JPS58105680A - Solid-state colored image pickup device - Google Patents

Abstract

PURPOSE:To reduce moires, by arranging each picture element of a solid-state image pickup element in such a way that picture elements on odd numbered lines are shifted by the share of half of picture element from those on even numbered lines, and by assigning color filters of complementary colors of cyan, yellow, green, and white for adjoining four picture elements. CONSTITUTION:The solid-state image pickup device of this invention is constituted in such a way that photoreceptor elements which constitute each picture element of the image pickup device are most densely arranged by shifting those on odd numbered lines by the share of half of picture element from those on even numbered lines. Color filters which are arranged correspondingly to each picture element are of those of complementary colors of cyan Cy, yellow Ye, green G, and white W, and these filters are assigned to each of adjoining four picture elements. Namely, the yellow and cyan filters are alternately arranged to picture elements on odd numbered lines and the green and white filters are alternately arranged to those on even numbered lines. This image pickup device is used by separating luminance signals and chrominance signals from signals on adjoining two lines of the signals outputted from the said element.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Field of Application of the Invention The present invention provides a solid-state color photographing device that is equipped with a large number of light receiving elements and that sequentially reads signal charges accumulated by each of these light receiving elements to obtain a color image signal. In particular, the present invention relates to a solid-state color photographing device that reduces moiré and provides high-quality images.

(2) Prior art In the past, camera tubes were used to convert light from the subject's weight into image signals, but in recent years, solid-state imaging elements have come into use.Solid-state imaging The sensor element is a combination of a charge transfer element, and the light receiving part also serves as a charge transfer element, or it is combined with a photodiode, or a large number of photodiodes are arranged in a lattice and a switch is provided at each contact point, and these are sequentially switched. There are devices that obtain image signals, but the structure and operation of these devices are well known, so details will be omitted.

Unlike camera tubes, solid-state image sensors do not perform analog scanning by deflecting the electron beam using a deflection coil or plate, but use clock pulses to perform digital scanning. It has a characteristic that the address on the photocathode of the sensor element can be easily extracted from the electrical signal output.

In order to configure a color imaging device using such a solid-state image pickup device, a three-color separation optical system (the prism is made of an f-color mirror) is used to separate the full color light of each of the three colors. However, separate groups of solid-state imaging elements are arranged for each color of light. In this case, the complex 3
Since a color separation optical system is required, it becomes large and expensive, and the advantage of using a solid-state sensor element is lost. Furthermore, since it is digital scanning, the scanning quality, width, etc. are fixed and cannot be changed, so there is a drawback that the standards for dimensional accuracy, aberration, etc. of the three-color separation optical system are extremely strict.

To this end, attempts have been made to spatially sample the light from the subject using striped color filters, to simplify the color separation system as much as possible, and to reduce the number of solid-state imaging devices used.

That is, as shown in FIG. 1, red (R) and green (G).

A method has been proposed in which a striped color filter 1 consisting of blue (B) filters is combined with a light receiving element array (not shown) of a solid-state imaging device.

However, if you use a striped color filter like this,
For example, if the subject is a landscape with a forest of utility poles, chimneys, etc., moiré will occur between the striped color filter and the projection of the subject, significantly reducing the image quality.

(3) Object of the Invention An object of the present invention is to provide a solid-state color imaging device that can reduce moiré and obtain a high-resolution image signal.

(4) General description of the invention Moiré between the projected image of the subject and the color filter often occurs when the spatial frequencies of the two almost match.In order to reduce this as much as possible, the spatial frequency of the color filter should be set high. This is possible by shifting the phase relationship between the odd-numbered rows and even-numbered rows of the color filter by half a pixel to achieve the highest spatial frequency.Also, to obtain a color signal, at least three colors are required. (J color filters including white are required. Therefore, if we place complementary color filters that can reduce the signal change for each adjacent picture element, corresponding to each of the light receiving elements arranged in the closest packing, Moiré content can be reduced and a video signal with high resolution inertia can be obtained.

