary to eliminate variations in pixel characteristics for each of the shared pixels by using the techniques disclosed in Patent Documents 2 to 6 described above. There is.

  However, as described above, all of the techniques disclosed in Patent Documents 3 to 6 described above devise the pixel structure on the solid-state imaging device side. For this reason, for example, the pixel structure according to A can reduce the optical non-uniformity of a plurality of pixels sharing a circuit (hereinafter, a plurality of pixels sharing a circuit is referred to as a shared pixel). However, it cannot be completely eliminated.

  Therefore, in a solid-state imaging device to which the pixel sharing technique is applied, conventionally, even if the conventional shading correction technique as described above is used due to variations in pixel characteristics of a plurality of pixels constituting the shared pixel. There is a problem that the image cannot be completely corrected, and as a result, a certain amount of lens shading remains in the corrected signal, which deteriorates the output image quality.

  Further, in any case of the above method A or B, which eliminates variations in pixel characteristics for each of the shared pixels, solid-state imaging up to the pixel configuration, layout, or pixel data readout configuration A large restriction is imposed on the element, and accordingly, a large restriction is also imposed on the entire imaging apparatus that processes the output of the solid-state imaging element to which the method A or B is applied. There is also a problem.

  When correcting imaging pixel data from pixels for the same color light, not only the above-described shading but generally correction is always performed using the same correction characteristics as the same characteristics. In the case of correcting the pixel data from the solid-state image sensor, the same problem as in the case of shading described above remains.

  In view of the above-mentioned problems, the present invention does not devise the pixel structure on the solid-state image sensor side, but appropriately corrects the image pixel data from the pixels for the same color light of the solid-state image sensor to which the pixel sharing technology is applied. An object of the present invention is to provide an imaging apparatus and an imaging pixel data correction method that can further reduce the influence on the output image quality.

In order to solve the above problems, the present invention provides:
A plurality of pixels arranged in a two-dimensional array is formed as a set of a plurality of predetermined pixels having the same pixel arrangement pattern, and the pixels corresponding to the predetermined plurality of pixels constituting each set A solid-state imaging device including an imaging surface configured to share a circuit necessary for the configuration;
Correction means for performing predetermined correction on the imaged pixel data from the pixel for each identical color light incident on the pixel through the optical system based on a correction control signal;
The correction control signal for each of the same color light is calculated according to the difference in pixel position in the array pattern of the predetermined plurality of pixels constituting each set, and the correction is performed. Correction control signal calculation means to be supplied to the means;
An imaging apparatus comprising:

  In the imaging apparatus according to the present invention having the above-described configuration, a predetermined plurality of pixels having the same pixel arrangement pattern are taken as one set, and these are used as shared pixels. The correction control signal generating means of the image pickup apparatus according to the present invention generates different correction control signals according to differences in pixel positions in the shared pixel array pattern even for the same color light pixel.

  Then, the correction unit performs correction processing for each pixel data using the correction control signal for the pixel data at the corresponding pixel position in the array pattern generated by the correction control signal generation unit. Thereby, the non-uniformity of the pixel characteristics based on the pixel position corresponding to the arrangement pattern in each of the plurality of pixels constituting the shared pixel is corrected and reduced.

  According to the present invention, a correction control signal for each of the same color light with respect to imaging data from a solid-state imaging device having a plurality of predetermined plurality of pixels having the same pixel arrangement pattern as a set and a shared pixel. In the image pickup apparatus using the solid-state image pickup device to which the pixel sharing pixel technology is applied, the common pixel is generated according to the difference in each pixel position in the array pattern and supplied to the correction unit. However, appropriate correction can be performed, and the influence on the output image quality can be further reduced.

  Hereinafter, embodiments of an imaging apparatus according to the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram illustrating a configuration example of a main part of an imaging apparatus 10 according to this embodiment, an optical system 1 including an imaging lens, a CMOS image sensor 2 as an example of a solid-state imaging device, and an analog signal processing unit. 3, a digital signal processing unit 4, a camera control microcomputer (microcomputer is abbreviated as a microcomputer) 5, a camera shake sensor 6, a lens driving driver unit 7, a human interface microcomputer 8, and a user interface 9. I have.

  The optical system 1 includes an actuator for adjusting the position of the imaging lens in order to correct camera shake. This actuator is driven and controlled by a lens driving signal from the lens driving driver section 7. The lens driving driver unit 7 generates a lens driving signal based on control from the camera control microcomputer 5 and controls driving of the actuator.

  In addition, the lens system 1 in the imaging apparatus of this embodiment includes a zoom mechanism that can change the focal length from the short focal side (wide angle side) to the long focal side (telephoto side). The lens driving driver unit 7 controls the zoom mechanism of the optical system 1 based on the zoom control signal received from the camera control microcomputer 5.

  The CMOS image sensor 2 is one in which a large number of pixels are arranged in the horizontal direction and the vertical direction and a pixel sharing technique is applied. In order to obtain a color image, a color filter is used as a light filter. It is arranged on the incident side.

  FIG. 2 shows an example of a pixel array and a color filter array on the imaging surface of the CMOS image sensor 2. FIG. 2A shows a so-called Bayer arrangement, in which a large number of rectangular pixels Ps are arranged in the horizontal direction and the vertical direction, and red R and green are arranged in every other horizontal pixel row. G color filters are arranged to alternately face the pixels, and in the remaining horizontal rows of pixels, the blue B and green G color filters are arranged to alternately oppose the pixels. In addition, the pixels to which the red R and blue B color filters are arranged are arranged so as not to be included in one column of pixels in the vertical direction.

  2B and 2C show a large number of rhombus-shaped pixels Pd arranged in the horizontal and vertical directions. This is an example of a pixel arrangement in which the apparent pixel pitch can be made shorter in the horizontal direction and the vertical direction than in the case of the Bayer array in FIG. However, as illustrated, the arrangement of the color filters is different between FIG. 2B and FIG. 2C.

  That is, in the pixel arrangement example of FIG. 2B, in every other horizontal pixel row, the red R and blue B color filters alternately face the pixels, and the red R and blue B colors. The filters are arranged so as to alternately face the pixels in the vertical direction, and only the green G color filter is arranged so as to face the pixels in every other horizontal row of pixels. It is a thing.

