JPS61295784A - Color image pickup device - Google Patents

Abstract

PURPOSE:To improve horizontal resolution with color-multiplexing with a comparatively low carrier, making color reproductivity with a high S/N ratio and widening a luminance signal band area by applying a scanning on an image pickup tube in the longitudinal direction of the stripe of a color stripe filter. CONSTITUTION:A signal obtained from an image pickup tube 1 on which a color stripe filter 1a is provided is AD-converted at a converter 3 through a pre-amplifier 2 and is sequentially written at a field memory 4 in the directions of points a11, a12, a13... and an information signal is sequentially read out in the rectangular direction to a write direction of points a11, a21, a31.... The signal out from a DA converter 5 is demodulated at a color demodulation circuit 6, however, it is a picture reversed by 90 deg. as it is and therefore, after a conversion at an AD converter 7, it is sequentially written at a field memory 8 in the direction of points a11, a21..., a12, a22..., a13, a23... and when reading out, it is sequentially read out in the rectangular direction to the write direction of points a11, a12..., a21, a22..., a31, a32... and with being converted at a DA converter 9, it is taken out from an output terminal 10.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a color imaging device, for example, in a single tube color television camera, a color multiplexed signal is obtained from an image pickup tube provided with a color stripe filter and color demodulated. Regarding equipment.

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 In the above-mentioned conventional methods, scanning is performed in a direction perpendicular to the longitudinal direction of the stripes. Since color multiplexing is performed using a relatively high carrier wave of MHZ, the noise is higher in the higher frequency range, and the modulation degree of the image pickup tube is lower in the higher frequency range.As a result, the S/N ratio is low, and the imaging Since the tube cannot faithfully reproduce the color stage 1 to live conditions, there is a problem in that color reproducibility deteriorates.

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.
The object of the present invention is to provide a color imaging device that can achieve a high signal-to-noise ratio, good color reproducibility of 1q, wide luminance signal band, and good horizontal resolution. do.

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. field memory 4,
The DA converter 5 and the color demodulation circuit 6 are means for obtaining a color multiplexed signal in a direction perpendicular to the scanning direction of the image pickup tube 1 and demodulating the color, and the ΔD converter 7, the field memory 8, and the DA converter 9 are color demodulation circuits. Each of the means for converting the output signal of No. 6 back into the imaging tube scanning direction.
This is an example.

The working color stripe filter 1a is arranged with the longitudinal direction of its stripes G, C, W parallel (substantially parallel) to the scanning direction of the image pickup tube 1,
A D converter 3, a field memory 4, and a DA converter 5 obtain a color multiplexed signal in a direction perpendicular to the scanning direction of the image pickup tube 1, and a color demodulation circuit 6 demodulates the color, and an AD converter 7, a field memory 8, The DA converter 9 changes the output signal of the color demodulation circuit 6Q in the scanning direction of the image pickup tube 1.

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. The device of the present invention is shown in FIG.
As shown in FIG. , C, and W are set to six for one set. 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 base component in the step energy method, the number of scanning lines is determined from the sampling theorem by the above set. If there are 4 or more addresses, it will be possible to reproduce the problem.

In FIG. 1, the color stripe filter 1a shown in FIG.
The signal obtained from the image pickup tube 1 equipped with
are supplied to the AD converter 3 through AD converter 3, where they are AD converted, and are stored in the field memory 4 as points an, adz shown in the second figure.
, ah3. -, a2+, a22°a23. ...a31
．． a32. a33. ... are sequentially written in the direction (FIG. 3(A)). The information signal written in the field memory 4 is perpendicular to the writing direction at points an and a.
2+, ash, -, adz, a22.
a32°..., ah3. a23. a33. ...
The signals are sequentially read out in the direction of , and supplied to the DA converter 5 where they are subjected to OA conversion.

The DA-converted 15 signal is as shown in Figure 4,
This signal 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
The harmonic component signal can be faithfully reproduced.

The signal taken out from the DA converter 5 is supplied to the color demodulation circuit 6, which has a similar configuration to the color demodulation circuit using the step energy method, and is color demodulated, but since the signal is read out in the vertical direction in the memory 4, it remains unchanged. Then, the screen will be 90' down. Therefore, the output signal of the color demodulation circuit 6 is AD converted by the AD converter 7 and then supplied to the field memory 8, and the points an, a2+, ash, -, adz, a22
．． a32. −.

a13. a23. a33. . . , in the direction shown in Fig. 3 (B)), and when reading, the points are written in the direction perpendicular to the writing direction, that is, the points an, adz, ao, =, a2.
+, az2゜a23. ..., ash, a32. a
33. ... are read out sequentially in the direction. The signal read from the memory 8 is subjected to DΔ conversion by the DA converter 9 and taken out from the output terminal 10.

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.

Fundamental wave component 15.75 for the period of group c and wi (corresponding to 1H in NTSC system) k l-I Z
Color multiplexing is performed using a relatively low carrier wave of 4.5kHz, which results in a higher signal-to-noise ratio than conventional equipment, and the image pickup tube can faithfully reproduce the state of color stripes, resulting in improved color reproduction. Improves sex.

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.

Note that when the scanning direction of the image pickup tube is set vertically, the longitudinal direction of the color stripe filter stripes is also set vertically, and the memory 4 is written in the vertical direction and read in the direction perpendicular to this. Just let it out.

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. It also has features such as being able to obtain good color reproducibility, widening the luminance signal band, and obtaining good horizontal resolution.

[Brief explanation of drawings]

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, and FIG. 3 is a diagram for explaining the state of writing to the field memory. FIG. 4 is an input signal waveform diagram of the color demodulation circuit in the apparatus of the present invention. 1... Image pickup tube, 1a... Color stripe filter, 3
゜7...△D converter, 4, 8... Field memory, 5゜9... OA converter, 6... Color demodulation circuit, 10
...Output terminal.

Claims (1)

[Claims] A color stripe filter is arranged with the longitudinal direction of its stripes parallel (substantially parallel) to the scanning direction of the image pickup tube, a color multiplexed signal is obtained in a direction perpendicular to the scanning direction, color demodulation is performed, and the color demodulated signal is used for color demodulation. A color imaging device characterized by being configured to convert back to the scanning direction of an imaging tube.