JPS61220581A - Signal processing circuit for image pickup device - Google Patents

Abstract

PURPOSE:To obtain a single tube or single plate color image pickup device with high quality picture by synthesizing a wide band chrominance signal by mixing the high area component of a luminance signal with the low area component of the chrominance component in a prescribed ratio and composing the luminance signal by gamma-processing of this wide band chrominance signal. CONSTITUTION:The high area component YH of the luminance signal and the low area components YL, RL and BL of each chrominance signal are obtained from a luminance signal Y and chrominance signals R and B that are obtained and separated from a single plate color image pickup element, by a BPF1A and an LPF1B, an LPF1C and an LPF1D. The low area components YL, RL and BL are added to a matrix circuit 2 and a GL component is synthesized. And at adders 3A, 3B and 3C, the luminance signals GL, RL and BL and the high area component YH of the luminance signal are added and wide band signals G, R and B are obtained from the adders. These wide band signals, after they are gamma-corrected by gamma correction circuits 4A, 4B and 4C, are added to an encoder 5 and a luminance signal and color difference signals I and Q are synthesized.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a deck or rl'i tube color imaging device.1-1 Particularly to improvement of a signal processing circuit and an optical low-pass filter of a single-tube color imaging device that spans a middle plate. Seki 1-ru.

BACKGROUND ART At least two types of hli color signals (complementary color signals specify a yellow signal Ye, a noan signal Cy, and a full color color signal -W).

Of course, each complementary color signal may contain a small amount of the golden U component. ) occur! 1'J plate or 1p tube color imaging devices are well known. Generally, the above three complementary color pixels (Y
A complementary color pixel array (abbreviated as complementary color array) comprising one green pixel G and one green pixel G is well known.
Three- and four-color complementary color arrays, hereinafter referred to as four-color complementary color arrays, are widely used in single-panel or single-tube color imaging devices. In addition, each pixel row has three types of color pixels,
An Mli color arrangement in which at least two types of color pixels among the three types of color pixels described above generate complementary color signals is also well known, and will be described below.
It is abbreviated as a three-color complementary color arrangement. - In the above-mentioned single-chip color or QJ tube color imaging device having a three-color or four-color complementary color arrangement, the low frequency component of the video signal received from the imaging device is generally used as a luminance signal. Koi 1
This is to obtain maximum luminance resolution. In order to separate a predetermined color signal from the above-mentioned imaging device, multiple color separation methods are used.The main first color separation method is a frequency separation method, and the video signal output from the imaging device The red and blue signals are separated from the high-frequency components of the signal.The second color separation method is a phase separation method, in which each color pixel signal is separated in turn by a switch or sample Frebold circuit.

Then, the separated color pixel signals are added and subtracted to synthesize a predetermined color signal. In single-tube color imaging devices, a four-color complementary color array is generally used, and the odd (even) circle element is Y (!
, Cy are arranged in an intersecting rlH, and the even (odd) circular elements are G,
W is arranged at intersection Tl:. A single-tube color imager with a three-color complementary color array is also possible, but the luminance resolution will be reduced.

In the deck color solid-state image sensor, a four-color complementary color array and a three-color complementary color array are used. The disadvantage of a single-chip color image sensor with a three-color complementary color array is that it has a small luminance resolution.
A technology in which the color pixels of a pixel row are arranged horizontally displaced by a 1/2 pixel pitch, and the signals and charges of two adjacent pixel rows are output independently in one horizontal scanning period (hereinafter referred to as Frame 1, output technology). ) or is solved by f. The first in deck color solid-state image sensors
In the four-color complementary color arrangement, the odd (even) numbered circular elementary rows are arranged alternately as Ye and G (W), and the even (odd) numbered circular elementary rows are arranged as CY, W (G
) are arranged alternately, and the added signals of two vertically adjacent pixel rows are approximately the luminance signal Y='/c+cy=c
This is a complementary color array with −+w. For example, JP 58-175
In the first four-color complementary color array disclosed in 864, a frame output technique is used.

In the second four-color complementary color array, odd (even) yJi pixel rows are Y e,
It is a complementary color arrangement in which Cy is arranged alternately, and even (odd) circular element rows are arranged alternately in G and W. For example, equity 56-3
In a second four-color complementary color arrangement disclosed in US Pat. In the third four-color complementary color arrangement, odd (even) numbered circular element rows are arranged with Ye and Cy alternating,
Even (odd) circular pixel rows are arranged alternately in G and W, and the Nth pixel row is a complementary color arrangement that is displaced by one pixel pitch in the horizontal direction with respect to the N@2 pixel row. For example, JP60-3'2
In the third complementary color array disclosed in No. 90, signal charges of two vertically adjacent pixel rows are mixed and output.