  2C, in every other horizontal pixel row, red R and green G color filters are arranged so as to alternately face the pixels, and blue B And green G color filters are arranged alternately so as to be opposed to the pixels in every other row, and in every other horizontal row of pixels, the color of green G Only the filters are arranged so as to face the pixels, and the pixels where the red R and blue B color filters are arranged are arranged so as not to be included in one column of pixels in the vertical direction.

  The above is an example in the case of the configuration of a so-called single-plate solid-state imaging device. For each color light of red R, green G, and blue B, as shown in FIGS. One solid-state imaging device, that is, a solid-state imaging device Ir for red light, a solid-state imaging device Ig for green light, and a solid-state imaging device Ib for blue light may be provided as a three-plate configuration. FIG. 2D shows a case where a solid-state imaging device in which a large number of rectangular pixels are arranged in the horizontal direction and the vertical direction is used, as in FIG. 2A. Also, FIG. Is a case where a solid-state imaging device in which a large number of rhombus pixels are arranged in the horizontal direction and the vertical direction is used, as in the case of FIGS. 2B and 2C.

  Here, the pixel facing the red R color filter is a pixel for red light, the pixel facing the blue B color filter is a pixel for blue light, and the green G color filter is facing. These pixels are green light pixels. In FIG. 2, R, G, and B indicate not only each color filter but also each color light pixel.

  Needless to say, in the case of a monochrome imaging element instead of the color imaging element as in this example, the color filter is not provided opposite to the monochrome light pixel. In the case of a three-plate image sensor as shown in FIGS. 2D and 2E, for all pixels on the imaging surfaces of the solid-state imaging devices Ir, Ig, and Ib for each color light. One color filter is provided oppositely. Both are objects of the present invention.

  The CMOS image sensor 2 of this example can have any of the configurations shown in FIGS. 2A to 2E. However, in this embodiment described below, for simplicity of explanation, FIG. In the case of the Bayer array of A).

  In this embodiment, the output from the CMOS image sensor 2 is, for example, one channel. It is assumed that this one-channel reading method from the CMOS image sensor is performed as shown in FIG. That is, as shown in FIG. 3, for a large number of pixels Ps of the CMOS image sensor, the imaged pixel data is sequentially read out by one channel from the left, one row at a time, and scanned horizontally across one screen. When all the horizontal lines have been read, the process proceeds to the next line, and the entire screen is read while scanning in the horizontal direction.

  Therefore, in this example, the output pixel sequence from the CMOS image sensor 2 is the order in which the pixel array is scanned in the horizontal direction.

  In general, the CMOS image sensor is suitable not only for the above-described 1-channel reading but also for multi-channel parallel reading, but the present invention is not essentially dependent on such a reading system. In this embodiment, for the sake of explanation, an example of the reading sequence as shown in FIG. 3 will be described for reading. Of course, the application of the present invention is not limited to this reading format. Instead, the embodiments described below can be applied to other readout formats as appropriate.

  The CMOS image sensor 2 of this embodiment has a pixel structure to which the pixel sharing technique described above is applied. FIG. 4A, FIG. 4B, and FIG. 4C show three examples of shared pixel array patterns in the case of a Bayer array.

  In each of FIG. 4A, FIG. 4B, and FIG. 4C, the upper stage shows an array pattern of shared pixels in the CMOS image sensor 2, and a plurality of pixels connected by thick lines in the figure. Is a shared pixel.

  In each of FIGS. 4A, 4B, and 4C, the middle stage is referred to as an identifier (shared pixel ID (Identification)) for each pixel position in the pixel arrangement pattern of the shared pixels. ).

  In each of FIGS. 4A, 4B, and 4C, the lower stage represents the output pixel sequence from the CMOS image sensor 2 by the shared pixel ID. This output sequence of the shared pixel ID in the lower stage is a case where attention is paid only to the arrangement pattern of the shared pixels, and the difference in the color filter corresponding to each pixel is not considered here. In the lower description, H in 1H, 2H, 3H,... Represents a horizontal row, that is, a horizontal line.

  The example of FIG. 4A is a case where two pixels in the vertical direction are shared pixels. That is, in this example, two pixels above and below two horizontal lines adjacent to each other are shared pixels. In the first horizontal line (1H, 3H, 5H,...) Of the two adjacent horizontal lines forming the shared pixel relationship, the red light pixel R and the green light pixel. G appear alternately, and in the second horizontal line (2H, 4H, 6H,...) Of the two adjacent horizontal lines constituting the shared pixel relationship, blue The light pixels B and the green light pixels G appear alternately. In this example, the shared pixel ID is determined in consideration of each color light.

  Therefore, as shown in the middle part of FIG. 4A, the shared pixel ID is assigned to the red light pixel R on the first horizontal line (1H, 3H, 5H,...) “0” is assigned, ID “1” is assigned to the green light pixel G, and “0” and “1” appear alternately.

  In the second horizontal line (2H, 4H, 6H,...), ID “2” is assigned to the green light pixel G, and ID “3” is assigned to the blue light pixel B. And “2” and “3” appear alternately.

  Therefore, the pixel output sequence represented by the shared pixel ID is “0” and “1” in the odd horizontal lines of the 1H, 3H, 5H,... As shown in the lower part of FIG. Appear alternately, and “2” and “3” appear alternately on the 2H, 4H, 6H,... Even-numbered horizontal lines.

  The example in FIG. 4B is a case where two pixels in the vertical direction are shared pixels, as in the example in FIG. 4A. In this example, one pixel in the horizontal direction is used. Each time, the pixels constituting the shared pixel are at pixel positions shifted by one pixel in the vertical direction. Also in this example, in order to determine the shared pixel ID in consideration of each color light, the same four types of IDs “0”, “1”, “2”, “3” as in the example of FIG. Will be assigned.

  Therefore, as shown in the middle part of FIG. 4B, the shared pixel ID is assigned to each color light pixel in the same manner as in the example of FIG. 4A, and the pixel sequence represented by the shared pixel ID is As shown in the lower part of FIG. 4B, it is exactly the same as the case of FIG.

  The example of FIG. 4C is a case where the pixels at the four zigzag arrangement positions in the vertical direction are shared pixels. In other words, the four pixels constituting the shared pixel extend over four horizontal lines.