Figure 2 shows shea/(cy), yellow (Ye)%gri7(G
) and white (W) complementary color filters are arranged in a close-packed manner. For example, to show an example of MOS type, R
, G, and B are R:G:B=1=5=1, so Cy, Yes Go can be obtained by reading two lines simultaneously.
If the summed signal of W is used as it is for the 1il signal (Y), '1' = 0.27R + 0.66G + 0.07B, which is a value relatively close to the luminance signal of the NTSC system.

(5) Example Hereinafter, the invention will be explained in detail with reference to examples.

FIG. 2 is a diagram showing a color filter used in the solid-state color imaging device according to the present invention. The color filter is a small area cyan (
cy), yellow (Ye)g IJ:' (G), white (W) color filter element Cy.

It consists of ye, G, and w. Furthermore, the color filter is configured such that each of the color filter elements Cy, Ye, G, and W is adjacent to the other three types of color filters. Third
The figure shows the arrangement of light-receiving elements 2 that constitute the imaging surface of the solid-state sensor element, and each light-receiving element 2 corresponds to CY, Ye, G, and W of the color filter element shown in Figure 2, respectively. It is arranged as follows. Note that the horizontal scanning unit 3, vertical scanning W54, and interlace scanning ash, which are scanning means for time-sequentially obtaining the image signal from the light-receiving element 2, are well known in the art, and therefore their explanation will be omitted. When the color filter having the configuration shown in FIG. 2 is used, the intense spectrum only in the horizontal scanning direction, which is caused by the striped color filter shown in FIG. 1, is not generated, and moiré is less likely to occur. Also, R and 1tR=W-C)'=Ye-G,
It can be obtained by B=W-Ye=C)'-G, but if two rows are read out simultaneously with the filter arrangement shown in FIG.
Since the calculation directions for obtaining R and B are opposite for every other row, a moiré suppression effect is produced. Therefore, a high quality 1lffif11 that does not easily cause moiré can be obtained.

FIG. 4 shows an output signal obtained from the solid-state image carrier shown in FIG. 3 when the color filter shown in FIG. 2 is used.

5 to 8 show an embodiment of a circuit for processing an image signal from a solid-state mechanical element.

In FIG. 5, first, the output signal from the solid tank f# element shown in FIG. Then, each output signal is input to bandpass filters IIA and IIB, and then demodulated into R and B by detection circuits 12A and 12B, and is contaminated. Here, as is clear from Fig. 4, the detection circuit 1
From 2A and 12B, B and R signals are output while being switched for each field. Therefore, each field is switched by changeover switches 13A and 13B, and separated into B and R signals, respectively.

Note that this is a 14fl field changeover switch 13A gas generator.

In addition, the luminance signal is transmitted to 81 of the solid-state mechanical element shown in Fig. 3.
The signal output from S2 is amplified by preamplifiers 6A and 6B, inputted to adder circuit 8A, and the output signal is passed through low-pass filter 10. The reason why the output signal from 82 is input to the preamplifier 6B and then delayed by the delay circuit 7 is because the shift register used for reading out the signal cannot operate at high speed, so the output signal from the solid-state sensor is delayed as shown in FIG. This is because the output signal is output in the time relationship shown in FIG. 2, so the output signal is returned to the time relationship corresponding to the filter arrangement shown in FIG. 2 to improve the degree of resolution.

FIG. 6 shows a signal processing circuit using sampling. First, the video signal from the solid-state camera device is amplified by preamplifiers 6A and 6B, and then input to sampling gates 15A to 15D to be separated into white W, green G, yellow Ye, and cyan Cy. .

16 is a sampling pulse generator. As shown in FIG. 4, the output signals G, W, Ye, and Cy of the sampling gates 15A to 15D are output at t'iW during the next horizontal scanning period.
, G, Cy, Ye. Therefore, the horizontal scanning frequency is 1
Just in case, switch 17A changes the output from 5A to 15D.
-17B is separated into each color. Note that 18 is a pulse generator for operating the switches 17A-17B at the horizontal scanning frequency. The thus obtained white W, yellow ye, cyan cy, and green 7G are R(=W-Cy=Y
e-G) and B (=W-Ye=Cy-G) are input to subtraction circuits 9A to 9D.

Then, from the outputs of the subtraction circuits 9A and 9B, the R signal,
A B signal is obtained from 9C and 9D. The luminance signal Y is as explained in FIG. 5.