This signal output technique is abbreviated as field storage/single line output technique. In a conventional single-tube color or single-chip color imaging device, the above-mentioned image is obtained by using the low-frequency component of the video signal output from the imaging device, the luminance signal Y, and the frequency separation or phase separation technique described in I-). red isolated from traffic light, 1
1r Shinshu - low frequency components RL, BL to color 1'
V Shinfan (eg λPoY, 1.Q,) is synthesized. in general,
1. Low-frequency components YL and F of the luminance signal Y shown below, BL
The color difference signals 'YeL-Y L, BL -Y L are synthesized from the luminance signal (8-'+'Y and - from the above two types of color difference signals U), and the color 'r■ signal is synthesized from the above two types of color-difference signals U. .Color with good linearity] ゛■ To output a signal, -1'-
-゛ In conventional imaging devices, the above Y, T, L, HL or Y H, Y
L, TIL.

+31. were each subjected to gamma correction. Tatashi Y
IT is a high frequency component of luminance signal 1-Y. 1. However, this gamma compensation 1 [:, method is R9, B signal] is respectively A
Compared to the gamma correction IO method that uses 1 gamma correction and 2 gamma correction,
Since it generates an error signal, it is compared to a three-tube imaging device.1. However, there was a problem with the brightness signal or color signal. In order to improve this drawback, JP-A-60-313
86 and 'r' v academic journal VOL, 37. No I O
, 773 pages, + 9841' V Society National Conference Proceedings, 98 [f is the low-frequency component of red, blue, and green signals.
B.L., G.T.

Separate and gamma correct the above RL, BL, GL to create complementary L', BL', GLo, and use the gamma from RL', +1 L', GLo in The low-frequency component YL' of the rF-compensated luminance signal is synthesized, and
．． YL' above.

Two color difference signals RL"-YT from IEL" and I3L'
, ', BL'-YL' is disclosed.

In this way, the linearity of the bow can be improved. However, the above linearity improvement 9% technology has L'
−10, I I Rr, ゛, the low frequency component Y'L of the luminance signal Y° created by gamma-correcting the wideband luminance signal Y
This has the disadvantage that there is an error in the reproduced color signal because of the difference in color signals. In order to improve this drawback, JP-A-60-3290
L1 separated YLJ collar, BL Gara GI, total synthesis L, Sol, Tel-written) RL, BT, , , G
Gamma correct each L to RL", RL', GL"
and YL from RL', BL', GL' written in
', and the above YL', TIL'
, +3L', low-frequency components Yl,° of the gamma-corrected luminance signal and two types of color difference signals R7'-YL', L'-YL' are generated. JP-A-6O-32QO has the high-frequency component YTl of the broadband luminance signal No. 5 Y, which is the low-frequency component of the video signal output from the imaging device, and YL', RL of 1.
'YL', RT, °-YI,.

The high-frequency component Y11 of the above broadband luminance signal Y was added to R L , B L , and G L separated for Elan Sodeichi by 1-7. Later, we will disclose the implementation of gamma hfr IT.

Japanese Patent Application No. 59-69836.1 filed based on the present invention
06!197, 168434, and 207729 are prior inventions of the present invention.

DISCLOSURE OF THE INVENTION (Problems with the Prior Art) Despite the prior art described in the section, a solution is needed in order to generate a good color 1゛v signal from a single tube color or TL imager. There's a problem. The first problem is to improve the linearity of the high-frequency component Y of the luminance signal 73-y. Conventionally, YH uses the high-frequency component Y'II of the gamma-corrected luminance signal Y'. As a result, the linearity of the high-frequency component YH of the reproduced luminance signal Y was poor.The second problem is that the conventional (n-tube color or () middle plate non-color imaging device Since the luminance signal or color signal is synthesized using , false signals may occur when the vertical correlation of light is small.

(Objectives of the Invention) The present invention aims to solve these problems 1-1 by improving the image quality of a single-tube color or deck color imaging device. In order to achieve the object of paragraph I-, two individual claims are disclosed. The basic features of the invention are explained below.