  As shown in the middle part of FIG. 4C, the shared pixel ID is different from the two horizontal lines (four horizontal lines) as the shared pixel, even in the case of the same red light pixel R. Of the first horizontal line and the third horizontal line), two IDs “0” and ID “4” are assigned to these two red light pixels R, Similarly, even in the same red light pixel R, the shared pixels include two different horizontal line positions (second horizontal line and fourth horizontal line of the four horizontal lines). Two IDs “3” and “7” are assigned to the two pixels B for blue light.

  Since the same green light pixel G includes four pixels located at positions across all four horizontal lines constituting the shared pixel, the ID “1” is assigned to these four green light pixels G. ”, ID“ 2 ”, ID“ 5 ”, and ID“ 7 ”.

  Therefore, as shown in the lower part of FIG. 4C, the pixel output sequence represented by the shared pixel ID is ID “0” and ID “1” in the first horizontal line of the four horizontal lines constituting the shared pixel. Appear alternately, ID “2” and ID “3” appear alternately on the second horizontal line of the four horizontal lines, and ID “4” appear on the third horizontal line of the four horizontal lines. ID “5” appears alternately, and in the fourth horizontal line of the four horizontal lines, ID “6” and ID “7” appear alternately, and this is repeated every four horizontal lines. Will appear.

  The shared pixel array pattern in the CMOS image sensor 2 of this embodiment may be any of FIGS. 4A, 4B, and 4C. In this embodiment, the CMOS image sensor 2 is, for example, a diagram. 4 (A) is provided with shared pixels of the shared pixel array pattern.

  The light incident on the optical system 1 is photoelectrically converted in the CMOS image sensor 2 having the above-described configuration, and then output as an electrical signal, that is, as image pickup pixel data. The CMOS image sensor 2 performs read start / stop control, read position control, and the like according to a control signal from the camera control microcomputer 5.

  In this example, the output imaging pixel data of one channel from the CMOS image sensor 2 is supplied to the analog signal processing unit 3 and subjected to processing such as sample hold and automatic gain control, and then A / D ( (Analog-digital) conversion and input to the digital signal processing unit 4.

  In this example, the analog output signal from the CMOS image sensor 2 has been described as being configured to sample and hold, automatic gain control, and A / D conversion in the analog signal processing unit 3. The configuration of the analog signal processing unit 3 may be taken in.

  The digital signal processing unit 4 converts the imaging pixel signal RAW (raw data) supplied from the analog signal processing unit 3 into digital imaging pixel data, and performs a camera control microcomputer on the converted digital imaging pixel data. Various signal processing is performed in accordance with the instructions in 5. Various signal processing performed in the digital signal processing unit 4 includes so-called camera signal processing such as white balance processing, gamma processing, and color difference signal processing, and detection data for camera control (data indicating captured image information in the screen, For example, brightness, contrast, hue, and the like) are included.

  As will be described later, the digital signal processing unit 4 includes a reference timing signal generator, and generates various timing signals from the reference timing signal generator. The timing signal includes a horizontal synchronization signal HD and a vertical synchronization signal VD for the captured image data, and the digital signal processing unit 4 converts the horizontal synchronization signal HD, the vertical synchronization signal VD, and other necessary timing signals into a CMOS image. Supply to the sensor 2. Although not shown, the timing signal from the reference timing signal generator of the digital signal processing unit 4 is also supplied to the camera control microcomputer 5.

  The CMOS image sensor 2 reads the imaged pixel data from each pixel in the above-described readout format of FIG. 3, and includes a readout unit and a readout timing signal generator for that purpose. Then, the readout timing generator of the CMOS image sensor 2 generates a readout timing signal synchronized with the horizontal synchronization signal HD and the vertical synchronization signal VD received from the digital signal processing unit 4, and captures the image pickup pixels from the CMOS image sensor 2. Data is read based on a control signal from the camera control microcomputer 5.

  In this embodiment, the digital signal processing unit 4 further includes a shading correction processing unit for each shared pixel as a configuration for correcting the non-uniformity of the shared pixel. The details of will be described later.

  The camera control microcomputer 5 grasps the current state of the captured image based on the detection data sent from the digital signal processing unit 4 and the camera shake information of the imaging device 10 sent from the camera shake sensor 6, and the human interface microcomputer 8 Control is performed according to various setting modes sent via. That is, the camera control microcomputer 5 sets the read area designation data to the CMOS image sensor 2, the captured image control data to the digital signal processing unit 4, the lens control data to the lens driving driver unit 7, and the gain for automatic gain control. Control data is supplied to the analog signal processing unit 3, respectively.

  The CMOS image sensor 2 sequentially reads out signals of arbitrary areas designated by the read area designation data in the imaging area of the imaging surface of the CMOS image sensor 2, and outputs the signals to the analog signal processing unit 3. .

  The digital signal processing unit 4, the lens driving driver unit 7, and the analog signal processing unit 3 perform processing according to the control value sent from the camera control microcomputer 5, and perform desired signal processing / timing generation / lens driving.・ Gain processing is realized.

  The user interface 9 includes a key operation unit for accepting user operation input, and a display for notifying the mode of the imaging device 10 and camera information. Menu operations and the like performed by the user are controlled by the human interface microcomputer 8 via the user interface 9.

  The human interface microcomputer 8 detects, based on a user operation instruction input through the user interface 9, what kind of shooting mode and zoom magnification the user is currently selecting and what kind of control is desired. Then, the detection output is sent to the camera control microcomputer 5 as user instruction information.

  At the same time, the camera control microcomputer 5 transmits the obtained camera control information (subject distance, F value, zoom position, shutter speed, magnification, etc.) to the human interface microcomputer 8 and the current interface via the display of the user interface 9. The camera information is notified to the user. Details of these blocks are omitted here because they are not directly related to the present invention.

[Description of Detailed Configuration Example of Digital Signal Processing Unit 4]
FIG. 5 shows a detailed configuration example of the digital signal processing unit 4. In this example, the digital signal processing unit 4 includes a camera signal preprocessing unit 41, a shared pixel-specific shading correction processing unit 42, a camera signal main processing unit 43, a reference timing signal generator 44, and a communication interface 45. Is provided.

