JP2003047014A - Imaging device - Google Patents

Abstract

(57) [Problem] To improve color reproducibility in an imaging device, when a luminance signal is generated from an RGB signal after nonlinear processing, a high-frequency component of the luminance signal deteriorates. A solid-state imaging device outputs pixel data obtained by mixing two pixels in a vertical direction, and the pixel data is output as a plurality of signals delayed by a predetermined line by a delay circuit. The YH generation means 12 generates a high frequency component YH of the luminance signal from the signal output from the delay circuit 11,
The means 13 performs gamma processing on the YH signal and outputs it as YHγ. The RGB generating means 14 generates an RGB signal from the signal output from the delay circuit 11, and the RGBγ means 15 performs γ processing on each of the RGB signals, and outputs signals Rγ, Gγ,
Bγ, and the matrix means 16 outputs the signals Rγ, G
A luminance signal YL and a color difference signal C are generated from γ and Bγ, and the luminance signal YL is added to YHγ by an adder 17 and output as a luminance signal Y.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus for generating a luminance signal and a color signal from RGB signals (three primary color signals).

[0002]

2. Description of the Related Art In recent years, image pickup devices such as video cameras and digital still cameras are required to have higher image quality.

An example of a conventional image pickup apparatus will be described below with reference to the drawings.

FIG. 9 shows the structure of a conventional image pickup apparatus. In FIG. 9, 90 is a delay circuit, 91 is a first matrix circuit, and 92 and 93 are LPFs (Low Pass Filters).
r), 94 is the second matrix circuit, 95, 96, 97
Is a gamma conversion circuit, 98 is a third matrix circuit, 99
Is an aperture correction circuit, 910 is a line memory, 911
Is an encoder.

The operation of the image pickup apparatus configured as described above will be described below.

First, in the delay circuit 90, a CCD (Charge Cou
The signal output from the pled device), the signal output from the CCD delayed by one horizontal scanning period, and the signal output further delayed by one horizontal scanning period are distributed to predetermined output terminals. The matrix circuit 91 outputs the first luminance signal Y1 and the color difference signals Cr, Cb, and the second matrix circuit 94 further outputs the first luminance signal Y1, LPF 92,
The color difference signals Cr and Cb passed through 93 are input to obtain RGB signals. Then, the RGB signals are subjected to non-linear processing by gamma conversion circuits 95, 96 and 97, and then converted into a second luminance signal Y2 and second color difference signals RY and BY by a third matrix circuit 98. , The second luminance signal Y2 is subjected to aperture correction by the aperture correction circuit 99, and the encoder 911 inputs the second luminance signal subjected to aperture correction and the second color difference signals RY and BY to output a video output. obtain.
As the conventional image pickup apparatus as described above, for example, Japanese Patent Laid-Open No.
There is one described in Japanese Patent Publication No. 14333.

[0007]

However, in the above configuration, since the RGB signals are generated by using the first luminance signal Y1 directly generated from the signal output from the CCD, the third matrix is generated. Although the second luminance signal Y2 generated in the circuit 98 is generated from the RGB signal, the color reproducibility is deteriorated, and the aperture correction is performed on the second luminance signal Y2. Besides, the line memory 910 is required, and when the circuit is configured, there is a problem that the circuit scale increases.

In view of the above problems, the present invention provides an image pickup apparatus which realizes color reproducibility faithful to a subject without reducing the circuit scale and degrading the frequency characteristic of the high frequency region of the high frequency component.

