JP3988457B2 - Imaging apparatus and signal processing method for solid-state imaging device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an imaging apparatus including a single-plate solid-state imaging device having a primary color filter array and a signal processing method for the solid-state imaging device. More specifically, the signal processing of an imaging device and a solid-state imaging device that expands the dynamic range by replacing a green filter at a specific position with a gray filter and using an output signal from a pixel in which the gray filter is arranged Regarding the method.
[0002]
[Prior art]
For example, the imaging method of a color camera using a CCD (Charge Coupled Device) type solid-state imaging device can be broadly divided into a single plate type in which color information can be obtained with one CCD and a three plate type with three CCDs. There are two more types of single plate type. As one of them, there is a simultaneous type in which color information can be obtained simultaneously. This is provided with a color filter (on-chip color filter) corresponding to each pixel (sensor unit).
[0003]
There are many types of color coding (color arrangement) of the color filter. Among them, there is an array called a Bayer array disclosed in US Pat. No. 3,971,065, for example, using an R (red), G (green), and B (blue) primary color filter.
[0004]
This Bayer arrangement is shown in FIG. A green filter G is arranged in a checkered pattern, and a red (red) filter R and a blue (blue) filter B are further arranged in a checkered pattern in the remaining part. That is, when viewed in 4 pixels of 2 vertical pixels × 2 horizontal pixels, the green filter G is arranged at two diagonal positions, the red filter R is arranged at one of the remaining two places, and the blue filter B is arranged at the other. ing. When viewed as a whole, the green filters G are arrayed continuously in an oblique direction.
[0005]
The feature of this Bayer arrangement is that each G pixel in which the green filter G having a large contribution to the synthesis of the luminance signal is arranged is present in each row when viewed in the horizontal direction, and is also present for each column when viewed in the vertical direction. By doing so, the horizontal and vertical spatial frequency characteristics are isotropic and high resolution can be obtained. However, there are the following problems.
[0006]
[Problems to be solved by the invention]
FIG. 9 shows light transmission characteristics in the visible light region for the green filter G, the red filter R, and the blue filter B, respectively. Since the green filter G has a large sensitivity (sensitivity is given by an integral value of each characteristic curve R, G, B), the output signal of the G pixel in which the green filter G is disposed is saturated first.
[0007]
That is, as shown in FIG. 8, first, the output signal of the G pixel is saturated at the time of the exposure time Sg, and the output signal of the R pixel in which the red filter R having the next highest sensitivity is saturated is saturated at the time of Sr. Finally, the output signal of the B pixel where the least sensitive blue filter B is arranged is saturated at the time of Sb. Since the exposure time is proportional to the amount of incident light (to each pixel), it may be replaced with the amount of incident light.
[0008]
If the output signal of the G pixel is saturated, the G pixel cannot output a signal larger than the saturation point even if it receives a larger amount of light, and the green color information is lost. Even if the signal amount of the B pixel is not saturated, correct color reproduction cannot be performed. That is, in the case of the primary color Bayer arrangement, the dynamic range is determined by the saturation characteristic of the G pixel, and with the light quantity after Sg, the linearity with respect to the light quantity dependency is reduced with respect to the luminance signal, and with respect to the white object with respect to the color difference signal. This causes problems such as coloring.
[0009]
The present invention has been made in view of the above-described problems, and an object thereof is to provide an image pickup apparatus and a signal processing method for a solid-state image pickup device that realize an expansion of a dynamic range of luminance.