  The reference timing signal generator 44 generates the horizontal synchronization signal HD and the vertical synchronization signal VD described above, supplies them to the CMOS image sensor 2, and supplies the reference timing signal TG, which serves as a reference for pixel timing, to the camera signal preprocessing unit 41. And supplied to the shared pixel-specific shading correction processing unit 42. The reference timing signal generator 44 also supplies various timing signals to the camera signal main processing unit 43. Further, although not shown, the reference timing signal generator 44 also supplies various timing signals to the camera control microcomputer 5.

  The communication interface 45 supplies various detection values DET obtained from the camera signal main processing unit 43 to the camera control microcomputer 5. As described above, the camera control microcomputer 5 generates a control signal such as an automatic gain control signal based on the received various detection values DET and supplies the control signal to the corresponding processing unit.

  The communication interface 45 receives the camera signal processing control parameter Pm from the camera control microcomputer 5 and sends necessary control signals to the camera signal preprocessing unit 41, the shared pixel-specific shading correction processing unit 42, and the camera signal main processing unit 43. To supply. As a result, the camera signal preprocessing unit 41, the shared pixel-specific shading correction processing unit 42, and the camera signal main processing unit 43 are configured such that the processing operation can be controlled by the camera control microcomputer 5.

  The camera signal preprocessing unit 41 receives the captured image signal RAW from the analog signal processing unit 3 and executes a processing group that should be performed as a preceding stage of the shading correction processing, and includes, for example, a digital clamp processing. Since the processing group performed by the camera signal preprocessing unit 41 is not directly related to the present invention, a detailed description thereof is omitted here.

  The output of the camera signal preprocessing unit 41 is supplied to the shading correction processing unit 42 for each shared pixel. The shared pixel-specific shading correction processing unit 42 executes a shading correction process for each pixel constituting the shared pixel (for each pixel having the same shared pixel ID).

  In this embodiment, as shown in FIG. 6, only the imaged pixel data from the pixels in the effective pixel region VFL out of all the pixel regions AFL on the imaging surface are processed by the shading correction processing unit 42 for each shared pixel. To do. For this reason, the camera signal preprocessing unit 41 and the shared pixel-specific shading correction processing unit 42 indicate an area instruction indicating whether or not the imaging pixel data sent from the analog signal processing unit 3 is in the effective pixel area VFL. Information Sfl is sent from the camera control microcomputer 5 through the communication interface 45.

  In this embodiment, information related to the shared pixel ID described with reference to FIG. 4, that is, shared pixel ID setting information Sid is transmitted from the camera control microcomputer 5 to the communication interface in the shading correction processing unit 42 for each shared pixel. Sent through 45. Further, a reference timing signal TG (including a pixel clock), a horizontal synchronization signal HD, and a vertical synchronization signal VD are sent from the reference timing signal generator 44 to the shading correction processing unit 42 for each shared pixel.

  The detailed configuration and processing operation of the shading correction processing unit 42 for each shared pixel will be described in detail later. The outline is as follows.

  That is, in this embodiment, the shading correction processing unit 42 for each shared pixel obtains a shading characteristic generated by the optical system 1 including the photographing lens in advance, and on the imaging surface of the CMOS image sensor 2 according to the shading characteristic. A correction control signal for correcting the imaging pixel data from the pixel so as to match the brightness of the pixel at the center of the imaging surface, that is, a gain control signal for correcting the brightness, from the optical axis center of the photographing lens. This is stored as a correction control signal for the pixel at the distance position. Even if the pixels for the same color light are used, different correction control signals are generated if the shared pixel ID is different.

  In this embodiment, this correction control signal is stored for each shared pixel ID, that is, corresponding to each of a plurality of pixels constituting the shared pixel.

  Then, a correction control signal to be referred to is selected from among a plurality of stored correction control signals depending on which of the plurality of pixels constituting the shared pixel is the input imaging pixel data. Also, the pixel position of the input imaging pixel data is converted into a distance position from the optical axis center of the imaging lens, and a correction control signal stored in advance is searched by the converted distance position, and each imaging pixel data is searched. A correction control signal for is obtained.

  For this reason, first, in the shading correction processing unit 42 for each shared pixel, based on the quasi-timing signal TG (including the pixel clock), the horizontal synchronization signal HD, and the vertical synchronization signal VD from the reference timing signal generation unit 44, Coordinate position information is calculated as to which position in the effective pixel area VFL the imaged pixel data Pd input from the processing unit 41 is.

  Then, the coordinate position information of the pixel is converted into coordinates corresponding to the form of shading characteristics generated in the image (coordinates of the distance position from the optical axis center of the photographing lens).

  Further, in the shading correction processing unit 42 for each shared pixel, a plurality of imaging pixel data Pd input from the camera signal pre-processing unit 41 is configured by the shared pixel ID setting information Sid (shared pixel ID information). A correction control signal determined by conversion coordinates (coordinates of a distance position from the center of the optical axis of the photographing lens) and a shared pixel ID is detected from correction control signals stored in advance. Choose to get.

  Then, the shading correction processing unit 42 for each shared pixel performs shading correction by correcting the gain of the imaging pixel data Px input from the camera signal preprocessing unit 41 using the obtained correction control signal. The corrected imaging pixel data Pxc is supplied to the camera signal main processing unit 43.

  In the camera signal main processing unit 43, various camera signals configured by known techniques such as noise reduction / defect correction / demosaic / white balance / resolution conversion in response to a control instruction from the camera control microcomputer 5 through the communication interface 45. Processing is performed, and luminance data Y and color data C as output data are supplied to a subsequent video system processing block (not shown). The detailed contents of the camera signal main processing unit 43 are not directly related to the present invention, and are omitted here.

[Detailed Configuration Example of Shading Correction Processing Unit 42 by Shared Pixel]
FIG. 7 is a block diagram illustrating a detailed configuration example of the shared pixel-specific shading correction processing unit 42. The shading correction processing unit 42 for each shared pixel in this example includes a delay adjustment unit 421 provided for the imaging pixel data Px sent from the camera signal preprocessing unit 41 as a main line signal, a gain correction unit 422 for each shared pixel, , A timing generation unit 423, a correction control signal calculation unit 424, and a communication interface 425.