[0009]

In order to solve the above problems, an image pickup device of the present invention is a delay for outputting a plurality of signals obtained by delaying a pixel signal output from a solid-state image pickup device in units of one horizontal scanning period. A circuit, YH generation means for generating a high-frequency component (hereinafter, YH signal) of a luminance signal from a signal output from the solid-state image sensor and a signal output from the delay circuit, and a signal output from the solid-state image sensor. RGB generating means for generating R, G and B signals from the signal output from the delay circuit, and YH generated by the YH generating means.
YHγ means for performing gamma processing on the signal, RGBγ means for performing gamma processing on the signal generated by the RGB generating means, and a matrix for generating a luminance signal and a color difference signal from the R, G, B signals gamma processed by the RGBγ means. And a synthesizing means for synthesizing the luminance signal generated by the matrix means and the YH signal subjected to the γ processing by the YHγ means and outputting as a luminance signal.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a single-plate color image pickup device, a delay circuit for outputting a plurality of signals obtained by delaying a pixel signal output from a solid-state image pickup device in units of one horizontal scanning period, and the solid-state image pickup device. YH generation means for generating a high frequency component (hereinafter, YH signal) of a luminance signal from the signal output from the element and the signal output from the delay circuit, and the signal output from the solid-state image sensor and the delay circuit RGB generating means for generating R, G and B signals from the signal output from the above, YHγ means for performing a gamma process on the YH signal generated by the YH generating means, and a signal generated by the RGB generating means. RGBγ means for performing gamma processing, and matrix means for generating a luminance signal and a color difference signal from the R, G, B signals gamma processed by the RGBγ means. Wherein the γ processed YH signal from the matrix unit luminance signal generated from said YHγ means synthesizes and is obtained by a synthesizing means for outputting a luminance signal.

Further, in the above invention, the YH generating means generates a luminance signal by adding a signal output from the solid-state image pickup device and a signal output from the delay circuit between arbitrary adjacent pixels, and with respect to the luminance signal. The high frequency component is extracted and output.

Further, in the above invention, the RGB generating means extracts the low frequency component from the signal output from the solid-state image pickup device and the signal output from the delay circuit and outputs the LPF, and the signal output from the LPF. From R signal,
And a matrix circuit for generating the G signal and the B signal.

In the image pickup apparatus of the present invention having the above-described simple structure, the color signals are generated from the R, G, B signals, so that the color reproducibility is not deteriorated, and further, even in the high frequency component, Degradation can be prevented by the YH signal component.

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1 shows the configuration of an image pickup apparatus according to the first embodiment of the present invention. Figure 1
In the figure, 10 is a single-plate type solid-state image sensor (CCD), 11 is a delay circuit, 12 is YH generating means, 13 is YHγ means, 14 is RGB generating means, and 15 is RGBγ. Means, 16 is matrix means, and 17 is an adder.

The operation of the image pickup apparatus configured as described above will be described below with reference to FIGS. 1, 2, 3, and 4.

The solid-state image sensor 10 has pixel data YM (Ye (yellow) + Mg (magenta)), CG (Cy (cyan) + Gr (green)) obtained by mixing two pixels in the vertical direction,
YG (Ye + Gr) and CM (Cy + Mg) are output, and the pixel data output from the solid-state image sensor 10 is the delay circuit 1.
Signal L0 without delay by 1 and signal L delayed by 1 line
A signal L2 delayed by one or two lines, a signal L3 delayed by three lines, a signal L4 delayed by four lines, a signal L5 delayed by five lines, and a signal L6 delayed by six lines are output. The YH generation means 12 generates YH which is a high frequency component of the luminance signal from L0 to L6, and the YHγ means 13 performs gamma (γ) processing on the YH signal and outputs it as YHγ. RG
The B generation means 14 uses L0 to L6 to generate R (red), G (green),
The B (blue) three primary color signals are generated, and the RGBγ means 15 performs γ processing on each of R, G, and B to obtain Rγ, Gγ, and Bγ.
Output as.

The matrix means 16 includes Rγ, Gγ and Bγ.
The luminance signal YL and the color difference signal C are generated from the luminance signal YL
Is added to the signal YHγ by the adder 17 and output as the luminance signal Y. In the matrix means 16, the luminance signal Y
L is generated by the calculation shown in (Equation 1) below.

