JPS6211385A - Color image pickup device - Google Patents

Abstract

PURPOSE:To upgrade S/N and to attain an excellent color-reproducibility by executing the scanning of the titled device in the longitudinal direction of the steak of a color stribe filter, and executing the color multiplex with a carrier wave of comparatively low frequency. CONSTITUTION:The color stribe filter 1a of the pickup tube 1 is constituted by repeated fine filter stribes of G, C, and W, and the scanning is done in the logitudinal direction of the streaks of the filter 1a. The signal obtained by the image pickup tube 1 is A/D-converted 3 and is supplied to field memories 4a and 4b. The G, C, and W of the filter 1a is so set as a group equivalent to 1H of NTSC system. At the end the 1H, the signal is thinned out in the horizontal direction, and the scanning lines are sequentially written in the memory 4a with a shift of 1/6 of the sampling period T between each of them. At the end of 2H, the group of signal written in the memory 4a is read out sequentially in the vertical direction, and the information in horizontal direction of the said group is written in the memory 4b by a switching circuit 5. The outputs from the both are processed by a D/A converter 6, color decoding circuit 7, and an adder 9, and color-multiplexed with a carrier wave of low frequency.

Description

[Detailed description of the invention] Industrial application field book. The present invention relates to a color imaging device, and relates to a device for obtaining a color multiplexed signal from an image pickup tube provided with a color stripe filter and demodulating the color in, for example, a single-tube color television camera.

2. Prior Art Regarding the conventional single-tube color television camera, for example, the present applicant has disclosed Japanese Patent Application No. 54-28450 (Japanese Patent Publication No. 59-35).
For example, G (green), C (cyan),
A color multiplexed signal is obtained by scanning in a direction perpendicular to the longitudinal direction of the stripes of a color stripe filter consisting of repeating W (transparent) stripes.

Problems to be Solved by the Invention The above-mentioned conventional device performs scanning in a direction perpendicular to the longitudinal direction of the stripes. This means that color multiplexing is performed using a high carrier wave, and the noise is higher in the higher frequencies.
Also, since the modulation degree of the image pickup tube is lower in the higher frequencies, as a result,
The signal-to-noise ratio is low, and the image pickup tube cannot faithfully reproduce the state of the color stripe, resulting in poor color reproducibility.

In addition, since this device scans in a direction perpendicular to the longitudinal direction of the stripes, a color-multiplexed signal is obtained in the scanning direction.As a result, the luminance signal band is limited by the color-multiplexed carrier wave, and the band is There was a problem in that it became narrow and good horizontal resolution could not be obtained.

The present invention achieves color multiplexing using relatively low carrier waves.
It is an object of the present invention to provide a color decoy image device that can obtain a high signal-to-noise ratio, good color reproducibility, wide signal band, and good horizontal resolution. shall be.

Means for Solving the Problems In FIG. 1, a color stripe filter 1a includes an optical color separation means, an AD converter 3, and an AD converter 3, in which the longitudinal direction of its stripes is arranged parallel (substantially parallel) to the scanning direction of the image pickup tube 1. Memo 1J4a, 4b,
The switching circuit 5, the DA converter 6, and the color demodulation circuit 7 shift the pitch in the direction perpendicular to the scanning direction of the image pickup tube 1 at least every field, and output color multiplexed signals of one set of G, C, and W in the direction perpendicular to the scanning direction. The accelerator 9 is an embodiment of a means for adding a set of color multiplexed signals to obtain a luminance signal.

Function A color stripe filter 1a consisting of a plurality of sets of different filter strips G, C, and W is arranged with the longitudinal direction of the stripes parallel (substantially parallel) to the scanning direction of the image pickup tube 1.
The D converter 3, the switching circuit 5, the memories 4a and 4b, and the DA converter 6 shift the pitch in the direction perpendicular to the scanning direction of the image pickup tube 1 by at least every other field, so that the above-mentioned sets of colors are generated in the direction perpendicular to the scanning direction. A multiplexed signal is obtained and color demodulated in a color demodulation circuit 7, and a set of color multiplexed signals is added in an addition "a9" to obtain a luminance signal.