  The correction control signal calculation unit 424 has N correspondence tables (look-up tables) in which distance positions from the optical axis center of the photographing lens are associated with correction control signals (gain control signals) for shading characteristics at the distance positions. (N is an integer of 2 or more). That is, as shown in FIG. 7, the correction control signal calculation unit 424 includes N look-up tables LUT1 to LUTN.

  Here, the number N of lookup tables included in the correction control signal calculation unit 424 is equal to the number of shared pixel IDs or an integral multiple thereof in this example. This is not necessarily equal to the number of color lights (number of color channels) handled by the CMOS image sensor 2 of the image pickup apparatus of this embodiment, but is the same color light and has different shared pixel IDs M (M is 2 or more). If there are (integer) pixels, it means that each pixel is provided. That is, it corresponds to the number obtained by adding (M−1) for each color channel having M shared pixel IDs to the number of color lights (number of color channels) handled by the CMOS image sensor 2.

  This example is the case of FIG. 4A, and as shown in FIGS. 8A to 8D, the shared pixel ID is 4 of “0”, “1”, “2”, “3”. It is a piece. That is, for the red color light pixel R and the blue color light pixel B, one shared pixel ID is set, while for the green color light pixel G, two shared pixel IDs are set. Therefore, the total is 4. Therefore, the correction control signal calculation unit 42 includes at least four lookup tables in this example.

  Here, in FIG. 8, the pixel to be corrected is denoted by Px_O and circled, and the corresponding relationship with the surrounding pixels for each color light is shown. As shown in FIG. 8, in this embodiment, the plurality of types of color light handled by the CMOS image sensor 2 are three types of color light (R, G, B), but the green pixel light has a shared pixel ID. Since two are set, the correction control signal calculation unit 424 includes four lookup tables.

  Here, as shown in FIG. 8B, in the green light pixel G with the shared pixel ID = “1”, the red light pixel R is arranged on the left and right, and the blue light pixel B is arranged on the top and bottom. This is hereinafter referred to as a green light pixel G1. Further, as shown in FIG. 8C, in the green light pixel G with the shared pixel ID = “2”, the blue light pixel B is arranged on the left and right, and the red light pixel R is arranged on the top and bottom. This is hereinafter referred to as a green light pixel G2.

  In the imaging device having the shared pixel pattern in the Bayer array in the example of FIG. 4A, the shading characteristics were measured for these four types of color light pixels R, G1, G2, and B. Then, the characteristics shown in FIG. 9 were obtained, and the characteristics shown in FIG. 10 were obtained at the wide-angle end of the zoom lens. 9 and 10, the horizontal axis is the distance from the optical axis center position of the photographing lens, and the center of the horizontal axis is the optical axis center position of the photographing lens.

  9 and 10 also show that the shading characteristics are different between the green light pixels G1 and G2. As shown in FIGS. 9 and 10, since the shading characteristics are different between the telephoto side end and the wide angle side end, the lookup table included in the correction control signal calculation unit 424 includes four types of color light pixels. R, G1, G2, and B are preferably a total of eight, four for the telephoto end of the zoom lens and four for the wide-angle end of the zoom lens.

  However, in this embodiment, as the look-up tables LUT1 to LUTN included in the correction control signal calculation unit 424, four color light pixels R, G1, G2, and B (N = N = 4) for the sake of simplicity of explanation. 4).

  As will be described later, the correction control signal calculation unit 424 is supplied with a table selection signal SEL from the timing generation unit 423, and which of the N look-up tables LUT1 to LUTN is used based on the table selection signal SEL. Selection controlled.

  The stored data in the look-up tables LUT1 to LUTN must be in accordance with the color filter pattern and shared pixel pattern employed in the CMOS image sensor 2 to be used, and can be rewritten under the control of the camera control microcomputer 5. It is made up of.

  In the above description, the shading characteristics at the telephoto end and the wide-angle end of the zoom lens are taken into account. Further, the standard focal length position near the median value between the telephoto end and the wide-angle end is used. The shading in may be taken into account. In that case, a total of 12 look-up tables including four for the telephoto end of the zoom lens, four for the wide-angle end of the zoom lens, and four for the standard focal length position are stored in the correction control signal calculation unit 424. Try to provide it.

  In the imaging device, when the focal length position of the zoom lens set by the user at the time of shooting is a position between the telephoto end, the wide angle end, and the standard focal length position, the telephoto end, the wide angle end, and the standard The correction control signal may be generated by performing interpolation processing using three types of lookup tables for the focal length position. For example, if the focal length position of the zoom lens set by the user at the time of shooting is between the telephoto end and the standard focal length position, the distance between the set focal length position and the telephoto end and the standard focus What is necessary is just to perform an interpolation process using two types of look-up tables for the telephoto end and the standard focal length position by weighting each distance. Note that the zoom position is the focal length between the telephoto end and the wide-angle end even when the two types of look-up tables for the telephoto end and the wide-angle end are used. Even when it is the position, the same interpolation process can be performed to generate the correction control signal.

  In addition to the zoom position of the lens, factors such as focus position, image height, aperture amount, exit pupil position, and strobe light emission also have an effect on shading characteristics. An uptable may be provided in the correction control signal calculation unit 424. In that case, the camera control microcomputer 5 generates a table selection signal SEL corresponding to the state conditions of the plurality of elements, and generates the generated table selection signal SEL through the timing generation unit 423. 424 may be supplied. The timing generation unit 423 supplies the table selection signal SEL to the correction control signal calculation unit 424 in accordance with the pixel timing.

  The correction control signal calculation unit 424 also converts a pixel coordinate position on the imaging surface of the CMOS image sensor 2 into a distance position from the optical axis center position of the photographing lens for referring to the lookup table. Is provided.

  The delay adjustment unit 421 gives the processing delays in the timing generation unit 423 and the correction control signal calculation unit 424 to the input imaging pixel data Px, and sets the timing in the correction processing in the shared pixel-specific gain correction unit 41 described later. It is for matching.

  The timing generation unit 423 receives the reference timing signal TG, the horizontal synchronization signal HD, and the vertical synchronization signal VD from the reference timing signal generation unit 44, and also receives the area instruction information Sfl from the camera control microcomputer 5 through the communication interface 425. For each pixel read according to the reading method shown in FIG. 3, a counter signal CNT indicating the coordinate position on the imaging surface is generated.

