WO2014006931A1 - カラー撮像素子および撮像装置 - Google Patents
カラー撮像素子および撮像装置 Download PDFInfo
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
- H04N23/80—Camera processing pipelines; Components thereof
- H04N23/84—Camera processing pipelines; Components thereof for processing colour signals
- H04N23/843—Demosaicing, e.g. interpolating colour pixel values
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
- H04N25/10—Circuitry of solid-state image sensors [SSIS]; Control thereof for transforming different wavelengths into image signals
- H04N25/11—Arrangement of colour filter arrays [CFA]; Filter mosaics
- H04N25/13—Arrangement of colour filter arrays [CFA]; Filter mosaics characterised by the spectral characteristics of the filter elements
- H04N25/133—Arrangement of colour filter arrays [CFA]; Filter mosaics characterised by the spectral characteristics of the filter elements including elements passing panchromatic light, e.g. filters passing white light
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
- H04N25/10—Circuitry of solid-state image sensors [SSIS]; Control thereof for transforming different wavelengths into image signals
- H04N25/11—Arrangement of colour filter arrays [CFA]; Filter mosaics
- H04N25/13—Arrangement of colour filter arrays [CFA]; Filter mosaics characterised by the spectral characteristics of the filter elements
- H04N25/135—Arrangement of colour filter arrays [CFA]; Filter mosaics characterised by the spectral characteristics of the filter elements based on four or more different wavelength filter elements
Definitions
- the present invention relates to a color image pickup device and an image pickup apparatus, and more particularly to a color image pickup device capable of reducing the occurrence of color moire and increasing the resolution, and an image pickup apparatus using such a color image pickup device.
- a single color filter is provided on each pixel, so each pixel has only single color information.
- the output image of the single-chip color image sensor is a RAW image (mosaic image)
- a multi-channel image is obtained by a process of interpolating the missing color pixels from the surrounding pixels (mosaic processing).
- the problem in this case is the reproduction characteristics of the high-frequency image signal, and the color image sensor is more susceptible to aliasing than the black and white image sensor. It is an important issue to widen the reproduction band and to improve the resolution while suppressing the occurrence of).
- the primary color Bayer array which is the color array of color filters most widely used in single-plate color image sensors, arranges green (G) pixels in a checkered pattern and arranges red (R) and blue (B) in line-sequential fashion. Therefore, there is a problem in reproduction accuracy when generating a high-frequency signal in the oblique direction for the G signal and in the horizontal and vertical directions for the R and B signals.
- FIG. 16A When a black and white vertical stripe pattern (high-frequency image) as shown in FIG. 16A is incident on a color imaging device having a color filter with a Bayer arrangement shown in FIG. 16B, it is distributed to the Bayer color arrangement.
- R is a light flat
- B is a dark flat
- G is a light and shade mosaic image, which is originally a monochrome image, Although there is no density difference (level difference) between RGB, depending on the color arrangement and the input frequency, a color is added.
- an oblique black-and-white high-frequency image as shown in FIG. 17A is incident on an image sensor having a Bayer array color filter shown in FIG. 17B, it is distributed to the Bayer color array.
- R and B are thin flat images and G is a dark flat color image. If the black value is 0 and the white value is 255, An oblique black-and-white high-frequency image is G only 255 and thus becomes green. In this way, with the Bayer array, an oblique high-frequency image cannot be reproduced correctly.
- an optical low-pass filter made of a birefringent material such as crystal is disposed in front of the color image pickup device, and this is avoided by optically dropping high frequencies.
- coloring due to folding of the high-frequency signal can be reduced, but there is a problem that the resolution is lowered due to its adverse effect.
- the color filter array of the color image sensor is configured such that an arbitrary pixel of interest satisfies an arrangement restriction condition in which any of the three colors including the color of the pixel of interest and the four sides of the pixel of interest are adjacent.
- Patent Document 1 A color imaging device having a random color arrangement has been proposed (Patent Document 1).
- a plurality of filters having different spectral sensitivities are provided, and the first filter and the second filter are alternately arranged at a first predetermined period in one diagonal direction of the pixel grid of the image sensor.
- an image sensor color image pickup device having a color filter array that is arranged and alternately arranged at a second predetermined period in the other diagonal direction (Patent Document 2).
- R and B of the three primary colors of RGB are arranged every three pixels in the horizontal and vertical directions, and G is arranged between these R and B (patent). Reference 4).
- JP 2000-308080 A JP 2005-136766 A Japanese Patent Laid-Open No. 11-285012 JP-A-8-23543 Special table 2010-512048 JP 2008-022521 A JP 2007-288403 A JP 2010-154493 A
- the color imaging element described in Patent Document 1 has a problem that since the filter arrangement is random, it is necessary to optimize each random pattern when performing the demosaic process in the subsequent stage, and the demosaic process becomes complicated.
- the random arrangement is effective for low-frequency color moire, but is not effective for false colors in the high-frequency part.
- the demosaicing process is a process of calculating (converting into simultaneous equations) all the RGB color information for each pixel from the RGB mosaic image associated with the color filter array of the single-plate color image sensor, and is demosaicing. Also referred to as processing or synchronization processing (same in this specification).
- the color imaging device described in Patent Document 2 has a problem that the pixel reproducibility in the limit resolution region (especially in an oblique direction) is not good because G pixels (luminance pixels) are arranged in a checkered pattern.
- the color imaging device described in Patent Document 3 has an advantage that the occurrence of false colors can be suppressed because filters of all colors exist on an arbitrary straight line, but since the ratio of the number of RGB pixels is equal, There is a problem that the high-frequency reproducibility is lowered as compared with the Bayer arrangement.
- the ratio of the number of G pixels that contributes most to obtain a luminance signal is twice the number of R and B pixels.
- the ratio of the number of G pixels to the number of R and B pixels is 6 times that of the Bayer arrangement, which is very high, and color reproducibility is degraded. .
- Patent Documents 5 to 8 disclose various arrangements regarding a color filter array including transparent pixels (white pixels), but the disclosure also suggests that the sampling frequency is improved by transparent pixels (white pixels). However, no proposal has been made to improve color reproducibility or prevent image quality defects caused by high-frequency components with a color filter array.
- the arrangement interval between G (green) pixels is large from the viewpoint of accurately performing so-called demosaic processing. That is, according to the sensitivity characteristics of human vision, the influence of G pixels on color reproduction accuracy (demosaic processing accuracy) is large.
- the G pixel interval is large in the 4 ⁇ 4 pixel region where the R pixel exists and the 4 ⁇ 4 pixel region where the B pixel exists, the accuracy of the demosaic processing is very low. . Further, even in the 4 ⁇ 4 pixel region where the G pixel exists, the R pixel / B pixel interval becomes large, and therefore the accuracy of the demosaic process is very low.
- the present invention has been made in view of such circumstances, and an object of the present invention is to provide a color imaging device that has a high accuracy of color reproducibility while improving the sampling frequency of transparent pixels (white pixels). It is another object of the present invention to provide an image pickup apparatus using such a color image pickup element.
- One embodiment of the present invention is a single plate type in which a color filter is provided over a plurality of pixels including photoelectric conversion elements arranged in a first direction and a second direction perpendicular to the first direction.
- a color image pickup device in which the color filter is arranged corresponding to M ⁇ N (M is an integer of 4 or more, and N is an integer of 4 or more) pixels in the first direction and the second direction.
- the color filter includes a first filter corresponding to transparency and a visible filter
- the second filter having a higher transmittance than the other visible light wavelength region with respect to the first visible light wavelength region in the light wavelength region is different from the first visible light wavelength region in the visible light wavelength region.
- Other visible light wavelength range relative to the second visible light wavelength range A third filter having a higher transmittance and other visible light with respect to a third visible light wavelength region different from the first visible light wavelength region and the second visible light wavelength region in the visible light wavelength region.
- the color corresponding to the first visible light wavelength region has a higher contribution ratio for obtaining the luminance signal than the color corresponding to the second visible light wavelength region and the color corresponding to the third visible light wavelength region.
- a first filter corresponding to at least one pixel is disposed, and a second filter corresponding to at least one pixel is provided on each pixel line extending in the first direction and each pixel line extending in the second direction.
- a filter is disposed, and each of the third filter and the fourth filter relates to a color imaging device disposed adjacent to the second filter.
- Another aspect of the present invention is a single plate type in which a color filter is disposed on a plurality of pixels formed of photoelectric conversion elements arranged in a first direction and a second direction perpendicular to the first direction.
- the color filter array corresponds to M ⁇ N (M is an integer of 4 or more, and N is an integer of 4 or more) pixels in the first direction and the second direction.
- the color filter includes a first filter corresponding to transparency, What is the second filter having a higher transmittance than the other visible light wavelength range with respect to the first visible light wavelength range in the visible light wavelength range, and the first visible light wavelength range in the visible light wavelength range? Other visible light wavelength ranges for different second visible light wavelength ranges A third filter having a higher transmittance and another visible light wavelength region different from the first visible light wavelength region and the second visible light wavelength region in the visible light wavelength region.
- a fourth filter having a transmittance higher than that of the optical wavelength region, and each of the first filter, the second filter, the third filter, and the fourth filter is arranged in at least one pixel in the basic array pattern.
- the transmittance peak of the second filter is in the wavelength range of 480 nm or more and 570 nm or less, and the transmittance peak of the third filter and the fourth filter is out of the range.
- a filter is disposed, and each of the third filter and the fourth filter relates to a color imaging device disposed adjacent to the second filter.
- Another aspect of the present invention is a single plate type in which a color filter is disposed on a plurality of pixels formed of photoelectric conversion elements arranged in a first direction and a second direction perpendicular to the first direction.
- the color filter array corresponds to M ⁇ N (M is an integer of 4 or more, and N is an integer of 4 or more) pixels in the first direction and the second direction.
- the color filter includes a first filter corresponding to transparency, What is the second filter having a higher transmittance than the other visible light wavelength range with respect to the first visible light wavelength range in the visible light wavelength range, and the first visible light wavelength range in the visible light wavelength range? Other visible light wavelength ranges for different second visible light wavelength ranges A third filter having a higher transmittance and another visible light wavelength region different from the first visible light wavelength region and the second visible light wavelength region in the visible light wavelength region.
- the first visible light wavelength range is in the range of the visible light wavelength from 500 nm to 560 nm, and extends in the second direction on each pixel line extending in the first direction in the color filter array.
- a first filter corresponding to at least one pixel on each pixel line and on each pixel line extending in each of the third direction and the fourth direction inclined with respect to the first direction and the second direction Is arranged and extends in the first direction
- a second filter corresponding to at least one pixel is disposed on each existing pixel line and each pixel line extending in the second direction, and each of the third filter and the fourth filter is a second filter.
- a color image pickup element arranged adjacent to each other.
- Another aspect of the present invention is a single plate type in which a color filter is disposed on a plurality of pixels formed of photoelectric conversion elements arranged in a first direction and a second direction perpendicular to the first direction.
- the color filter array corresponds to M ⁇ N (M is an integer of 4 or more, and N is an integer of 4 or more) pixels in the first direction and the second direction.
- the color filter includes a first filter corresponding to transparency, What is the second filter having a higher transmittance than the other visible light wavelength range with respect to the first visible light wavelength range in the visible light wavelength range, and the first visible light wavelength range in the visible light wavelength range? Other visible light wavelength ranges for different second visible light wavelength ranges A third filter having a higher transmittance and another visible light wavelength region different from the first visible light wavelength region and the second visible light wavelength region in the visible light wavelength region.
- the first visible light wavelength range includes a visible light wavelength range corresponding to a color that most contributes to the luminance signal among the three primary colors and a visible light wavelength range corresponding to a color different from the three primary colors
- the second filter Is a filter having a higher transmittance than the other visible light wavelength regions with respect to the visible light wavelength region corresponding to the color most contributing to the luminance signal among the three primary colors, and visible light corresponding to a color different from the three primary colors.
- a first filter corresponding to at least one pixel is disposed on each pixel line extending in each of the third direction and the fourth direction inclined with respect to the pixel line, and each pixel line extending in the first direction
- a second filter corresponding to at least one pixel is disposed on each pixel line extending in the upper and second directions, and each of the third filter and the fourth filter is disposed adjacent to the second filter.
- the present invention relates to a color imaging device.
- the first filter corresponding to transparency is arranged in the pixel line in each direction from the first direction to the fourth direction of the color filter array, in the high frequency region Brightness information can be obtained with high accuracy. As a result, the generation of false colors (color moire) can be reduced, and image data with excellent resolution can be obtained.
- the second filter is disposed at least on each pixel line in the first direction and on each pixel line in the second direction, the second filter can be efficiently used in the first direction and the second direction. It can be distributed.
- each of the third filter and the fourth filter is arranged adjacent to the second filter, the third filter and the fourth filter can be efficiently distributed and arranged in the first direction and the second direction.
- adjacent between filters includes not only the case where the filters are adjacent to each other in the first direction and the second direction, but also the case where the filters are adjacent to each other in the third direction and the fourth direction.
- the color filter arrangement can be performed according to the repetition pattern when performing the demosaic processing in the subsequent stage, and the conventional random pattern.
- the subsequent processing can be simplified as compared with the arrangement.
- two or more of the neighboring eight pixels of the pixel where the first filter is arranged, the pixel where the third filter is arranged, and the pixel where the fourth filter is arranged is disposed at the same time.
- the “peripheral adjacent 8 pixels” here are, for example, adjacent to the pixel of interest in the first direction and the second direction (total of 4 pixels) and adjacent in the third direction and the fourth direction. It consists of pixels (4 pixels in total).
- the second filter is arranged in one or more pixels among the adjacent eight pixels around each pixel in which the second filter is arranged.
- a large number of second filters can be efficiently distributed around the second filter, and the color reproduction accuracy for the color corresponding to the second filter can be improved.
- a third filter corresponding to at least one pixel and at least one pixel are provided on each pixel line extending in the first direction and on each pixel line extending in the second direction.
- a corresponding fourth filter is arranged on each pixel line extending in the first direction and on each pixel line extending in the second direction.
- each of the third filter and the fourth filter can be efficiently distributed in the first direction and the second direction, and corresponds to the third filter and the fourth filter.
- the color reproduction accuracy for colors can be improved.
- the number of pixels in which the first filter is arranged ⁇ the number of pixels in which the second filter is arranged ⁇ the number of pixels in which the third filter is arranged, and the first filter The number of pixels in which the second filter is arranged ⁇ the number of pixels in which the second filter is arranged ⁇ the number of pixels in which the fourth filter is arranged is satisfied.
- the first filter corresponding to transparency most, and it is possible to arrange the second filter more than the third filter and the fourth filter.
- the pixel in which the first filter is arranged is arranged adjacent to the pixel in which the second filter is arranged.
- the first filter and the second filter can be arranged adjacent to each other, and when performing the image data interpolation processing or the like on the pixel position of the first filter corresponding to transparency, the second filter It is possible to effectively use the image data obtained through the.
- the basic arrangement pattern is arranged such that the color filters are arranged in an arrangement pattern corresponding to M ⁇ N (M is an integer of 6 or more and N is an integer of 6 or more) pixels in the first direction and the second direction.
- the basic array pattern is a first sub-array and a second sub-array which are two types of sub-arrays in which color filters are arrayed in an array pattern corresponding to (M / 2) ⁇ (N / 2) pixels.
- the first filter, the second filter, the third filter, and the fourth filter each include two first sub arrays and two second sub arrays each having at least one pixel.
- the basic arrangement pattern is arranged such that the color filters are arranged in an arrangement pattern corresponding to M ⁇ N (M is an integer of 6 or more and N is an integer of 6 or more) pixels in the first direction and the second direction.
- the basic array pattern includes a first sub-array, a second sub-array, which are four types of sub-arrays in which color filters are arrayed in an array pattern corresponding to (M / 2) ⁇ (N / 2) pixels, A first sub-array, a fourth sub-array, wherein the first filter, the second filter, the third filter, and the fourth filter are arranged in at least one pixel, Each of the two subsequences, the third subsequence, and the fourth subsequence is included.
- the sub-array constituting the basic array pattern includes a pair of sub-arrays in which the position of the third filter and the position of the fourth filter in each sub-array are reversed.
- the third filter and the fourth filter can be provided with regularity so that both can be distributed and the demosaic processing is complicated even if the size of the basic array pattern is increased. Can be reduced.
- the first filter has a transmittance of 50% or more in the first visible light wavelength region, the second visible light wavelength region, and the third visible light wavelength region.
- the first visible light wavelength range, the second visible light wavelength range, and the third visible light wavelength range correspond to three primary colors
- the color filter corresponds to a visible light wavelength range corresponding to a color different from the three primary colors.
- a fifth filter having a higher transmittance than other visible light wavelength regions is further included.
- the first visible light wavelength region corresponds to green
- the second visible light wavelength region corresponds to red
- the third visible light wavelength region corresponds to blue
- An imaging apparatus for achieving the object of the present invention includes an imaging optical system, a color imaging element on which a subject image is formed via the imaging optical system, and image data generation for generating image data indicating the formed subject image
- a color imaging device according to any one of the above aspects.
- the first filter corresponding to transparency is arranged in one or more pixels in the pixel lines in each direction from the first direction to the fourth direction of the color filter array. Therefore, it is possible to obtain luminance information in a high frequency region with high accuracy, reduce the occurrence of false colors (color moire), and obtain image data with excellent resolution.
- one or more pixels corresponding to transparency are arranged in the pixel line in each direction from the first direction to the fourth direction, a color filter having excellent light sensitivity can be realized.
- the color filter arrangement can be processed according to the repetition pattern when performing the demosaicing process in the subsequent stage, and the conventional random arrangement Compared with, the subsequent processing can be simplified.
- FIG. 1 is a block diagram showing an electrical configuration of the digital camera.
- FIG. 2 is a front view of the imaging surface of the color image sensor.
- 3A and 3B are diagrams showing the color filter arrangement according to the first embodiment, in which FIG. 3A shows one basic arrangement pattern, and FIG. 3B shows three basic arrangement patterns in FIG. 3A in the horizontal and vertical directions. A state in which a total of nine are arranged one by one is shown.
- 4A and 4B are diagrams showing a color filter arrangement according to the second embodiment, in which FIG. 4A shows one basic arrangement pattern, and FIG. 4B shows three basic arrangement patterns in FIG. 4A in the horizontal and vertical directions. A state in which a total of nine are arranged one by one is shown.
- FIG. 5A and 5B are diagrams showing a basic arrangement pattern of a color filter according to the third embodiment.
- FIG. 5A shows one basic arrangement pattern
- FIG. 5B shows the basic arrangement pattern of FIG. 9 shows a state where a total of nine are arranged in three directions.
- 6A and 6B are diagrams showing a basic arrangement pattern of a color filter according to the fourth embodiment.
