JPH0581114B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an accumulation type color image sensor in which color signals of the same color in one pixel are added and read out.

[Prior Art] Recent color printers classify original color images (color negative film, etc.) into multiple scenes, select a predetermined color filter according to each scene, perform color correction, and produce prints with good color balance. I'm trying to get pictures. For this scene classification, the three-color density (blue density, green density, red density) obtained when the transmitted light of the color original image is averaged and the three-color density of the transmitted light at each point are used. The standard type is one in which the three-color density of the average transmitted light is almost constant, and control is performed so that the sum of the three-color light components of the print light transmitted through the color original image becomes gray. If the three-color density of the average transmitted light is abnormally biased, it is determined that there is a color defect.
Using characteristics such as pixel tint and the relationship between screen position and tint (balance of three color density), etc., it is classified into those that cause color fade, those shot under fluorescent lights, etc., and Perform appropriate color correction.

For the above-mentioned scene classification, a photographic image density information recording device is used to divide the original color image into about 100 to 200 pixels and measure the tint of each pixel. Therefore, when measuring the tint of a pixel, it is important to ensure that there is no deviation in color registration.

Storage type color image sensors such as CCD type, MOS type, and CPD type are widely used for image reading. This is a structure in which, for example, a blue filter, a green filter, and a red filter are attached in a mosaic shape on top of each photoelectric conversion unit, and three-color light is photoelectrically converted with one sensor.

[Problem that the invention seeks to solve]

However, when measuring an image with this single storage color image sensor, each photoelectric conversion unit measures light at a different position in the image, which essentially causes a shift in color registration. It was not possible to accurately measure the color tone of pixels.

SUMMARY OF THE INVENTION An object of the present invention is to provide an accumulation type color image sensor that can measure the color components of each pixel without being affected by color registration deviations.

[Means for solving problems]

In order to solve the above problems, in the present invention, three
Three types of photoelectric conversion units that photoelectrically convert and store primary color light are arranged alternately in a matrix, and a plurality of these multiple types of photoelectric conversion units are combined to form one pixel. It is designed to read out by adding things. In order to include two or more photoelectric conversion units of the same type in one pixel, they are grouped into M rows and N columns (one of M and N is an integer of 3 or more, and the other is an integer of 2 or more). Each pixel is defined as one pixel. In addition, the number of pixels is determined depending on the purpose of measurement, but in special cases,
It is also possible to measure the color components of the entire screen by using the entire screen as one pixel.

The colored lights include combinations of blue, green, and red, and combinations of cyan, magenta, and yellow, and the present invention can be used for any of these combinations, and is not specific to these. For example, a skin color may be added.

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

〔Example〕

FIG. 2 shows an example of the arrangement of photoelectric conversion sections of the storage type color image sensor of the present invention.
The storage color image sensor 10 includes a blue photoelectric conversion section 11 that photoelectrically converts blue light and stores it, and a green photoelectric conversion section 1 that photoelectrically converts and stores green light.
2. Red photoelectric conversion units 13 that photoelectrically convert red light and store it are alternately and regularly arranged. In order to eliminate deviations in color registration, the pixels are grouped into M rows and N columns, and each group constitutes one pixel. One of these integers M and N is 3 or more, and the other is 2 or more, so that two or more photoelectric conversion units of the same color are included in one pixel. In this embodiment, one pixel 10a is composed of a total of nine photoelectric conversion units, three for each color, grouped into three rows and three columns. In the drawing, 1
The photoelectric conversion numbers 11 to 13 are surrounded by dotted lines,
One pixel 10a is surrounded by a solid line.

FIG. 1 shows the basic structure of a storage type color image sensor. Within one pixel, signal charges accumulated in photoelectric conversion sections of the same color are simultaneously read out and added by an addition section. That is, the signals read out from the three blue photoelectric conversion units 11 are as follows:
The signals added by the adder 15 and read from the three green photoelectric converters 11 are added by the adder 16, and the signals read from the three green photoelectric converters 11 are as follows: The addition unit 17 adds the values. Note that the adders 15 to 17 may be provided not only for each pixel but also for each column or row of pixels. Furthermore, the addition section may be provided outside the storage color image sensor.