  Since the pixel clock is obtained from the reference timing signal, the counter signal CNT is obtained by counting the pixel clock and the horizontal synchronization signal HD with reference to the vertical synchronization signal VD in the effective pixel region. The counter signal CNT includes a signal (count value) indicating what number pixel of which number horizontal line of one frame of the effective pixel region. The timing generation unit 423 supplies the generated counter signal CNT to the correction control signal calculation unit 424.

  Further, in this example, the timing generation unit 423 receives the shared pixel ID setting information Sid from the camera control microcomputer 5, generates a table selection signal SEL of a lookup table, and supplies the table selection signal SEL to the correction control signal calculation unit 424. To. As described above, when considering the zoom position or the like, the timing generation unit 423 receives the information from the camera control microcomputer 5 and generates the table selection signal SEL of the lookup table. .

  In the correction control signal calculation unit 424, a lookup table corresponding to the shared pixel ID selected by the table selection signal SEL is selected from the plurality of lookup tables LUT1 to LUTN, and the selected lookup is performed. From the table, a correction control signal for shading correction is read and calculated for each pixel as described later.

  As described above, this correction control signal is the gain control signal GC, which is supplied to the shared pixel-specific gain correction unit 422. Then, in the shared pixel-specific gain correction unit 422, the imaging pixel data Px that has passed through the delay adjustment unit 421 is multiplied by a correction control signal, that is, a gain control signal GC, and shading correction is performed.

  In this embodiment, the on / off of the correction can be controlled. In this example, the camera control microcomputer 5 supplies a correction on / off signal corresponding to the user's shading correction on / off switching instruction operation through the user interface 9 to the timing generation unit 423 through the communication interface 425.

  The timing generation unit 423 receives the correction on / off signal SW from the camera control microcomputer 5 through the communication interface 425 and supplies the correction on / off signal SW to the shared pixel-specific gain correction unit 422. In the shared pixel-specific gain correction unit 422, when the correction on / off signal SW indicates correction on, the gain is corrected by the gain control signal GC as the correction control signal from the correction control signal calculation unit 424, and the shading characteristics are changed. Correction is executed, and the corrected imaged pixel data Pxc is output as an output signal of the shading correction processing unit 42 for each shared pixel.

  When the correction on / off signal SW indicates correction off, the shared pixel-specific gain correction unit 422 does not perform gain correction on the imaging pixel data, and uses the imaging pixel data from the delay adjustment unit 421 as it is. Output as imaging pixel data Pxc.

[Detailed Configuration Example of Correction Control Signal Calculation Unit 424]
In this embodiment, the correction control signal calculation unit 424 corrects an elliptical shading characteristic in which the peripheral light amount is reduced in an elliptical shape due to the photographing lens. FIG. 11 shows a block diagram of a configuration example of the correction control signal calculation unit 424 in this embodiment.

  As shown in FIG. 11, the correction control signal calculation unit 424 of this embodiment includes an optical axis center coordinate shift unit 4241, a coordinate axis rotation unit 4242, a pseudo distance calculation unit 4243, and a gain calculation unit 4244. Yes.

  The optical axis center coordinate shift unit 4241 receives the counter signal CNT from the timing signal generation unit 4, and indicates the coordinate position information of the correction target pixel with the upper left corner of the effective area of the imaging surface indicated by the counter signal CNT as the origin position. (See FIG. 12A) is converted into coordinate information (see FIG. 12B) with the optical axis center of the photographic lens as the origin. The position information of the correction target pixel converted from the optical axis center coordinate shift unit 4241 into the coordinate information with the optical axis center of the photographing lens as the origin is supplied to the coordinate axis rotation unit 4242.

  The coordinate axis rotation unit 4242 performs a process of rotating the coordinate axes so that the major axis direction and the minor axis direction of the ellipse coincide with the horizontal direction and the vertical direction according to the ellipse inclination of the ellipse shading characteristic to be corrected (see FIG. 12 (C)). The positional information of the correction target pixel obtained by rotating the coordinate axis from the coordinate axis rotation unit 4242 is supplied to the pseudo distance calculation unit 4243.

  The pseudo distance calculation unit 4243 calculates distance coordinate information from the optical axis referring to the look-up table for the correction target pixel corresponding to the inclination of the ellipse of the ellipse shading characteristic to be corrected (see FIG. 12D). , Hereinafter referred to as pseudo distance information), and supplies it to the gain calculation processing unit 4244.

  The gain calculation processing unit 4244 is provided with four look-up tables LUT1 to LUT4 for the N kinds of color light pixels R, G1, G2, and B in consideration of the shared pixel ID in the example described above. . Hereinafter, the lookup tables for the four types of color light pixels R, G1, G2, and B will be referred to as an R table, a G1 table, a G2 table, and a B table, respectively.

  The table information for shading correction of the R table, G1 table, G2 table, and B table is written in advance by the table setting information from the camera control microcomputer 5 as described above. It is configured so that it can be rewritten.

  The gain calculation processing unit 4244 is supplied with the table selection signal SEL from the timing generation unit 423. In this example, the table selection signal SEL includes four enable signals R_TBLEN, G1_TBLEN, G2_TBLEN, and B_TBLEN for the R table, G1 table, G2 table, and B table, respectively.

  As described above, in this embodiment, the case of FIG. 4A is handled. Therefore, in the gain calculation processing unit 4244, as shown in FIG. The correction control signal is calculated using the G1 table, and the correction control signal is calculated using the G2 table and the B table for even-numbered horizontal lines.

  Then, as shown in FIG. 14A, in the odd-numbered horizontal lines, the correction target pixel includes the red light pixel R and the first green light pixel G1 in synchronization with the pixel clock. Since each pixel (pixel) appears alternately, the table selection signal SEL, that is, four enable signals R_TBLEN for each of the R table, G1 table, G2 table, and B table, corresponding to the shared pixel ID, G1_TBLEN, G2_TBLEN, and B_TBLEN are as shown in FIG.

  Here, in FIG. 14, when the enable signal is at a high level, the look-up table is enabled (operating state), and when the enable signal is at a low level, the look-up table is disabled (non-operating state).