[0010]
[Means for Solving the Problems]
The imaging device according to the present invention includes an R pixel in which a red filter is disposed, a G pixel in which a green filter is disposed, a B pixel in which a blue filter is disposed, and a gray color whose sensitivity in the visible light region is smaller than that of the blue filter. A solid-state imaging device in which Gray pixels on which filters are arranged are two-dimensionally arranged; R pixel, G pixel, or B pixel that exists around the noticed Gray pixel Unsaturated output signal Output value calculated based on When, The output signal of the noticed Gray pixel itself and other signals present around the noticed Gray pixel. Gray pixel output signal Output value calculated based on Based on the ratio with Attention A gain is given to the output signal of the Gray pixel, and an R (Gray) signal and a G (Gray) signal Or B (Gray) signal The A carrier balance means to calculate,
R (Gray) signal, G (Gray) signal Or B (Gray) signal In Output signal after saturation R pixel, G pixel or B pixel Interpolation means for calculating an output signal.
[0011]
The signal processing method of the solid-state imaging device according to the present invention has an R pixel in which a red filter is arranged, a G pixel in which a green filter is arranged, a B pixel in which a blue filter is arranged, and a sensitivity in the visible light region is blue. A signal processing method of a solid-state imaging device in which Gray pixels in which a gray filter smaller than the filter is arranged are two-dimensionally arranged, R pixel, G pixel, or B pixel that exists around the noticed Gray pixel Unsaturated output signal Output value calculated based on When, The output signal of the noticed Gray pixel itself and other signals present around the noticed Gray pixel. Gray pixel output signal Output value calculated based on Based on the ratio with Attention A gain is given to the output signal of the Gray pixel, and an R (Gray) signal and a G (Gray) signal Or B (Gray) signal The Calculate R (Gray) signal, G (Gray) signal Or B (Gray) signal In Output signal after saturation R pixel, G pixel or B pixel Calculate the output signal.
[0012]
The gray filter has a wide range of sensitivity with respect to all the colors of red, green, and blue. Also, in the region where the output signal of each RGB pixel is not saturated, the output signal of each RGB pixel and the output signal of the Gray pixel both change linearly with the origin coincided with the exposure time. There is a certain correlation between the output signal of each pixel and the output signal of the Gray pixel. Furthermore, the gray filter has higher saturation characteristics than other RGB color filters.
[0013]
Therefore, even if the output signal of a pixel where a certain color filter of RGB is arranged is saturated, the output signal of the saturated pixel can be calculated from the output signal of the Gray pixel that is not yet saturated. This calculation is performed based on the correlation between the output signal of each RGB pixel and the output signal of the Gray pixel when not saturated.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0015]
The arrangement of the color filters of the solid-state image sensor according to this embodiment is shown in FIG. In the present embodiment, in the conventional primary color Bayer arrangement shown in FIG. 7, when viewed in a unit block of 2 pixels × 2 pixels, one of the two green filters G located diagonally is gray. It is replaced with the filter Gray. Specifically, the green filter G adjacent to the red filter R in the horizontal direction is replaced with a gray filter Gray.
[0016]
As shown in FIG. 9, the gray filter Gray has a substantially flat transmission characteristic with relatively little wavelength dependency in the visible light region. As in the case of other color filters, the transmittance can be adjusted by changing the content of a gray (gray) dye or pigment, and a desired sensitivity can be set. In the present embodiment, a gray filter Gray whose sensitivity (integrated value) in the visible light region is smaller than that of the blue filter B is used.
[0017]
The output signal of the solid-state imaging device (CCD) having the above color filter array is processed by the signal processing circuit shown in FIG. Each output signal from the R pixel in which the red filter R is arranged, the G pixel in which the green filter G is arranged, the B pixel in which the blue filter B is arranged, and the Gray pixel in which the gray filter Gray is arranged is a signal processing circuit. Various processes are performed at, and a luminance signal and a color difference signal are obtained for each pixel.
[0018]
Hereinafter, each processing block will be described.
[0019]
The carrier balance means 1 receives the output signals from the CCD (output signals of R, G, B, and Gray pixels) and performs the following processing.
As shown in FIG. 9, the gray filter Gray has a response to light of all hues in the visible light region. Therefore, by giving a predetermined gain to the output signal of the Gray pixel so that the output signal is equivalent to the sensitivity of each RGB pixel, the signal of the Gray pixel can be substituted as the output signal of each RGB pixel. is there. That is, R signal, G signal, and B signal can be newly generated from the Gray pixel. Such processing is called carrier balance. Hereinafter, the carrier balance will be specifically described.
