JPH04329788A - Color image pickup device - Google Patents

Abstract

PURPOSE:To obtain a picture with excellent resolution and S/N, and less moire by obtaining a luminance signal whose spectral characteristic is corrected by a simple method. CONSTITUTION:The image pickup device employs an image pickup element (sensor) 101 provided with R, G, B filters of the Bayer arrangement. When a discrimination circuit 131 discriminates it that a high frequency component in the horizontal direction is large base on an output of the image pickup element 101, a switch 128 is thrown to obtain a timing to eliminate a color difference carrier in the horizontal direction and when not, the switch 128 is thrown to obtain a timing to eliminate a color difference carrier in the vertical direction. Moreover, a 1st difference signal or a 3rd difference signal being an output of an adder 129 and a 2nd difference signal or a 4th difference signal being an output of an adder 130 are subject to a constant number of multiple processing, and the result is added to a luminance signal YS by an adder 117 thereby obtaining a luminance signal Y whose spectral characteristic is corrected.

Description

[Detailed description of the invention]

0001

[Industrial Field of Application] The present invention relates to a color imaging device equipped with an imaging device in which a plurality of light receiving elements (pixels) are two-dimensionally arranged.
The present invention relates to a color imaging device that can output images with a good N ratio.

0002

2. Description of the Related Art FIGS. 6, 7, and 8 are diagrams showing examples of color filter arrangement configurations of conventionally known color solid-state imaging devices. FIG. 6 shows a configuration called a so-called stripe filter in which a red light transmitting filter R, a green light transmitting filter G, and a blue light transmitting filter B are vertically arranged in a stripe shape. On the other hand, FIGS. 7 and 8 have a configuration called a mosaic filter, and in FIG. 7, the green light transmission filter G is vertically striped, and the red light transmission filter R and the blue light transmission filter B are each two stripes. In FIG. 8, magenta light transmission filter Mg, green light transmission filter Gr, cyan light transmission filter Cy, and yellow light transmission filter Ye are arranged horizontally between G filters in every other row and two columns. , 8 color filters of 4 pixels in the vertical direction form one unit, and are arranged in the order shown in the figure.

[0003] However, these image pickup devices having color filter arrays have the following problems. In other words, in an image sensor equipped with a color filter having the configuration shown in FIG. 6, color signal carriers are generated at a frequency that is 1/3 of the sampling frequency, so it is possible to resolve frequencies up to 1/2 of the sampling frequency, which is the Nyquist frequency. The resolution is inferior.

[0004] In an image sensor equipped with a color filter having the structure shown in FIG. 7, R filters and B filters with different bands are arranged vertically, so color moire tends to occur in the vertical direction, especially in chromatic images. An ugly scene appears.

[0005] An image sensor receiving a color filter having the configuration shown in FIG. 8 is composed of complementary color filters with a wide band, so color moire is less likely to occur than an image sensor having a color filter having the configuration shown in FIG. Since the color signal is formed from the difference signal between the output signals of pixels, the S/N ratio of the color signal is poor, and furthermore, when the output signal is quantized and digitally processed, the quantization error of the color signal becomes large. Undesirable.

Furthermore, since color signal carriers are generated at a frequency of 1/2 of the sampling frequency in both image sensors equipped with color filters having the configurations shown in FIGS. 7 and 8, the frequency of 1/2 of the sampling frequency, which is the Nyquist frequency, is cannot be resolved.

In contrast, US Patent No. 39710
There is an image sensor having a color filter array called a Bayer array, which is disclosed in Japanese Patent No. 65. As shown in FIG. 9, if the horizontal pitch of the pixels of the image sensor is PH and the vertical pitch is PV, the green light transmitting filter G has a horizontal pitch of 2PH and a vertical pitch of PV. The red light transmission filter R and the blue light transmission filter B are arranged in a rectangular lattice sampling structure with a pitch of 2PH in the horizontal direction and a pitch of 2PV in the vertical direction. be. It is known that when an image sensor having such a Bayer array is used, a good image with less moire and a good S/N ratio can be obtained.

