JPS6229293A - Color image pickup device - Google Patents

Abstract

PURPOSE:To offset the sampling folded distortion without generating a color beat by arranging so that a relative positive between a stripe and a sampling point on a scanning line is alternately shifted by 1/2 of a scanning line cycling pitch in the period of a horizontal scanning period and adding a color demodulation output with a signal delayed in the above-mentioned period. CONSTITUTION:A device is arranged so that the longitudinal directions of the stripes G, C and W of a color stripe filter 1a are arranged approximately in parallel with the scanning direction of an image pickup tube 1 and while operating a centering circuit 11 by a horizontal synchronizing signal inputted to a terminal 9, the relative position between the stripe and the sampling point on the scanning line is shifted by 1/2 of the scanning line cycling pitch with the period of the horizontal scanning period by a scan. And a color multiple signal is obtained and color-demodulated in a perpendicular direction with a scanning direction through an AD converter 3, memories 4a and 4b, a DA converter 6 and a color demodulation circuit 7, and through a delay circuit 12 and an adder 13, the color demodulation output is added on the signal period-delayed in the above stated and the color demodulation output not delayed. Thereby, the color multiplexing can be performed with a comparative low carrier and an S/N is heightened, thereby obtaining a good color reproductivity, a wide band luminance signal and a good horizontal resolution.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a color original image 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 demodulation is performed. related to a device for

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 stripe m 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 conventional method 6, scanning is performed in a direction perpendicular to the longitudinal direction of the stripes, so a relatively high carrier wave of JMH2 is generated for one cycle of the G, C, and W color strife filters. This means that the noise is higher in the higher frequencies, and the modulation degree of the image pickup tube is lower in the higher frequencies, so as a result, the S
The N ratio is low, and the i-picture tube cannot faithfully reproduce the state of the color stripe, resulting in poor color reproducibility.

In addition, since these devices scan 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 the area became narrow and good horizontal resolution could not be obtained.

The present invention achieves color multiplexing using relatively low carrier waves.
A color decoy image that can achieve a high signal-to-noise ratio, good color reproducibility, wide luminance signal band, good horizontal resolution, and eliminate sampling aliasing distortion. The purpose is to provide equipment.

Means for Solving the Problems In FIG. 1, the 1IIIi tube 1 is an imaging means that performs intermittent scanning, and the color stripe filter 1a is arranged so that the longitudinal direction of its stripes is parallel (substantially parallel) to the scanning direction of the imaging tube 1. optical color separation means, scanning line control terminal 9, waveform shaping circuit 10.
The centering circuit 11 is a means for making the relative positions of the stripes and the sampling points on the scanning line of the IN picture tube 1 alternately shifted by 1/2 of the scanning line repetition pitch with the period of the horizontal scanning period by scanning, and an AD converter 3; The memories 4a and 4b, the switching circuit 5, the DA converter 6, and the color 1 training circuit 7 are means for obtaining a color multiplexed signal in the direction perpendicular to the scanning direction and demodulating the color, and the delay circuit 12 and the adder 13 are for color demodulating output. 3A and 3B are embodiments of means for adding the period-delayed signal and the non-delayed color demodulation output.

The working color Strife filter 1a is arranged with its stripes G, C, W in the longitudinal direction parallel (substantially parallel) to the scanning direction of the @9 tube 1, and the centering circuit 1 is activated by the horizontal synchronizing signal inputted to the terminal 9.
1 is operated so that the relative positions of the stripes and the sampling points on the 111 m picture tube 10 scanning line are alternately shifted by 1/2 of the scanning line repetition pitch with the period of the horizontal scanning period due to scanning, and the AD converter 3 and the memory 4a, 4b, DA converter 6
A color demodulation circuit 7 obtains a color multiplexed signal in a direction perpendicular to the scanning direction and demodulates the color, and a delay circuit 12 and an adder 13 combine the color demodulation output with the signal delayed by the period and the undelayed color in output. to add.