[0019]

[Equation 1]

FIG. 2A is an example showing the configuration of the YH generating means 12, 20 is the Y generating means, and 21 is the HPF.
(High Pass Filter). The Y generating means 20 outputs the luminance signals Y10 and Y1 from the outputs L0 to L6 of the delay circuit 11.
1, Y12, Y13, Y14 are generated, and the HPF 21 generates a signal YH which is a high frequency component of the luminance signal from the luminance signals Y10 to Y14.

FIG. 2B is a schematic diagram showing a method of generating the luminance signals Y10 to Y14 in the Y generation means 20. The signals L0 to L6 input to the Y generation means 20 are arranged in the horizontal direction by 5 pixels. The brightness signal Y
10 to Y14 are generated by adding horizontal 3 pixels for each pixel as shown by the thick frame in the figure.

FIG. 3 is an example showing the configuration of the RGB generating means 14, 30 is an LPF, and 31 is an RGB matrix for generating RGB signals.

The LPF 30 applies the LPF in the horizontal, vertical and diagonal directions from the signals of L0 to L6 to the signals of the same color to make YM.
L, CGL, YGL, and CML are output, and the RGB matrix 31 generates R, G, and B signals from the signal output from the LPF 30 by the calculation shown in (Equation 2) below.

[0024]

[Equation 2]

FIG. 4 is a schematic diagram of the processing in the LPF 30, and FIG. 4A shows a state in which the signals L0 to L6 input to the LPF 30 are arranged horizontally by 5 pixels, and FIG. ) Is a coefficient applied to each pixel shown in FIG. The LPF 30 has the same structure as the pixel shown in FIG.
The coefficient of (b) is multiplied, and the addition processing is performed with the same signals. Then, as shown in FIG. 4C, horizontal, vertical, and diagonal addition processing is performed, high-frequency components are suppressed in the horizontal, vertical, and diagonal directions, and low-frequency pixel signals YML and C
GL, YGL and CML are obtained.

As described above, according to this embodiment, the solid-state image pickup device 10, the delay circuit 11, and the YH generating means 12 are provided.
, YHγ means 13, RGB generating means 14, RGB
By providing the γ means 15, the matrix means 16 and the adder 17, the high frequency components (YH) of the luminance signal are the signals YM, CG, YG and C output from the solid-state image sensor 10.
The luminance signal is generated by adding M, and the low frequency component (YL) of the luminance signal is composed of the luminance signal generated based on (Equation 1) from the R, G, B signals after the γ processing. It is possible to realize faithful color reproduction for a subject by generating the color signal from the R, G, B signals after the γ processing by the matrix means without impairing the frequency characteristics of the captured image.

In the above embodiment, the Y generation means 20
Describes that Y3 to Y14 are added horizontally for each pixel to generate Y10 to Y14. However, the contents are limited to those described in the above-described embodiment, such as adding 2 horizontal pixels to each pixel to generate Y10 to Y14. Not a thing. Also, LPF30
Describes that the pixel shown in FIG. 4A is multiplied by the coefficient of FIG. 4B, but the coefficient by which the pixel shown in FIG. 4A is multiplied is not limited to the contents described in the above embodiment. .

(Second Embodiment) FIG. 5 shows a structure of an image pickup apparatus according to a second embodiment of the present invention. In FIG. 5, 50 is a solid-state image sensor (CCD), 11 is a delay circuit, 52 is YH generation means, and 13 is Y.
Hγ means, 54 is RGB generating means, 15 is RGBγ means, 16 is matrix means, 1
7 is an adder.

Delay circuit 11, YHγ means 13, RGBγ
The means 15, the matrix means 16 and the adder 17 are the same as those in the first embodiment, and detailed description thereof will be omitted.

The operation of the image pickup apparatus configured as described above will be described below with reference to FIGS. 5, 6, 7, and 8.