FIG. 7 shows another embodiment of a signal processing circuit using sampling. The difference between the embodiment shown in FIG. 7 and the embodiment shown in FIG. 6 is that the pulses from the pulse generator 16 are switched by a changeover switch 19 at the horizontal scanning period, and at the time of sampling G, W, It is now possible to separate the colors into Ye and Cy. The other circuits are as explained in FIG.

FIG. 8 shows another embodiment of the color separation method using the bandpass filter shown in FIG. Preamplifier 6A and 6
B's output to the adder circuit 8B, preamplifier 6 input/output, and 6
A signal obtained by delaying the output of signal B by one picture element from delay circuits 7A and 7BK is input to adder circuit 8C. If the 8B output and 80 output are demodulated by the detection circuits 12A and 12B through pantone filters IIA and IIB, R and B signals are obtained.As explained in FIG. Field changeover switches 13A and 13B are used to switch each field so that a B signal is obtained from the detection circuit output 12A and an R signal is obtained from 12B.The reference numeral 14 is a field nox generator.Brightness The signals are as explained in FIG.

What is shown in FIG. 9 is a modification of the filter arrangement shown in FIG. In this filter arrangement, every other line has ye and C)
', the positional relationship between G and W is not interchanged as shown in Figure 2. Therefore, the changeover switches 13, 17 and 19 shown in FIGS. 5 to 8 are not necessary in the processing circuit. Accordingly, the pulse generators 14 and 18 are also unnecessary.

Examples thereof are shown in FIGS. 10 to 13. Explanation is number 5
Since they are the same as those in FIGS. 8 to 8, their description will be omitted.

In the above example, we have described a method of reading out two rows of photodetector columns simultaneously and processing the signals. However, it goes without saying that when reading out one row at a time, simultaneous signals can be processed using a delay line of one horizontal period. do not have. Further, although nine signal output lines are provided for each row in the example, it is also possible to design output lines for each color and perform base padding for signal processing, as in the case of other color filter arrangements.

(6) Summary As explained above, the color image device using the color filter and light-receiving element arrangement according to the present invention generates very little moiré and can obtain a high-resolution image signal, so it can provide high-definition images. Color solid images can be projected on the display.

[Brief explanation of drawings]

FIG. 1 shows a conventional striped color filter. FIG. 2 shows a color filter used in the color solid-state imaging device of the present invention, and FIG. 3 shows a solid-state imaging device used in the invention! Figure 4 is a diagram showing the arrangement of the light-receiving elements of the element, Figure 4 is a diagram showing the state of the output signal obtained in the filter arrangement shown in Figure 2, Figure 5 is a diagram showing the state of the output signal obtained in the filter arrangement shown in Figure 2.
From the figures, FIG. 8 shows an example of the signal processing circuit in the filter arrangement of FIG. 2, and FIG. 9 shows a modified filter arrangement of FIG.
FIGS. 10 to 1 are diagrams showing examples of the signal processing circuit in the filter arrangement of FIG. 9. 2... Light receiving element, 3... Horizontal scanning section, 4... Vertical scanning section, 5... Interlaced scanning section, 6A, 6B...
・Preamplifier, 7...Delay circuit, 8A...Addition circuit, 8B...Addition circuit, 9...Subtraction circuit, 10...
Low-pass filter, 12A, 12B...detection circuit, 1
3A, 13B...Selector switch, 14...Feed pulse generator, 15A-15D...Sampling gate, 16...Sambri 61 Do2tQ

Claims (1)

[Claims] 1. It has a plurality of light-receiving elements arranged in a two-dimensional manner and whose positional relationship between odd-numbered rows and even-numbered rows is shifted by half a picture element, and means for sequentially reading out signals from the cough light-receiving element to an output terminal, In a solid-state color imaging device in which color filters are disposed corresponding to each of the light receiving elements, any four adjacent color filters are a fully transmitting first filter and a second glyph color filter. The light receiving element is composed of a filter, and third and fourth filters that are complementary color filters that transmit the transmitted light component of the second filter and have mutually different transmitted light components, and that are output to the output end. A solid-state color imaging device characterized in that it is configured to separate a luminance signal and a color signal from two adjacent rows of signals.