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 scan in the longitudinal direction of the stripes of a color strife filter 1a consisting of repeated G, C, and W filter strips, and has 49 scanning lines. The number is a color] ~ The number that the live filter 1a is able to reproduce well in the sample, for example, G,
C.

The number is set to 6 for each W pair. This is said to be compatible with the step energy method, and in the step energy method, it is sufficient to reproduce the main wave component and the second harmonic component, so the number of scanning lines is determined by the above 1 from the sampling theorem. If there are 4 or more pieces for each group, it will be possible to reproduce it.

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

The cycle of the W1 set is set to correspond to 1H in the NTSC system. Horizontal direction II entered the scanning line control terminal 9
The signal Ho is converted into a switching signal whose polarity is switched every day during the horizontal scanning period by the waveform shaping circuit 10, and is supplied to the centering circuit 11. The image pickup tube 1 is controlled by the operation of the centering circuit 11 to scan an intermediate position between the scanning lines of the previous set every day, that is, every set, as shown in FIG. That is,
1st group S, No. 31183. . . , the scanning lines O of the second set S, . Third
Group S3. . . , at a position of 172 of the repetition pitch of scanning line A.

In FIG. 1, the color strife filter a shown in FIG.
The signal obtained from the image pickup tube 1 equipped with the
The data is supplied to the memories 4a and 4b, and written therein in response to a control signal from the switching circuit 5, and read therefrom.

At 1F1, the signal from the AD converter 3 is sent to the memory 4.
1-cut 811・a12・a13・° shown in Figure 2 (△) in a
゛°・821・a a,...a31. a32. a
33. They are written sequentially in the direction of... (Figure 3 (A))
. The first rough S1 written to the memory 4a on the 2nd day
The signal is generated in the direction perpendicular to the writing direction, that is, at point a11. a21
．． a31゜a41・a51・861・a12・a22・
a32/a52/862/a13/a23/a33/8
43・a53・a63 pa°.

While the signals from the AD converter 3 are read out sequentially in the direction of the points a71 . a72. a73'
'.

a81・”82・a83・°°°・”91・a92・a
93 degrees and below are sequentially written in the same direction as in the case of the 1H (FIG. 3(B)).

At the third gate, the signals of the second set S2 inputted and outputted to the memory 4b are directed in a direction perpendicular to the inputting and outputting direction, that is, points a71, a81,
a91・°°°・872・a82・892 pie・a73
．． a83. a93. ..., while the third set of signals from the AD converter 3 is newly written to the memory 4a.

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. The signal is supplied and DA-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 f1 is satisfied, the signal will be the same as the signal color multiplexed by the step energy method, and even if the numbering phase and its frequency change, the fundamental wave component signal and the second harmonic Faithfully reproduces the wave bottom signal.

The signal taken out from the DA converter 6 is supplied to a color demodulation circuit 7 having a similar configuration to a color demodulation circuit using a step energy method, where it is color demodulated, delayed by one day in a delay circuit 12, and then supplied to an adder 13. On the other hand, the signal is directly supplied to the adder 13 without going through the delay circuit 12, and both signals are processed and taken out from the output terminal 8.

Here, let us consider the relationship between the fundamental wave component, high-order harmonic component, and aliasing distortion caused by the sample of the color strife filter 1a. The fundamental wave component and high-order harmonic component of the color strife filter 1a are as shown in FIG. 5, and are G, C,
When 6 samples are sent to group W1, aliasing distortion (sideband) between the sample frequency and the bottom of the 5th harmonic occurs near the fundamental wave component, and aliasing distortion between the sample frequency and the 4th harmonic component appears. It occurs in the vicinity of the second harmonic component, resulting in a color beat. Note that the 3rd order 'mW4 wave component will not occur if the width of the filter strips of the color strife filter a is exactly correct, and is therefore shown by a broken line.