- FIG. 6A shows one basic arrangement pattern
- FIG. 6B shows the basic arrangement pattern of FIG. 9 shows a state where a total of nine are arranged in three directions.
- FIG. 7 is a diagram showing a basic arrangement pattern of color filters according to the fifth embodiment.
- FIG. 8 is a diagram showing a basic array pattern of color filters according to the sixth embodiment.
- FIG. 9 is a diagram showing a basic array pattern of color filters according to the seventh embodiment.
- 10A and 10B are diagrams showing a basic arrangement pattern of a color filter according to the eighth embodiment.
- FIG. 10A shows one basic arrangement pattern
- FIG. 10B shows the basic arrangement pattern of FIG. A state where a total of four are arranged in two in the direction is shown.
- 11A and 11B are diagrams showing a basic arrangement pattern of a color filter according to the ninth embodiment.
- FIG. 11A shows one basic arrangement pattern
- FIG. 11B shows the basic arrangement pattern of FIG. A state where a total of four are arranged in two in the direction is shown.
- FIG. 11A shows one basic arrangement pattern
- FIG. 11B shows the basic arrangement pattern of FIG. A state where a total of four are arranged in two in the direction is shown.
- FIG. 12 is a graph showing spectral sensitivity characteristics of a light receiving element in which an R filter (red filter), a G1 filter (first green filter), a G2 filter (second green filter), and a B filter (blue filter) are arranged. It is.
- FIG. 13 is a graph illustrating spectral sensitivity characteristics of a light receiving element in which an R filter, a G filter, a B filter, and a W filter (transparent filter) are arranged.
- FIG. 14 is a graph showing spectral sensitivity characteristics of a light receiving element in which an R filter, a G filter, a B filter, and an E filter (emerald filter) are arranged.
- FIG. 15 is a front view showing an example of a color filter array in a honeycomb arrangement.
- FIG. 16 is a diagram used for explaining the problem of a color imaging device having a color filter with a conventional Bayer array.
- FIG. 17 is another diagram used for explaining the problem of a color imaging device having a color
- FIG. 1 is a block diagram of a digital camera 9 having a color image sensor according to the present invention.
- the digital camera 9 broadly includes a photographing optical system 10, a color imaging device 12, a photographing processing unit 14, an image processing unit 16, a driving unit 18, a control unit 20, and the like.
- the photographing optical system 10 forms a subject image on the image pickup surface of the color image pickup device 12.
- the color image sensor 12 is provided above the light receiving surface of a plurality of pixels composed of photoelectric conversion elements arranged in the horizontal and vertical directions (two-dimensional arrangement) in the drawing on the imaging surface. This is a so-called single-plate color image pickup device including a color filter.
- “to upper” and “upper” indicate directions on the side where subject light is incident on the imaging surface of the color imaging element 12.
- the subject image formed on the color image sensor 12 is converted into a signal charge corresponding to the amount of incident light by the photoelectric conversion element of each pixel.
- the signal charge accumulated in each photoelectric conversion element is sequentially read out from the color imaging element 12 as a voltage signal (image signal) corresponding to the signal charge based on a drive pulse given from the drive unit 18 according to a command from the control unit 20.
- the image signal read from the color image sensor 12 is a signal indicating a mosaic image of a color corresponding to the color filter array of the color image sensor 12.
- the color image sensor 12 may be another type of image sensor such as a CCD (Charge-Coupled Device) -type image sensor or a CMOS (Complementary-Metal-Oxide-Semiconductor) -type image sensor.
- CCD Charge-Coupled Device
- CMOS Complementary-Metal-Oxide-Semiconductor
- the image signal read from the color image sensor 12 is input to the imaging processing unit 14.
- the imaging processing unit 14 is a correlated double sampling circuit (CDS) for removing reset noise included in the image signal, an AGC circuit for amplifying the image signal and controlling it to a certain level, and an A / D. It has a converter.
- the imaging processing unit 14 performs correlated double sampling processing and amplification on the input image signal, and then outputs RAW data converted to a digital image signal to the image processing unit 16.
- the color image sensor 12 is a MOS type image sensor, the A / D converter is often built in the image sensor, and the correlated double sampling may not be necessary.
- the image processing unit 16 calculates all RGB color information for each pixel from the RGB mosaic image associated with the color filter array of the single-chip color image pickup device 12 (simultaneously).
- a processing circuit (converted into a formula), a luminance / color difference signal generation circuit, a contour correction circuit, a color correction circuit, and the like.
- the image processing unit 16 performs necessary signal processing on the RAW data of the mosaic image input from the imaging processing unit 14 in accordance with a command from the control unit 20, and generates an RGB pixel signal having all RGB color information for each pixel. Based on this, image data (YUV data) composed of luminance data (Y data) and color difference data (Cr, Cb data) is generated.
- the image data generated by the image processing unit 16 is subjected to compression processing conforming to the JPEG standard for still images by a compression / decompression processing circuit, and compression processing conforming to the MPEG2 standard for moving images. After that, it is recorded on a recording medium (not shown) such as a memory card, and is output and displayed on a display means (not shown) such as a liquid crystal monitor.
- a recording medium such as a memory card
- a display means such as a liquid crystal monitor.
- the recording medium is not limited to the one that can be attached to and detached from the digital camera 9, and may be a built-in magneto-optical recording medium
- the display means is not limited to that provided in the digital camera 9 and is connected to the digital camera 9. It may be an external display.
- FIG. 2 a plurality of pixels 21 including photoelectric conversion elements PD that are two-dimensionally arranged in the horizontal direction and the vertical direction are provided on the imaging surface of the color imaging element 12.
- the horizontal direction corresponds to one of the first direction and the second direction of the present invention
- the vertical direction corresponds to the other direction of the first direction and the second direction of the present invention.
- a color filter array 22 composed of color filters disposed on each pixel 21 is provided (see FIG. 3A).
- the color filter of this example includes a W filter (first filter) corresponding to transparency, and another visible light wavelength region with respect to a green visible light wavelength region (first visible light wavelength region) in the visible wavelength region.
- W filter first filter
- second filter having higher transmittance and the red visible light wavelength region (second visible light wavelength region) different from the green visible light wavelength region in the visible wavelength region
- R filter third filter
- B filter having a transmittance higher than the visible light wavelength region of blue
- the visible light wavelength region of blue that is different from the visible wavelength region of green and the visible wavelength region of red in the visible wavelength region
- a B filter fourth filter having a higher transmittance than the other visible light wavelength region with respect to the third visible light wavelength region.
- the color filter array 22 includes red (R), green (G), and blue (B) primary color filters (hereinafter referred to as R filter, G filter, and B filter) 23R, 23G, and 23B and a transparent filter ( W filter) 23W, and any one of the RGBW filters 23R, 23G, 23B, and 23W is disposed on each pixel 21.
- R filter, G filter, and B filter red (R), green (G), and blue (B) primary color filters
- W filter transparent filter
- each filter and the transmission visible wavelength region will be described later (see FIG. 12).
- the color filter array 22 according to this embodiment has the following characteristics.
- the color filter array 22 has a basic array pattern P1 that is a square array pattern corresponding to 4 ⁇ 4 pixels (M ⁇ N pixels) in the horizontal and vertical directions.
- the basic array pattern P1 is repeatedly arranged in the horizontal direction and the vertical direction.
- the basic array pattern P1 includes filters for each color of the R filter 23R, the G filter 23G, the B filter 23B, and the transparent filter 23W. Therefore, in the color filter array 22, the R filter 23R, the G filter 23G, the B filter 23B, and the transparent filter 23W are arranged with periodicity.
- the first filter horizontal row 25a is “a filter row (pixel line) in which the transparent filter 23W, the R filter 23R, the transparent filter 23W, and the G filter 23G are juxtaposed in the horizontal direction”
- the second filter horizontal row 25b is “ The horizontal filter 25W, the G filter 23G, the transparent filter 23W, and the R filter 23R are juxtaposed
- the third filter horizontal row 25c is “the B filter 23B, the transparent filter 23W, the G filter in the horizontal direction”.
- 23G and the transparent filter 23W are juxtaposed
- the fourth filter horizontal row 25d is “a filter row in which the G filter 23G, the transparent filter 23W, the B filter 23B, and the transparent filter 23W are juxtaposed in the horizontal direction”. is there.
- first filter vertical column 27a second filter vertical column 27b, third filter
- a vertical column 27c and a fourth filter vertical column 27d are formed.
- the adjacent set of transparent filters 23W in the first filter vertical row 27a and the third filter vertical row 27c and the adjacent set of transparent filters 23W in the second filter vertical row 27b and the fourth filter vertical row 27d are vertical. Staggered with respect to direction.
- the G filters 23G are arranged in a distributed manner in the horizontal direction and the vertical direction, and one pixel exists in every filter horizontal row and filter vertical row.
- the R filter 23R and the B filter 23B are also distributed in the horizontal direction and the vertical direction, and one of the R filter 23R and the B filter 23B exists in all the filter horizontal rows and filter vertical rows. .
- each filter horizontal row and each filter vertical row in the basic array pattern P1 is composed of a 2-pixel transparent filter 23W, a 1-pixel G filter 23G, and a 1-pixel R filter 23R or B filter 23B.
- the pixel lines (filter lines) in the horizontal direction (H), the vertical direction (V), and the diagonal direction (NE, NW) are included.
- a transparent filter 23W is disposed.
- NE means the diagonally upper right (lower left) direction and corresponds to one of the third direction and the fourth direction of the present invention.
- NW means a diagonally lower right (upper left) direction and corresponds to the other direction of the third direction and the fourth direction of the present invention.
- the RGBW filters 23R, 23G, 23B, and 23W have a square shape
- the NE direction and the NW direction are directions of 45 ° with respect to the horizontal direction and the vertical direction, respectively. Note that this angle can be increased or decreased according to the increase or decrease in the length of each side in the horizontal direction or vertical direction of the RGBW filters 23R, 23G, 23B, and 23W.
- the diagonal direction is diagonal (NE, NW direction).
- the NE direction and the NW direction are 45 ° with respect to the horizontal direction and the vertical direction, respectively.
- the transparent filter 23W in the color filter array 22 is arranged in each pixel line in the horizontal direction (H), vertical direction (V), and diagonal direction (NE, NW) of the color filter array 22.
- the luminance information in the high frequency region can be sampled regardless of the direction of high frequency in the input image. That is, since high-frequency luminance information can be sampled, an optical low-pass filter can be eliminated, and the sensitivity can be improved by a relatively large number of transparent filter pixels (W pixels).
- the optical low-pass filter for reducing (suppressing) the occurrence of false colors can be omitted. Even when an optical low-pass filter is applied, it is possible to apply a filter having a weak function of cutting a high-frequency component for preventing the occurrence of false colors, so that the resolution is not impaired.
- the G color has a higher contribution rate for obtaining the luminance (Y) signal than the R and B colors. That is, the contribution ratio of the R and B colors is lower than that of the G color, and the G color is the color that contributes most to the luminance signal among the three primary colors. Since such a G filter 23G is arranged in each pixel line in the horizontal direction (H) and the vertical direction (V) of the color filter array 22, color reproduction of demosaic processing in a high-frequency region in the horizontal direction and the vertical direction is performed. Accuracy can be improved. As an example, according to the following formula (1), the above-described image processing unit 16 can generate a Y signal from an RGBW pixel signal having color information of all RGB for each pixel.
- G color color corresponding to the first visible light wavelength range
- B color color corresponding to the second visible light wavelength range and color corresponding to the third visible light wavelength range.
- the contribution ratio for obtaining a luminance signal is higher than
- color reproducibility can be improved by arranging G pixels that have a large influence on color reproducibility due to the sensitivity characteristics of the human eye in each pixel line extending in the horizontal and vertical directions. it can.
- the numbers of R, G, B, and W pixels corresponding to the RGBW filters 23R, 23G, 23B, and 23W in the basic array pattern P1 are 2 pixels, 4 pixels, 2 pixels, and 8 pixels, respectively.
- the ratio of the number of pixels is 1: 2: 1: 4 (W pixel number ⁇ G pixel number ⁇ R pixel number; W pixel number ⁇ G pixel number ⁇ B pixel number). Therefore, the color filter array 22 according to the present embodiment includes the G filter 23G twice as large as the R filter 23R and B filter 23B, and twice as large as the G filter 23G (four times as large as the R filter 23R and B filter 23B).
- a transparent filter 23W is included.
- pixels that make a relatively large contribution to obtain a luminance signal are the W pixel and the G pixel. Therefore, in the color filter array 22, since the ratio of the number of pixels of these W pixels and G pixels occupies 12/16 (3/4) of the whole, aliasing at the time of demosaic processing can be effectively suppressed. In addition, high frequency reproducibility is also improved.
- the transparent filter 23W is included in all the diagonal pixel lines, and the G filter 23G is 3
- the R filter 23R and the B filter 23B are included in the 2/4 diagonal pixel line.
- each diagonal pixel line including the R filter 23R and the B filter 23B is arranged with another diagonal pixel line including the R filter 23R and the B filter 23B of the same color at a position adjacent to one.
- the pixel lines adjacent to each other in the diagonal direction means that when a filter having a square with one side length of 1 is used, the interval between the pixel lines is ⁇ 2 / 2 pixel interval.
- the pixel interval is a pixel interval (pitch) from the center point of the reference pixel to the center point of the adjacent pixel.
- the RGBW filters 23R, 23G, 23B, and 23W having such arrangement characteristics are arranged in the color filter array 22
- the RGB filters 23R, 23G, and so on are arranged on adjacent pixel lines extending in the oblique direction (NE, NW). Since 23B is respectively arranged, color moire (false color) that can be generated by an input image having a high frequency component in an oblique direction (NE, NW) can be effectively suppressed.
- the transparent filter 23W is included in all the oblique pixel lines, clearer image data can be obtained.
- each of the R filter (R pixel) and the B filter (B pixel) is disposed adjacent to the G filter (G pixel). That is, each of the R pixel and the B pixel has a G pixel at a pixel position adjacent to one of the vertical and horizontal directions (vertical direction / horizontal direction) or the diagonal direction (a position adjacent to the vertical direction and the diagonal direction in this embodiment). Be placed.
- the R pixels and the B pixels are evenly arranged in the color filter array 22 (in the basic array pattern P1), the accuracy of the demosaic process can be improved, and the color reproducibility can be improved.
- each of the R pixel, the G pixel, and the B pixel is equal in the color filter array 22. It is preferable to disperse and arrange. Therefore, by arranging the R pixel and the B pixel adjacent to the G pixel arranged so that one or more pixels exist in each pixel line in the horizontal direction and the vertical direction, the R pixel and the B pixel are efficiently arranged. Arranged in a scattered state, the accuracy of demosaic processing can be improved.
- G filters are arranged in two or more of the neighboring eight pixels surrounding each of the pixels other than the G pixels (W pixel, R pixel, and B pixel).
- the G pixels having a large influence on the color reproducibility are arranged in an evenly distributed state, and 2 pixels among the 8 neighboring pixels of the interpolation target pixels (W pixel, R pixel, and B pixel) other than the G pixels.
- G pixels are arranged in one or more pixels (one pixel at an oblique position in the present embodiment) among the eight adjacent pixels surrounding each G pixel.
- two G pixels are arranged in 9 pixels consisting of the G pixel and its neighboring 8 pixels, so that the accuracy of color reproduction in the demosaic process can be further increased.
- the color filter array 22 shown in FIG. 3B can be obtained even if an array pattern corresponding to 4 ⁇ 4 pixels shifted in the horizontal direction and / or the vertical direction from the basic array pattern shown in FIG.
- a color filter having an array equivalent to 22 can be configured.
- the demosaicing process in the subsequent stage is simplified, the color reproduction accuracy of the demosaic process in the high frequency region is improved, and the aliasing in the demosaic process is performed. Suppression and improvement of high frequency reproducibility, and higher resolution and higher sensitivity are possible.
- FIG. 4A and 4B are diagrams showing a basic arrangement pattern of the color filter according to the second embodiment.
- FIG. 4A shows one basic arrangement pattern P2
- FIG. 4B shows the basic arrangement pattern P2 in the horizontal direction and the vertical direction. A state in which a total of nine of three are arranged is shown.
- the arrangement of the color filters of this embodiment is an arrangement in which the R filter 23R and the B filter 23B of the color filter according to the first embodiment shown in FIG. 1 are replaced. That is, the position of the R filter 23R in the color filter array according to the first embodiment corresponds to the position of the B filter 23B in the color filter array according to the second embodiment, and the B filter in the color filter array according to the first embodiment. The position of 23B corresponds to the position of the R filter 23R in the color filter array according to the second embodiment.
- the color filter array 22 according to the present embodiment has the following characteristics.
- the color filter array 22 also includes a basic array pattern P2 that is a square array pattern corresponding to 4 ⁇ 4 pixels (M ⁇ N pixels) in the horizontal direction and the vertical direction, and the basic array pattern P2 is in the horizontal direction. And repeatedly arranged in the vertical direction. Therefore, in the color filter array 22, the R filter 23R, the G filter 23G, the B filter 23B, and the transparent filter 23W are arranged with periodicity. Therefore, when performing demosaic processing of R, G, B signals, etc., processing can be performed according to a repetitive pattern, and when the image is reduced by thinning out in units of the basic array pattern P2, it is common before and after the thinning out processing.
- the processing circuit can be used.
- the first filter horizontal row 25a is “a filter row in which the transparent filter 23W, the B filter 23B, the transparent filter 23W, and the G filter 23G are juxtaposed in the horizontal direction”
- the second filter horizontal row 25b is “transparent in the horizontal direction”.
- the filter 23W, the G filter 23G, the transparent filter 23W and the B filter 23B are juxtaposed
- the third filter horizontal row 25c is “the R filter 23R, the transparent filter 23W, the G filter 23G and the transparent filter in the horizontal direction”.
- the fourth filter horizontal row 25d is a “filter row in which the G filter 23G, the transparent filter 23W, the R filter 23R, and the transparent filter 23W are juxtaposed in the horizontal direction”. Therefore, in the basic array pattern P2 of this example, four types of filter vertical columns extending in parallel to the vertical direction are formed.
- each filter horizontal column and each filter vertical column in the basic array pattern P2 includes a two-pixel transparent filter 23W, a one-pixel G filter 23G, and a one-pixel R filter 23R or B filter 23B.
- the pixel lines (filter lines) in the horizontal direction (H), the vertical direction (V), and the diagonal direction (NE, NW) are included.
- a transparent filter 23W is disposed.
- the numbers of R, G, B, and W pixels corresponding to the RGBW filters 23R, 23G, 23B, and 23W in the basic array pattern P2 are 2 pixels, 4 pixels, 2 pixels, and 8 pixels, respectively.
- the ratio of the number of pixels is 1: 2: 1: 4.