[0008]

However, even if an image sensor having the Bayer array is used, the following problems occur. That is, FIGS. 10(a) and 10(b) respectively show the characteristics of the first quadrant when the positions of signal carriers generated in the image sensor of the color filter shown in FIG. 9 are expressed on a two-dimensional frequency plane (fH, fV). It is a diagram. Here, Figure 10 (
The characteristic diagram on the frequency plane shown in a) shows that a luminance signal is formed by switching the output signal from each pixel of the image sensor in FIG.
In the characteristic diagram on the frequency plane shown in ), a luminance signal is formed using only the signal from the pixel in which the G filter of the image sensor shown in FIG. 9 is arranged.

In either case, (1/2P
It can be seen that color signal carriers are generated at (H,0) and (0,1/2PV). In other words, even in the case of an image sensor having a Bayer arrangement, the sampling frequency is 1
Since a color signal carrier is generated at a frequency of /2, it is not possible to resolve frequencies up to 1/2 of the sampling frequency, which is the Nyquist frequency.

Furthermore, a brightness signal with correct spectral characteristics cannot be obtained by switching the output signal from each pixel or by simply synthesizing the brightness signal using only the signal from the pixel in which the G filter is arranged. This adversely affects the color reproducibility of the output image. For this reason, conventional processing has been carried out to replace only the low-frequency components of the luminance signal with a luminance signal having the correct spectral characteristics, but this significantly increases the circuit scale to form the luminance signal with the correct spectral characteristics. .

The present invention was made in view of these problems, and it is possible to obtain a luminance signal with corrected spectral characteristics by a simple method, and has good resolution, little moire, and S/
It is an object of the present invention to provide a color imaging device that can obtain images with a good N ratio.

0012

Means for Solving the Problems In the present invention, in order to achieve the above object, a color imaging device is configured as follows (1).

(1) A color imaging device that converts a subject image into an electrical signal having brightness information and color information, and includes the following components a, b, c, and d. a. An image sensor in which pixels are arranged in a rectangular grid with a pitch PH in the horizontal direction and a pitch PV in the vertical direction. b. PH in the horizontal direction with a pitch of 2 PH in the horizontal direction and a pitch PV in the vertical direction provided corresponding to the pixels.
a first color filter having an offset sampling structure offset by a horizontal pitch of 2PH,
A color filter array comprising a second color filter and a third color filter having a rectangular grid sampling structure with a vertical pitch of 2 PV. c. Based on the first color signal, second color signal, and third color signal output from the pixels corresponding to the first color filter, second color filter, and third color filter, the first color signal is Of the color signals, only the signals from pixels in the same column as the pixels of the second color signal are synchronized, and a first difference signal obtained by taking the difference from the second color signal, and a third difference signal of the first color signal are synthesized. a first color signal forming means for forming the color information from a second difference signal obtained by synchronizing only the signals from the pixels in the same column as the pixels of the color signal, and taking the difference from the third color signal; The second of the first color signals
A third difference signal obtained by synchronizing only the signals from the pixels in the same row as the pixels of the color signal, and taking the difference from the second color signal, and the first
A second color signal that synchronizes only the signals from pixels in the same row as the pixels of the third color signal among the color signals, and forms the color information from a fourth difference signal obtained by taking the difference from the third color signal. color information forming means, the color information forming means switching between the first color information forming means and the second color information forming means according to a frequency component in the scanning direction of the subject image or in a direction perpendicular thereto; .

d. The first difference signal or the third difference signal and the second difference signal or the fourth difference signal are each multiplied by a constant, and these are multiplied by the first color signal, the second color signal, and the third difference signal. Luminance information forming means for forming the luminance information by adding it to a signal obtained by combining at least one or more of the color signals.

[0015]

[Operation] With the configuration (1) above, carriers of color difference signals for black and white objects located at (1/2PH, 0) and (0,1/2PV) on the two-dimensional frequency space disappear, suppressing moire. be done.