(1) Complementary color signals of at least two scales (hereinafter F,
Complementary color signals are either red or green (both J and
Please specify the traffic lights that include green lights. ), from the video signal output from the deck or single-tube color imaging device, at least the low-frequency components of the optical signal, the low-frequency components of the front signal, and the low-frequency components of the green signal are separated, and the above-mentioned In a signal processing circuit for an imaging device that separately gamma-processes the low-frequency components of three types of color signals, the high-frequency components of the luminance signal are mixed with the low-frequency components of the red, blue, and green signals at a predetermined ratio. and synthesize broadband red, blue, and green signals 12. Part 1. The broadband red, blue, and green signals described above are gamma-processed separately, and the gamma-processed red, blue, and green signals described in I-1 are substantially used to generate the luminance signal. Yok is a signal 1.H processing circuit of an image pickup device characterized by a 4-LC which synthesizes the high-frequency components.

(2), by mixing the high frequency components of the luminance signal with the low frequency components of the red, blue, and green signals listed in l- in approximately the same ratio, -1
The wideband three color signals described above are synthesized, each of the wideband three color signals is subjected to gamma processing, and the gamma-processed three color signals 1j are substantially used to generate a luminance signal. 2. The signal processing circuit for an imaging device according to claim 1, characterized in that the signal processing circuit synthesizes a high-frequency component of the signal processing circuit or the high-frequency component thereof.

(3) Separate each color pixel signal from the video signal output from the 'l'I plate color solid-state image sensor, and separate each color pixel signal from the wideband luminance signal, wideband red signal, and wideband 1 to the above broadband luminance signal, and separate the broadband green signal from the broadband red signal, and ), the broadband red signal, and the broadband red signal. i't, the green signal are each gamma-processed separately, and the luminance signal or its high-frequency component is synthesized by substantially using only the gamma-processed three fish signals listed in item 1. A signal processing circuit for an imaging device according to item 1.

(4) A signal 8-processing circuit for an imaging device according to any one of the first, second and third items, characterized in that it processes a video signal U output from an imaging device having four color pixels.

(5) A signal processing circuit for an imaging device according to any one of the first, second, and third items, characterized in that the signal processing circuit processes a video signal output from a single-plate color solid-state imaging device having three color pixels.

(6) In a single-chip color solid-state imaging device that mixes the signal charges of two adjacent pixel rows in one field period and outputs them separately, and is equipped with an optical low-pass filter, the above-mentioned optical low-pass filter splits light diagonally 1■
A single-chip color solid-state imaging device.

(7) The optical low-pass filter described in I-- generates two spectra that are approximately 1 pixel pinch apart in the vertical direction and (7) separated by approximately 1 pixel pinch or 0.5 pixel pitch in the horizontal direction. 7. The single-chip color solid-state imaging device according to item 6.

Detailed features and advantages of the invention are described below.

Kureno, 1 Conventional? The high frequency component Y'1l of the luminance signal p3 y' output from the 11-tube color or medium-plate color imaging device = (0
,3R罎0 59G-I O,I In)'tl is the luminance signal Y'lT -0,3R output from the three-tube camera
'l140.

5': J G'1T-1-0, ] IIB'l-T. However, the above II represents the high frequency component of the signal. For example, Q'+tube color or (J single tube color imaging device has Y'1l=(0, I I
Generates I()II and Y'1 when red light or human power is applied.
Output l=(0,3R)'H. Similarly, for the three-tube color camera, Y'LI=0°11 R'T1. Y'H-0, 3
Output R'TI. The error in Y11 shown in 1 is very large, and only when the golden light W (Y=11.G..B) is input, the two coincide.

In order to improve the above-mentioned drawbacks, a single-tube color or Iljl power plate-video signal 2 output from the image pickup device (from the low-frequency component RL of the red signal, the low-frequency component GL of the green signal
, separates the low frequency component BL of the green signal, and RI as described below,
, I(L, GL is the high frequency component of the luminance signal YT
1 at a predetermined ratio, a wideband three-color signal R=R
L-14] XYI(,G=OL102 XYI-T,
Synthesize 3XYT-1 to R=BL+, and then synthesize the above R
, G, and B are each gamma corrected to become R'', G'
, B', and synthesizes the high frequency component Y' TI of the luminance signal Y' from -1 TI'', G, and n.Generally, Y'TI=0.3°H+0 .59G'
ll+0. I IR'll.

In this way, the high-frequency component Y'H of the luminance signal of a single-tube color or single-chip color imaging device becomes Y' of a three-tube camera.
Very similar to TI.

Claim 2 In a preferred embodiment of claim 1, RL.

Y T-1 approximately equal to G L and B L is mixed. In this way, RI(= GI(= B H
It can output the same color output as a human-powered three-tube camera.

Claim 3 In a preferred embodiment of claim 1, broadband R9c is obtained from each color pixel signal of a single-chip color imaging device.