- the ratio of the number of W pixels and G pixels occupies 12/16 (3/4) of the whole, so that aliasing at the time of demosaic processing is suppressed. And high frequency reproducibility is improved.
- the transparent filter 23W includes all the diagonal pixels.
- the G filter 23G is included in the 3/4 diagonal pixel line
- the R filter 23R and the B filter 23B are included in the 2/4 diagonal pixel line.
- each diagonal pixel line including the R filter 23R and the B filter 23B is arranged with another diagonal pixel line including the R filter 23R and the B filter 23B of the same color at a position adjacent to one.
- the RGB filters 23R, 23G, and 23B are respectively arranged in the adjacent pixel lines extending in the oblique direction (NE, NW), colors that can be generated by an input image having a high-frequency component in the oblique direction (NE, NW). Moire (false color) can be effectively suppressed.
- the transparent filter 23W is included in all the oblique pixel lines, clearer image data can be obtained.
- each of the R filter (R pixel) and the B filter (B pixel) is located at a pixel position (vertical / horizontal direction) or adjacent pixel position (an oblique direction).
- G pixels are arranged at positions adjacent to each other in the vertical direction and the oblique direction.
- G filters are arranged in two or more of the adjacent eight pixels surrounding each pixel other than the G pixels (W pixel, R pixel, and B pixel). Then, the G pixels are arranged in an evenly distributed state. G pixels are arranged in one or more pixels (one pixel at an oblique position in the present embodiment) among the eight adjacent pixels surrounding each of the G pixels. Thereby, the accuracy of color reproduction in demosaic processing can be further increased.
- the demosaicing process in the subsequent stage is simplified, the color reproduction accuracy of the demosaic process in the high frequency region is improved, and the aliasing in the demosaic process is performed. Suppression and improvement of high frequency reproducibility, and higher resolution and higher sensitivity.
- FIG. 5A and 5B are diagrams showing a basic array pattern of color filters according to the third embodiment.
- FIG. 5A shows one basic array pattern P3, and
- FIG. 5B shows the basic array pattern P2 in the horizontal and vertical directions. A state in which a total of nine of three are arranged is shown.
- first filter horizontal row 25a is “a filter row in which the transparent filter 23W, the B filter 23B, the transparent filter 23W, and the G filter 23G are juxtaposed in the horizontal direction”
- second filter horizontal row 25b is “transparent in the horizontal direction”.
- the filter 23W, the G filter 23G, the transparent filter 23W and the R filter 23R are juxtaposed, and the third filter horizontal row 25c is “the R filter 23R, the transparent filter 23W, the G filter 23G and the transparent filter in the horizontal direction”.
- the fourth filter horizontal row 25d is a “filter row in which the G filter 23G, the transparent filter 23W, the B filter 23B, and the transparent filter 23W are juxtaposed in the horizontal direction”.
- the color filter array 22 according to the present embodiment has the following characteristics.
- the color filter array 22 also includes a basic array pattern P3 that is a square array pattern corresponding to 4 ⁇ 4 pixels (M ⁇ N pixels) in the horizontal direction and the vertical direction. And repeatedly arranged in the vertical direction. Therefore, in the color filter array 22, the R filter 23R, the G filter 23G, the B filter 23B, and the transparent filter 23W are arranged with periodicity. Therefore, when performing demosaic processing of R, G, B signals, etc., processing can be performed according to a repetitive pattern, and when the image is reduced by thinning processing in units of the basic array pattern P3, it is common before and after the thinning processing.
- the processing circuit can be used.
- the transparent filter 23W has two pixels in every filter horizontal column and filter vertical column.
- the G filter 23G has one pixel in every filter horizontal column and filter vertical column.
- one pixel of the R filter 23R and the B filter 23B exists in all the filter horizontal rows and the filter vertical rows. Accordingly, each filter horizontal row and each filter vertical row in the basic array pattern P3 is composed of a 2-pixel transparent filter 23W, a 1-pixel G filter 23G, and a 1-pixel R filter 23R or B filter 23B.
- each pixel line (filter line) in the horizontal direction (H), vertical direction (V), and diagonal direction (NE, NW) is included.
- a transparent filter 23W is disposed.
- the numbers of R, G, B, and W pixels corresponding to the RGBW filters 23R, 23G, 23B, and 23W in the basic array pattern P3 are 2 pixels, 4 pixels, 2 pixels, and 8 pixels, respectively.
- the ratio of the number of pixels is 1: 2: 1: 4.
- the ratio of the number of W pixels and G pixels occupies 12/16 (3/4) of the whole, so that aliasing at the time of demosaic processing is suppressed. And high frequency reproducibility is improved.
- the transparent filter 23W includes all the diagonal pixels.
- the G filter 23G is included in a 3/4 diagonal pixel line
- the R filter 23R and the B filter 23B are included in a 2/4 diagonal pixel line or a 1/4 diagonal pixel line.
- the RGB filters 23R, 23G, and 23B are respectively arranged in the adjacent pixel lines extending in the oblique direction (NE, NW)
- Moire (false color) can be effectively suppressed.
- the transparent filter 23W is included in all the oblique pixel lines, clearer image data can be obtained.
- each of the R filter (R pixel) and the B filter (B pixel) is located at a pixel position (vertical / horizontal direction) or adjacent pixel position (an oblique direction).
- G pixels are arranged at positions adjacent to each other in the vertical direction and the oblique direction.
- G filters are arranged in two or more of the adjacent eight pixels surrounding each pixel other than the G pixels (W pixel, R pixel, and B pixel). Then, the G pixels are arranged in an evenly distributed state. In addition, G pixels are arranged in one or more pixels (one pixel at an oblique position in the present embodiment) among the eight adjacent pixels surrounding each of the G pixels. Thereby, the accuracy of color reproduction in demosaic processing can be further increased.
- the demosaicing process in the subsequent stage is simplified, the color reproduction accuracy of the demosaic process in the high frequency region is improved, and the aliasing in the demosaic process is performed. Suppression and improvement of high frequency reproducibility, and higher resolution and higher sensitivity are possible.
- FIG. 6A and 6B are diagrams showing a basic arrangement pattern of the color filter according to the fourth embodiment.
- FIG. 6A shows one basic arrangement pattern P4, and
- FIG. 6B shows the basic arrangement pattern P2 in the horizontal direction and the vertical direction. A state in which a total of nine of three are arranged is shown.
- the arrangement of the color filters of this embodiment is an arrangement in which the R filter 23R and the B filter 23B of the color filter according to the third embodiment shown in FIG. 5 are replaced. Therefore, the position of the R filter 23R in the color filter array according to the third embodiment corresponds to the position of the B filter 23B in the color filter array according to the fourth embodiment, and the B filter in the color filter array according to the third embodiment.
- the position of 23B corresponds to the position of the R filter 23R in the color filter array according to the fourth embodiment.
- first filter horizontal column 25a is “a filter row in which the transparent filter 23W, the R filter 23R, the transparent filter 23W, and the G filter 23G are juxtaposed in the horizontal direction”
- second filter horizontal row 25b is “transparent in the horizontal direction”.
- the filter 23W, the G filter 23G, the transparent filter 23W and the B filter 23B are juxtaposed, and the third filter horizontal row 25c is “the B filter 23B, the transparent filter 23W, the G filter 23G and the transparent filter in the horizontal direction”.
- the fourth filter horizontal row 25d is a “filter row in which the G filter 23G, the transparent filter 23W, the R filter 23R, and the transparent filter 23W are juxtaposed in the horizontal direction”.
- the color filter array 22 according to the present embodiment has the following characteristics.
- the color filter array 22 also includes a basic array pattern P4 that is a square array pattern corresponding to 4 ⁇ 4 pixels (M ⁇ N pixels) in the horizontal direction and the vertical direction, and the basic array pattern P4 is in the horizontal direction. And repeatedly arranged in the vertical direction. Therefore, in the color filter array 22, the R filter 23R, the G filter 23G, the B filter 23B, and the transparent filter 23W are arranged with periodicity. Therefore, when performing demosaic processing of R, G, B signals, etc., processing can be performed according to a repetitive pattern, and when the image is reduced by performing thinning processing in units of the basic array pattern P4, it is common before and after the thinning processing.
- the processing circuit can be used.
- each filter horizontal column and each filter vertical column in the basic array pattern P4 includes a two-pixel transparent filter 23W, a one-pixel G filter 23G, and a one-pixel R filter 23R or B filter 23B.
- the pixel lines (filter lines) in the horizontal direction (H), the vertical direction (V), and the diagonal direction (NE, NW) are included.
- a transparent filter 23W is disposed.
- the numbers of R, G, B, and W pixels corresponding to the RGBW filters 23R, 23G, 23B, and 23W in the basic array pattern P4 are 2 pixels, 4 pixels, 2 pixels, and 8 pixels, respectively.
- the ratio of the number of pixels is 1: 2: 1: 4.
- the ratio of the number of W pixels and G pixels occupies 12/16 (3/4) of the whole, so that aliasing at the time of demosaic processing is suppressed. And high frequency reproducibility is improved.
- the transparent filter 23W includes all the diagonal pixels.
- the G filter 23G is included in a 3/4 diagonal pixel line
- the R filter 23R and the B filter 23B are included in a 2/4 diagonal pixel line or a 1/4 diagonal pixel line.
- the RGB filters 23R, 23G, and 23B are respectively arranged in the adjacent pixel lines extending in the oblique direction (NE, NW)
- Moire (false color) can be effectively suppressed.
- the transparent filter 23W is included in all the oblique pixel lines, clearer image data can be obtained.
- each of the R filter (R pixel) and the B filter (B pixel) is located at a pixel position (vertical / horizontal direction) or adjacent pixel position (an oblique direction).
- G pixels are arranged at positions adjacent to each other in the vertical direction and the oblique direction.
- G filters are arranged in two or more of the adjacent eight pixels surrounding each pixel other than the G pixels (W pixel, R pixel, and B pixel). Then, the G pixels are arranged in an evenly distributed state. In addition, G pixels are arranged in one or more pixels (one pixel at an oblique position in the present embodiment) among the eight adjacent pixels surrounding each of the G pixels. Thereby, the accuracy of color reproduction in demosaic processing can be further increased.
- the demosaicing process in the subsequent stage is simplified, the color reproduction accuracy of the demosaic process in the high frequency region is improved, and the aliasing in the demosaic process is performed. Suppression and improvement of high frequency reproducibility, and higher resolution and higher sensitivity.
- FIG. 7 is a diagram showing a basic array pattern P5 of color filters according to the fifth embodiment.
- the basic arrangement pattern P5 of the color filter arrangement uses the basic arrangement pattern P1 (see FIG. 3A) according to the first embodiment as the first sub-array (A arrangement), and the second embodiment includes
- the basic array pattern P2 (see FIG. 4A) is set as a second sub array (B array), and each of these two types of first sub arrays and second sub arrays is included. Therefore, the position of the R filter 23R in the first sub array corresponds to the position of the B filter 23B in the second sub array, and the position of the B filter 23B in the first sub array and the R filter in the second sub array Corresponds to the position of 23R.
- the first sub array (A array) and the second sub array (B array) are arranged adjacent to each other in the horizontal direction and the vertical direction, and the horizontal direction and the vertical direction as a whole. Is a basic array pattern P5 corresponding to 8 ⁇ 8 pixels.
- the color filter array 22 according to the present embodiment has the following characteristics.
- the color filter array 22 includes a basic array pattern P5 that is a square array pattern corresponding to 8 ⁇ 8 pixels (M ⁇ N pixels) in the horizontal direction and the vertical direction, and the basic array pattern P5 is in the horizontal direction. And repeatedly arranged in the vertical direction. Therefore, in the color filter array 22, the R filter 23R, the G filter 23G, the B filter 23B, and the transparent filter 23W are arranged with periodicity. Therefore, when performing demosaic processing of R, G, B signals, etc., processing can be performed according to a repetitive pattern, and when the image is reduced by thinning processing in units of the basic array pattern P5, it is common before and after the thinning processing.
- the processing circuit can be used.
- each filter horizontal column and each filter vertical column in the basic array pattern P5 includes a 4-pixel transparent filter 23W, a 2-pixel G filter 23G, a 1-pixel R filter 23R, and a 1-pixel B filter 23B. Composed.
- the pixel lines (filter lines) in the horizontal direction (H), the vertical direction (V), and the diagonal direction (NE, NW) are included.
- a transparent filter 23W is disposed.
- an R filter 23R third filter
- a B filter 23B fourth filter corresponding to one pixel on each filter horizontal row and each filter vertical row.
- the G color corresponding to the G filter 23G but also the R color and the B color corresponding to the R filter (R pixel) and the B filter (B pixel) are demosaiced in a high frequency region in the horizontal direction and the vertical direction. Color reproduction accuracy can be improved. Therefore, since the color reproducibility accuracy in the high frequency region can be improved for all three primary colors, it is possible to acquire clear image data with very high resolution.
- the numbers of R, G, B, and W pixels corresponding to the RGBW filters 23R, 23G, 23B, and 23W in the basic array pattern P5 are 8 pixels, 16 pixels, 8 pixels, and 32 pixels, respectively.
- the ratio of the number of pixels is 1: 2: 1: 4 (W pixel number ⁇ G pixel number ⁇ R pixel number; W pixel number ⁇ G pixel number ⁇ B pixel number).
- the ratio of the number of W pixels and G pixels occupies 48/64 (3/4) of the whole, so that aliasing at the time of demosaic processing is suppressed. And high frequency reproducibility is improved.
- the transparent filter 23W is a pixel line (diagonal pixel line) extending in the NW direction and the NE direction, and among the eight pixel lines adjacent to each other, the transparent filter 23W includes all the diagonal pixels.
- the G filter 23G is included in a 6/8 diagonal pixel line.
- each diagonal pixel line including the R filter 23R and the B filter 23B is arranged with another diagonal pixel line including the R filter 23R and the B filter 23B of the same color at a position adjacent to at least one of them.
- the RGB filters 23R, 23G, and 23B are respectively arranged in the adjacent pixel lines extending in the oblique direction (NE, NW), colors that can be generated by an input image having a high-frequency component in the oblique direction (NE, NW). Moire (false color) can be effectively suppressed.
- the transparent filter 23W is included in all the oblique pixel lines, clearer image data can be obtained.
- each of the R filter (R pixel) and the B filter (B pixel) is located at a pixel position (vertical / horizontal direction) or adjacent pixel position (an oblique direction).
- G pixels are arranged at positions adjacent to each other in the vertical direction and the oblique direction.
- the position of the R filter 23R in the first sub array corresponds to the position of the B filter 23B in the second sub array, and the position of the B filter 23B in the first sub array and the second
- the positions of the R filter 23R in the sub array correspond to each other, and the W filter 23W and the G filter 23G are arranged at the same position between the first sub array and the second sub array. For this reason, even if the size of the basic array pattern is increased, it is possible to reduce the complexity of the demosaic process.
- G filters are arranged in two or more of the adjacent eight pixels surrounding each pixel other than the G pixels (W pixel, R pixel, and B pixel). Then, the G pixels are arranged in an evenly distributed state. In addition, G pixels are arranged in one or more pixels (one pixel at an oblique position in the present embodiment) among the eight adjacent pixels surrounding each of the G pixels. Thereby, the accuracy of color reproduction in demosaic processing can be further increased.
- the color filter array 22 constituted by the basic arrangement pattern P5 shown in FIG. 7 can also be constituted by other basic arrangement patterns, and 8 shifted from the basic arrangement pattern shown in FIG. 7 in the horizontal direction and / or the vertical direction.
- An array pattern corresponding to ⁇ 8 pixels may be used as a basic array pattern.
- the color filter array 22 according to the present embodiment has the above-described features, the demosaicing process in the subsequent stage is simplified, the color reproduction accuracy of the demosaic process in the high frequency region is improved, and the aliasing in the demosaic process is performed. Suppression and improvement of high frequency reproducibility, and higher resolution and higher sensitivity are possible.
- the color filter array 22 according to the present embodiment is excellent in high frequency reproducibility in the horizontal direction and the vertical direction because the R filter 23R and the B filter 23B are also arranged in each filter horizontal row and each filter vertical row.
- FIG. 8 is a diagram showing a basic array pattern P6 of color filters according to the sixth embodiment.
- the basic arrangement pattern P6 of the color filter arrangement according to the present embodiment uses the basic arrangement pattern P4 (see FIG. 6A) according to the fourth embodiment as the first sub-array (A arrangement), and is the same as the third embodiment.
- Such a basic array pattern P3 (see FIG. 5A) is defined as a second sub-array (B array), and each of these two types of first sub-array and second sub-array is included. Therefore, the position of the R filter 23R in the first sub array corresponds to the position of the B filter 23B in the second sub array, and the position of the B filter 23B in the first sub array and the R filter in the second sub array Corresponds to the position of 23R.
- the first sub array (A array) and the second sub array (B array) are arranged adjacent to each other in the horizontal direction and the vertical direction, and as a whole the horizontal direction and the vertical direction. Is a basic array pattern P6 corresponding to 8 ⁇ 8 pixels.
- the color filter array 22 according to the present embodiment has the following characteristics.
- the color filter array 22 includes a basic array pattern P6 that is a square array pattern corresponding to 8 ⁇ 8 pixels (M ⁇ N pixels) in the horizontal direction and the vertical direction, and the basic array pattern P6 is in the horizontal direction. And repeatedly arranged in the vertical direction. Therefore, in the color filter array 22, the R filter 23R, the G filter 23G, the B filter 23B, and the transparent filter 23W are arranged with periodicity. Therefore, when performing demosaic processing of R, G, B signals, etc., processing can be performed according to a repetitive pattern, and when the image is reduced by thinning processing in units of the basic array pattern P6, it is common before and after the thinning processing.
- the processing circuit can be used.
- each filter horizontal column and each filter vertical column in the basic array pattern P6 includes a 4-pixel transparent filter 23W, a 2-pixel G filter 23G, a 1-pixel R filter 23R, and a 1-pixel B filter 23B. Composed.
- the pixel lines (filter lines) in the horizontal direction (H), the vertical direction (V), and the diagonal direction (NE, NW) are included.
- a transparent filter 23W is disposed.
- the G filters 23G (second filters) corresponding to two pixels are arranged on each filter horizontal column and each filter vertical column. It is possible to improve the color reproduction accuracy of the demosaic process in the high frequency region in the vertical direction.
- an R filter 23R third filter
- a B filter 23B fourth filter corresponding to one pixel on each filter horizontal row and each filter vertical row.
- the G color corresponding to the G filter 23G but also the R color and the B color corresponding to the R filter (R pixel) and the B filter (B pixel) are demosaiced in a high frequency region in the horizontal direction and the vertical direction.
- Color reproduction accuracy can be improved. Therefore, since the color reproducibility accuracy in the high frequency region can be improved for all three primary colors, it is possible to acquire clear image data with very high resolution.