Further, a signal obtained by multiplying the first and second or third and fourth difference signals by a constant is added to the luminance information obtained by combining, and the spectral characteristics of the luminance information are corrected.

[0017]

[Examples] The present invention will be explained in detail below using examples. FIG. 1 is a block diagram of a "color imaging device" which is a first embodiment of the present invention. The image sensor (sensor) 101 is shown in FIG.
A Bayer array R, G, B filter (filter array) shown in (a) is provided. Image sensor 101 to 1
The image signal read out for each pixel is separated into R, G, and B signals by the color separation unit 102, and then the gains of the R, G, and B signals are obtained from the white balance sensor (AWB) 120 by the white balance unit 111. The white balance is adjusted based on the color temperature information obtained, and then γ conversion is performed in a γ conversion unit 112, and then A/D conversion is performed in an A/D (analog-digital) converter 103.

The brightness signal is transmitted through the switch circuit (SWY) 126
are arranged in the reading order by switching, and are taken out as a luminance signal YS containing high-frequency components. This luminance signal YS is a first difference signal or a third difference signal R (γ power) − G1 (γ power), a second difference signal or a fourth difference signal B (γ power) − G2 ( The adder 117 adds the signal obtained by adding a constant multiple of
A (digital-to-analog) converter 118 performs D/A conversion and outputs the signal.

On the other hand, among the outputs of the A/D converter 103, G
The (γ power) signal is transmitted by the switch (SW) 128 as shown in FIG.
G at the positions shown at the two timings, timing 1 shown in a) or timing 2 shown in (b).
It is separated into a G1 (γ power) signal and a G2 (γ power) signal. This is possible by switching the switch 128, for example, every horizontal scanning period. These two timings 1,
The switching between 2 and 2 is performed by a determination circuit 131, which will be described later, in accordance with the luminance signal of the subject. G separated in this way
1 (γ power) signal and G2 (γ power) signal are sent to interpolation filters 106 and 10 together with R (γ power) signal and B (γ power) signal.
The signals R (γ power), G1 (γ power), G2 (γ power), and B (γ power) are input to 7, 108, and 109 and are synchronized, respectively.
). Note that the interpolation filters 106 to 109 perform not only synchronization by interpolation, but also linear processing such as two-dimensional low-pass filtering and edge emphasis. Since these processes are linear processes, the order may be replaced with processes such as addition processing and matrix processing, which will be described later.

The synchronized R (γ power) signal, G1 (γ
The adder 129 converts the signal to the first difference signal and the third difference signal R (to the γ power) - G1 (to the γ power), and the B (to the γ power) signal and the G2 (to the γ power) signal to the adder 130. The second difference signal and the fourth difference signal B (γ power) − G2 (γ power) are inputted to the color difference signal matrix processing unit 113,

00
21]

[Math 1]

The following conversion is performed, and the color difference signals R-Y,B
-Y is generated.

Here, G1 (γ power), G2 (γ power)
Assuming that the signal is switched at timing 1 shown in Fig. 2(a), in the frequency space (1/2PH, 0)
Assume that a black-and-white subject is captured by the image sensor 101. This object has vertical stripes with a period of 2PH, and for such an object, R (γ power) = G1 (γ power),
Since B (γ power) = G2 (γ power), the adder 129
, 130, the R (γ power)-G1 (γ power) signal and the B (γ power) −G2 (γ power) signal are both zero. Therefore, the color difference signals R-Y and B-Y output from the color difference matrix processing section 113 also become zero and are not output. This means that the carrier of the color difference signal at the frequency (1/2PH, 0) disappears. In other words, the carrier of the R (γ power) signal and the carrier of the G1 (γ power) signal on the frequency (1/2PH, 0) are in phase, and the carrier of the B (γ power) signal is in phase. The carriers of the G2 (γ power) signals are in phase, so these first
, the carrier of the second difference signal R (γ power) - G1 (γ power), B (γ power) - G2 (γ power) can be eliminated at this frequency, so no color difference signal carrier is generated. It is.