Embodiment FIG. 1 is a block system diagram of an embodiment of the device of the present invention, and FIG.
The figure is a diagram showing the relationship between color stripe filters and scanning lines used in the apparatus of the present invention. As shown in FIG. 2, the apparatus of the present invention is configured to scan in the longitudinal direction of stripes of a color stripe filter 1a consisting of repeated G, C, and W filter strips. is the number of samples that the color stripe filter 1a can reproduce, for example, 1 of G, C, and W.
The number is set to 6 per group. This device is said to be compatible with the step energy method, and since it is only necessary to reproduce the fundamental wave component and the second harmonic component in the step energy method, the number of scanning lines can be determined based on the sampling theorem. If there are four or more, it can be reproduced.

In FIG. 1, the color stripe filter 1a shown in FIG.
The signal obtained from the GL tube 1 is supplied to the AD converter 3 via the preamplifier 2, where it is AD converted and stored in the field memory 4a.

4b, and is written therein or read out therefrom in accordance with a control signal from the switching circuit 5.

Here, G and C of the color stripe filter 1a.

The cycle of the W1 set is set to correspond to 1H in the NTSC system. First, the first field will be explained. In the 1H of the first field, the signal from the AD converter 3 is stored in the memory 4a at the points a, a, a, and a, shown in the second diagram.
..., a21. a22. ...”31-a32゜11
12..., the information is thinned out in the horizontal direction and written sequentially with a shift of 1/6 of the sampling period IIJT for each scanning line (FIG. 3(A)). In the 2H, the signals of the first set S1 written in the memory 4a are directed in a direction perpendicular to the writing direction, that is, at point a11. a21゜831・a41・a5
1・a61・a12・a22・a32・a52. a62
．． ..., while the signal from the △D converter 3 is stored in the memory 4b at points a11゜a72・°゛・a8
1・a82 size・"91・"92 size or less Thin out the information horizontally in the same direction as on the first day, and sequentially shift each scanning line by 1/6 of the Zumbling circumference T. (FIG. 3(B)).

At the 3rd H, the signals of the second set S2 written in the memory 4b are directed in a direction perpendicular to the writing direction, that is, points 811, a81,
The signals of the third set from the AD converter 3 are newly written to the memory 4a while being sequentially read out in the directions of a91, °°, 8γ2, a82, a92, °°.

Hereinafter, in this way, each dark blue is written to the memory 4a, 4b and the reading is repeated alternately, and in the end, each dark blue is read out one by one, that is, one day at a time, as the information of the first field F1 on the time axis of the NTSC system. The signal is then supplied to the DA converter 6, where it is DA-converted.

The signal obtained by DA* conversion is a signal in which each group is arranged on the simultaneous time axis as shown in Fig. 4 (A), and is similar to the color multiplexed signal obtained by the general step energy method. In this case, if the above sampling theorem conditions are satisfied, the signal will be similar to the signal color multiplexed by the step energy method, and even if the sampling phase and its frequency change, the fundamental wave component signal and the second harmonic component signal will be the same. Component signals can be faithfully reproduced.

Next, the second field will be explained. In the 1H of the second field, the signal from the AD converter is transferred to the memory 4a.
point a41. a42. ..., a51. a52゜°°°
・a61・a62・°°°・a71・a72・°°°・
a81・a ,..., a91. a92. ..., are sequentially written in the direction. In the 2H, the signal written in the memory 4a is directed in the direction perpendicular to the writing direction, that is, at the point a41'
a51'a61・a71・a81・a91・a42・
a52・a62・a72. a82. a92. ..., while the signals from the AD converter 3 are sequentially written into the memory 4b as signals for the next six scanning lines in the same direction as in the case of the 1H.

From now on, by repeating this kind of reading and writing,
The information in the second field F2 is read out on the time axis of the NTSC system with a 1/2 pitch shift in each set in the vertical direction relative to the information in the first field, and r) is DA-converted by the A converter 6.