- the numbers of R, G, B, and W pixels corresponding to the RGBW filters 23R, 23G, 23B, and 23W in the basic array pattern P6 are 8 pixels, 16 pixels, 8 pixels, and 32 pixels, respectively.
- the ratio of the number of pixels is 1: 2: 1: 4 (W pixel number ⁇ G pixel number ⁇ R pixel number; W pixel number ⁇ G pixel number ⁇ B pixel number).
- the ratio of the number of W pixels and G pixels occupies 48/64 (3/4) of the whole, so that aliasing at the time of demosaic processing is suppressed. And high frequency reproducibility is improved.
- the transparent filter 23W includes all the diagonal pixels.
- the G filter 23G is included in a 6/8 diagonal pixel line.
- each diagonal pixel line including the R filter 23R and the B filter 23B is arranged with another diagonal pixel line including the R filter 23R and the B filter 23B of the same color at a position adjacent to at least one of them.
- the RGB filters 23R, 23G, and 23B are respectively arranged in the adjacent pixel lines extending in the oblique direction (NE, NW), colors that can be generated by an input image having a high-frequency component in the oblique direction (NE, NW). Moire (false color) can be effectively suppressed.
- the transparent filter 23W is included in all the oblique pixel lines, clearer image data can be obtained.
- each of the R filter (R pixel) and the B filter (B pixel) is located at a pixel position (vertical / horizontal direction) or adjacent pixel position (an oblique direction).
- G pixels are arranged at positions adjacent to each other in the vertical direction and the oblique direction.
- the position of the R filter 23R in the first sub array corresponds to the position of the B filter 23B in the second sub array, and the position of the B filter 23B in the first sub array and the second
- the positions of the R filter 23R in the sub array correspond to each other, and the W filter 23W and the G filter 23G are arranged at the same position in the first sub array and the second sub array. For this reason, even if the size of the basic array pattern is increased, it is possible to reduce the complexity of the demosaic process.
- G filters are arranged in two or more of the adjacent eight pixels surrounding each pixel other than the G pixels (W pixel, R pixel, and B pixel). Then, the G pixels are arranged in an evenly distributed state. In addition, G pixels are arranged in one or more pixels (one pixel at an oblique position in the present embodiment) among the eight adjacent pixels surrounding each of the G pixels. Thereby, the accuracy of color reproduction in demosaic processing can be further increased.
- the color filter array 22 constituted by the basic arrangement pattern P6 shown in FIG. 8 can also be constituted by other basic arrangement patterns, and is 8 shifted from the basic arrangement pattern shown in FIG. 8 in the horizontal direction and / or the vertical direction.
- An array pattern corresponding to ⁇ 8 pixels may be used as a basic array pattern.
- the color filter array 22 according to the present embodiment has the above-described features, the demosaicing process in the subsequent stage is simplified, the color reproduction accuracy of the demosaic process in the high frequency region is improved, and the aliasing in the demosaic process is performed. Suppression and improvement of high frequency reproducibility, and higher resolution and higher sensitivity are possible.
- the color filter array 22 according to the present embodiment is excellent in high frequency reproducibility in the horizontal direction and the vertical direction because the R filter 23R and the B filter 23B are also arranged in each filter horizontal row and each filter vertical row.
- FIG. 9 is a diagram showing a basic array pattern P7 of color filters according to the seventh embodiment.
- the basic array pattern P7 of the color filter array according to this embodiment is a first sub-array (A array) obtained by rotating the basic array pattern P1 (see FIG. 3A) according to the first embodiment by 90 degrees.
- An array pattern obtained by rotating the basic array pattern P2 (see FIG. 4A) according to the second embodiment by 90 degrees is defined as a second sub array (B array), and these two types of first sub array and first array Contains two subsequences, two each.
- the first sub-array includes “a horizontal filter row in which the G filter 23G, the B filter 23B, the transparent filter 23W, and the transparent filter 23W are juxtaposed in the horizontal direction”, and “the transparent filter 23W, the transparent filter 23W in the horizontal direction, “Filter horizontal row in which G filter 23G and R filter 23R are juxtaposed”, “Filter horizontal row in which B filter 23B, G filter 23G, transparent filter 23W and transparent filter 23W are juxtaposed in the horizontal direction”, and “horizontal direction”
- the transparent filter 23W, the transparent filter 23W, the filter horizontal row in which the R filter 23R and the G filter 23G are juxtaposed are sequentially arranged in the vertical direction.
- the second sub-array includes “a horizontal filter row in which G filter 23G, R filter 23R, transparent filter 23W and transparent filter 23W are juxtaposed in the horizontal direction” and “transparent filter 23W, transparent filter 23W, G in the horizontal direction”. “Filter horizontal row in which filter 23G and B filter 23B are juxtaposed”, “Filter horizontal row in which R filter 23R, G filter 23G, transparent filter 23W and transparent filter 23W are juxtaposed in the horizontal direction”, and “transparent in horizontal direction” A filter horizontal row in which the filter 23W, the transparent filter 23W, the B filter 23B, and the G filter 23G are juxtaposed is sequentially arranged in the vertical direction.
- the position of the R filter 23R in the first sub array corresponds to the position of the B filter 23B in the second sub array
- the position of the B filter 23B in the first sub array and the R filter in the second sub array Corresponds to the position of 23R.
- the first sub array (A array) and the second sub array (B array) are arranged adjacent to each other in the horizontal direction and the vertical direction, and as a whole the horizontal direction and the vertical direction. Is a basic array pattern P7 corresponding to 8 ⁇ 8 pixels.
- the color filter array 22 according to the present embodiment has the following characteristics.
- the color filter array 22 includes a basic array pattern P7 that is a square array pattern corresponding to 8 ⁇ 8 pixels (M ⁇ N pixels) in the horizontal direction and the vertical direction. And repeatedly arranged in the vertical direction. Therefore, in the color filter array 22, the R filter 23R, the G filter 23G, the B filter 23B, and the transparent filter 23W are arranged with periodicity. Therefore, when performing demosaic processing of R, G, B signals, etc., processing can be performed according to a repetitive pattern, and when the image is reduced by thinning processing in units of the basic array pattern P7, it is common before and after the thinning processing.
- the processing circuit can be used.
- each filter horizontal column and each filter vertical column in the basic array pattern P7 includes a 4-pixel transparent filter 23W, a 2-pixel G filter 23G, a 1-pixel R filter 23R, and a 1-pixel B filter 23B. Composed.
- the pixel lines (filter lines) in the horizontal direction (H), the vertical direction (V), and the diagonal direction (NE, NW) are included.
- a transparent filter 23W is disposed.
- an R filter 23R third filter
- a B filter 23B fourth filter corresponding to one pixel on each filter horizontal row and each filter vertical row.
- the G color corresponding to the G filter 23G but also the R color and the B color corresponding to the R filter (R pixel) and the B filter (B pixel) are demosaiced in a high frequency region in the horizontal direction and the vertical direction.
- Color reproduction accuracy can be improved. Therefore, since the color reproducibility accuracy in the high frequency region can be improved for all three primary colors, it is possible to acquire clear image data with very high resolution.
- the numbers of R, G, B, and W pixels corresponding to the RGBW filters 23R, 23G, 23B, and 23W in the basic array pattern P7 are 8 pixels, 16 pixels, 8 pixels, and 32 pixels, respectively.
- the ratio of the number of pixels is 1: 2: 1: 4 (W pixel number ⁇ G pixel number ⁇ R pixel number; W pixel number ⁇ G pixel number ⁇ B pixel number).
- the ratio of the number of W pixels and G pixels occupies 48/64 (3/4) of the whole, so that aliasing at the time of demosaic processing is suppressed. And high frequency reproducibility is improved.
- the transparent filter 23W includes all the diagonal pixels.
- the G filter 23G is included in a 6/8 diagonal pixel line.
- the RGB filters 23R, 23G, and 23B are arranged in the adjacent pixel lines extending in the oblique direction (NE, NW), respectively, and thus are generated by an input image having a high frequency component in the oblique direction (NE, NW). Moist color moire (false color) can be effectively suppressed.
- the transparent filter 23W is included in all the oblique pixel lines, clearer image data can be obtained.
- each of the R filter (R pixel) and the B filter (B pixel) is located at a pixel position (vertical / horizontal direction) or adjacent pixel position (an oblique direction).
- G pixels are arranged at positions adjacent to each other in the horizontal direction and the diagonal direction.
- the position of the R filter 23R in the first sub array corresponds to the position of the B filter 23B in the second sub array, and the position of the B filter 23B in the first sub array and the second
- the positions of the R filter 23R in the sub array correspond to each other, and the W filter 23W and the G filter 23G are arranged at the same position in the first sub array and the second sub array. For this reason, even if the size of the basic array pattern is increased, it is possible to reduce the complexity of the demosaic process.
- G filters are arranged in two or more of the adjacent eight pixels surrounding each pixel other than the G pixels (W pixel, R pixel, and B pixel). Then, the G pixels are arranged in an evenly distributed state. In addition, G pixels are arranged in one or more pixels (one pixel at an oblique position in the present embodiment) among the eight adjacent pixels surrounding each of the G pixels. Thereby, the accuracy of color reproduction in demosaic processing can be further increased.
- the color filter array 22 constituted by the basic arrangement pattern P7 shown in FIG. 9 can also be constituted by other basic arrangement patterns, and is shifted from the basic arrangement pattern shown in FIG. 9 in the horizontal direction and / or the vertical direction.
- An array pattern corresponding to ⁇ 8 pixels may be used as a basic array pattern.
- the color filter array 22 according to the present embodiment has the above-described features, the demosaicing process in the subsequent stage is simplified, the color reproduction accuracy of the demosaic process in the high frequency region is improved, and the aliasing in the demosaic process is performed. Suppression and improvement of high frequency reproducibility, and higher resolution and higher sensitivity are possible.
- the color filter array 22 according to the present embodiment is excellent in high frequency reproducibility in the horizontal direction and the vertical direction because the R filter 23R and the B filter 23B are also arranged in each filter horizontal row and each filter vertical row.
- FIG. 10A and 10B are diagrams showing a basic array pattern of color filters according to the eighth embodiment.
- FIG. 10A shows one basic array pattern P8, and
- FIG. 10B shows the basic array pattern P8 in the horizontal and vertical directions. A state in which a total of four are arranged two by two is shown.
- the color filter array according to the present embodiment includes two types of sub-arrays (first sub-array (A array) and second sub-array (B array)) to form a basic array pattern P8.
- first sub-array (A array) and second sub-array (B array) to form a basic array pattern P8.
- the first sub-array (A array) corresponds to 3 ⁇ 3 pixels ((M / 2) ⁇ (N / 2) pixels) in the horizontal direction and the vertical direction, and the transparent filter 23W is applied to the pixels at the four corners and the center pixel. Is placed. Further, a G filter 23G is disposed at each of pixel positions adjacent to the upper and lower sides (vertical direction) of the central transparent filter 23W, and one of the pixel positions adjacent to the left and right (horizontal direction) of the central transparent filter 23W (in FIG. 10). The B filter 23B is arranged at the left position, and the R filter 23R is arranged at the other (right position in FIG. 10).
- the second sub array (B array) corresponds to 3 ⁇ 3 pixels in the horizontal direction and the vertical direction, and the transparent filter 23W is arranged at the pixel at the four corners and the pixel at the center. Further, a G filter 23G is arranged at each of pixel positions adjacent to the left and right (horizontal direction) of the central transparent filter 23W, and one of the pixel positions adjacent to the upper and lower (vertical direction) of the central transparent filter 23W (in FIG. 10).
- the B filter 23B is disposed at the upper position
- the R filter 23R is disposed at the other (lower position in FIG. 10).
- the first sub-array and the second sub-array are adjacent to each other in the horizontal direction and the vertical direction, and as a whole, the basic sub-pattern P8 corresponds to 6 ⁇ 6 pixels in the horizontal direction and the vertical direction. ing.
- the transparent filter 23W is arranged on each pixel line extending in the horizontal direction and on each pixel line extending in the second direction. Further, the transparent filter 23W is also arranged on each pixel line that extends in each of the diagonal directions that form 45 ° with the horizontal direction and the vertical direction, and that includes three or more pixels.
- a G filter 23G for two pixels and an R filter 23R and a B filter 23B for one pixel are arranged.
- the position of the G filter 23G in the first sub array corresponds to the position of the B filter 23B and the R filter 23R in the second sub array, and the position of the R filter 23R and the B filter 23B in the first sub array
- the position of the G filter 23G in the second sub array corresponds.
- the color filter array 22 according to the present embodiment has the following characteristics.
- the color filter array 22 includes a basic array pattern P8 that is a square array pattern corresponding to 6 ⁇ 6 pixels (M ⁇ N pixels) in the horizontal direction and the vertical direction, and the basic array pattern P8 is in the horizontal direction. And repeatedly arranged in the vertical direction. Therefore, in the color filter array 22, the R filter 23R, the G filter 23G, the B filter 23B, and the transparent filter 23W are arranged with periodicity. Therefore, when performing demosaic processing of R, G, B signals, etc., processing can be performed according to a repetitive pattern, and when the image is reduced by thinning processing in units of the basic array pattern P8, it is common before and after the thinning processing.
- the processing circuit can be used.
- the transparent filter 23W is present in one or more pixels in all the filter horizontal columns and the filter vertical columns, and the first filter horizontal column 25a, the third filter horizontal column 25c, and the fourth filter horizontal column.
- the column 25d, the sixth filter horizontal column 25f, the first filter vertical column 27a, the third filter vertical column 27c, the fourth filter vertical column 27d, and the sixth filter vertical column 27f there are four transparent filters 23W.
- a transparent filter 23W is arranged in each pixel line to be configured.
- the G filter 23G corresponding to one pixel or two pixels is arranged on each filter horizontal column and each filter vertical column, so that the horizontal direction and the vertical direction It is possible to improve the color reproduction accuracy of demosaic processing in the high-frequency region.
- the numbers of R, G, B, and W pixels corresponding to the RGBW filters 23R, 23G, 23B, and 23W in the basic array pattern P8 are 4, 8, 4, and 20 pixels, respectively.
- the ratio of the number of pixels is 1: 2: 1: 5 (W pixel number ⁇ G pixel number ⁇ R pixel number; W pixel number ⁇ G pixel number ⁇ B pixel number).
- the ratio of the number of pixels of W pixels and G pixels occupies 28/36 (7/9), so that aliasing during the demosaic process is suppressed. And high frequency reproducibility is improved.
- the transparent filter 23W includes all the diagonal pixels among the six pixel lines that are pixel lines (diagonal pixel lines) extending in the NW direction and the NE direction and adjacent to each other.
- the G filter 23G is included in a 4/6 diagonal pixel line.
- each diagonal pixel line including the R filter 23R and the B filter 23B is arranged with another diagonal pixel line including the R filter 23R and the B filter 23B of the same color at a position adjacent to one.
- the RGB filters 23R, 23G, and 23B are respectively arranged in the adjacent pixel lines extending in the oblique direction (NE, NW), colors that can be generated by an input image having a high-frequency component in the oblique direction (NE, NW). Moire (false color) can be effectively suppressed.
- the transparent filter 23W is included in all the oblique pixel lines, clearer image data can be obtained.
- each of the R filter (R pixel) and the B filter (B pixel) is located at a pixel position adjacent to either the top, bottom, left, right (vertical direction / horizontal direction) or diagonal direction.
- G pixels are arranged.
- the R pixel and the B pixel are evenly arranged in the color filter array 22 (in the basic array pattern P8), the accuracy of the demosaic process can be improved, and the color reproducibility can be improved.
- the first sub-array and the second sub-array have a rotationally symmetric relationship in the basic array pattern, it is possible to reduce the complexity of the demosaic process even when the size of the basic array pattern increases. .
- G filters are arranged in two or more of the adjacent eight pixels surrounding each pixel other than the G pixels (W pixel, R pixel, and B pixel). Then, the G pixels are arranged in an evenly distributed state. Thereby, the accuracy of color reproduction in demosaic processing can be further increased.
- the color filter array 22 constituted by the basic arrangement pattern P8 shown in FIG. 10A can also be constituted by other basic arrangement patterns, and the horizontal direction and / or from the basic arrangement pattern shown in FIG. An array pattern corresponding to 6 ⁇ 6 pixels shifted in the vertical direction may be used as the basic array pattern.
- the demosaicing process in the subsequent stage is simplified, the color reproduction accuracy of the demosaic process in the high frequency region is improved, and the aliasing in the demosaic process is performed. Suppression and improvement of high frequency reproducibility, and higher resolution and higher sensitivity are possible.
- FIG. 11A and 11B are diagrams showing a basic array pattern of color filters according to the ninth embodiment.
- FIG. 11A shows one basic array pattern P9
- FIG. 11B shows the basic array pattern P9 in the horizontal and vertical directions. A state in which a total of four are arranged two by two is shown.
- the color filter array 22 includes a basic array pattern P9 that is a square array pattern corresponding to 6 ⁇ 6 pixels (M ⁇ N pixels) in the horizontal direction and the vertical direction, and the basic array pattern P9 is in the horizontal direction. And repeatedly arranged in the vertical direction.
- the basic array pattern P9 includes four types of first sub-arrays (A arrays) in which color filters are arranged in an array pattern corresponding to 3 ⁇ 3 pixels ((M / 2) ⁇ (N / 2) pixels). Each includes a second sub-sequence (B sequence), a third sub-sequence (C sequence), and a fourth sub-sequence (D sequence).
- the first sub-array (A array) includes “a horizontal filter row in which the transparent filter 23W, the R filter 23R, and the transparent filter 23W are juxtaposed in the horizontal direction” and “a B filter 23B, a transparent filter 23W, and a G filter in the horizontal direction”.
- the filter horizontal row in which 23G is juxtaposed and the filter horizontal row in which the transparent filter 23W, the G filter 23G, and the transparent filter 23W are juxtaposed in the horizontal direction are sequentially arranged in the vertical direction.
- the second sub-array includes “a horizontal filter row in which the transparent filter 23W, the G filter 23G, and the transparent filter 23W are juxtaposed in the horizontal direction” and “an R filter 23R, a transparent filter 23W, and a G in the horizontal direction”.
- the filter horizontal row in which the filter 23G is juxtaposed and the “filter horizontal row in which the transparent filter 23W, the B filter 23B, and the transparent filter 23W are juxtaposed in the horizontal direction” are sequentially arranged in the vertical direction.
- the third sub-array includes “a horizontal filter row in which the transparent filter 23W, the B filter 23B, and the transparent filter 23W are juxtaposed in the horizontal direction” and “a G filter 23G, a transparent filter 23W, and R in the horizontal direction”.
- the filter horizontal row in which the filters 23R are juxtaposed and the “filter horizontal row in which the transparent filter 23W, the G filter 23G, and the transparent filter 23W are juxtaposed in the horizontal direction” are sequentially arranged in the vertical direction.