Next, assuming that the G1 (γ power) and G2 (γ power) signals are switched at timing 2 shown in FIG. Suppose that a subject is captured by the image sensor 101. This object has horizontal stripes with a period of 2 PV, and for such an object, the R (γ power) - G1 (γ power) signal and B (γ power) - G signal output from adders 129 and 130 are used.
2 (γ power) signals are all zero. Therefore, the color difference signals RY, B output from the color difference matrix processing section 113
-Y also becomes zero and is not output. This means that the frequency (0
, 1/2PV), which means that the carrier of the color difference signal disappears. Another interpretation is that the frequency (0, 1
/2PV) and the carrier of the R (γ power) signal on G1
The carriers of the (γ power) signal are in the same phase, and the carriers of the B (γ power) signal and the G2 (γ power) signal are in the same phase. Therefore, these third and fourth difference signals R(γ
Since the carrier can be extinguished at this frequency of (γ power) - G1 (γ power), B (γ power) - G2 (γ power),
No carrier of the color difference signal is generated.

These color difference signals are then D/A converted by D/A converters 114 and 115 and output.

Furthermore, the third difference signal R (γ power) −G1 (
The fourth difference signal B (γ power) - G2 (γ power) is multiplied by a constant by constant coefficient multipliers 132 and 133, and
34 and added to the luminance signal YS in an adder 117 to obtain a luminance signal Y whose spectral characteristics have been corrected.

This principle will be explained below. Image sensor 10
The output signals from each pixel of 1 are simply combined, and the obtained luminance signal is designated as YS. In this embodiment, the luminance signal YS is obtained by switching the output signal from each pixel by the switch circuit 126, but it is also possible to use one of the color-separated color signals, for example, the G signal, as it is. It may be something. On the other hand, let YL be the luminance signal corrected so that the spectral characteristics are equal to the visibility. The luminance signal YL can be formed by a linear combination of the synchronized color signals.

[0028]

[Math 2]

It can be expressed as: In the case of NTSC system, δ=0.30, α+β=0.59, ε=0.11
...(2). Luminance signal Y
L has a lower band than the luminance signal YS. Among the luminance signals YS, the luminance signals having the same band as YL are designated as YS.
Let it be L.

At this time, the luminance signal Y is corrected by replacing the low frequency portion YSL of YS with a luminance signal YL having correct spectral characteristics. That is, Y = (YS - YSL) + YL = YL + (YL
-YSL) ... (3) Here, the luminance signal YSL can be expressed as a linear combination of each color signal. this

[0031]

[Math 3]

[0032] In this case, the contents in the parentheses on the right side of equation (3) are as follows. That is,

[0033]

[Math 4]

Here, if δ-s=t-α, then s+t=α+δ δ+α+β+ε=s+t+u+w (=1), so β+ε
=u+w Therefore ε-w=u-β Here C1 = δ-s=t-α
…
...(5) C2 = ε-w=u-β

...(6), then

[0035]

[Math 5]

Substituting this into equation (3),

[0037]

[Math 6]

[0038] Therefore, correction of the spectral characteristics of the luminance signal Y is performed using the first luminance signal YS obtained by simple synthesis.
, the second difference signal or the third and fourth difference signals R (γ power) −
This can be done by adding a constant times G1 (γ power) and R (γ power)−G2 (γ power).

When the luminance signal YS is obtained by switching by the switch circuit 126, s, t, u, w in equation (4) are s=t=u=w=0.25.
...(8
), so from equations (2), (5), and (6), α=0.
20, β = 0.39, C1 = 0.05, C2 = -0.14
...(9) is obtained.

Furthermore, when the luminance signal YS is the G signal used as it is, s, t, u, w in equation (4) are
s=w=0, t=u=0.5
...(10)
Therefore, from (2), (5), and (6), α=0.20
, β=0.39 C1 =0.30, C2 =0.11
...(11
) is obtained.