[0020]
For example, a case where carrier balance is performed for Gray (3, 2) pixel located at address (3, 2) in FIG. 1 will be described as an example. First, consider a case where a G signal is generated from Gray (3, 2) pixels.
[0021]
When the G signal is expressed as a G (Gray) signal in the sense that it is generated from the Gray pixel, it is given by G (Gray) signal = α × {Gray (3, 2) pixel output signal}. α is obtained based on the correlation between the output signal of the G pixel and the output signal of the Gray pixel before saturation. That is, as shown in FIG. 3, the fact that the ratio of the output signal of the G pixel before saturation and the output signal of the Gray pixel is constant is used. Specifically, it is obtained as follows.
[0022]
The average value of the output signal of the Gray (3, 2) pixel itself and the output signal of other Gray pixels existing around the Gray (3, 2) pixel is defined as Gray (Av.). The periphery of the Gray (3, 2) pixel is a range of m rows × n columns centering on the Gray (3, 2) pixel. The average value of the output signals of the G pixels existing within the same m rows × n columns is defined as G (Av.).
[0023]
From the ratio of these Gray (Av.) And G (Av.), Α is obtained by α = G (Av.) / Gray (Av.).
[0024]
In calculating G (Av.), Only the output signal of the G pixel that is not saturated is used. That is, G (Av.) Is obtained as an average of the output signals of only the G pixels in which the output signal is not saturated among all the G pixels existing in the range of m rows × n columns. Whether the output signal is saturated or not is determined when the CCD is manufactured because the CCD is given a known value, for example, a saturation point of 500 mV. It can be easily done by judging whether or not.
[0025]
Next, a case where an R signal is generated from Gray (3, 2) pixels will be described. When the R signal is an R (Gray) signal, R (Gray) signal = β × {Gray (3, 2) pixel output signal}. β is obtained based on the correlation between the output signal of the R pixel before saturation and the output signal of the Gray pixel. That is, as shown in FIG. 3, the fact that the ratio between the output signal of the R pixel before saturation and the output signal of the Gray pixel is constant is used. Specifically, it is obtained as follows.
[0026]
The average value of the output signal of the Gray (3, 2) pixel itself and the output signal of other Gray pixels existing around the Gray (3, 2) pixel is defined as Gray (Av.). The periphery of the Gray (3, 2) pixel is a range of m rows × n columns centering on the Gray (3, 2) pixel. Let R (Av.) Be the average value of the output signals of the R pixels existing within the same m rows × n columns.
[0027]
From the ratio of Gray (Av.) And R (Av.), Β is obtained by β = R (Av.) / Gray (Av.). As in the case of G (Av.) Described above, R (Av.) Is the output of only R pixels in which the output signal is not saturated among all the R pixels existing in the range of m rows × n columns. Obtained as the average of the signal. Whether the output signal is saturated or not is determined by determining whether a known saturation point (for example, 500 mV) has been reached as in the case of G (Av.).
[0028]
Similarly, when the B signal is generated from the Gray (3, 2) pixel, if the B signal is a B (Gray) signal, the output of B (Gray) signal = γ × {Gray (3, 2) pixel. Signal}. γ is obtained based on the correlation between the output signal of the B pixel and the output signal of the Gray pixel before saturation. That is, as shown in FIG. 3, the fact that the ratio between the output signal of the B pixel before saturation and the output signal of the Gray pixel is constant is used. Specifically, it is obtained as follows.
[0029]
The average value of the output signal of the Gray (3, 2) pixel itself and the output signal of other Gray pixels existing around the Gray (3, 2) pixel is defined as Gray (Av.). The periphery of the Gray (3, 2) pixel is a range of m rows × n columns centering on the Gray (3, 2) pixel. Let B (Av.) Be the average value of the output signals of the B pixels existing within the same m rows × n columns.