- the fourth sub-array includes “a horizontal filter row in which the transparent filter 23W, the G filter 23G, and the transparent filter 23W are juxtaposed in the horizontal direction” and “a G filter 23G, a transparent filter 23W, and a B in the horizontal direction”.
- the filter horizontal row in which the filter 23B is juxtaposed and the “filter horizontal row in which the transparent filter 23W, the R filter 23R and the transparent filter 23W are juxtaposed in the horizontal direction” are sequentially arranged in the vertical direction.
- the first sub-array (A array) and the fourth sub-array (D array) are arranged in one diagonal direction, and the second sub-array (B array) and the third sub-array are arranged.
- the array (C array) is arranged in the other diagonal direction.
- the R filter 23R, the G filter 23G, the B filter 23B, and the transparent filter 23W are arranged with periodicity. Therefore, when performing demosaic processing of R, G, B signals, etc., processing can be performed according to a repetitive pattern, and when the image is reduced by thinning processing in units of the basic array pattern P9, it is common before and after the thinning processing.
- the processing circuit can be used.
- the transparent filter 23W is present in one or more pixels in all the filter horizontal rows and filter vertical rows, and the first filter horizontal row 25a, the third filter horizontal row 25c, and the fourth filter horizontal row.
- the sixth filter horizontal column 25f, the first filter vertical column 27a, the third filter vertical column 27c, the fourth filter vertical column 27d, and the sixth filter vertical column 27f there are four transparent filters 23W.
- each pixel line in the horizontal direction (H) and the vertical direction (V) and three or more pixels in the diagonal direction (NE, NW) are included.
- a transparent filter 23W is arranged in each pixel line to be configured.
- the G filters 23G corresponding to one pixel or two pixels are arranged on each filter horizontal column and each filter vertical column, so the horizontal direction and the vertical direction It is possible to improve the color reproduction accuracy of demosaic processing in the high-frequency region.
- the numbers of R, G, B, and W pixels corresponding to the RGBW filters 23R, 23G, 23B, and 23W in the basic array pattern P9 are 4 pixels, 8 pixels, 4 pixels, and 20 pixels, respectively.
- the ratio of the number of pixels is 1: 2: 1: 5 (W pixel number ⁇ G pixel number ⁇ R pixel number; W pixel number ⁇ G pixel number ⁇ B pixel number).
- the ratio of the number of pixels of W pixels and G pixels occupies 28/36 (7/9), so that aliasing during the demosaic process is suppressed. And high frequency reproducibility is improved.
- the transparent filter 23W includes all the diagonal pixels among the six pixel lines that are pixel lines (diagonal pixel lines) extending in the NW direction and the NE direction and adjacent to each other.
- the G filter 23G is included in a 4/6 diagonal pixel line.
- each diagonal pixel line including the R filter 23R and the B filter 23B is arranged with another diagonal pixel line including the R filter 23R and the B filter 23B of the same color at a position adjacent to one.
- the RGB filters 23R, 23G, and 23B are respectively arranged in the adjacent pixel lines extending in the oblique direction (NE, NW), colors that can be generated by an input image having a high-frequency component in the oblique direction (NE, NW). Moire (false color) can be effectively suppressed.
- the transparent filter 23W is included in all the oblique pixel lines, clearer image data can be obtained.
- each of the R filter (R pixel) and the B filter (B pixel) is located at a pixel position adjacent to either the top, bottom, left, right (vertical direction / horizontal direction) or diagonal direction.
- G pixels are arranged.
- the R pixels and the B pixels are evenly arranged in the color filter array 22 (in the basic array pattern P9), the accuracy of the demosaic process can be improved, and the color reproducibility can be improved.
- the first sub-array to the fourth sub-array are in a rotationally symmetric relationship in the basic array pattern, it is possible to reduce the complexity of the demosaic process even if the size of the basic array pattern increases. it can.
- G filters are arranged in two or more of the adjacent eight pixels surrounding each pixel other than the G pixels (W pixel, R pixel, and B pixel). Then, the G pixels are arranged in an evenly distributed state. In addition, G pixels are arranged in one or more pixels (one pixel at an oblique position in the present embodiment) among the eight adjacent pixels surrounding each of the G pixels. In particular, in the present embodiment, there are two or more G pixels in a 3 ⁇ 3 pixel area (including G pixels). Thereby, the accuracy of color reproduction in demosaic processing can be further increased.
- the W pixel is arranged adjacent to either the top / bottom / left / right (vertical / horizontal direction) or diagonal direction with respect to the “G pixel having a large contribution to luminance”. Therefore, it is possible to improve the accuracy of color reproduction at the W pixel position in the color interpolation process (demosaic process) of the W pixel.
- the color filter array 22 constituted by the basic arrangement pattern P9 shown in FIG. 11A can also be constituted by another basic arrangement pattern, and the horizontal arrangement and / or the horizontal arrangement pattern shown in FIG. An array pattern corresponding to 6 ⁇ 6 pixels shifted in the vertical direction may be used as the basic array pattern.
- the demosaicing process in the subsequent stage is simplified, the color reproduction accuracy of the demosaic process in the high frequency region is improved, and the aliasing in the demosaic process is performed. Suppression and improvement of high frequency reproducibility, and higher resolution and higher sensitivity are possible.
- first filter transparent filter
- first visible light wavelength range green wavelength range
- second filter G filter
- second visible light wavelength range red
- third wavelength third filter
- fourth filter B filter
- the G filter 23G of G color has been described as an example of the second filter of the present invention, but instead of the G filter 23G or a part of the G filter 23G, the following is described.
- a filter that satisfies any of the conditions may be used.
- Colors corresponding to other color filters (a color corresponding to the second visible light wavelength region and a third visible light wavelength region) except for the transparent (white) filter (W filter)
- a color filter corresponding to a higher color than the G filter 23G can be used as the second filter.
- a color filter having a contribution rate for obtaining a luminance signal of 50% or more can be used as the second filter.
- the contribution rate of G (green) color accounts for 59% of colors (RGB) other than W (transparent), so the G filter is used as the second filter. Yes. Note that the contribution ratio of colors other than the G color can also be obtained through experiments and simulations.
- Condition (2) is that the peak of the transmittance of the filter is in the range of wavelengths from 480 nm to 570 nm.
- a value measured with a spectrophotometer is used as the transmittance of the filter.
- This wavelength range is a range determined to distinguish the first visible light wavelength region, the second visible light wavelength region, and the third visible light wavelength region of the present invention, and the above-described contribution rate. Is a range determined so as to include peaks such as R color and B color in which R is relatively low and peaks such as G color in which the contribution ratio is relatively high. Therefore, a filter having a transmittance peak in the wavelength range of 480 nm to 570 nm can be used as the second filter. Note that filters whose transmittance peaks are outside the wavelength range of 480 nm to 570 nm are the third filter and the fourth filter (R filter 23R, B filter 23B, etc.) of the present invention.
- the condition (3) is that the transmittance in the wavelength range of 500 nm to 560 nm is higher than the transmittance of the third filter and the fourth filter (R filter 23R and B filter 23B). Also in this condition (3), the value measured with a spectrophotometer, for example, is used as the transmittance of the filter.
- the wavelength range of the condition (3) is also a range determined to distinguish the first visible light wavelength range of the present invention from the second visible light wavelength range and the third visible light wavelength range.
- the transmittance of the filter having a color having the above-described contribution rate relatively higher than that of the R color, the B color, or the like is higher than the transmittance of the RB filters 23R and 23B. Therefore, a filter having a relatively high transmittance within a wavelength range of 500 nm to 560 nm can be used as the second filter, and a filter having a relatively low transmittance can be used as the third filter and the fourth filter. .
- Condition (4) is that a filter of two or more colors including a color that contributes most to the luminance signal (for example, G color of RGB) among the three primary colors and a color different from the three primary colors is used as the second filter. Is to use. In this case, filters corresponding to colors other than the colors of the second filter are the third filter and the fourth filter.
- the first visible light wavelength region, the second visible light wavelength region, and the third visible light wavelength region correspond to the three primary colors (for example, RBG), and the color filter is in addition to the color filters corresponding to the three primary colors. You may further include the color filter which has the transmittance
- each of the first visible light wavelength region, the second visible light wavelength region, and the third visible light wavelength region includes a plurality of wavelength regions, a plurality of colors corresponding to the plurality of wavelength regions are the first.
- the visible light wavelength region, the second visible light wavelength region, and the third visible light wavelength region can also be handled.
- the G color G filter 23G as the second filter is not limited to one type, and for example, a plurality of types of G filters 23G can be used as the second filter. That is, the G filter 23G of the color filter (basic arrangement pattern) according to each of the above embodiments may be appropriately replaced with the first G filter 23G1 or the second G filter 23G2.
- the first G filter 23G1 transmits G light in the first wavelength band
- the second G filter 23G2 transmits G light in the second wavelength band having a high correlation with the first G filter 23G1 (see FIG. 12).
- an existing G filter for example, the G filter 23G of the first embodiment
- a filter having a high correlation with the first G filter 23G1 can be used.
- the peak value of the spectral sensitivity curve of the light receiving element in which the second G filter 23G2 is arranged has a wavelength range of, for example, 500 nm to 535 nm (near the peak value of the spectral sensitivity curve of the light receiving element in which the existing G filter is arranged).
- a method described in Japanese Patent Application Laid-Open No. 2003-284084 is used as a method for determining the color filters of four colors (R, G1, G2, B).
- the color of the image acquired by the color imaging device is set to four types, and the color information acquired is increased, so that the color can be more accurately compared with the case where only three types of colors (RGB) are acquired.
- RGB three types of colors
- each G filter 23G1, 23G2 (the sensitivity peak of each G pixel) is in the wavelength range of 480 nm to 570 nm.
- the transmittances of the G filters 23G1 and 23G2 are higher than the transmittances of the RB filters 23R and 23B within a wavelength range of 500 nm to 560 nm. For this reason, each G filter 23G1, 23G2 also satisfies the above-mentioned conditions (2), (3).
- G filters 23G1 and 23G2 may be changed as appropriate. Moreover, you may increase the kind of G filter 23G to three or more types.
- the transparent filter 23W is a transparent color filter, and may be referred to by other names such as a white filter.
- the transparent filter 23W can transmit light corresponding to the wavelength range of visible light, for example, light of each color of RGB (first visible light wavelength range, second visible light wavelength range, and third visible light wavelength range). This is a filter having a light transmittance of 50% or more.
- the transparent filter has a high transmittance in each wavelength band of RGB, and is actually a filter having color characteristics close to transparency.
- the transmittance peak of the transparent filter 23W (white pixel sensitivity peak) is in the wavelength range of 480 nm to 570 nm. Further, the transmittance of the transparent filter 23W is higher than the transmittance of the RB filters 23R and 23B within a wavelength range of 500 nm to 560 nm.
- E filter a color filter mainly composed of color filters corresponding to RGBW colors is shown.
- a part of these color filters may be other color filters, for example, emerald filter E ( A fifth filter, an emerald pixel) may be used.
- G filter 23G it is preferable to dispose an emerald filter instead of a part of the second filter (G filter 23G). In this way, by using a color filter array of four colors in which a part of the G filter 23G is replaced with an emerald filter, it is possible to improve reproduction of high-frequency components of luminance, reduce jegginess, and improve resolution. can do.
- the peak of transmittance of the emerald filter E (the peak of sensitivity of the E pixel) is in the range of wavelengths from 480 nm to 570 nm. Further, the transmittance of the emerald filter E is higher than the transmittance of the RB filters 23R and 23B within a wavelength range of 500 nm to 560 nm. For this reason, the emerald filter E satisfies the above-mentioned conditions (2) and (3).
- the emerald filter E has a peak on the shorter wavelength side than the G filter 23G, but has a peak on the longer wavelength side than the G filter 23G (it looks a little yellowish). In some cases.
- those satisfying the conditions of the present invention can be selected.
- an emerald filter E that satisfies the condition (1) can be selected.
- the color filter array including the color filters for the primary colors RGB has been described.
- G is added to C (cyan), M (magenta), and Y (yellow) which are complementary colors of the primary colors RGB.
- the present invention can also be applied to a color filter array constituted by four complementary color filters and a transparent filter 23W.
- the color filter satisfying any of the above conditions is the second filter of the present invention, and the other color filters are the third filter, the fourth filter, and the fifth filter.
- Each color filter array of each of the above embodiments includes a basic array pattern in which color filters of each color are two-dimensionally arrayed in the horizontal direction (H) and the vertical direction (V), and this basic array pattern is in the horizontal direction (H ) And the vertical direction (V), but the present invention is not limited to this.
- the basic arrangement pattern is repeatedly arranged in an oblique direction (NE, NW) using a so-called honeycomb arrangement basic arrangement pattern obtained by rotating the basic arrangement pattern of each of the above-described embodiments by 45 ° around the optical axis.
- a color filter may be configured by an array pattern.
- the oblique directions (NE, NW) are the first and second directions of the present invention
- the horizontal and vertical directions are the third and fourth directions of the present invention.
- FIG. 15 shows a color filter array in which the basic array pattern P1 according to the first embodiment described above is arrayed in a honeycomb shape and has a basic array pattern P10.
- a first filter (W filter or the like) corresponding to at least one pixel is arranged on each pixel line extending in each of the fourth directions, ”“ each pixel line extending in the first direction.
- a second filter (G filter or the like) corresponding to at least one pixel is disposed on each pixel line extending in the upper and second directions, and a third filter and a fourth filter (R filter, B filter, etc.).
- each of the first filter, the second filter, the third filter, and the fourth filter is arranged for at least one pixel. Because If the corresponding number of pixels of the basic arrangement pattern is not particularly limited.
- the basic array pattern may be arranged in an array pattern corresponding to the number of other pixels.
- the size of the basic array pattern is preferably 10 ⁇ 10 pixels or less which is not too large, and the basic array pattern corresponding to 6 ⁇ 6 pixels or 4 ⁇ 4 pixels performs signal processing. It is more preferable from the viewpoint of simplification.
- color filter array of the color image sensor of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.
- the color filter arrays of the above embodiments and modifications may be combined as appropriate.
- a color image sensor mounted on a digital camera has been described.
- a color image sensor mounted on various electronic devices (imaging devices) having a shooting function such as a smartphone, a mobile phone, and a PDA.
- imaging devices imaging devices
- the present invention can also be applied.
