JPS6229292A - Color image pickup device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of color beat offsetting the sampling folding distortion by tilting the longitudinal direction of a stripe with a prescribed angle so that a relative position between a stripe and an adjacent sampling point on a scanning line is shifted by 1/2 of a scanning line cycling pitch and using or adding alternately the adjacent sampling points with the longitudinal direction of the stripe on a perpendicular direction. CONSTITUTION:The longitudinal direction of the stripe is arranged being tilted to the scanning direction of an image pickup tube 1 with a prescribed angle so that the relative position between the stripes G, C and W of a color filter 1a and the adjacent sampling point on the scanning line of the image pickup tube 1 is shifted by 1/2 of the cycling pitch of a scanning line A. And by using alternately the adjacent sampmling points on each of the scanning lines on the perpendicular direction with the longitudinal direction of the stripe through an AD converter 3, memories 4a and 4b, a switching circuit 5 and a DA converter 6, or by adding the adjacent sampling points on each scanning line pairing them on the perpendicu lar direction with the longitudinal direction of the stripe through the AD converter 3, the memories 4a and 4b, the switching circuit 5, a delay circuit 9 and an adder 10, a color multiple signal can be obtained in the longitudinal direction of the stripe, performing color demodulation at a color demodulation circuit 7. Thereby, color multiplexing can be performed with a comparative low carrier and an S/N is raised, thereby obtaining good color reproductivity, a wide band luminance signal band area and good horizontal resolution.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a color R image device, for example, in a single tube color television camera, a color multiplexed signal is obtained from an R image tube provided with a color stripe filter. The present invention relates to a device for color demodulation.

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 method performs scanning in a direction perpendicular to the longitudinal direction of the stripes, so a relatively high carrier wave of 4 MHz is used for each cycle of the G, C, and W color stripe filters. This means that the colors are multiplexed, and the noise is higher in the higher frequencies, and
Since the modulation degree of the image pickup tube is lower in the higher frequencies, as a result, the S/N
The 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 possible to obtain a high signal-to-noise ratio, good color reproducibility, wide luminance signal band, and good horizontal resolution. It is an object of the present invention to provide a color R@ device which can obtain accurate color multiplexed signal waveforms even if the longitudinal direction and the scanning direction are not completely parallel, and which can eliminate sampling aliasing distortion.

Means for Solving the Problems In FIG. 1, a color stripe filter 1a includes an optical color separation means arranged with the longitudinal direction of its stripes inclined at a predetermined angle with respect to the scanning direction of the image pickup tube 1, an AD converter 3, memory 4a,
4b, a switching circuit 5, a DA converter 6, and a color demodulation circuit 7 are embodiments of a means for obtaining color multiplexed signals for each set of G, C, and W in a direction perpendicular to the longitudinal direction of the stripes and color #Migl.

The stripes are aligned in the longitudinal direction of the image pickup tube 1 so that the relative positions of the stripes G, C, and W of the working color stripe filter 1a and adjacent sampling points on the scanning line of the image pickup tube 1 are shifted by 1/2 of the repetition pitch of the scanning line A. Arranged at an angle with the scanning direction,
The D converter 3, the memories 4a and 4b, the switching circuit 5, and the DA converter 6 use adjacent sampling points on each scanning line alternately in the longitudinal and perpendicular directions of the stripes. 4b, switching circuit 5, delay [G[9(10),
An adder 10 adds adjacent sampling points on each scanning line to pairs in a direction perpendicular to the longitudinal direction of the stripes to obtain a color multiplexed signal in the longitudinal direction of the stripes, which is then color demodulated by a color demodulation circuit 7. .

Embodiment FIG. 1 is a block diagram of a first embodiment of the apparatus of the present invention, and FIG. 2 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 perform scanning at a predetermined angle with respect to the longitudinal direction of the stripes of a color stripe filter 1a consisting of repeated G, C, and W filter strips. The stripes are arranged so that the relative positions of adjacent sampling points on the scanning line of the image carrier are shifted by, for example, 1/2 of the scanning line repetition pitch, and the number of scanning lines A is for one set of G, C, and W. It is set to 6. That is, the point a12 is the upper point a1 in the direction substantially perpendicular to the scanning direction.
The point a13 is arranged between the upper point a12 and the point a22 in the direction substantially perpendicular to the scanning direction, and is arranged in the same relationship as the other points.