[0030]
From the ratio of Gray (Av.) And B (Av.), Γ is obtained by γ = B (Av.) / Gray (Av.). Also in this case, B (Av.) Is obtained as an average of the output signals of only the B pixels in which the output signal is not saturated among all the B pixels existing in the range of m rows × n columns. Whether the output signal is saturated or not is also determined by determining whether a known saturation point (for example, 500 mV) has been reached.
[0031]
As described above, as shown in FIG. 3, even after the G pixel is saturated with Sg, the R pixel is Sr, and the B pixel is saturated with sb, the Gray pixel using the gray filter with low sensitivity is not saturated. Therefore, the gain (× α, × β, × γ) as described above is given to the output signal (for example, S) of the Gray pixel at that time, and the output signal after saturation of the G, R, and B pixels ( (Shown by a one-dot chain line in FIG. 3).
[0032]
In determining α, the ratio of G (Av.) And Gray (Av.) Is not the ratio, but the sum of output signals of Gray pixels existing in the range of m rows × n columns described above, and the same m You may calculate by ratio with the sum of the output signal of G pixel which exists in the range of a row xn column. However, in this case, it is necessary to match the number of Gray pixels and G pixels to be summed. The same is true for β and γ.
[0033]
Next, the white balance process performed by the white balance unit 2 after the carrier balance will be described.
[0034]
For example, when a white object is imaged, the output signals from the R, G, and B pixels should be at the same level (R signal: G signal: B signal = 1: 1: 1). Due to the difference in spectral characteristics, the level is not always the same. At this time, a gain is given to each of the R signal, the G signal, and the B signal so that the white image is obtained (R signal: G signal: B signal = 1: 1: 1). Thereby, the sensitivity difference for each pixel of RGB can be corrected so that a white subject appears white. This is called white balance, and is a process performed even in an imaging apparatus having a normal color filter array that does not use a gray filter.
[0035]
Normally, as shown in FIG. 4, white balance is achieved by matching the R and B signals to the G signal. In the figure, the white balanced R signal is represented by R ′ and the B signal is represented by B ′. In order to clearly show the R ′ signal and the B ′ signal, the drawing is shifted from the origin 0 in the figure. As apparent from FIG. 4, in the conventional white balance, the maximum levels of the G signal, the R ′ signal, and the B ′ signal after the white balance are different. That is, white balance can be achieved only at the stage until the G signal is saturated.
[0036]
Therefore, in the present embodiment, as shown in FIG. 5, the white balance of the G (Gray) signal, the R (Gray) signal, and the B (Gray) signal generated from the Gray pixel with the carrier balance described above is obtained. The white balanced signals are indicated by R ″, G ″, and B ″, respectively (in this case, they are also shifted from the origin 0 for the sake of clarity of illustration). The same value can be taken without change.
[0037]
Next, pixel interpolation processing will be described.
[0038]
In the single-plate imaging device, only signals corresponding to the colors of the filters arranged in the pixels are output from the RGB pixels. That is, an R component R signal is output from the R pixel in which the red filter R is arranged, but a G component G signal and a B component B signal are not output. Similarly, only the G signal is output from the G pixel, the R signal and the B signal are not output, only the B signal is output from the B pixel, and the R signal and the G signal are not output.
[0039]
However, when the output signal of each pixel is processed in the subsequent stage, three RGB signals are required for each pixel. That is, the luminance signal and the color difference signal are obtained for each pixel, but three signals of RGB are required for the calculation. For this reason, it is necessary to generate and interpolate color signals other than the color signals possessed by each pixel. This is called pixel interpolation.
[0040]
There are various methods of pixel interpolation than before, but the main point is to use output signals of pixels around the interpolation target pixel. For example, when it is desired to generate a G signal for the R pixel, a value obtained by estimation from the output signal of the G pixel located around the R pixel that is the interpolation target is set as the G signal of the R pixel to be interpolated. . In addition, there is a method that uses not only G pixels but also all surrounding RGB pixels.