- DESCRIPTION OF SYMBOLS 9 Digital camera, 10 ... Shooting optical system, 12 ... Color imaging device, 14 ... Shooting processing part, 16 ... Image processing part, 18 ... Drive part, 20 ... Control part, 21 ... Pixel, 22 ... Color filter array, 23B ... B filter, 23G ... G filter, 23G1 ... first G filter, 23G2 ... second G filter, 23R ... R filter, 23W ... transparent filter, 25a-25f ... filter horizontal row, 27a-27f ... filter vertical row, P1-P10 ... Basic array pattern
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Abstract
Description
図1は本発明に係るカラー撮像素子を備えるデジタルカメラ9のブロック図である。デジタルカメラ9は、大別して、撮影光学系10、カラー撮像素子12、撮影処理部14、画像処理部16、駆動部18、制御部20などを備えている。
図2に示すように、カラー撮像素子12の撮像面には、水平方向及び垂直方向に2次元配列された光電変換素子PDで構成される複数の画素21が設けられている。ここで、水平方向は本発明の第1の方向及び第2の方向のうちの一方向に相当し、垂直方向は本発明の第1の方向及び第2の方向のうちの他方向に相当する。
本実施形態に係るカラーフィルタ配列22は、下記の特徴を有する。
図3(a)及び図3(b)に示すように、カラーフィルタ配列22は、水平方向及び垂直方向に関し4×4画素(M×N画素)に対応する正方配列パターンとなる基本配列パターンP1を含み、この基本配列パターンP1が水平方向及び垂直方向に繰り返し配置される。この基本配列パターンP1は、Rフィルタ23R、Gフィルタ23G、Bフィルタ23B、透明フィルタ23Wの各色のフィルタを含む。したがって、カラーフィルタ配列22では、Rフィルタ23R、Gフィルタ23G、Bフィルタ23B、透明フィルタ23Wが周期性をもって配列される。
基本配列パターンP1では、水平方向に平行に延在する4種類の画素ライン(第1のフィルタ水平列25a、第2のフィルタ水平列25b、第3のフィルタ水平列25c、第4のフィルタ水平列25d)が、垂直方向に順次配列される(図3(a)参照)。第1のフィルタ水平列25aは「水平方向に透明フィルタ23W、Rフィルタ23R、透明フィルタ23W及びGフィルタ23Gが並置されるフィルタ列(画素ライン)」であり、第2のフィルタ水平列25bは「水平方向に透明フィルタ23W、Gフィルタ23G、透明フィルタ23W及びRフィルタ23Rが並置されるフィルタ列」であり、第3のフィルタ水平列25cは「水平方向にBフィルタ23B、透明フィルタ23W、Gフィルタ23G及び透明フィルタ23Wが並置されるフィルタ列」であり、第4のフィルタ水平列25dは「水平方向にGフィルタ23G、透明フィルタ23W、Bフィルタ23B及び透明フィルタ23Wが並置されるフィルタ列」である。このフィルタ配列により、本実施形態に係る基本配列パターンP1では、垂直方向に平行に延在する4種類の画素ライン(第1のフィルタ垂直列27a、第2のフィルタ垂直列27b、第3のフィルタ垂直列27c、第4のフィルタ垂直列27d)が形成される。
また、本実施形態に係るカラーフィルタ配列22の基本配列パターンP1では、水平方向に延在する各画素ライン(フィルタ水平列)上及び垂直方向に延在する各画素ライン(フィルタ垂直列)上に、1画素分に対応するGフィルタ23G(第2のフィルタ)が配置される。
このように、G色(第1の可視光波長域に対応する色)は、R色及びB色(第2の可視光波長域に対応する色及び第3の可視光波長域に対応する色)よりも、輝度信号を得るための寄与率が高い。
基本配列パターンP1内のRGBWフィルタ23R、23G、23B、23Wに対応するR画素、G画素、B画素、W画素の画素数は、それぞれ2画素、4画素、2画素、8画素になり、RGBW画素の各画素数の比率は1:2:1:4になる(W画素数≧G画素数≧R画素数;W画素数≧G画素数≧B画素数)。したがって、本実施形態に係るカラーフィルタ配列22は、Rフィルタ23R及びBフィルタ23Bの2倍のGフィルタ23Gを含み、またGフィルタ23Gの2倍(Rフィルタ23R及びBフィルタ23Bの4倍)の透明フィルタ23Wを含む。RGBW画素のうち、輝度信号を得るために相対的に大きく寄与する画素はW画素及びG画素である。したがって、カラーフィルタ配列22では、これらのW画素及びG画素の画素数の比率が全体の12/16(3/4)を占めるため、デモザイク処理時におけるエリアシングを効果的に抑制することができ、かつ高周波再現性も良好になる。
図3(b)に示す基本配列パターンP1には、NW方向及びNE方向に関して、「透明フィルタ23W及びGフィルタ23Gが配列される画素ライン」と、「透明フィルタ23W、Gフィルタ23G及びRフィルタ23Rが配列される画素ライン」と、「透明フィルタ23W、Rフィルタ23R及びBフィルタ23Bが配列される画素ライン」と、「透明フィルタ23W、Gフィルタ23G及びBフィルタ23Bが配列される画素ライン」とが1:1:1:1の割合で含まれる。
本実施形態に係るカラーフィルタ配列22によれば、Rフィルタ(R画素)及びBフィルタ(B画素)の各々は、Gフィルタ(G画素)と隣接配置される。すなわち、R画素及びB画素の各々は、上下左右(垂直方向/水平方向)或いは斜め方向のいずれかに隣接する画素位置(本実施形態では垂直方向及び斜め方向に隣接する位置)にG画素が配置される。これにより、R画素及びB画素がカラーフィルタ配列22内(基本配列パターンP1内)において均等に配置され、デモザイク処理の精度を向上することができ、色再現性を良好にすることができる。
また本実施形態のカラーフィルタ配列22において、G画素以外の画素(W画素、R画素及びB画素)の各々を取り囲む周辺隣接8画素のうち2画素以上に、Gフィルタ(G画素)が配置される。これにより、色再現性に対して影響の大きいG画素が均等にばらけた状態で配置され、 G画素以外の補間対象画素(W画素、R画素及びB画素)の周辺隣接8画素のうち2画素以上存在するG画素によって、 デモザイク処理(補間処理)における色再現の精度を高くすることができる。
また本実施形態のカラーフィルタ配列22において、W画素は「輝度への寄与率の大きなG画素」に隣接して配置されるため、W画素の色補間処理(デモザイク処理)において、W画素位置における色再現の精度を高めることができる。
図4は、第2実施形態に係るカラーフィルタの基本配列パターンを示す図であり、(a)は1つの基本配列パターンP2を示し、(b)は基本配列パターンP2を水平方向及び垂直方向に3つずつ計9つ配置した状態を示す。
本実施形態に係るカラーフィルタ配列22も、水平方向及び垂直方向に関し4×4画素(M×N画素)に対応する正方配列パターンとなる基本配列パターンP2を含み、この基本配列パターンP2が水平方向及び垂直方向に繰り返し配置される。したがって、カラーフィルタ配列22では、Rフィルタ23R、Gフィルタ23G、Bフィルタ23B、透明フィルタ23Wが周期性をもって配列される。そのため、R、G、B信号のデモザイク処理等を行う際に繰り返しパターンに従って処理を行うことができ、また基本配列パターンP2の単位で間引き処理して画像を縮小する場合に、間引き処理前後において共通の処理回路を使用することができる。
基本配列パターンP2でも、水平方向に平行に延在する4種類のフィルタ水平列が、垂直方向に順次配列される(図4(a)参照)。第1のフィルタ水平列25aは「水平方向に透明フィルタ23W、Bフィルタ23B、透明フィルタ23W及びGフィルタ23Gが並置されるフィルタ列」であり、第2のフィルタ水平列25bは「水平方向に透明フィルタ23W、Gフィルタ23G、透明フィルタ23W及びBフィルタ23Bが並置されるフィルタ列」であり、第3のフィルタ水平列25cは「水平方向にRフィルタ23R、透明フィルタ23W、Gフィルタ23G及び透明フィルタ23Wが並置されるフィルタ列」であり、第4のフィルタ水平列25dは「水平方向にGフィルタ23G、透明フィルタ23W、Rフィルタ23R及び透明フィルタ23Wが並置されるフィルタ列」である。したがって、本例の基本配列パターンP2では、垂直方向に平行に延在する4種類のフィルタ垂直列が形成される。
また、本実施形態に係る基本配列パターンP2でも、各フィルタ水平列上及び各フィルタ垂直列上に、1画素分に対応するGフィルタ23G(第2のフィルタ)が配置されるため、水平方向及び垂直方向に関する高周波領域でのデモザイク処理の色再現精度を向上させることができる。
基本配列パターンP2内のRGBWフィルタ23R、23G、23B、23Wに対応するR画素、G画素、B画素、W画素の画素数は、それぞれ2画素、4画素、2画素、8画素になり、RGBW画素の各画素数の比率は1:2:1:4になる。このように、本実施形態に係るカラーフィルタ配列22でも、W画素及びG画素の画素数の比率が全体の12/16(3/4)を占めるため、デモザイク処理時におけるエリアシングを抑制することができ、かつ高周波再現性も良好になる。
本実施形態に係るカラーフィルタ配列22においても、NW方向及びNE方向に延在する画素ライン(斜め画素ライン)であって相互に隣接する4つの画素ラインのうち、透明フィルタ23Wは全ての斜め画素ラインに含まれ、Gフィルタ23Gは3/4の斜め画素ラインに含まれ、Rフィルタ23R及びBフィルタ23Bは2/4の斜め画素ラインに含まれる。特に、Rフィルタ23R及びBフィルタ23Bを含む各斜め画素ラインは一方に隣接する位置に同色のRフィルタ23R及びBフィルタ23Bを含む他の斜め画素ラインが配置される。したがって、斜め方向(NE、NW)に延在する近接画素ラインにRGBフィルタ23R、23G、23Bはそれぞれ配置されるので、斜め方向(NE、NW)に高周波成分を有する入力像によって発生しうる色モワレ(偽色)を効果的に抑制することができる。特に本例では透明フィルタ23Wが全ての斜め画素ラインに含まれるため、より鮮明な画像データを得ることができる。
本実施形態に係るカラーフィルタ配列22においても、Rフィルタ(R画素)及びBフィルタ(B画素)の各々は、上下左右(垂直方向/水平方向)或いは斜め方向のいずれかに隣接する画素位置(本実施形態では垂直方向及び斜め方向に隣接する位置)にG画素が配置される。これにより、R画素及びB画素がカラーフィルタ配列22内(基本配列パターンP2内)において均等に配置され、デモザイク処理の精度を向上することができ、色再現性を良好にすることができる。
また本実施形態のカラーフィルタ配列22においても、G画素以外の画素(W画素、R画素及びB画素)の各々を取り囲む周辺隣接8画素のうち2画素以上に、Gフィルタ(G画素)が配置され、G画素が均等にばらけた状態で配置される。G画素の各々を取り囲む周辺隣接8画素のうち1画素以上(本実施形態では斜め位置の1画素)に、G画素が配置される。これにより、デモザイク処理における色再現の精度をより高くすることができる。
また本実施形態のカラーフィルタ配列22においても、W画素は「輝度への寄与率の大きなG画素」に隣接して配置されるため、W画素の色補間処理(デモザイク処理)において、W画素位置における色再現の精度を高めることができる。
図5は、第3実施形態に係るカラーフィルタの基本配列パターンを示す図であり、(a)は1つの基本配列パターンP3を示し、(b)は基本配列パターンP2を水平方向及び垂直方向に3つずつ計9つ配置した状態を示す。
本実施形態に係るカラーフィルタ配列22も、水平方向及び垂直方向に関し4×4画素(M×N画素)に対応する正方配列パターンとなる基本配列パターンP3を含み、この基本配列パターンP3が水平方向及び垂直方向に繰り返し配置される。したがって、カラーフィルタ配列22では、Rフィルタ23R、Gフィルタ23G、Bフィルタ23B、透明フィルタ23Wが周期性をもって配列される。そのため、R、G、B信号のデモザイク処理等を行う際に繰り返しパターンに従って処理を行うことができ、また基本配列パターンP3の単位で間引き処理して画像を縮小する場合に、間引き処理前後において共通の処
理回路を使用することができる。
本実施形態の基本配列パターンP3においても、透明フィルタ23Wは、全てのフィルタ水平列及びフィルタ垂直列に2画素ずつ存在する。またGフィルタ23Gは、全てのフィルタ水平列及びフィルタ垂直列に1画素ずつ存在する。また、全てのフィルタ水平列及びフィルタ垂直列に、Rフィルタ23R及びBフィルタ23Bのうちのいずれかが1画素存在する。したがって、基本配列パターンP3における各フィルタ水平列及び各フィルタ垂直列は、2画素の透明フィルタ23Wと、1画素のGフィルタ23Gと、1画素のRフィルタ23R又はBフィルタ23Bとから構成される。
また、本実施形態に係る基本配列パターンP3でも、各フィルタ水平列上及び各フィルタ垂直列上に、1画素分に対応するGフィルタ23G(第2のフィルタ)が配置されるため、水平方向及び垂直方向に関する高周波領域でのデモザイク処理の色再現精度を向上させることができる。
基本配列パターンP3内のRGBWフィルタ23R、23G、23B、23Wに対応するR画素、G画素、B画素、W画素の画素数は、それぞれ2画素、4画素、2画素、8画素になり、RGBW画素の各画素数の比率は1:2:1:4になる。このように、本実施形態に係るカラーフィルタ配列22でも、W画素及びG画素の画素数の比率が全体の12/16(3/4)を占めるため、デモザイク処理時におけるエリアシングを抑制することができ、かつ高周波再現性も良好になる。
本実施形態に係るカラーフィルタ配列22においても、NW方向及びNE方向に延在する画素ライン(斜め画素ライン)であって相互に隣接する4つの画素ラインのうち、透明フィルタ23Wは全ての斜め画素ラインに含まれ、Gフィルタ23Gは3/4の斜め画素ラインに含まれ、Rフィルタ23R及びBフィルタ23Bは2/4の斜め画素ライン又は1/4の斜め画素ラインに含まれる。したがって、斜め方向(NE、NW)に延在する近接画素ラインにRGBフィルタ23R、23G、23Bはそれぞれ配置されるので、斜め方向(NE、NW)に高周波成分を有する入力像によって発生しうる色モワレ(偽色)を効果的に抑制することができる。特に本例では透明フィルタ23Wが全ての斜め画素ラインに含まれるため、より鮮明な画像データを得ることができる。
本実施形態に係るカラーフィルタ配列22においても、Rフィルタ(R画素)及びBフィルタ(B画素)の各々は、上下左右(垂直方向/水平方向)或いは斜め方向のいずれかに隣接する画素位置(本実施形態では垂直方向及び斜め方向に隣接する位置)にG画素が配置される。これにより、R画素及びB画素がカラーフィルタ配列22内(基本配列パターンP3内)において均等に配置され、デモザイク処理の精度を向上することができ、色再現性を良好にすることができる。
また本実施形態のカラーフィルタ配列22においても、G画素以外の画素(W画素、R画素及びB画素)の各々を取り囲む周辺隣接8画素のうち2画素以上に、Gフィルタ(G画素)が配置され、G画素が均等にばらけた状態で配置される。また、G画素の各々を取り囲む周辺隣接8画素のうち1画素以上(本実施形態では斜め位置の1画素)に、G画素が配置される。これにより、デモザイク処理における色再現の精度をより高くすることができる。
また本実施形態のカラーフィルタ配列22においても、W画素は「輝度への寄与率の大きなG画素」に隣接して配置されるため、W画素の色補間処理(デモザイク処理)において、W画素位置における色再現の精度を高めることができる。
図6は、第4実施形態に係るカラーフィルタの基本配列パターンを示す図であり、(a)は1つの基本配列パターンP4を示し、(b)は基本配列パターンP2を水平方向及び垂直方向に3つずつ計9つ配置した状態を示す。
本実施形態に係るカラーフィルタ配列22も、水平方向及び垂直方向に関し4×4画素(M×N画素)に対応する正方配列パターンとなる基本配列パターンP4を含み、この基本配列パターンP4が水平方向及び垂直方向に繰り返し配置される。したがって、カラーフィルタ配列22では、Rフィルタ23R、Gフィルタ23G、Bフィルタ23B、透明フィルタ23Wが周期性をもって配列される。そのため、R、G、B信号のデモザイク処理等を行う際に繰り返しパターンに従って処理を行うことができ、また基本配列パターンP4の単位で間引き処理して画像を縮小する場合に、間引き処理前後において共通の処理回路を使用することができる。
本実施形態の基本配列パターンP4においても、透明フィルタ23Wは、全てのフィルタ水平列及びフィルタ垂直列に2画素ずつ存在する。またGフィルタ23Gは、全てのフィルタ水平列及びフィルタ垂直列に1画素ずつ存在する。また、全てのフィルタ水平列及びフィルタ垂直列に、Rフィルタ23R及びBフィルタ23Bのうちのいずれかが1画素存在する。したがって、基本配列パターンP4における各フィルタ水平列及び各フィルタ垂直列は、2画素の透明フィルタ23Wと、1画素のGフィルタ23Gと、1画素のRフィルタ23R又はBフィルタ23Bとから構成される。
また、本実施形態に係る基本配列パターンP4でも、各フィルタ水平列上及び各フィルタ垂直列上に、1画素分に対応するGフィルタ23G(第2のフィルタ)が配置されるため、水平方向及び垂直方向に関する高周波領域でのデモザイク処理の色再現精度を向上させることができる。
基本配列パターンP4内のRGBWフィルタ23R、23G、23B、23Wに対応するR画素、G画素、B画素、W画素の画素数は、それぞれ2画素、4画素、2画素、8画素になり、RGBW画素の各画素数の比率は1:2:1:4になる。このように、本実施形態に係るカラーフィルタ配列22でも、W画素及びG画素の画素数の比率が全体の12/16(3/4)を占めるため、デモザイク処理時におけるエリアシングを抑制することができ、かつ高周波再現性も良好になる。
本実施形態に係るカラーフィルタ配列22においても、NW方向及びNE方向に延在する画素ライン(斜め画素ライン)であって相互に隣接する4つの画素ラインのうち、透明フィルタ23Wは全ての斜め画素ラインに含まれ、Gフィルタ23Gは3/4の斜め画素ラインに含まれ、Rフィルタ23R及びBフィルタ23Bは2/4の斜め画素ライン又は1/4の斜め画素ラインに含まれる。したがって、斜め方向(NE、NW)に延在する近接画素ラインにRGBフィルタ23R、23G、23Bはそれぞれ配置されるので、斜め方向(NE、NW)に高周波成分を有する入力像によって発生しうる色モワレ(偽色)を効果的に抑制することができる。特に本例では透明フィルタ23Wが全ての斜め画素ラインに含まれるため、より鮮明な画像データを得ることができる。
本実施形態に係るカラーフィルタ配列22においても、Rフィルタ(R画素)及びBフィルタ(B画素)の各々は、上下左右(垂直方向/水平方向)或いは斜め方向のいずれかに隣接する画素位置(本実施形態では垂直方向及び斜め方向に隣接する位置)にG画素が配置される。これにより、R画素及びB画素がカラーフィルタ配列22内(基本配列パターンP4内)において均等に配置され、デモザイク処理の精度を向上することができ、色再現性を良好にすることができる。
また本実施形態のカラーフィルタ配列22においても、G画素以外の画素(W画素、R画素及びB画素)の各々を取り囲む周辺隣接8画素のうち2画素以上に、Gフィルタ(G画素)が配置され、G画素が均等にばらけた状態で配置される。また、G画素の各々を取り囲む周辺隣接8画素のうち1画素以上(本実施形態では斜め位置の1画素)に、G画素が配置される。これにより、デモザイク処理における色再現の精度をより高くすることができる。