The luminance signal Y whose spectral characteristics have been corrected in this way is D/A converted by the D/A converter 118 and output. In general, the color difference signals R-Y, B-Y and the low-frequency component YL of luminance have sufficiently narrow bands compared to the luminance signal Y, so
Interpolated and simultaneous R (γ power), G1 (γ power), G2
(γ power), B (γ power) signal adders 129, 130,
Color difference matrix processing section 113, luminance signal generation circuit 127
The processing may be performed using a slower clock than the processing of the luminance signal Y by thinning out or the like.

Note that when recording the output signal obtained from the processing block diagram shown in FIG. 1 in analog form, the D/A converter 1
18, 114, and 115 are necessary, but some magnetic media, magneto-optical media, E2 PROM (electrica
It is not necessary to include it when digitally recording on a memory card such as llyerasabl PROM).

Next, the determination circuit 131 will be explained. FIG. 3(a) shows one configuration of this determination circuit. Here, the luminance signal Y output from the switch circuit 126 is applied with a horizontal band pass filter 31 to extract horizontal high frequency components. This is input to the comparison circuit 32 and compared with a certain threshold level. and,
If it is determined that the high frequency component in the horizontal direction is larger than the threshold level, timing 1 is selected to eliminate the carrier of the horizontal color difference signal; otherwise, the carrier of the vertical color difference signal is eliminated. Timing 2 is selected (see FIG. 2).

Further, the determination circuit 131 may have the configuration shown in FIG. 3(b). That is, the luminance signal Y output from the switch circuit 126 is applied to the vertical band pass filter 61 to extract the high frequency component in the vertical direction. This is input to a comparison circuit 62 and compared with a certain threshold level. If it is determined that the high frequency component in the vertical direction is larger than the threshold level, timing 2 is selected to eliminate the carrier of the vertical color difference signal, and if not, the carrier of the horizontal color difference signal is deleted. Timing 1 for extinguishing is selected.

As explained above, in this embodiment, since a Bayer array color filter is used, there is little moire, the S/N ratio is good, and the signal processing means suitable for the Bayer array is used. The resolution is good.

Furthermore, brightness information whose spectral characteristics have been corrected can be obtained using a simple method.

Next, a second embodiment of the present invention will be described. Figure 4
shows a signal processing block diagram of the “color imaging device” of this embodiment. The image sensor (sensor) 401 is provided with R, G, and B filters in a Bayer array as shown in FIG. An image signal read out pixel by pixel from the image sensor 401 is separated into R, G, and B signals by a color separation unit 402, and then a white balance unit 411 adjusts the gains of the R, G, and B signals to a white balance sensor 420. The white balance is adjusted based on the color temperature information obtained from the γ conversion unit 412.
The signal is γ-converted by the A/D converter 403, and then A/D converted by the A/D converter 403.

The luminance signal is a G (γ-th power) signal which is subjected to two-dimensional interpolation of the offset sampling structure by an interpolation filter 425, and then D/A converted by a D/A converter 418 and output. Note that the interpolation filter performs not only synchronization by interpolation, but also processes such as two-dimensional low-pass filtering and edge enhancement.

On the other hand, among the outputs of the A/D converter 403, G
(γ power) signal is generated by the switch 428 at two timings, timing 1 shown in FIG. 2(a) or timing 2 shown in FIG.
(γ power) signal and G2 (γ power) signal. This can be done by switching the switch 428, for example, every horizontal scanning period. Switching between the two timings 1 and 2 is performed by a determination circuit 431, which will be described later, in accordance with the luminance signal of the subject.