FIG. 3 shows a specific configuration of the present invention. The photoelectric conversion section 11 for blue, the photoelectric conversion section 12 for green, and the photoelectric conversion section 13 for red are composed of equivalently expressed photodiodes 21 to 49 and a filter, and photoelectrically convert incident light. , the obtained signal charge is stored in a floating capacitor. Here, photodiodes 21, 24, 2
9, 32, 34, 37, 38, 41, 45, 48
is for blue color, and photodiodes 22, 25,
33, 35, 36, 39, 42, 47, 49 are for green, and photodiodes 23, 2
6, 27, 28, 30, 31, 40, 43, 4
4 and 46 are for red. In order to read out the signal charges accumulated in these photodiodes 21-49, vertical MOS switches 51-79 are connected in series with each photodiode 21-49, respectively.

In this embodiment, since one pixel is composed of three rows, three vertical selection lines 82a to 82c from the top
is connected to the first one of the vertical scanning shift register 85.
It is connected to the output terminal D1 of the second stage. This vertical selection line 82a has vertical MOS switches 51 to 5.
6 gates are connected to each other. Further, the vertical selection line 82b is connected to the vertical MOS switches 57 to 57.
62 gates are connected to each other. Furthermore,
A vertical MOS switch 63 is connected to the vertical selection line 82c.
~67 gates are connected respectively.

In order to read out the signals of each pixel belonging to the second row, the fourth to sixth vertical selection lines 83
a to 83c are wired and then connected to the second stage output terminal D2 of the vertical scanning shift register 85. These vertical selection lines 83a to 83c,
Similarly to the vertical selection lines 82a to 82c described above, the gates of the vertical MOS switches 68 to 79 are connected to each other.

A horizontal selection line 86a for blue, a horizontal selection line 86b for green, and a horizontal selection line 86c for red are wired next to the photodiodes in the first row, and vertical MOS switches of the corresponding colors are connected to them. There is. Also, next to the photodiodes in the second row, three horizontal selection lines 87a to 87 are provided for each color.
c is wired. Similarly, three horizontal selection lines 88a to 88 are placed next to the photodiodes in the third column.
c is wired, and three horizontal selection lines 89a to 89c are wired beside the photodiode in the fourth column. Since the fifth and subsequent columns are also the same, only the reference numerals are given and the explanation is omitted.

In order to add and extract color signals of the same color contained in the same pixel, the blue horizontal selection lines 86a, 87a, and 88a are connected, and the blue horizontal selection lines 86a, 87a, and 88a are connected to each other.
MOS switches 95a are connected in series.
Similarly, green horizontal selection lines 86b, 87b, and 88
b is connected, and a green horizontal MOS switch 95b is connected in series to this. Furthermore, the red horizontal selection lines 86c, 87c, and 88c are connected, and a red horizontal MOS switch 95c is connected in series thereto. These horizontal MOS switches 95
The gates of a to 95c are wired and then connected to the first output terminal D1 of the horizontal scanning shift register 97.

Similarly, for the pixels in the second column, a horizontal MOS switch 96a for blue, a horizontal MOS switch 96b for green, and a horizontal MOS switch 96c for red are provided in order to add and extract the values for each color.
These horizontal MOS switches 96a-96c are wired together and then connected to the second output terminal D2 of the horizontal scanning shift register 97.

The horizontal MOS switches 95a to 95c, 96
The drains of a to 96c are respectively connected to output lines 98a to 98c provided for each color. That is, the blue horizontal MOS switches 95a and 96
a is connected to the blue output line 98a, and green horizontal MOS switches 95b and 96b are connected to the green output line 98b. Similarly, horizontal for red
MOS switch 95c, 96c is red output line 9
Connected to 8c.

Next, the operation of the circuit shown in FIG. 3 will be explained. Colored light passes through a filter to photodiode 2
1 to 49, a photocurrent corresponding to the incident light is generated, and signal charges are accumulated in the floating capacitor. The signal charges accumulated in each floating capacitor are scanned and read out by a vertical scanning shift register 85 and a horizontal scanning shift register 97.