[0041]
At this time, if the output signal of the pixel used for the interpolation calculation (G pixel in the above example) is not saturated, normal interpolation processing is performed using the output of the G pixel as it is. This processing is performed by the Green standard area interpolation means 3G in FIG. Here, the standard region means a range from 0 to Sg in FIG. 3 for a region before the output signal is saturated, that is, a G pixel. In the Green standard area interpolation means 3G, a process of interpolating the G signal to the B pixel is also performed.
[0042]
Similarly, the Red standard region interpolation unit 3R performs a process of interpolating R signals into G and B pixels, and the Blue standard region interpolation unit 3B performs a process of interpolating B signals into R and G pixels. The processing performed by the Green standard region interpolation unit 3G, the Red standard region interpolation unit 3R, and the Blue standard region interpolation unit 3B is performed when the output signal of the pixel used for the interpolation calculation is not saturated.
[0043]
When the output signal of the pixel used for the interpolation calculation is saturated (this determination is made based on whether or not a known saturation point has been reached in the same manner as in the carrier balance described above), the Green saturation region interpolation means 4G Pixel interpolation is performed by the Red saturation region interpolation unit 4R and the Blue saturation region interpolation unit 4B.
[0044]
For example, let us consider a case where an R signal is interpolated to a G pixel by the Red saturation region interpolation unit 4R. Here, when the R pixel to be used for the interpolation calculation is saturated, the output signal of the R pixel after saturation is obtained using the output signal of the adjacent Gray pixel in the horizontal direction of the R pixel.
[0045]
That is, even at a level at which the R pixel is saturated, the gray pixel with low sensitivity is not saturated, and the R (Gray) signal generated by the carrier balance described above is used from the output signal of the gray pixel that is not saturated. Thus, the output signal of the R pixel after saturation is obtained. Specifically, the average value of the R (Gray) signals of the adjacent Gray pixels on the horizontal direction of the R pixel is used as the output signal of the R pixel. As a result, even if the R pixel is saturated, an output signal that accurately reflects the amount of light received by the R pixel can be obtained. By using the output signal of the R pixel, the G pixel that is the interpolation target pixel is obtained. Pixel interpolation can be performed accurately.
[0046]
If the B pixel is saturated, for example, the average value of the B (Gray) signals of the adjacent Gray pixels in the vertical direction is used as the output signal of the B pixel after saturation. When the G pixel is saturated, for example, the average value of the G (Gray) signals of the four Gray pixels at the diagonal position of the G pixel is used as the output signal of the G pixel after saturation.
[0047]
Note that Gray pixels are also used in the interpolation calculation. In the case of Gray pixels, RGB component signals, R (Gray) signals, G (Gray) signals, and B (Gray) signals are transmitted with the carrier balance described above. Since these are obtained, these are used as they are for pixel interpolation. Of course, the Gray pixel itself can obtain RGB signals independently by the above-described carrier balance, so that it is not necessary to perform pixel interpolation using surrounding pixels.
[0048]
As described above, if each of the RGB signals is obtained by the Red standard region interpolation unit 3R, the Green standard region interpolation unit 3G, and the Blue standard region interpolation unit 3B, it is used as it is for subsequent processing. If there is a saturated pixel and the operation cannot be performed by the Red standard region interpolation unit 3R, the Green standard region interpolation unit 3G, and the Blue standard region interpolation unit 3B, the Red saturation region interpolation unit 4R and the Green saturation region interpolation are performed. The RGB signals obtained by the means 4G and the blue saturation area interpolation means 4B are used for subsequent processing. The selection control is performed by the luminance signal area control means 5 and the color difference signal area control means 6.
[0049]
Thereafter, the RGB signals output from the luminance signal area control means 5 are sent to the gamma correction means 8 via the contour correction means 7, and the RGB signals output from the color difference signal area control means 6 are sent to the gamma correction means 8. Supplied.