  That is, in the odd-numbered horizontal line, the R table enable signal R_TBLEN is in an enabled state (operating state) for the odd-numbered pixels, and the G1 table enable signal G1_TBLEN is For even-numbered pixels, the G1 table is in an enabled state (operating state). The G2 table and B table enable signals G2_TBLEN and B_TBLEN both turn the G2 table and B table into a disabled state (non-operating state).

  Next, as shown in FIG. 14C, in the even-numbered horizontal line, the correction target pixel includes the second green light pixel G2 and the blue light pixel B in synchronization with the pixel clock. Since each pixel appears alternately, corresponding to the shared pixel ID, a table selection signal SEL, that is, four enable signals R_TBLEN, G1_TBLEN for each of the R table, G1 table, G2 table, and B table, G2_TBLEN and B_TBLEN are as shown in FIG.

  That is, in the even-numbered horizontal line, the enable signal G2_TBLEN for the G2 table is in a state in which the G2 table is enabled (operating state) for the odd-numbered pixels, and the enable signal B_TBLEN for the B table is At even-numbered pixels, the B table is in an enabled state (operating state). The R table and G1 table enable signals R_TBLEN and G1_TBLEN both turn the R table and the G1 table into a disabled state (non-operating state).

  In the gain calculation processing unit 4244, the enabled lookup table is referred to using the pseudo distance information from the pseudo distance calculation unit 4243 as reference information, and a corresponding gain control signal (shared pixel-specific gain control signal). The GC is read from the lookup table, output, and supplied to the shared pixel-specific gain correction unit 422.

[Configuration Example of Gain Correction Unit 422 by Shared Pixel]
FIG. 15 shows a block diagram of a configuration example of the shared pixel-specific gain correction unit 422 in this embodiment. In this embodiment, the shared pixel-specific gain correction unit 422 includes a multiplier 4221 that executes a shading correction process and a selector 4222.

  The imaging pixel data from the delay adjustment unit 421 is supplied to the multiplier 4221 and also supplied to one input terminal of the selector 4222. The multiplier 4221 is supplied with the shared pixel-specific gain control signal GC from the correction control signal calculation unit 424, and multiplies the pixel data to be corrected by the shading correction process. The imaged pixel data subjected to this correction processing is supplied from the multiplier 4221 to the other input terminal of the selector 4222.

  The selector 4222 is supplied with the correction on / off signal SW from the timing generation unit 423, and when the correction on / off signal SW indicates correction on, the imaging pixel subjected to the shading correction from the multiplier 4221 is displayed. When data is output from the selector 4222 and the correction on / off signal SW indicates correction off, the imaged pixel data from the delay adjustment unit 421 is output from the selector 4222 without being subjected to the shading correction process. Is done. The output of the selector 4222 is used as the output Pxc of the shading correction processing unit 42 for each shared pixel.

  As described above, in the imaging apparatus of this embodiment, even when the solid-state imaging device is configured to use the shared pixel technology, appropriate shading correction can be performed, and the influence on the output image quality is further reduced. be able to.

[Other Embodiments]
<Configuration by software processing>
In the embodiment described above, the shading correction process for each shared pixel is a process using hardware, but may be a software process using a microcomputer. For example, FIG. 16 is a flowchart showing an outline of the flow of processing when the software processing is performed.

 That is, the microcomputer first acquires pixel data of pixels adjacent to the correction target pixel (step S101).

 Next, the coordinate position of the correction target pixel on the imaging surface is calculated by counting the pixel clock, the horizontal synchronization signal HD, and the vertical synchronization signal VD (step S102). Subsequently, the calculated coordinate position of the correction target pixel on the imaging surface is converted into a distance coordinate position (pseudo distance coordinate position) from the optical axis of the photographing lens (step S103).

 Next, referring to the shared pixel ID of the correction target pixel, a lookup table used for shading correction is selected from a plurality of lookup tables prepared in advance (step S104).

 Then, the selected lookup table is referred to by the pseudo distance coordinate position information obtained in step S103, and the shared pixel-specific gain correction signal GC is acquired (step S105). The gain correction is performed by performing a calculation process of multiplying the acquired pixel-specific gain correction signal GC by the pixel data of the correction target pixel (step S106). As a result, imaged pixel data subjected to shading correction is obtained.

 Next, it is determined whether or not the process for the imaged pixel data is to be ended (step S107). If it is determined in step S107 that the process has ended, the process routine ends.

<Change of target image sensor>
In the above description of the embodiment, the color filter, the readout channel, and the pixel sharing method arranged for the solid-state image sensor have been described with limited examples. The present invention is not limited to this limitation, and can be widely applied without departing from the gist of the present invention.

  For example, in the example of FIG. 4, the output pixel sequence represented by the shared pixel ID is a case where the color of the color filter is considered, but when each color of the color filter arranged for the solid-state image sensor is not considered. The shared pixel ID and the output pixel sequence represented by the shared pixel ID in the three examples of the shared pixel array pattern shown in FIGS. 4A, 4B, and 4C are as shown in FIG. It will be a thing.

  The example of FIG. 17 is an example in the case of using a three-plate type image sensor as shown in FIGS. 2D and 2E, for example, and FIG. 17 is a solid-state image sensor for red light. Is shown.

  In the case of this example, the shared pixel IDs in the three examples of the array pattern of the shared pixels shown in the upper part of each of FIGS. 17A, 17B, and 17C are as shown in the middle part. The output pixel sequence represented by the shared pixel ID is as shown in the lower part of each.

  In this case, a lookup table corresponding to the shared pixel ID shown in the middle part of FIG. 17 is prepared, and a lookup table is selected by a table selection signal based on the shared pixel ID of the correction target pixel. A gain control signal for each shared pixel for shading correction is obtained using the selected lookup table, and shading correction is executed.

  The shading correction for the imaging pixel data from the solid-state image pickup device for green light and the solid-state image pickup device for blue light is similarly performed by preparing a lookup table for each.

[Other Embodiments and Modifications]
Note that the above description is all about the case where the present invention is applied to shading correction. However, as described above, the correction processing for the imaging pixel data targeted by the present invention is limited to shading correction. However, it can be applied to all cases where the correction processing, which has been conventionally performed for each color light, should be performed on the image pixel data from the solid-state image sensor using the shared pixel technology. is there.