The thus separated G1 (γ power) signal and G2 (γ power) signal are the R (γ power) signal and B (γ power) signal.
Along with the signal, interpolation filters 406, 407, 408, 4
09, and the respective synchronized signals R (γ power) and G
1 (γ power), G2 (γ power), and B (γ power). Note that the interpolation filter not only performs synchronization by interpolation, but also performs two
Linear processing such as dimensional low-pass filtering and edge enhancement is also performed. Since these processes are linear processes, the order may be switched with processes such as addition processing, which will be described later. The synchronized R (γ power) signal and G1 (γ power) signal become a difference signal R (γ power) − G1 (γ power) in the adder 429, and B
The (γ power) signal and the G2 (γ power) signal are converted into a difference signal B (γ power)−G2 (γ power) by an adder 430, and the color difference signal R is processed by the color difference signal matrix processing unit 413 as in the first embodiment. -Y, BY are generated.

Here, assuming that switching between the G1 (γ1) and G2 (γ1) signals is performed at timing 1 shown in FIG.
) is captured by the image sensor 401. This object has vertical stripes with a period of 2PH, and for such an object, the R (γ power) - G1 (γ power) signal, B (γ power) - G2 (γ power) signal output from the adders 429 and 430 are (squared) signals are all zero. Therefore, the color difference signals R-Y and B-Y become zero and are not output. This means that the carrier of the color difference signal at the frequency (1/2PH, 0) disappears. If you interpret it another way,
The carrier of the R (γ power) signal and the carrier of the G1 (γ power) signal on the frequency (1/2PH, 0) are in phase, and the carrier of the B (γ power) signal and the G2 (γ power) signal are in phase. The carriers are in phase, so these first and second difference signals R (γ power) - G1 (γ power), B (γ power) - G2
Since carriers at this frequency of (γ power) can be eliminated, carriers of color difference signals are not generated.

Next, assuming that the G1 (γ power) and G2 (γ power) signals are switched at the timing shown in FIG. Assume that the subject is captured by the image sensor 401. This object has horizontal stripes with a period of 2PV, and for such an object, R (γ power) - G1 (γ power), B (γ power) - G2 output from adders 429 and 430.
(γ power) signals are all zero. Therefore, the color difference signal R-
Y and BY become zero and are not output. This means that the carrier of the color difference signal at the frequency (0,1/2 PV) disappears. Another interpretation is that the frequency (0
, 1/2PV) and the carrier of the R (γ power) signal and G
The carriers of 1 (γ power) signals are in the same phase, and B (γ power)
The carrier of the signal and the carrier of the G2 (γ power) signal are in the same phase, therefore, their third and fourth difference signals R(γ
Since the carriers at these frequencies of B (gamma power) - G1 (gamma power) and B (gamma power) - G2 (gamma power) can be eliminated, carriers of color difference signals are not generated. These color difference signals are converted into D/A converters 414 and 415.
A is converted and output. Note that generally the color difference signals RY,
B-Y has a sufficiently narrow band compared to the luminance signal Y, so the interpolated and synchronized R (γ power), Y1 (γ power), Y2 (
The processing of the γ power), B (γ power) signals by the adders 429, 430, etc. may be performed using a clock slower than the processing of the luminance signal by performing thinning or the like.

Note that when recording the output signal obtained from the processing block diagram shown in FIG. 4 in analog form, the D/A converter 4
18, 414, and 415 are necessary, but they do not need to be included when digitally recording on some kind of magnetic medium, magneto-optical medium, E2 PROM, etc.

Next, the determination circuit 431 will be explained. Also in this embodiment, a determination circuit having the configuration shown in FIG. 3 is used. In the configuration of FIG. 3A, the luminance signal Y output from the interpolation filter 425 is applied to the horizontal band pass filter 31 to extract the high frequency component in the horizontal direction. This is input to the comparison circuit 32 and compared with a certain threshold level. If it is determined that the high frequency component in the horizontal direction is larger than the threshold level, timing 1 is selected to eliminate the carrier of the horizontal color difference signal, and if not, the carrier of the vertical color difference signal is deleted. Timing 2 for extinction is selected (see FIG. 2).