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 Zumbling theorem. If there are four or more, it can be reproduced.

In FIG. 1, the color stripe filter 1a shown in FIG.
has been established! The signal obtained from the Il picture tube 1 is supplied to the AD converter 3 via the preamplifier 2, where it is AD converted, and then supplied to the memories 4a and 4b, where it is written in accordance with the control signal from the switching circuit 5. It is read from here.

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. Therefore, on the first day, the AD converter 3
The signals from are stored in the memory 4a at points a11 and a12 shown in the second diagram.
・a13・°°゛・a21・a22・a23・・・・a
31. a32. a33. ... are sequentially written in the direction (FIG. 3(A)). On the 2nd, the first set of signals S1 written in the memory 4a is composed of two points adjacent to each other in the scanning direction and six points adjacent to each other in a direction substantially perpendicular to the scanning direction.
In groups of two points, each adjacent point in the scanning direction and in a direction approximately perpendicular to this is alternately scanned.
・a21・a22・831・Q32'841・a42・
a51, a52, a61, a62, a13, a14. a
23. a24. While the AD
The signal from the converter 3 is stored at the point a71゜a7υa in the memory 4b.
73. °°°, a81. a82. ...Hereafter, the signals of the second set S2 are written in the same direction as in the case of the 1H (Fig. 3 (B)) On the 3rd day, the signals of the second set S2 written in the memory 4b are the same as the case of the first set S1. at point a71゜a , a , a
, . . , a73, .

Thereafter, in this way, one set at a time is written into the memories 4a and 4b, and reading is repeated alternately, and in the end, one set at a time, that is, one day's worth is read out on the time axis of the NTSC system, and the data is sent to the DA converter 6. It is supplied and OA converted here.

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, and is similar to a color multiplexed signal obtained by a general step energy method. In this case, if the above sampling theorem conditions are satisfied, the signal will be the same as 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 will be The signal can be faithfully reproduced.

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 at an output terminal 8J.

In this way, in the apparatus 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 W11GL tube can faithfully reproduce the state of color stripes, resulting in improved 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 band can be widened and good horizontal resolution can be obtained.

The number of color stripe filters 1a in the device of the present invention is 240 (corresponding to one field in the NTSC system).
The vertical resolution for one set is 2 TV lines, and the total vertical resolution is 480 TV lines, which is determined by the number of scanning lines of the NTSC system, and the vertical resolution is the same as the conventional device.

Here, let us consider the relationship between the fundamental wave component, higher harmonic component, and aliasing distortion caused by the sample of the color stripe filter 1a. The fundamental wave component and high-order harmonic component of the color stripe filter 1a are as shown in FIG. 5, and are G, C,
When 6 samples are taken for group W1, aliasing distortion (sideband) between the sample frequency and the 5th harmonic component occurs near the fundamental wave component, and aliasing distortion between the sample frequency and the 4th harmonic component occurs at the 4th harmonic component. It occurs near the base of the second harmonic, and as a result, color bee 1
cause ~. Note that the third harmonic component does not occur if the widths of the filter strips of the color stripe filter 1a are exactly equal, and is therefore shown by a broken line.

Looking at FIG. 2, each sampling point is located between adjacent sampling points, so points a11... a21°a31. a
411a51. -0 pair and point a121a22゜a32
．． a42. a52. ..., the sample phase is shifted by 180'' with respect to the color stripe filter 1a, and this is the aliasing distortion (■) shown in FIG.

This shows that the pair ■ and the pair ■ have opposite polarities. Therefore, if sampling is performed as in the above embodiment, the aliasing distortions of set 2 and set 2 cancel each other out, thereby preventing color beats from occurring.