[0050]
The contour correcting means 7 detects an edge of the image, and performs a process for enhancing the detected edge and showing it clearly.
[0051]
The gamma correction unit 8 performs the following processing. A CRT display (CRT display) has non-linear input / output characteristics, and light emission on the low luminance side is not proportional to the input signal and tends to be small. Therefore, when the RGB signals are directly displayed on the CRT display, the low luminance side appears to be crushed, in other words, it looks dark. This is called the gamma characteristic of a CRT display. At this time, the input RGB signals are subjected to non-linear processing having characteristics opposite to the gamma characteristics of the CRT display, so that a natural contrast can be obtained when viewed on the CRT display. This is called gamma correction.
[0052]
The RGB signals subjected to the gamma correction are sent to the luminance signal synthesizing unit 9 and the color difference signal synthesizing unit 10, respectively. The luminance signal synthesizing unit generates a luminance signal, and the color difference signal synthesizing unit 10 generates a color difference signal. Is done.
[0053]
As described above, RGB signals can be generated from Gray pixels even after RGB pixels are saturated. A luminance signal that is conventionally determined by the saturation characteristic of the G signal is obtained by using the R (Gray) signal, G (Gray) signal, and B (Gray) signal generated from the Gray pixel. The dynamic range of can be expanded. For example, when the gray filter disposed in the Gray pixel is set to a sensitivity characteristic that is 1 / N (N is an integer) of the blue filter under a white light source, the Gray pixel has a dynamic range N times that of the B pixel. Can be expanded.
[0054]
Furthermore, color reproducibility can be improved by obtaining a color difference signal using an R (Gray) signal, a G (Gray) signal, and a B (Gray) signal generated from Gray pixels.
[0055]
The embodiment of the present invention has been described above. Of course, the present invention is not limited to this, and various modifications can be made based on the technical idea of the present invention.
[0056]
In the Bayer arrangement shown in FIG. 7, the green filter G horizontally adjacent to the blue filter B may be replaced with a gray filter Gray. Furthermore, the arrangement of the color filters is not limited to the Bayer arrangement, and the present invention can be applied to other primary color arrangements.
[0057]
An example of another color arrangement to which the present invention is applied is shown in FIG. FIG. 6 shows a color arrangement called a so-called G stripe. Green filters G are arranged in a vertical row every other row, and red filters R and blue filters B are arranged in rows between the green filters G. The red filter R and the blue filter B are in a checkered arrangement. When the present invention is applied to this color arrangement, for example, the green filter G marked with * in the figure, that is, the green filter G adjacent to the left of the red filter R may be replaced with a gray filter. Alternatively, the green filter G not marked with *, that is, the green filter G on the right side of the red filter R may be replaced with a gray filter. Note that other arrangements of the red filter R and the blue filter B are also conceivable as the color arrangement of the G stripe.
[0058]
The present invention can be applied not only to a CCD solid-state image sensor but also to a MOS solid-state image sensor.
[0059]
【The invention's effect】
As described above, in the present invention, by using a gray filter that has sensitivity in a wide range with respect to all the colors of red, green, and blue, and has higher saturation characteristics than RGB color filters, Even if an output signal of a pixel in which a certain color filter of RGB is arranged is saturated, an output signal of the saturated pixel can be calculated from an output signal of a Gray pixel in which a gray filter that is not yet saturated is arranged. As a result, the dynamic range of the luminance signal, which is conventionally determined by the saturation characteristics of the G signal, can be expanded.
Furthermore, by using the R (Gray) signal, G (Gray) signal, and B (Gray) signal generated from Gray pixels, white balance is used, so that even after each RGB pixel originally provided is saturated, it is accurate. White balance can be taken.
[Brief description of the drawings]
FIG. 1 is a diagram showing a color filter array of a solid-state imaging device according to an embodiment of the present invention.
FIG. 2 is a block diagram illustrating a configuration of an imaging apparatus according to an embodiment of the present invention.