Since a camera signal processing LSI (Large-Scale Integration) generally corresponds to a plurality of types of image pickup devices, depending on the image pickup device,
(1) The shared pixel technology is used and the shading difference for each shared pixel is large (2) The shared pixel technology is used, but the shading difference for each shared pixel is small (3) The shared pixel technology in the first place There are cases where it is necessary to cope with variations in the image pickup device group such as not using the.

  In the above-described embodiment, the case (1) has been described specifically. However, when the image sensor (2) or (3) is used as an image sensor, a lookup for each shared pixel is performed. Just write the same correction data in the table. Alternatively, the table selection signal SEL may be set from the camera control microcomputer so as to be fixed, and only a specific lookup table may be used.

 Note that the configuration of the above-described embodiment has been described specifically for the shared pixel pattern and the reading method illustrated in FIG. 4A for convenience of description, but can be flexibly applied to another shared pixel pattern and the reading method. It is desirable to configure the timing generation unit 423 and the like in a programmable manner so that it can cope.

  In the above description of the embodiment, the solid-state imaging device is a CMOS image sensor, but may be a CCD image sensor.

It is a figure which shows the hardware structural example of embodiment of the imaging device by this invention. It is a figure for demonstrating the example of the pixel arrangement | sequence and color filter arrangement | positioning of a solid-state image sensor used with embodiment of the imaging device by this invention. It is a figure for demonstrating the example of the reading method of the captured image data from the solid-state image sensor used by embodiment of the imaging device by this invention. It is a figure for demonstrating the array pattern and shared pixel ID of the shared pixel in the solid-state image sensor used by embodiment of the imaging device by this invention. It is a figure which shows the hardware structural example of the principal part of embodiment of the imaging device by this invention. It is a figure used in order to explain an embodiment of an imaging device by this invention. It is a figure which shows the hardware structural example of the one part block in the hardware structural example of FIG. FIG. 8 is a diagram used for explaining a hardware configuration example of FIG. 7. FIG. 8 is a diagram used for explaining a hardware configuration example of FIG. 7. FIG. 8 is a diagram used for explaining a hardware configuration example of FIG. 7. It is a figure which shows the hardware structural example of the one part block in the hardware structural example of FIG. FIG. 12 is a diagram used for explaining a processing operation in the hardware configuration example of FIG. 11. FIG. 12 is a diagram used for explaining a processing operation in the hardware configuration example of FIG. 11. FIG. 12 is a diagram used for explaining a processing operation in the hardware configuration example of FIG. 11. It is a figure which shows the hardware structural example of the one part block in the hardware structural example of FIG. It is a figure which shows the flowchart for demonstrating the principal part of other Embodiment of the imaging device by this invention. It is a figure for demonstrating the other example of the shared pixel ID pattern in the imaging device by this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 2 ... CMOS imager, 4 ... Digital signal processing part, 5 ... Camera control microcomputer, 42 ... Shading correction processing part classified by shared pixel, 44 ... Reference | standard timing signal generator, 422 ... Gain correction part classified by shared pixel, 423 ... Timing generation part 424 ... correction control signal calculation unit, 4244 ... gain calculation processing unit

Claims (6)

A plurality of pixels arranged in a two-dimensional array is formed as a set of a plurality of predetermined pixels having the same pixel arrangement pattern, and the pixels corresponding to the predetermined plurality of pixels constituting each set A solid-state imaging device including an imaging surface configured to share a circuit necessary for the configuration;
Correction means for performing predetermined correction on the imaged pixel data from the pixel for each identical color light incident on the pixel through the optical system based on a correction control signal;
The correction control signal for each of the same color light is calculated according to the difference in pixel position in the array pattern of the predetermined plurality of pixels constituting each set, and the correction is performed. Correction control signal calculation means to be supplied to the means;
An imaging apparatus comprising: The imaging device according to claim 1,
The predetermined correction is performed by using the correction control signal to calculate non-uniformity in incident light amount according to a difference in pixel position on the imaging surface of light incident on the imaging surface through the optical system. An imaging apparatus characterized by correcting the gain. The imaging device according to claim 1,
The correction control signal calculation unit includes a correction control signal table in which a pixel position on the imaging surface is associated with the correction control signal at the pixel position, and the corresponding correction control signal is input using the pixel position as an input. The correction control signal table is provided for each of the same color light by the number of the predetermined plurality of pixels constituting each set, and each of the correction patterns in the array pattern is calculated. The image pickup apparatus, wherein the correction control signal table is selected according to a difference in pixel position. The imaging device according to claim 3.
Equipped with zoom mechanism,
The correction control signal table includes the number of the predetermined plurality of pixels constituting each set for each of the same color light at each predetermined zoom magnification, and is selected by the zoom mechanism. The correction control signal table to be used is selected according to the zoom magnification being used. A plurality of pixels arranged in a two-dimensional array is formed as a set of a plurality of predetermined pixels having the same pixel arrangement pattern, and the pixels corresponding to the predetermined plurality of pixels constituting each set An imaging pixel data correction method for correcting imaging pixel data from a solid-state imaging device including an imaging surface configured to share a circuit necessary for the configuration,
A correction step of performing a predetermined correction based on a correction control signal for the imaging pixel data for each identical color light incident on the imaging surface through an optical system;
Prior to the correction step, the correction control signal for each of the same color light is set according to the difference in pixel position in the array pattern of the predetermined plurality of pixels constituting each set, respectively. A correction control signal calculation step for calculating,
An imaging pixel data correction method comprising: A plurality of pixels arranged in a two-dimensional array is formed as a set of a plurality of predetermined pixels having the same pixel arrangement pattern, and the pixels corresponding to the predetermined plurality of pixels constituting each set In an imaging device including a solid-state imaging device configured to share a circuit necessary for the configuration,
A correction step of performing a predetermined correction based on a correction control signal for the imaging pixel data for each identical color light incident on the imaging surface through an optical system;
Prior to the correction step, the correction control signal for each of the same color light is set according to the difference in pixel position in the array pattern of the predetermined plurality of pixels constituting each set, respectively. A correction control signal calculation step for calculating,
A program for running

Images