FIG. 6 shows a block system diagram of a second embodiment of the apparatus of the present invention, in which the same components as in FIG. 1 are given the same numbers and their explanations will be omitted. In the figure, memories 4a, 4
b is read at point a11. a21゜a31・”'= ”6
1 = ``12-a22= ``'-aG2''a13゜a
23. ..., and the DA converter 6
When converted, a color multiplexed signal shown in FIG. 7 is obtained.

This color multiplexed signal is delayed in the delay circuit 9 by the time t required to read out one set of G, C, and W, and is added to the undelayed signal in the adder 10. In other words, the signals of the group (2) and the signals of the group (2) described above are added, so that the aliasing distortions of the respective groups cancel each other out. Other operations and effects are the same as in the first embodiment.

FIG. 8 shows a block system diagram of a third embodiment of the apparatus of the present invention. In the figure, the same components as those in FIG. 1 are given the same numbers and their explanations will be omitted. In scanning with the image pickup tube 1, the time required from a certain point to an adjacent point is defined as the king (Figure 2)
. The output of the preamplifier 2 is delayed by a time T in a delay circuit 11 and added to the undelayed signal in an adder 10.

The added signals are AD converted by the AD converter 3, written into the memories 4a and 4b, and read out in the vertical direction as in the second embodiment.

By the above addition, the signals of group 1 and the signals of group 2 are added, and the aliasing distortion of each group is canceled out.

Note that FIG. 9 is a schematic diagram showing the state of sampling according to still another embodiment of the apparatus of the present invention. In this case, the sampling position is sequentially shifted by 1/6T in the scanning direction, and it is possible to obtain the same effect as in each of the embodiments described above.

Note that when the scanning direction of the image pickup tube is set vertically, the color stripe filter is installed so that the longitudinal direction of the stripes is also vertical, and data is written in the memories 4a and 4b in the vertical direction, and at right angles to this. Read in the direction J: .

Effects of the Invention According to the apparatus 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. In addition, it is possible to obtain good color reproducibility, to obtain a wide luminance signal band, and to obtain good horizontal resolution. The longitudinal direction of the stripe is tilted at a predetermined angle with the scanning direction so that the relative position is shifted by 1/2 of the scanning line repetition bit. Since the sampling aliasing distortion is used or added, the sampling aliasing distortion can be canceled out, and color beats do not occur.

[Brief explanation of drawings]

1 and 2 are respectively a block diagram of a first embodiment of the device of the present invention and a schematic diagram showing the relationship between the color stripe filter used in the device of the present invention and basic sampling;
4 is an input signal waveform diagram of the color demodulation circuit in the apparatus of the present invention. FIG. 5 is a diagram for explaining aliasing distortion due to samples. 7 is a block system diagram and a color multiplex signal waveform diagram of the second embodiment of the device of the present invention, FIG. 8 is a block system diagram of the third embodiment of the device of the present invention, and FIG. 9 is a diagram of the further embodiment of the device of the present invention. FIG. 7 is a schematic diagram for explaining the state of sampling according to another embodiment. 1...Sho image tube, 1a...color stripe filter, 3
...ΔD converter, 4a, 4b...memory, 5...
Switching circuit, 6...DA converter, 7... Color demodulation circuit,
8...Output terminal, 9, 11...Delay circuit, 10...
・Adder. Continuation of Figure 2, page 1 Inventor Hiroshi Kitamura In-house in Moriya-cho, Kanayō-ku, Yokohama Inventor Asakura In-house in Moriya-machi, Kanayō-ku, Yokohama City

Claims (1)

[Claims] The relative position between the stripes of the color stripe filter and adjacent sampling points on the scanning line of the image pickup tube is 1/1 of the scanning line repetition pitch.
2. The stripes are arranged so that the longitudinal direction of the stripes is inclined at a predetermined angle with respect to the scanning direction of the image pickup tube, and adjacent sampling points on each scanning line are alternately used in the longitudinal direction of the stripes and a direction perpendicular to the stripes. Color imaging characterized in that it is configured to add together sets of adjacent sampling points on a line in the longitudinal direction and perpendicular direction of the stripes to obtain a color multiplexed signal in the longitudinal direction of the stripes and perform color demodulation. Device.