When reading out the signal charges, the vertical scanning shift register 85 first outputs a vertical scanning pulse to its first stage output terminal D1. In this state, the horizontal scanning shift register 97 outputs the output terminal D1.
Shift the horizontal scanning pulse from D2 to D2. First, when a horizontal scanning pulse is output from the first stage output terminal D1, the horizontal MOS switch 95
a to 95c are turned on, and vertical MOS switches 51 to 53, 57 to 59, and 63 to 65 are also turned on. As a result, signal charges within one pixel arranged in three rows and three columns are read out simultaneously. At this time, since the horizontal selection lines are connected for each color, the signal charges accumulated in the blue photodiodes 21, 29, and 34 are added to the blue horizontal selection lines.
Blue output line 98 via MOS switch 95a
It will be output from a. At the same time, the signal charges accumulated in the green photodiodes 22, 33, and 35 are added and output from the green output line 98b via the green horizontal MOS switch 95b. Furthermore, a red photodiode 23,
The signal charges accumulated in 27 and 28 are added and output from the red output line 98c via the red horizontal MOS switch 95c. This results in 3×3
The signal charges accumulated in each photoelectric conversion unit belonging to one pixel are simultaneously read out, added up, and then taken out separately for each color.

Next, the horizontal scanning shift register 97 outputs a horizontal scanning pulse from the second output terminal D2,
Turn on horizontal MOS switches 96a to 96c at the same time
let As a result, the nine photoelectric conversion units belonging to the pixel in the first row and second column are simultaneously scanned, the outputs of each photoelectric conversion unit are added for each color, and then the output lines 98a to 98c are Take out each piece separately.

When the scanning of the horizontal scanning shift register 97 is completed, the reading of the signal charges of each pixel in the first row is completed. Next, the vertical scanning shift register 85
outputs a vertical scanning pulse from output terminal D2,
In this state, the horizontal scanning shift register 97 performs one scan, thereby sequentially scanning the pixels in the second row from the first column, adding the three color signals of each pixel, and then taking out the pixels. Thereafter, each pixel is scanned in the same way, signals are added for each color, and this is added to the output lines 98a to 98.
It is taken out from 8c.

In the above example, it is a MOS type, but this
It may be a CCD type or the like. In this CCD type, signals can be added by partially stopping transfer and adding signal charges that have been shifted later.

〔Effect of the invention〕

In the present invention having the above configuration, three types of photoelectric conversion units that photoelectrically convert and accumulate three primary color lights are arranged in a matrix, and M columns and N columns (M and N are integers of 3 or more, The other is an integer greater than or equal to 2), and these are grouped into one pixel, so that two or more of the same type of photoelectric conversion units are included in this one pixel, and in the same pixel, those of the same color are added and read out. This makes it possible to measure the tint of each pixel without causing a shift in color registration.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the principle of the present invention. FIG. 2 is an explanatory diagram showing an example of the arrangement of photoelectric conversion sections of a storage type color image sensor. FIG. 3 is an explanatory diagram showing a part of an accumulation type color image sensor in which signals of the same color are added within the same pixel and then read out separately for each color. 11... Photoelectric conversion section for blue color, 12... Photoelectric conversion section for green color, 13... Photoelectric conversion section for red color, 15-1
7...Addition section, 21-49...Photodiode, 51-79...Vertical MOS switch, 95a
~95c, 96a~96c...Horizontal MOS switch, 98a~98c...Output line.

Claims (1)

[Claims] 1. Three types of photoelectric conversion units that photoelectrically convert three primary color lights and accumulate the resulting signal charges are arranged alternately in a matrix, and each photoelectric conversion unit arranged in this matrix is They are grouped into M rows and N columns (where M and N are integers of 3 or more, and the other is integers of 2 or more), and these are treated as one pixel, and within each pixel, signal charges of the same color are added and read out. A storage type color image sensor characterized by the following configuration. 2. The storage type color image according to claim 1, wherein photoelectric conversion units of the same color are connected to the same output line within the same pixel, and are added when read out simultaneously. sensor. 3 The three primary color lights are blue light, green light, and red light, the integers M and N are 3, and there are three photoelectric conversion units for blue, three photoelectric conversion units for green, and three photoelectric conversion units for green. Claims 1 or 2, characterized in that one pixel is constituted by a red photoelectric conversion section.
Accumulative color image sensor as described in section.