The solid-state image pickup device 50 has pixel data Mg (magenta), Gr (green), and Y arranged on the image pickup surface.
The pixel data that outputs e (yellow) and Cy (cyan) and is output from the solid-state image sensor 50 is a signal L0 without delay by the delay circuit 11, a signal L1 delayed by one line, a signal L2 delayed by two lines, and three lines Delayed signal L3,4
Line-delayed signal L4, line-delayed signal L5,
The signal L6 delayed by 6 lines is output. The YH generating means 52 generates a signal YH which is a high frequency component of the luminance signal from the signals L0 to L6, and the YHγ means 13 outputs the signal YH.
Gamma processing is performed on the output and YHγ is output. The RGB generating means 54 generates three primary color signals of R, G and B from the signals of L0 to L6, and the RGBγ means 15 performs γ processing on each of R, G and B and outputs them as Rγ, Gγ and Bγ.

The matrix means 16 generates a luminance signal YL and a color difference signal C from the Rγ, Gγ and Bγ signals, and the luminance signal Y
L is added to the signal YHγ by the adder 17 and output as a luminance signal Y.

FIG. 6A is an example showing the configuration of the YH generating means 52, 60 is the Y generating means, and 21 is the HPF.
Is. The Y generation means 60 is a signal L output from the delay circuit 11.
0 to L6 to luminance signals Y10, Y11, Y12, Y1
3, Y14 is generated, and the HPF 21 generates the luminance signals Y10 to Y.
A signal YH which is a high frequency component of the luminance signal is generated from 14.

FIG. 6B is a schematic diagram showing a method of generating the luminance signals Y10 to Y14 in the Y generation means 60. The signals of L0 to L6 input to the Y generation means 60 are horizontally arranged in 5 pixels. Represents the aligned state, the luminance signal Y
Each of 10 to Y14 is generated by adding horizontal and vertical four pixels for each pixel like a thick frame.

FIG. 7 shows an example of the structure of the RGB generating means 54. Reference numeral 70 is an LPF, and 71 is an RGB matrix for generating RGB signals.

The LPF 70 is a signal L output from the delay circuit 11.
From 0 to L6, signals of the same color are horizontally, vertically, and diagonally applied to the LPF, and output as MgL, GrL, YeL, and CyL, and the RGB matrix 71 is shown in (Formula 3) below from the signal output from the LPF 70. R, G,
B signal is generated.

[0037]

[Equation 3]

FIG. 8 is a schematic diagram showing processing in the LPF 70, and FIG. 8A shows L0 to L input to the LPF 70.
6 shows a state in which 5 signals are arranged in the horizontal direction by 5 pixels, and FIG. 8B shows a coefficient to be applied to each pixel shown in FIG. 8A. The LPF 70 multiplies the pixel shown in FIG. 8A by the coefficient shown in FIG. 8B, and performs addition processing on the same signals. Then, as shown in FIG. 8C, horizontal, vertical,
The addition processing in the diagonal direction is performed, high-frequency components are suppressed in the horizontal, vertical, and diagonal directions, and each pixel signal MgL in the low frequency band,
GrL, YeL and CyL are obtained.

As described above, according to the present embodiment, the solid-state image pickup device 50, the delay circuit 11, and the YH generating means 52.
, YHγ means 13, RGB generating means 54, RGB
By providing the γ means 15, the matrix means 16 and the adder 17, the high frequency component of the luminance signal is composed of the luminance signal generated by the addition of the signals Mg, Gr, Ye and Cy output from the solid-state image sensor. , The low-frequency component of the luminance signal is composed of the luminance signal generated based on (Equation 1) from the R, G, and B signals after the γ processing, without impairing the frequency characteristic of the captured image, and By generating the color signal from the R, G, B signals after the γ processing by the matrix means, it is possible to realize color reproduction faithful to the subject.

In the above embodiment, the solid-state image pickup device 50 has the pixel data Mg, G arranged on the image pickup surface.
Although it is described that r, Ye, and Cy are output, the pixel data arranged on the imaging surface is not limited to the contents described in the above-described embodiments, such as R, G, B, and G. Further, it is described that the Y generation means 60 adds horizontal and vertical four pixels for each pixel to generate signals Y10 to Y14, but for example, adds horizontal and vertical nine pixels for each pixel and signals Y10 to Y14.
The present invention is not limited to the contents described in the above embodiment, such as generating 14. Further, the LPF 70 has been described as multiplying the pixel shown in FIG. 8A by the coefficient shown in FIG. 8B.
The coefficient by which the pixel shown in (a) is multiplied is not limited to the contents described in the above embodiment.