また本実施形態のカラーフィルタ配列22においても、W画素は「輝度への寄与率の大きなG画素」に隣接して配置されるため、W画素の色補間処理(デモザイク処理)において、W画素位置における色再現の精度を高めることができる。
図7は、第5実施形態に係るカラーフィルタの基本配列パターンP5を示す図である。
本実施形態に係るカラーフィルタ配列22は、水平方向及び垂直方向に関し8×8画素(M×N画素)に対応する正方配列パターンとなる基本配列パターンP5を含み、この基本配列パターンP5が水平方向及び垂直方向に繰り返し配置される。したがって、カラーフィルタ配列22では、Rフィルタ23R、Gフィルタ23G、Bフィルタ23B、透明フィルタ23Wが周期性をもって配列される。そのため、R、G、B信号のデモザイク処理等を行う際に繰り返しパターンに従って処理を行うことができ、また基本配列パターンP5の単位で間引き処理して画像を縮小する場合に、間引き処理前後において共通の処理回路を使用することができる。
本実施形態に係る基本配列パターンP5では、水平方向に平行に延在する8種類のフィルタ水平列が垂直方向に順次配列され、垂直方向に平行に延在するフィルタ垂直列も8種類形成される。
また、本実施形態に係る基本配列パターンP5では、各フィルタ水平列上及び各フィルタ垂直列上に、2画素分に対応するGフィルタ23G(第2のフィルタ)が配置されるため、水平方向及び垂直方向に関する高周波領域でのデモザイク処理の色再現精度を向上させることができる。
基本配列パターンP5内のRGBWフィルタ23R、23G、23B、23Wに対応するR画素、G画素、B画素、W画素の画素数は、それぞれ8画素、16画素、8画素、32画素になり、RGBW画素の各画素数の比率は1:2:1:4になる(W画素数≧G画素数≧R画素数;W画素数≧G画素数≧B画素数)。このように、本実施形態に係るカラーフィルタ配列22でも、W画素及びG画素の画素数の比率が全体の48/64(3/4)を占めるため、デモザイク処理時におけるエリアシングを抑制することができ、かつ高周波再現性も良好になる。
本実施形態に係るカラーフィルタ配列22においても、NW方向及びNE方向に延在する画素ライン(斜め画素ライン)であって相互に隣接する8つの画素ラインのうち、透明フィルタ23Wは全ての斜め画素ラインに含まれ、Gフィルタ23Gは6/8の斜め画素ラインに含まれる。また、Rフィルタ23R及びBフィルタ23Bを含む各斜め画素ラインは少なくとも一方に隣接する位置に同色のRフィルタ23R及びBフィルタ23Bを含む他の斜め画素ラインが配置される。したがって、斜め方向(NE、NW)に延在する近接画素ラインにRGBフィルタ23R、23G、23Bはそれぞれ配置されるので、斜め方向(NE、NW)に高周波成分を有する入力像によって発生しうる色モワレ(偽色)を効果的に抑制することができる。特に本例では透明フィルタ23Wが全ての斜め画素ラインに含まれるため、より鮮明な画像データを得ることができる。
本実施形態に係るカラーフィルタ配列22においても、Rフィルタ(R画素)及びBフィルタ(B画素)の各々は、上下左右(垂直方向/水平方向)或いは斜め方向のいずれかに隣接する画素位置(本実施形態では垂直方向及び斜め方向に隣接する位置)にG画素が配置される。これにより、R画素及びB画素がカラーフィルタ配列22内(基本配列パターンP5内)において均等に配置され、デモザイク処理の精度を向上することができ、色再現性を良好にすることができる。また、基本配列パターンにおいて、第1のサブ配列におけるRフィルタ23Rの位置と第2のサブ配列におけるBフィルタ23Bの位置とが対応し、第1のサブ配列におけるBフィルタ23Bの位置と第2のサブ配列におけるRフィルタ23Rの位置とが対応するとともに、第1のサブ配列と第2のサブ配列との間においてWフィルタ23WとGフィルタ23Gとが同じ位置となるように配置されている。このため、基本配列パターンのサイズが大きくなっても、デモザイク処理が複雑化することを軽減することができる。
また本実施形態のカラーフィルタ配列22においても、G画素以外の画素(W画素、R画素及びB画素)の各々を取り囲む周辺隣接8画素のうち2画素以上に、Gフィルタ(G画素)が配置され、G画素が均等にばらけた状態で配置される。また、G画素の各々を取り囲む周辺隣接8画素のうち1画素以上(本実施形態では斜め位置の1画素)に、G画素が配置される。これにより、デモザイク処理における色再現の精度をより高くすることができる。
また本実施形態のカラーフィルタ配列22においても、W画素は「輝度への寄与率の大きなG画素」に隣接して配置されるため、W画素の色補間処理(デモザイク処理)において、W画素位置における色再現の精度を高めることができる。
図8は、第6実施形態に係るカラーフィルタの基本配列パターンP6を示す図である。
本実施形態に係るカラーフィルタ配列22は、水平方向及び垂直方向に関し8×8画素(M×N画素)に対応する正方配列パターンとなる基本配列パターンP6を含み、この基本配列パターンP6が水平方向及び垂直方向に繰り返し配置される。したがって、カラーフィルタ配列22では、Rフィルタ23R、Gフィルタ23G、Bフィルタ23B、透明フィルタ23Wが周期性をもって配列される。そのため、R、G、B信号のデモザイク処理等を行う際に繰り返しパターンに従って処理を行うことができ、また基本配列パターンP6の単位で間引き処理して画像を縮小する場合に、間引き処理前後において共通の処理回路を使用することができる。
本実施形態に係る基本配列パターンP6では、水平方向に平行に延在する8種類のフィルタ水平列が垂直方向に順次配列され、垂直方向に平行に延在するフィルタ垂直列も8種類形成される。
また、本実施形態に係る基本配列パターンP6では、各フィルタ水平列上及び各フィルタ垂直列上に、2画素分に対応するGフィルタ23G(第2のフィルタ)が配置されるため、水平方向及び垂直方向に関する高周波領域でのデモザイク処理の色再現精度を向上させることができる。
基本配列パターンP6内のRGBWフィルタ23R、23G、23B、23Wに対応するR画素、G画素、B画素、W画素の画素数は、それぞれ8画素、16画素、8画素、32画素になり、RGBW画素の各画素数の比率は1:2:1:4になる(W画素数≧G画素数≧R画素数;W画素数≧G画素数≧B画素数)。このように、本実施形態に係るカラーフィルタ配列22でも、W画素及びG画素の画素数の比率が全体の48/64(3/4)を占めるため、デモザイク処理時におけるエリアシングを抑制することができ、かつ高周波再現性も良好になる。
本実施形態に係るカラーフィルタ配列22においても、NW方向及びNE方向に延在する画素ライン(斜め画素ライン)であって相互に隣接する4つの画素ラインのうち、透明フィルタ23Wは全ての斜め画素ラインに含まれ、Gフィルタ23Gは6/8の斜め画素ラインに含まれる。また、Rフィルタ23R及びBフィルタ23Bを含む各斜め画素ラインは少なくとも一方に隣接する位置に同色のRフィルタ23R及びBフィルタ23Bを含む他の斜め画素ラインが配置される。したがって、斜め方向(NE、NW)に延在する近接画素ラインにRGBフィルタ23R、23G、23Bはそれぞれ配置されるので、斜め方向(NE、NW)に高周波成分を有する入力像によって発生しうる色モワレ(偽色)を効果的に抑制することができる。特に本例では透明フィルタ23Wが全ての斜め画素ラインに含まれるため、より鮮明な画像データを得ることができる。
本実施形態に係るカラーフィルタ配列22においても、Rフィルタ(R画素)及びBフィルタ(B画素)の各々は、上下左右(垂直方向/水平方向)或いは斜め方向のいずれかに隣接する画素位置(本実施形態では垂直方向及び斜め方向に隣接する位置)にG画素が配置される。これにより、R画素及びB画素がカラーフィルタ配列22内(基本配列パターンP6内)において均等に配置され、デモザイク処理の精度を向上することができ、色再現性を良好にすることができる。また、基本配列パターンにおいて、第1のサブ配列におけるRフィルタ23Rの位置と第2のサブ配列におけるBフィルタ23Bの位置とが対応し、第1のサブ配列におけるBフィルタ23Bの位置と第2のサブ配列におけるRフィルタ23Rの位置とが対応するとともに、第1のサブ配列と第2のサブ配列においてWフィルタ23WとGフィルタ23Gとが同じ位置となるように配置されている。このため、基本配列パターンのサイズが大きくなってもデモザイク処理が複雑化することを軽減することができる。
また本実施形態のカラーフィルタ配列22においても、G画素以外の画素(W画素、R画素及びB画素)の各々を取り囲む周辺隣接8画素のうち2画素以上に、Gフィルタ(G画素)が配置され、G画素が均等にばらけた状態で配置される。また、G画素の各々を取り囲む周辺隣接8画素のうち1画素以上(本実施形態では斜め位置の1画素)に、G画素が配置される。これにより、デモザイク処理における色再現の精度をより高くすることができる。
また本実施形態のカラーフィルタ配列22においても、W画素は「輝度への寄与率の大きなG画素」に隣接して配置されるため、W画素の色補間処理(デモザイク処理)において、W画素位置における色再現の精度を高めることができる。
図9は、第7実施形態に係るカラーフィルタの基本配列パターンP7を示す図である。
本実施形態に係るカラーフィルタ配列22は、水平方向及び垂直方向に関し8×8画素(M×N画素)に対応する正方配列パターンとなる基本配列パターンP7を含み、この基本配列パターンP7が水平方向及び垂直方向に繰り返し配置される。したがって、カラーフィルタ配列22では、Rフィルタ23R、Gフィルタ23G、Bフィルタ23B、透明フィルタ23Wが周期性をもって配列される。そのため、R、G、B信号のデモザイク処理等を行う際に繰り返しパターンに従って処理を行うことができ、また基本配列パターンP7の単位で間引き処理して画像を縮小する場合に、間引き処理前後において共通の処理回路を使用することができる。
本実施形態に係る基本配列パターンP7では、水平方向に平行に延在する8種類のフィルタ水平列が垂直方向に順次配列され、垂直方向に平行に延在するフィルタ垂直列も8種類形成される。
また、本実施形態に係る基本配列パターンP7では、各フィルタ水平列上及び各フィルタ垂直列上に、2画素分に対応するGフィルタ23G(第2のフィルタ)が配置されるため、水平方向及び垂直方向に関する高周波領域でのデモザイク処理の色再現精度を向上させることができる。
基本配列パターンP7内のRGBWフィルタ23R、23G、23B、23Wに対応するR画素、G画素、B画素、W画素の画素数は、それぞれ8画素、16画素、8画素、32画素になり、RGBW画素の各画素数の比率は1:2:1:4になる(W画素数≧G画素数≧R画素数;W画素数≧G画素数≧B画素数)。このように、本実施形態に係るカラーフィルタ配列22でも、W画素及びG画素の画素数の比率が全体の48/64(3/4)を占めるため、デモザイク処理時におけるエリアシングを抑制することができ、かつ高周波再現性も良好になる。
本実施形態に係るカラーフィルタ配列22においても、NW方向及びNE方向に延在する画素ライン(斜め画素ライン)であって相互に隣接する4つの画素ラインのうち、透明フィルタ23Wは全ての斜め画素ラインに含まれ、Gフィルタ23Gは6/8の斜め画素ラインに含まれる。このように、斜め方向(NE、NW)に延在する近接画素ラインにRGBフィルタ23R、23G、23Bはそれぞれ配置されるので、斜め方向(NE、NW)に高周波成分を有する入力像によって発生しうる色モワレ(偽色)を効果的に抑制することができる。特に本例では透明フィルタ23Wが全ての斜め画素ラインに含まれるため、より鮮明な画像データを得ることができる。
本実施形態に係るカラーフィルタ配列22においても、Rフィルタ(R画素)及びBフィルタ(B画素)の各々は、上下左右(垂直方向/水平方向)或いは斜め方向のいずれかに隣接する画素位置(本実施形態では水平方向及び斜め方向に隣接する位置)にG画素が配置される。これにより、R画素及びB画素がカラーフィルタ配列22内(基本配列パターンP7内)において均等に配置され、デモザイク処理の精度を向上することができ、色再現性を良好にすることができる。また、基本配列パターンにおいて、第1のサブ配列におけるRフィルタ23Rの位置と第2のサブ配列におけるBフィルタ23Bの位置とが対応し、第1のサブ配列におけるBフィルタ23Bの位置と第2のサブ配列におけるRフィルタ23Rの位置とが対応するとともに、第1のサブ配列と第2のサブ配列においてWフィルタ23WとGフィルタ23Gとが同じ位置となるように配置されている。このため、基本配列パターンのサイズが大きくなってもデモザイク処理が複雑化することを軽減することができる。
また本実施形態のカラーフィルタ配列22においても、G画素以外の画素(W画素、R画素及びB画素)の各々を取り囲む周辺隣接8画素のうち2画素以上に、Gフィルタ(G画素)が配置され、G画素が均等にばらけた状態で配置される。また、G画素の各々を取り囲む周辺隣接8画素のうち1画素以上(本実施形態では斜め位置の1画素)に、G画素が配置される。これにより、デモザイク処理における色再現の精度をより高くすることができる。
また本実施形態のカラーフィルタ配列22においても、W画素は「輝度への寄与率の大きなG画素」に隣接して配置されるため、W画素の色補間処理(デモザイク処理)において、W画素位置における色再現の精度を高めることができる。
図10は、第8実施形態に係るカラーフィルタの基本配列パターンを示す図であり、(a)は1つの基本配列パターンP8を示し、(b)は基本配列パターンP8を水平方向及び垂直方向に2つずつ計4つ配置した状態を示す。
本実施形態に係るカラーフィルタ配列22は、水平方向及び垂直方向に関し6×6画素(M×N画素)に対応する正方配列パターンとなる基本配列パターンP8を含み、この基本配列パターンP8が水平方向及び垂直方向に繰り返し配置される。したがって、カラーフィルタ配列22では、Rフィルタ23R、Gフィルタ23G、Bフィルタ23B、透明フィルタ23Wが周期性をもって配列される。そのため、R、G、B信号のデモザイク処理等を行う際に繰り返しパターンに従って処理を行うことができ、また基本配列パターンP8の単位で間引き処理して画像を縮小する場合に、間引き処理前後において共通の処理回路を使用することができる。
本実施形態に係る基本配列パターンP8では、水平方向に平行に延在する6種類のフィルタ水平列が垂直方向に順次配列され、垂直方向に平行に延在するフィルタ垂直列も6種類形成される。
また、本実施形態に係る基本配列パターンP8でも、各フィルタ水平列上及び各フィルタ垂直列上に、1画素分又は2画素分に対応するGフィルタ23Gが配置されるため、水平方向及び垂直方向に関する高周波領域でのデモザイク処理の色再現精度を向上させることができる。
基本配列パターンP8内のRGBWフィルタ23R、23G、23B、23Wに対応するR画素、G画素、B画素、W画素の画素数は、それぞれ4画素、8画素、4画素、20画素になり、RGBW画素の各画素数の比率は1:2:1:5になる(W画素数≧G画素数≧R画素数;W画素数≧G画素数≧B画素数)。このように、本実施形態に係るカラーフィルタ配列22でも、W画素及びG画素の画素数の比率が全体の28/36(7/9)を占めるため、デモザイク処理時におけるエリアシングを抑制することができ、かつ高周波再現性も良好になる。
本実施形態に係るカラーフィルタ配列22においても、NW方向及びNE方向に延在する画素ライン(斜め画素ライン)であって相互に隣接する6つの画素ラインのうち、透明フィルタ23Wは全ての斜め画素ラインに含まれ、Gフィルタ23Gは4/6の斜め画素ラインに含まれる。また、Rフィルタ23R及びBフィルタ23Bを含む各斜め画素ラインは一方に隣接する位置に同色のRフィルタ23R及びBフィルタ23Bを含む他の斜め画素ラインが配置される。したがって、斜め方向(NE、NW)に延在する近接画素ラインにRGBフィルタ23R、23G、23Bはそれぞれ配置されるので、斜め方向(NE、NW)に高周波成分を有する入力像によって発生しうる色モワレ(偽色)を効果的に抑制することができる。特に本例では透明フィルタ23Wが全ての斜め画素ラインに含まれるため、より鮮明な画像データを得ることができる。
本実施形態に係るカラーフィルタ配列22においても、Rフィルタ(R画素)及びBフィルタ(B画素)の各々は、上下左右(垂直方向/水平方向)或いは斜め方向のいずれかに隣接する画素位置にG画素が配置される。これにより、R画素及びB画素がカラーフィルタ配列22内(基本配列パターンP8内)において均等に配置され、デモザイク処理の精度を向上することができ、色再現性を良好にすることができる。また、基本配列パターンにおいて、第1のサブ配列と第2のサブ配列が回転対称の関係にあるため、基本配列パターンのサイズが大きくなってもデモザイク処理が複雑化することを軽減することができる。
また本実施形態のカラーフィルタ配列22においても、G画素以外の画素(W画素、R画素及びB画素)の各々を取り囲む周辺隣接8画素のうち2画素以上に、Gフィルタ(G画素)が配置され、G画素が均等にばらけた状態で配置される。これにより、デモザイク処理における色再現の精度をより高くすることができる。
また本実施形態のカラーフィルタ配列22においても、W画素は「輝度への寄与率の大きなG画素」に隣接して配置されるため、W画素の色補間処理(デモザイク処理)において、W画素位置における色再現の精度を高めることができる。
図11は、第9実施形態に係るカラーフィルタの基本配列パターンを示す図であり、(a)は1つの基本配列パターンP9を示し、(b)は基本配列パターンP9を水平方向及び垂直方向に2つずつ計4つ配置した状態を示す。
本実施形態に係るカラーフィルタ配列22は、水平方向及び垂直方向に関し6×6画素(M×N画素)に対応する正方配列パターンとなる基本配列パターンP9を含み、この基本配列パターンP9が水平方向及び垂直方向に繰り返し配置される。この基本配列パターンP9は、カラーフィルタが3×3画素((M/2)×(N/2)画素)に対応する配列パターンで配列された4種類の第1のサブ配列(A配列)、第2のサブ配列(B配列)、第3のサブ配列(C配列)及び第4のサブ配列(D配列)をそれぞれ1つずつ含む。
本実施形態に係る基本配列パターンP9では、水平方向に平行に延在する6種類のフィルタ水平列が垂直方向に順次配列され、垂直方向に平行に延在するフィルタ垂直列も6種類形成される。
また、本実施形態に係る基本配列パターンP9でも、各フィルタ水平列上及び各フィルタ垂直列上に、1画素分又は2画素分に対応するGフィルタ23Gが配置されるため、水平方向及び垂直方向に関する高周波領域でのデモザイク処理の色再現精度を向上させることができる。
基本配列パターンP9内のRGBWフィルタ23R、23G、23B、23Wに対応するR画素、G画素、B画素、W画素の画素数は、それぞれ4画素、8画素、4画素、20画素になり、RGBW画素の各画素数の比率は1:2:1:5になる(W画素数≧G画素数≧R画素数;W画素数≧G画素数≧B画素数)。このように、本実施形態に係るカラーフィルタ配列22でも、W画素及びG画素の画素数の比率が全体の28/36(7/9)を占めるため、デモザイク処理時におけるエリアシングを抑制することができ、かつ高周波再現性も良好になる。
本実施形態に係るカラーフィルタ配列22においても、NW方向及びNE方向に延在する画素ライン(斜め画素ライン)であって相互に隣接する6つの画素ラインのうち、透明フィルタ23Wは全ての斜め画素ラインに含まれ、Gフィルタ23Gは4/6の斜め画素ラインに含まれる。また、Rフィルタ23R及びBフィルタ23Bを含む各斜め画素ラインは一方に隣接する位置に同色のRフィルタ23R及びBフィルタ23Bを含む他の斜め画素ラインが配置される。したがって、斜め方向(NE、NW)に延在する近接画素ラインにRGBフィルタ23R、23G、23Bはそれぞれ配置されるので、斜め方向(NE、NW)に高周波成分を有する入力像によって発生しうる色モワレ(偽色)を効果的に抑制することができる。特に本例では透明フィルタ23Wが全ての斜め画素ラインに含まれるため、より鮮明な画像データを得ることができる。