The B signal is separated, and Y'H is synthesized by gamma-correcting the broadband R, G, and B signals, respectively. In this way, the linearity of Y''I4 becomes almost the same as that of a three-tube camera.In one aspect of this embodiment, by reducing the wideband R1+(-) from the wideband luminance signal C Please create a broadband green signal G.

In another aspect of this embodiment, broadband TI, G, B (in or separated by A1, or by one minute apart from each color pixel signal output from the +1'J-plate color image pickup device) is obtained. Also, the luminance signal Y produced from the I, G, and II signals is substantially the same as the luminance signal Y produced directly from the intermediate color imager.

Claim 4: Can be used in a single-tube color or single-plate color imaging device with a 4-color hli color arrangement.

Clay L 5 Claim 1 has a three-color complementary color arrangement (can be used in 11-color solid-state image pickup devices).

Claim [i clay lb I ij especially signal type 6 of two adjacent pixel rows
: Suitable for a jp-plate color solid-state image sensor that outputs jp images mixedly or independently. 1. However, the deck color solid-state image sensor f- described in I. generates false luminance or color signals when two adjacent pixel rows have a small vertical correlation. In order to improve this drawback, the CJ of the present invention is characterized in that the optical low-pass filter is arranged diagonally.

If you do this, it will be possible to reduce both the high frequency component in the horizontal direction and the heavy component in the superposition direction of the light. Conventionally, it has been proposed to use two filters for this purpose, but according to the present invention, expensive filters can be saved.3, Clay 1.7 Preferred embodiment of claim 6 In, 1. The filter described above separates the human body's 1 or 05 pixel pitch light in the horizontal direction, and separates the light by approximately 1 pixel pitch in the vertical direction. In this way, moiré is greatly reduced.

Other features and advantages of the invention are illustrated by the following examples.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a signal processing circuit for a deck color solid-state image pickup device representing one embodiment of claim 1. A luminance signal Y, a red signal R, and a blue signal B are separated by a well-known method from the video signal (borrowed from each color pixel) output from the solid-state image sensor. Y T, D, L P separated by L P F I R
Iya I7 separated by P I C and L P Ii”
ID is separated and 8 r (L is converted into GL by matrix circuit 2. Each of the low-pass filters L P F has a pass band of 0.5 MIIz.
Δ(pass band 0.5MHz to 3.2M I-T
Y II separated by Z) is an adder circuit 3Δ, 1B, 3G
Then, the broadband color signals R1G, +( outputted from the adder circuits 3A, 31(, 3C) are mixed into the above RL, C1, , I(L), respectively.
/IC performs gamma correction and inputs manually to encoder 5.

And the encoder 5 outputs luminance signals Y'-0, 3R'-+
0.59G'10, I In'' and color difference signals 1', Q'
Or R'-Y', B'-Y' is LPF6A (3,2M
11z) and L P F f31(,6G(0,5MHz
). In FIG. 1, the gamma correction circuit 4
G', R', T output from Δ, 4B, 4C
It is possible to create color difference signals R'L-Y'L and R'L-Y'L by band-limiting each 3° to 0°5 MHz. - The problem is that the luminance signal Y or its high-frequency component YI- (or their gamma correction signals Y', Y'l+) cannot be input manually to Goo-5. Inputting the part does not substantially change the gist of the present invention, i.e.,
The basic principle of the present invention is to synthesize the high-frequency component Y'H of the gamma-corrected luminance signal +1-Y' from the gamma-corrected color signals R', G', and 13° output from the gamma correction circuits 3A, 3R, and 3G. It is a characteristic. FIG. 2 is a signal processing circuit diagram representing another embodiment of the present invention. A wide-band luminance signal Y, a wide-band red signal R, and a wide-band front bow B are separated from each color pixel signal output from the Li plate color solid-state image sensor, and the LPF has a passband of about 3.2 MHz. I
The above Y is band-limited by A, I C, and I D.

R,! 3 is converted into a broadband green signal G by a matrix circuit 2. Then, the above R, G, and B signals (are gamma compensated by gamma correction circuits 4Δ, 4B, and 4C, respectively).Then, they are input to the encoder 5 later.Then, Y' output from the encoder 5, T' and Q' are each L P
F 6Δ(32Ml-1z), LPP6B, 6C(0,
5MHz). In this example,
The high-frequency components of G', R', and R' include moire components, but the moire components of each color signal cancel each other out, so the above G'
The moire component of Y' TI synthesized from H, R'H, B''II is small.
It is possible to omit C2ID. In another embodiment, it is possible to directly synthesize a broadband green signal from each color pixel array map output from a solid-state image sensor.