[0041]

As described above, according to the present invention, the delay circuit for outputting a plurality of signals obtained by delaying the pixel signal output from the solid-state image pickup device in units of one horizontal scanning period, and the signal output from the solid-state image pickup device. And YH generation means for generating a high frequency component (YH signal) of the luminance signal from the signal output from the delay circuit, and R, G, B from the signal output from the delay circuit.
RGB generating means for generating a signal, YHγ means for performing γ processing on the YH signal generated by the YH generating means, and R
R for performing γ processing on the signal generated by the GB generating means
GBγ means and R, G, which have been subjected to γ processing by the RGBγ means
Matrix means for generating the luminance signal YL and the color difference signal C from the B signal, and the luminance signal Y generated by the matrix means
By providing a means for synthesizing the Y and YH signals that have been subjected to the γ processing by the LH and YHγ means, it is possible to realize color reproducibility faithful to the subject without degrading the frequency characteristics of the high frequency region of the high frequency component.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an image pickup apparatus according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a configuration and an operation of a YH generation unit of the imaging device.

FIG. 3 is a block diagram showing a configuration of RGB generating means of the image pickup apparatus.

FIG. 4 is a schematic diagram illustrating a process in an LPF of an RGB generating unit of the image pickup apparatus.

FIG. 5 is a block diagram showing a configuration of an image pickup apparatus according to a second embodiment of the present invention.

FIG. 6 is an explanatory diagram of a configuration and an operation of a YH generation unit of the imaging device.

FIG. 7 is a block diagram showing a configuration of RGB generating means of the imaging device.

FIG. 8 is a schematic diagram illustrating a process in the LPF of the RGB generation unit of the imaging device.

FIG. 9 is a block diagram showing a configuration of a conventional imaging device.

[Explanation of symbols]

10 Solid-state image sensor 11 Delay circuit 12 YH generation means 13 YHγ means 14 RGB generating means 15 RGBγ means 16 Matrix means 17 adder

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yasutoshi Yamamoto             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F term (reference) 5C065 AA01 BB19 CC01 DD02 GG01                 5C066 AA01 CA08 EE02 KM02

Claims (3)

[Claims] 1. A single-plate color imaging device, a delay circuit for outputting a plurality of signals obtained by delaying a pixel signal output from a solid-state imaging device in units of one horizontal scanning period, and a signal output from the solid-state imaging device. And the high frequency component of the luminance signal (hereinafter referred to as YH) from the signal output from the delay circuit.
YH generation means for generating a signal), RGB generation means for generating an R signal, a G signal and a B signal from the signal output from the solid-state image sensor and the signal output from the delay circuit, and the YH generation means. YHγ means for performing gamma processing on the generated YH signal, RGBγ means for performing gamma processing on the signal generated by the RGB generating means, and R, G, B gamma processed by the RGBγ means.
Matrix means for generating a luminance signal and a color difference signal from the signal, and a synthesizing means for synthesizing the luminance signal generated by the matrix means and the YH signal subjected to the γ processing by the YHγ means and outputting as a luminance signal. Imaging device. 2. A YH generating means adds a signal output from a solid-state image sensor and a signal output from a delay circuit to adjacent pixels to generate a luminance signal, and extracts a high frequency component from the luminance signal. The image pickup apparatus according to claim 1, wherein the image pickup apparatus outputs the image. 3. An LPF for extracting low-frequency components from a signal output from a solid-state image sensor and a signal output from a delay circuit by an RGB generator, and outputting the LPF, and an R signal, G from the signal output from the LPF. The image pickup apparatus according to claim 1, comprising a matrix circuit for generating a signal and a B signal.