本実施形態に係るカラーフィルタ配列22においても、Rフィルタ(R画素)及びBフィルタ(B画素)の各々は、上下左右(垂直方向/水平方向)或いは斜め方向のいずれかに隣接する画素位置にG画素が配置される。これにより、R画素及びB画素がカラーフィルタ配列22内(基本配列パターンP9内)において均等に配置され、デモザイク処理の精度を向上することができ、色再現性を良好にすることができる。また、基本配列パターンにおいて、第1のサブ配列から第4のサブ配列がそれぞれ回転対称の関係にあるため、基本配列パターンのサイズが大きくなってもデモザイク処理が複雑化することを軽減することができる。
また本実施形態のカラーフィルタ配列22においても、G画素以外の画素(W画素、R画素及びB画素)の各々を取り囲む周辺隣接8画素のうち2画素以上に、Gフィルタ(G画素)が配置され、G画素が均等にばらけた状態で配置される。また、G画素の各々を取り囲む周辺隣接8画素のうち1画素以上(本実施形態では斜め位置の1画素)に、G画素が配置される。特に本実施形態では、(G画素を含む)3×3画素の領域内において2画素以上のG画素が存在する。これにより、デモザイク処理における色再現の精度をより高くすることができる。
また本実施形態のカラーフィルタ配列22においても、W画素は「輝度への寄与率の大きなG画素」に対して上下左右(垂直方向/水平方向)或いは斜め方向のいずれかに隣接して配置されるため、W画素の色補間処理(デモザイク処理)において、W画素位置における色再現の精度を高めることができる。
上述の各実施形態では、「第1のフィルタ:透明フィルタ」、「第1の可視光波長域:緑の波長域、第2のフィルタ:Gフィルタ」、「第2の可視光波長域:赤の波長域、第3のフィルタ:Rフィルタ」及び「第3の可視光波長域:青の波長域、第4のフィルタ:Bフィルタ」とした例について説明したが、カラーフィルタで使用しうる色はこれらの色に限定されるものではなく、以下の条件を満たす色に対応するカラーフィルタを用いることもできる。
上記各実施形態では、本発明の第2のフィルタとしてG色のGフィルタ23Gを例に挙げて説明を行ったが、Gフィルタ23Gの代わりに、あるいはGフィルタ23Gの一部に代えて、下記条件のいずれかを満たすフィルタを用いてもよい。
輝度信号を得るための寄与率が、透明(ホワイト)フィルタ(Wフィルタ)を除く、他のカラーフィルタに対応する色(第2の可視光波長域に対応する色及び第3の可視光波長域に対応する色)よりも高い色に対応するカラーフィルタを、第2のフィルタとしてGフィルタ23Gの代わりに用いることができる。例えば、透明フィルタ(Wフィルタ)を除いたフィルタ色のうちで、輝度信号を得るための寄与率が50%以上である色フィルタを第2のフィルタとして使用することができ、上述の実施形態では式(1)で示されるように、G(緑)色の寄与率が、W(透明)以外の色(RGB)のうちで59%を占めるため、Gフィルタを第2のフィルタとして使用している。なお、G色以外の色の寄与率についても実験やシミュレーションにより取得可能である。
条件(2)は、フィルタの透過率のピークが波長480nm以上570nm以下の範囲内にあることである。フィルタの透過率は、例えば分光光度計で測定された値が用いられる。この波長範囲は、本発明の第1の可視光波長域と、第2の可視光波長域及び第3の可視光波長域とを区別するために定められた範囲であって、前述の寄与率が相対的に低くなるR色、B色などのピークが含まれず、かつ寄与率が相対的に高くなるG色などのピークが含まれるように定められた範囲である。したがって、透過率のピークが波長480nm以上570nm以下の範囲内にあるフィルタを第2のフィルタとして用いることができる。なお、透過率のピークが波長480nm以上570nm以下の範囲外となるフィルタが本発明の第3のフィルタ及び第4のフィルタ(Rフィルタ23R、Bフィルタ23B等)となる。
条件(3)は、波長500nm以上560nm以下の範囲内での透過率が第3のフィルタ及び第4のフィルタ(Rフィルタ23RやBフィルタ23B)の透過率よりも高いことである。この条件(3)においても、フィルタの透過率は例えば分光光度計で測定された値が用いられる。この条件(3)の波長範囲も、本発明の第1の可視光波長域と、第2の可視光波長域及び第3の可視光波長域とを区別するために定められた範囲であって、R色やB色などよりも前述の寄与率が相対的に高くなる色を有するフィルタの透過率が、RBフィルタ23R、23Bなどの透過率よりも高くなる範囲である。したがって、透過率が波長500nm以上560nm以下の範囲内で相対的に高いフィルタを第2のフィルタとして用い、透過率が相対的に低いフィルタを第3のフィルタ及び第4のフィルタとして用いることができる。
条件(4)は、3原色のうち最も輝度信号に寄与する色(例えばRGBのうちのG色)と、この3原色とは異なる色とを含む2色以上のフィルタを、第2のフィルタとして用いることである。この場合には、第2のフィルタの各色以外の色に対応するフィルタが第3のフィルタ及び第4のフィルタとなる。
したがって、第2のフィルタとしてのG色のGフィルタ23Gは一種類に限定されるものではなく、例えば複数種類のGフィルタ23Gを第2のフィルタとして用いることもできる。すなわち上述の各実施形態に係るカラーフィルタ(基本配列パターン)のGフィルタ23Gが、第1Gフィルタ23G1又は第2Gフィルタ23G2に適宜置き換えられてもよい。第1Gフィルタ23G1は第1の波長帯域のG光を透過し、第2Gフィルタ23G2は第1Gフィルタ23G1と相関の高い第2の波長帯域のG光を透過する(図12参照)。
透明フィルタ23Wは、透明色のフィルタであり、ホワイトフィルタ等、他の呼称で呼ばれることもある。透明フィルタ23Wは、可視光の波長域に対応する光を透過可能であり、例えばRGBの各色の光(第1の可視光波長域、第2の可視光波長域及び第3の可視光波長域における光)の透過率が50%以上となるフィルタである。一般には、透明フィルタはRGBの各波長帯域において透過率が高く、実際には透明に近い色特性を有するフィルタであること多い。
上述の実施形態では、主としてRGBW色に対応する色フィルタから成るカラーフィルタが示されているが、これらの色フィルタ(RGBフィルタ)の一部を他の色フィルタとしてもよく、例えばエメラルドフィルタE(第5のフィルタ、エメラルド画素)としてもよい。特に第2のフィルタ(Gフィルタ23G)の一部に代えてエメラルドフィルタを配置することが好ましい。このようにGフィルタ23Gの一部をエメラルドフィルタで置き換えた4色のカラーフィルタ配列を用いることで、輝度の高域成分の再現を向上させ、ジャギネスを低減させるとともに、解像度感の向上を可能とすることができる。
上述の各実施形態では、原色RGBに関するカラーフィルタで構成されるカラーフィルタ配列について説明したが、例えば原色RGBの補色であるC(シアン)、M(マゼンタ)、Y(イエロー)に、Gを加えた4色の補色系のカラーフィルタと透明フィルタ23Wとによって構成されるカラーフィルタ配列にも本発明を適用することができる。この場合も上記条件のいずれかを満たすカラーフィルタを本発明の第2のフィルタとし、他のカラーフィルタを第3のフィルタ、第4のフィルタ、及び第5のフィルタとする。
上記各実施形態の各カラーフィルタ配列は、各色のカラーフィルタが水平方向(H)及び垂直方向(V)に2次元配列されてなる基本配列パターンを含み、かつこの基本配列パターンが水平方向(H)及び垂直方向(V)に繰り返し配置されてなるが、本発明はこれに限定されるものではない。
上述の実施形態では、4×4画素に対応する基本配列パターン、6×6画素に対応する基本配列パターン、及び8×8画素に対応する基本配列パターンについて説明したが、基本配列パターンの対応画素数はこれらに限定されるものではない。
Claims (16)
- 第1の方向及び当該第1の方向に垂直な第2の方向に配列された光電変換素子で構成される複数の画素上にカラーフィルタが配設されてなる単板式のカラー撮像素子であって、
前記カラーフィルタの配列は、前記カラーフィルタが前記第1の方向及び前記第2の方向にM×N(Mは4以上の整数、及びNは4以上の整数)画素に対応する配列パターンで配列されてなる基本配列パターンを含み、かつ当該基本配列パターンが前記第1の方向及び前記第2の方向に繰り返されて配置されてなり、
前記カラーフィルタは、透明に対応する第1のフィルタと、可視光波長域中の第1の可視光波長域に対して他の可視光波長域よりも高い透過率を持つ第2のフィルタと、可視光波長域中の前記第1の可視光波長域とは異なる第2の可視光波長域に対して他の可視光波長域よりも高い透過率を持つ第3のフィルタと、可視光波長域中の前記第1の可視光波長域及び前記第2の可視光波長域とは異なる第3の可視光波長域に対して他の可視光波長域よりも高い透過率を持つ第4のフィルタとを少なくとも含み、
前記基本配列パターンにおいて、前記第1のフィルタ、前記第2のフィルタ、前記第3のフィルタ及び前記第4のフィルタの各々が少なくとも1画素配置され、
前記第1の可視光波長域に対応する色は、前記第2の可視光波長域に対応する色及び前記第3の可視光波長域に対応する色よりも、輝度信号を得るための寄与率が高く、
前記カラーフィルタの配列において、前記第1の方向に延在する各画素ライン上、前記第2の方向に延在する各画素ライン上、及び前記第1の方向及び前記第2の方向に対して傾いた第3の方向及び第4の方向の各々に延在する各画素ライン上に少なくとも1画素に対応する前記第1のフィルタが配置され、前記第1の方向に延在する各画素ライン上及び前記第2の方向に延在する各画素ライン上に少なくとも1画素に対応する前記第2のフィルタが配置され、前記第3のフィルタ及び前記第4のフィルタの各々は前記第2のフィルタと隣接して配置されるカラー撮像素子。 - 第1の方向及び当該第1の方向に垂直な第2の方向に配列された光電変換素子で構成される複数の画素上にカラーフィルタが配設されてなる単板式のカラー撮像素子であって、
前記カラーフィルタの配列は、前記カラーフィルタが前記第1の方向及び前記第2の方向にM×N(Mは4以上の整数、及びNは4以上の整数)画素に対応する配列パターンで配列されてなる基本配列パターンを含み、かつ当該基本配列パターンが前記第1の方向及び前記第2の方向に繰り返されて配置されてなり、
前記カラーフィルタは、透明に対応する第1のフィルタと、可視光波長域中の第1の可視光波長域に対して他の可視光波長域よりも高い透過率を持つ第2のフィルタと、可視光波長域中の前記第1の可視光波長域とは異なる第2の可視光波長域に対して他の可視光波長域よりも高い透過率を持つ第3のフィルタと、可視光波長域中の前記第1の可視光波長域及び前記第2の可視光波長域とは異なる第3の可視光波長域に対して他の可視光波長域よりも高い透過率を持つ第4のフィルタとを少なくとも含み、
前記基本配列パターンにおいて、前記第1のフィルタ、前記第2のフィルタ、前記第3のフィルタ及び前記第4のフィルタの各々が少なくとも1画素配置され、
前記第2のフィルタの透過率のピークが波長480nm以上570nm以下の範囲内にあり、前記第3のフィルタ及び前記第4のフィルタの透過率のピークが前記範囲外にあり、
前記カラーフィルタの配列において、前記第1の方向に延在する各画素ライン上、前記第2の方向に延在する各画素ライン上、及び前記第1の方向及び前記第2の方向に対して傾いた第3の方向及び第4の方向の各々に延在する各画素ライン上に少なくとも1画素に対応する前記第1のフィルタが配置され、前記第1の方向に延在する各画素ライン上及び前記第2の方向に延在する各画素ライン上に少なくとも1画素に対応する前記第2のフィルタが配置され、前記第3のフィルタ及び前記第4のフィルタの各々は前記第2のフィルタと隣接して配置されるカラー撮像素子。 - 第1の方向及び当該第1の方向に垂直な第2の方向に配列された光電変換素子で構成される複数の画素上にカラーフィルタが配設されてなる単板式のカラー撮像素子であって、
前記カラーフィルタの配列は、前記カラーフィルタが前記第1の方向及び前記第2の方向にM×N(Mは4以上の整数、及びNは4以上の整数)画素に対応する配列パターンで配列されてなる基本配列パターンを含み、かつ当該基本配列パターンが前記第1の方向及び前記第2の方向に繰り返されて配置されてなり、
前記カラーフィルタは、透明に対応する第1のフィルタと、可視光波長域中の第1の可視光波長域に対して他の可視光波長域よりも高い透過率を持つ第2のフィルタと、可視光波長域中の前記第1の可視光波長域とは異なる第2の可視光波長域に対して他の可視光波長域よりも高い透過率を持つ第3のフィルタと、可視光波長域中の前記第1の可視光波長域及び前記第2の可視光波長域とは異なる第3の可視光波長域に対して他の可視光波長域よりも高い透過率を持つ第4のフィルタとを少なくとも含み、
前記基本配列パターンにおいて、前記第1のフィルタ、前記第2のフィルタ、前記第3のフィルタ及び前記第4のフィルタの各々が少なくとも1画素配置され、
前記第1の可視光波長域は、可視光波長500nm以上560nm以下の範囲内であり、
前記カラーフィルタの配列において、前記第1の方向に延在する各画素ライン上、前記第2の方向に延在する各画素ライン上、及び前記第1の方向及び前記第2の方向に対して傾いた第3の方向及び第4の方向の各々に延在する各画素ライン上に少なくとも1画素に対応する前記第1のフィルタが配置され、前記第1の方向に延在する各画素ライン上及び前記第2の方向に延在する各画素ライン上に少なくとも1画素に対応する前記第2のフィルタが配置され、前記第3のフィルタ及び前記第4のフィルタの各々は前記第2のフィルタと隣接して配置されるカラー撮像素子。 - 第1の方向及び当該第1の方向に垂直な第2の方向に配列された光電変換素子で構成される複数の画素上にカラーフィルタが配設されてなる単板式のカラー撮像素子であって、
前記カラーフィルタの配列は、前記カラーフィルタが前記第1の方向及び前記第2の方向にM×N(Mは4以上の整数、及びNは4以上の整数)画素に対応する配列パターンで配列されてなる基本配列パターンを含み、かつ当該基本配列パターンが前記第1の方向及び前記第2の方向に繰り返されて配置されてなり、
前記カラーフィルタは、透明に対応する第1のフィルタと、可視光波長域中の第1の可視光波長域に対して他の可視光波長域よりも高い透過率を持つ第2のフィルタと、可視光波長域中の前記第1の可視光波長域とは異なる第2の可視光波長域に対して他の可視光波長域よりも高い透過率を持つ第3のフィルタと、可視光波長域中の前記第1の可視光波長域及び前記第2の可視光波長域とは異なる第3の可視光波長域に対して他の可視光波長域よりも高い透過率を持つ第4のフィルタとを少なくとも含み、
前記基本配列パターンにおいて、前記第1のフィルタ、前記第2のフィルタ、前記第3のフィルタ及び前記第4のフィルタの各々が少なくとも1画素配置され、
前記第1の可視光波長域は、3原色のうち最も輝度信号に寄与する色に対応する可視光波長域と前記3原色とは異なる色に対応する可視光波長域を含み、前記第2のフィルタは、前記3原色のうち最も輝度信号に寄与する色に対応する可視光波長域に対して他の可視光波長域よりも高い透過率を持つフィルタと、前記3原色とは異なる色に対応する前記可視光波長域に対して他の可視光波長域よりも高い透過率を持つフィルタとを含み、
前記カラーフィルタの配列において、前記第1の方向に延在する各画素ライン上、前記第2の方向に延在する各画素ライン上、及び前記第1の方向及び前記第2の方向に対して傾いた第3の方向及び第4の方向の各々に延在する各画素ライン上に少なくとも1画素に対応する前記第1のフィルタが配置され、前記第1の方向に延在する各画素ライン上及び前記第2の方向に延在する各画素ライン上に少なくとも1画素に対応する前記第2のフィルタが配置され、前記第3のフィルタ及び前記第4のフィルタの各々は前記第2のフィルタと隣接して配置されるカラー撮像素子。 - 前記カラーフィルタの配列において、前記第1のフィルタが配置される画素、前記第3のフィルタが配置される画素及び前記第4のフィルタが配置される画素の各々の周辺隣接8画素のうち2画素以上に、前記第2のフィルタが配置される請求項1から4のいずれか1項に記載のカラー撮像素子。
- 前記カラーフィルタの配列において、前記第2のフィルタが配置される画素の各々の周辺隣接8画素のうち1画素以上に、前記第2のフィルタが配置される請求項5に記載のカラー撮像素子。
- 前記基本配列パターンにおいて、前記第1の方向に延在する各画素ライン上及び前記第2の方向に延在する各画素ライン上に、少なくとも1画素に対応する前記第3のフィルタ及び少なくとも1画素に対応する前記第4のフィルタが配置される請求項1から6のいずれか1項に記載のカラー撮像素子。
- 前記基本配列パターンにおいて、
第1のフィルタが配置される画素の数≧第2のフィルタが配置される画素の数≧第3のフィルタが配置される画素の数、
及び、
第1のフィルタが配置される画素の数≧第2のフィルタが配置される画素の数≧第4のフィルタが配置される画素の数、
という関係を満たす請求項1から7のいずれか1項に記載のカラー撮像素子。 - 前記カラーフィルタの配列において、前記第1のフィルタが配置される画素は前記第2のフィルタが配置される画素に隣接して配置される請求項1から8のいずれか1項に記載のカラー撮像素子。
- 前記基本配列パターンは、前記カラーフィルタが前記第1の方向及び前記第2の方向にM×N(Mは6以上の整数、及びNは6以上の整数)画素に対応する配列パターンで配列されてなり、
前記基本配列パターンは、前記カラーフィルタが(M/2)×(N/2)画素に対応する配列パターンで配列された2種類のサブ配列である第1のサブ配列及び第2のサブ配列であって、前記第1のフィルタ、前記第2のフィルタ、前記第3のフィルタ及び前記第4のフィルタの各々が少なくとも1画素配置される第1のサブ配列及び第2のサブ配列をそれぞれ2つずつ含む請求項1から9のいずれか1項に記載のカラー撮像素子。 - 前記基本配列パターンは、前記カラーフィルタが前記第1の方向及び前記第2の方向にM×N(Mは6以上の整数、及びNは6以上の整数)画素に対応する配列パターンで配列されてなり、
前記基本配列パターンは、前記カラーフィルタが(M/2)×(N/2)画素に対応する配列パターンで配列された4種類のサブ配列である第1のサブ配列、第2のサブ配列、第3のサブ配列及び第4のサブ配列であって、前記第1のフィルタ、前記第2のフィルタ、前記第3のフィルタ及び前記第4のフィルタの各々が少なくとも1画素配置される第1のサブ配列、第2のサブ配列、第3のサブ配列及び第4のサブ配列をそれぞれ1つずつ含む請求項1から9のいずれか1項に記載のカラー撮像素子。 - 前記基本配列パターンを構成する前記サブ配列は、各サブ配列における前記第3のフィルタの位置と前記第4のフィルタの位置とが逆転した位置関係にあるサブ配列のペアを含む請求項10又は11に記載のカラー撮像素子。
- 前記第1のフィルタは、前記第1の可視光波長域、前記第2の可視光波長域及び前記第3の可視光波長域において、50%以上の透過率を有する請求項1から12のいずれか1項に記載のカラー撮像素子。
- 前記第1の可視光波長域、前記第2の可視光波長域及び前記第3の可視光波長域は3原色に対応し、
前記カラーフィルタは、前記3原色とは異なる色に対応する可視光波長域に対して他の可視光波長域よりも高い透過率を持つ第5のフィルタを更に含む請求項1から13のいずれか1項に記載のカラー撮像素子。 - 前記第1の可視光波長域は緑に対応し、前記第2の可視光波長域は赤に対応し、前記第3の可視光波長域は青に対応する請求項1から14のいずれか1項に記載のカラー撮像素子。
- 撮影光学系と、
前記撮影光学系を介して被写体像が結像するカラー撮像素子と、
前記結像した被写体像を示す画像データを生成する画像データ生成部と、
を備え、
前記カラー撮像素子は請求項1から15のいずれか1項に記載のカラー撮像素子である、
撮像装置。
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