In this embodiment as well, the high-frequency components of each color signal have moire, but the mole of the high-frequency component YTr of the luminance signal synthesized from these color signals is small. 4 is an example of a four-color complementary color arrangement suitable for the deck color solid-state image sensor of the present invention, in which two adjacent pixel rows are output in parallel during one horizontal scanning period, and each color pixel signal is transmitted through a switch or a sample bold circuit. separated by Frequency separation is also possible.

Also, perform addition/subtraction for color separation after band-limiting each pixel portion of the same color using LPI.

In this case as well, the moire is offset. Figure 5 shows the Qi of the present invention.
This is another example of a four-color complementary color arrangement suitable for a plate color solid-state image sensor. The (ffi) charges of two adjacent pixel rows are mixed and output. FIG. 6 shows a three-color complementary color arrangement suitable for the single-chip color solid-state image sensor of the present invention. The signal in the 4-row 2 pixel row is output to the ``)-charge'' column. Fig. 7 is a cross-sectional view of one embodiment of a deck color camera explaining claim 6. A lens 7, a crystal filter 8, and an infrared filter The signal light 11 is manually applied to the solid-state image sensor 10 via 1.9. The signal light 11 separated by the filter 8 is applied to two-color pixels (4, vertically adjacent C and diagonally adjacent).

[Brief explanation of drawings]

1 and 2 are respectively communication processing circuit diagrams representing one embodiment of the present invention. 3, 3, 4, 5, and 6 are diagrams of a deck color solid-state image sensor suitable for the present invention. FIG. 2 is a color pixel array diagram showing a complementary color array of FIG. FIG. 7 is a sectional view of one embodiment of a known 111-plate color camera. Figure 8 ("Color pixel distribution of the deck color solid-state image sensor in Figure 7)
B around the time

Claims (7)

[Claims] (1), at least two types of complementary color signals (in the following,
The complementary color signal specifies a signal that includes either a red signal, a blue signal, or both, and a green signal. ) is used to separate at least the low-frequency components of the red signal, the low-frequency components of the blue signal, and the low-frequency components of the green signal from the video signal output from the single-chip or single-tube color imaging device that generates the above three types of color signals. In a signal processing circuit for an imaging device that separately gamma-processes the low-frequency components of the luminance signal, the high-frequency components of the luminance signal are mixed with the low-frequency components of the red, blue, and green signals at a predetermined ratio, and a wideband red signal is generated. , synthesize the blue and green signals, and gamma-process the broadband red, blue, and green signals separately, and use virtually only the gamma-processed red, blue, and green signals to generate the luminance signal. Or a signal processing circuit for an imaging device, which is characterized by synthesizing the high-frequency components thereof. (2) Mix the high-frequency components of the luminance signal with the low-frequency components of the red, blue, and green signals in roughly the same proportions to synthesize the three wide-band color signals, and then synthesize the three wide-band color signals. The signal of the imaging device according to item 1, characterized in that each color signal is gamma-processed, and the luminance signal or its high-frequency component is synthesized by substantially using only the gamma-processed three color signals. processing circuit. (3) Separate each color pixel signal from the video signal output from the single-chip color solid-state image sensor, and synthesize a wideband luminance signal, a wideband red signal, and a wideband blue signal from each separated color pixel signal, and Separate a broadband green signal from the broadband luminance signal, broadband red signal, and broadband blue signal, and gamma-process the broadband red, blue, and green signals separately, and 3
2. The signal processing circuit for an imaging device according to claim 1, wherein the signal processing circuit for an image pickup device is configured to synthesize a luminance signal or its high-frequency component by substantially using only a color signal. (4) A signal processing circuit for an imaging device according to any one of the first, second, and third items, characterized in that the signal processing circuit processes a video signal output from an imaging device having four color pixels. (5) A signal processing circuit for an imaging device according to any one of the first, second, and third items, characterized in that the signal processing circuit processes a video signal output from a single-plate color solid-state imaging device having three color pixels. (6) In a single-chip color solid-state imaging device that outputs the signal charges of two adjacent pixel rows together or separately in one field period, and is equipped with an optical low-pass filter, the above-mentioned optical low-pass filter filters light. A single-chip color solid-state imaging device that is characterized by dispersing light in diagonal directions. (7) The above optical low-pass filter is characterized in that it generates two spectral lights that are vertically separated by about one pixel pitch and horizontally separated by about one pixel pitch or about 0.5 pixel pitch. 7. The single-chip color solid-state imaging device according to claim 6.