In the configuration of FIG. 3(b), the interpolation filter 42
A vertical band pass filter 61 is applied to the luminance signal Y outputted from 5 to extract high frequency components in the vertical direction. This is input to a comparison circuit 62 and compared with a certain threshold level. If it is determined that the high frequency component in the vertical direction is larger than the threshold level, timing 2 is selected to eliminate the carrier of the vertical color difference signal, and if not, the carrier of the horizontal color difference signal is deleted. Timing 1 for extinction is selected (see FIG. 2).

Note that the color filters of the image sensor do not necessarily have to be R, G, and B filters, and as shown in FIG. A Bayer array in which the filters are similar to the filter), R, and B, or a Bayer array in which the first, second, and third color filters are W (white), R, and B as shown in FIG. 5(b), etc., may be used. Separating the first color signal as shown in FIGS. 2(a) and (b),
When the first to fourth difference signals are formed, the color difference signals R-Y, B
-Y may be anything as long as it can be determined by linear calculation using a matrix from the first to fourth difference signals as shown in the above-mentioned "Equation 1". (The coefficient of the matrix is “Math. 1”
It doesn't have to be the same as. )

[0057]

[Effects of the Invention] As explained above, according to the present invention,
By installing a Bayer array filter array on the image sensor and applying appropriate signal processing, it is possible to obtain luminance information with corrected spectral characteristics using a simple method, with good resolution, little moire, and high S/N. A color imaging device that can obtain images with good ratio can be provided.

[Brief explanation of drawings]

[Figure 1] Block diagram of the first embodiment

[Figure 2] Explanatory diagram of the first embodiment

[Figure 3] Block diagram of determination circuit

[Figure 4] Block diagram of second embodiment

[Figure 5] Diagram showing an example of Bayer array

[Figure 6] Diagram showing an example of arrangement of color filters

[Figure 7] Diagram showing an example of arrangement of color filters

[Figure 8] Diagram showing an example of arrangement of color filters

[Figure 9] Diagram showing an example of Bayer array

[Figure 10] Figure 9
Diagram showing the position of the signal carrier by the color filter of

[Explanation of symbols]

101 Image sensor 106-109 Interpolation filter 128 Switch 129,130 Adder 131 Judgment circuit 132, 133 Constant coefficient multiplier 117, 134 Adder

Claims (1)

[Claims] Claim 1: A color imaging device that converts a subject image into an electrical signal having brightness information and color information, comprising:
, b, c, and d. a. An image sensor in which pixels are arranged in a rectangular grid with a pitch PH in the horizontal direction and a pitch PV in the vertical direction. b. PH in the horizontal direction with a pitch of 2 PH in the horizontal direction and a pitch PV in the vertical direction provided corresponding to the pixels.
a first color filter having an offset sampling structure offset by a horizontal pitch of 2PH,
A color filter array comprising a second color filter and a third color filter having a rectangular grid sampling structure with a vertical pitch of 2 PV. c. Based on the first color signal, second color signal, and third color signal output from the pixels corresponding to the first color filter, second color filter, and third color filter, the first color signal is Of the color signals, only the signals from pixels in the same column as the pixels of the second color signal are synchronized, and a first difference signal obtained by taking the difference from the second color signal, and a third difference signal of the first color signal are synthesized. a first color signal forming means for forming the color information from a second difference signal obtained by synchronizing only the signals from the pixels in the same column as the pixels of the color signal, and taking the difference from the third color signal; The second of the first color signals
A third difference signal obtained by synchronizing only the signals from the pixels in the same row as the pixels of the color signal, and taking the difference from the second color signal, and the first
A second color signal that synchronizes only the signals from pixels in the same row as the pixels of the third color signal among the color signals, and forms the color information from a fourth difference signal obtained by taking the difference from the third color signal. color information forming means, the color information forming means switching between the first color information forming means and the second color information forming means according to a frequency component in the scanning direction of the subject image or in a direction perpendicular thereto; . d. The first difference signal or the third difference signal and the second difference signal or the fourth difference signal are each multiplied by a constant, and these are multiplied by the first color signal, the second color signal, and the third difference signal. Luminance information forming means for forming the luminance information by adding it to a signal obtained by combining at least one or more of the color signals.