FIG. 3 shows output characteristics of G pixels, R pixels, B pixels, and Gray pixels before saturation with respect to exposure time (incident light amount), and G generated from Gray pixels after saturation of G pixels, R pixels, and B pixels. It is a figure which shows (Gray) signal, R (Gray) signal, and B (Gray) signal.
FIG. 4 is a white balance output characteristic diagram of RGB signals according to a conventional method.
FIG. 5 is a white balance output characteristic diagram of a G (Gray) signal, an R (Gray) signal, and a B (Gray) signal generated from Gray pixels.
FIG. 6 is a diagram showing a modification of the color filter array to which the present invention is applied.
FIG. 7 shows a Bayer array.
FIG. 8 is an output characteristic diagram of G pixels, R pixels, and B pixels with respect to exposure time (incident light amount).
FIG. 9 is a diagram illustrating transmission characteristics in the visible light region of the four color filters illustrated in FIG. 1;
[Explanation of symbols]
1 ... carrier balance means, 2 ... white balance means, 3R ... Red standard area interpolation means, 3G ... Green standard area interpolation means, 3B ... Blue standard area interpolation means, 4R ... Red saturated area interpolation means, 4G... Green saturated area interpolation means, 4B... Blue saturation area interpolation means, 5... Luminance signal area control means, 6... Color difference signal area control means, 7. 9: Luminance signal synthesis means, 10 ... Color difference signal synthesis means.

Claims (5)

Gray in which an R pixel in which a red filter is arranged, a G pixel in which a green filter is arranged, a B pixel in which a blue filter is arranged, and a gray filter whose sensitivity in the visible light region is smaller than that of the blue filter is arranged. A solid-state imaging device in which pixels are two-dimensionally arranged;
An output value calculated based on an unsaturated output signal of an R pixel, a G pixel, or a B pixel existing around the noticed Gray pixel, an output signal of the noticed Gray pixel itself, and the noticed Based on a ratio with an output value calculated based on an output signal of another Gray pixel existing around the Gray pixel, a gain is given to the output signal of the noticed Gray pixel, and an R (Gray) signal Carrier balance means for calculating a G (Gray) signal or a B (Gray) signal;
Wherein R (Gray) signal, on the basis of the G (Gray) signal or the B (Gray) signal, the R pixels after the output signal is saturated, interpolation means for calculating an output signal of the G pixel or the B pixel An imaging apparatus comprising: The imaging device according to claim 1, wherein the green filter horizontally adjacent to the red filter or the green filter horizontally adjacent to the blue filter arranged in a Bayer manner is replaced with the gray filter. . The imaging apparatus according to claim 1, further comprising a white balance unit that performs white balance processing using the R (Gray) signal, the G (Gray) signal, and the B (Gray) signal. Gray in which an R pixel in which a red filter is arranged, a G pixel in which a green filter is arranged, a B pixel in which a blue filter is arranged, and a gray filter whose sensitivity in the visible light region is smaller than that of the blue filter is arranged. A signal processing method for a solid-state imaging device in which pixels are two-dimensionally arranged,
An output value calculated based on an unsaturated output signal of an R pixel, a G pixel, or a B pixel existing around the noticed Gray pixel, an output signal of the noticed Gray pixel itself, and the noticed Based on a ratio with an output value calculated based on an output signal of another Gray pixel existing around the Gray pixel, a gain is given to the output signal of the noticed Gray pixel, and an R (Gray) signal calculates the G (Gray) signal or B (Gray) signal,
Wherein R (Gray) signal, on the basis of the G (Gray) signal or the B (Gray) signal, the R pixels after the output signal is saturated, to calculate the output signal of the G pixel or the B pixel A signal processing method for a solid-state imaging device. 5. The signal processing method for a solid-state imaging device according to claim 4, wherein white balance processing is performed using the R (Gray) signal, the G (Gray) signal, and the B (Gray) signal.

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