The signal taken out from the DA converter 6 is supplied to a color demodulation circuit 7 having a configuration similar to a step energy type color demodulation circuit, where it is color demodulated and taken out from an output terminal 8 as a color signal.

On the other hand, the signal taken out from the DA converter 6 is supplied to the adder 9, where it is added to each pair of G, C, and W to form a luminance signal (FIG. 4 (B)), which is taken out from the output terminal 10. Ru.

Note that even if the luminance signal is added with G, C, and W as described above to eliminate the luminance drop caused by the filter,
It can also be obtained by cutting off frequencies equal to or higher than the period indicated by T in the figure.

In this way, in the device of the present invention, the color stripe filter 1a
Since we are scanning in the longitudinal direction of the stripes, G.

For the period of 1 set of C and W (corresponding to 1H in the NTSC system), the fundamental wave component is 15.75 kHz x 6 = 94.
Color multiplexing is performed using a relatively low carrier wave of 5kHz, which results in a higher signal-to-noise ratio than conventional equipment, and the image pickup tube can faithfully reproduce the state of the color stripes, improving color reproducibility. Become good.

Furthermore, since the device of the present invention scans in the longitudinal direction of the stripes, there is no color multiplexing in the horizontal direction, and as a result, the same resolution as black and white can be obtained, and the luminance signal band is limited by color multiplexed carrier waves. Therefore, the m range can be widened, and good horizontal resolution can be obtained.

Note that the vertical deviation of the second field signal with respect to the first field is not limited to 1/2 pitch as in the above embodiment.

Note that when the scanning direction of the image pickup tube is set vertically, it is installed so that it is perpendicular to the longitudinal direction of the stripes of the color stripe filter, and data is written in the memories 4a and 4b in the vertical direction, and the direction perpendicular to this is written. All you have to do is read it out.

Furthermore, the present invention is not limited to the one in which the information is thinned out horizontally and the sampling buzzer is shifted by 1/6 for each scanning line as in the above embodiment; Of course, sampling may be performed without shifting each scanning line.

Effects of the Invention According to the device of the present invention, since the image pickup tube is scanned in the longitudinal direction of the stripes of the color stripe filter, color multiplexing is performed using a relatively low carrier wave, thereby increasing the S/N ratio. Furthermore, since there is no color multiplexing in the horizontal direction, the same resolution as black and white can be obtained, and the luminance signal band is not limited by color multiplexed carrier waves. , the band can be widened and good horizontal resolution can be obtained.Furthermore, since one set of color multiplexed signals is obtained in the direction perpendicular to the scanning direction, the signal can be read out on the 1H time axis of the NTSC system. As a result, there is no need for a means to convert the time axis, and the memory space is also small.Furthermore, assuming that there are n scanning lines for one set, the luminance signal can be obtained from n scanning lines. Furthermore, since the pitch is shifted in the vertical direction every other field to obtain a color multiplexed signal, the above set can be made to correspond to 1H of the NTSC system. When set to , it has the advantage of increasing the vertical resolution within the 1H range.

[Brief explanation of the drawing]

1 and 2 are respectively a block diagram of an embodiment of the device of the present invention and a schematic diagram of a color stripe filter used in the device of the present invention; FIG. 3 is a diagram for explaining the state of writing to memory; FIG. 4 is an input signal waveform diagram and a luminance signal waveform diagram of the color demodulation circuit in the apparatus of the present invention. 1...-11i3 & tube, 1a... Color stripe filter, 3... AD converter, 4a, 4b... Memory, 5
...Switching circuit, 6-.OA converter, 7.Color demodulation circuit, 8.10..Output terminal, 9..Adder.

Claims (1)

[Claims] A color stripe filter consisting of a plurality of sets of different filter strips is arranged with the longitudinal direction of the stripes parallel (substantially parallel) to the scanning direction of the image pickup tube, and at least every other field in a direction perpendicular to the scanning direction. Shifting the pitch of the color multiplexed signals to obtain one set of color multiplexed signals in a direction perpendicular to the scanning direction, color demodulating the two sets of color multiplexed signals, and adding the one set of color multiplexed signals to obtain a luminance signal. Color imaging device.