Therefore, in this embodiment, in the adder 13, for example, the first set S1
and the signal of the second IIS2, which has a scanning line at an intermediate position between the scanning lines of the first set S1, are added.
The sampling points of the second set S2 and the sampling points of the second set S2 have a sample phase of 180 with respect to the color stripe filter a.
This indicates that the aliasing distortions (1) and (2) shown in FIG. 5 have opposite polarities in the first set S1 and the second I'IS2. Therefore, if the addition is performed as in the above embodiment, the aliasing distortions of the first set S2 and the second set S2 are canceled out, thereby preventing color beats from occurring.

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 k HZ
．． Color multiplexing is performed using a relatively low carrier wave of 5 kHz, and scanning is intermittent.As a result, the signal-to-noise ratio is higher than that of conventional equipment, and the image pickup tube can faithfully reproduce the state of color stripes, so color Improves reproducibility.

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 a color multiplexed carrier wave. It is possible to widen the band and achieve good IL horizontal resolution (q) without being limited by this.

As mentioned above, the number of sets of color strife filters 1a in the apparatus of the present invention is 240 sets (corresponding to one field in the NTSC system), and the vertical resolution for each set is 27V tree, and the overall vertical resolution is 4807V. NTSC as a book
It is determined by the number of scanning lines of the system, and the vertical resolution type is the same as the conventional device.

FIG. 6 shows a block system diagram of a second embodiment of the device of the present invention, and in the figure, the same components as in FIG. 1 are given the same numbers and their explanations will be omitted. In the figure, a vertical synchronizing signal Vo input to a scanning line control terminal 14 is converted into a switching signal whose polarity is switched every vertical synchronizing period V by a waveform shaping circuit 15, and is supplied to a centering circuit 11. The image pickup tube 1 is controlled by the operation of the centering circuit 11 so as to scan and cover the middle position of the scanning line of the true field every 1v, that is, every 1 field, as shown in FIGS. 7(A) and 7(B). If the scanning line of the first field is A (Fig. 7 (A)), then the scanning line of the second field is F (FIG. 7 (B)).
) is 1/2 of the repetition pitch of scanning line A in the first field
position.

Thereafter, a color demodulation signal is obtained from the color demodulation circuit 7 through a circuit similar to 8 of the first embodiment, and is stored in the field memory 16.
After being written for one field, the signal is read out and supplied to the adder 13, while being supplied directly to the adder 13 without going through the field memory 16, and both signals are added and taken out from the output terminal 8.

In this case, since the pitch of the scanning lines is shifted by 1/2 for each field, the sampling aliasing distortion between fields can be canceled by the above-mentioned addition.

In FIG. 6, even if the output of the color demodulation circuit 7 is taken out as it is and supplied to the monitor receiver, substantially the same result as the above-mentioned addition can be obtained since the eye has an integral effect.

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 the figure, a swing control signal of t periods which has entered the scanning line control terminal 17 is converted into a switching signal whose polarity is changed every period by a waveform shaping circuit 18, and is supplied to a centering circuit 11. The image pickup tube 1 is controlled by the operation of the centering circuit 11 so that the scanning lines are alternately displaced in the vertical direction every period, as shown in FIG. That is, point b11. b13. . . corresponds to scanning line A in FIG. 7(A), and points b12 . The positions of . . . are controlled so as to correspond to the scanning line O in FIG.

The signal taken out from the preamplifier 2 is delayed by the delay circuit 19 and supplied to the adder 13, while the signal is supplied as is to the adder 13 without going through the delay circuit 19, and both signals are added and AD converted. is supplied to vessel 3.

In this case, since the pitch of the sampling points in the vertical direction is shifted by 1/2 for each cycle, the sampling aliasing distortion is canceled out by the above addition, resulting in 4! ? Ru. Furthermore, it goes without saying that aliasing distortion can be offset by providing a delay circuit corresponding to the pitch after DA conversion.

When the scanning direction of the J3 and R picture tubes is vertical, the longitudinal direction of the color stripe filter stripes is also vertical, and the memory 6 is written in the vertical direction, and the direction perpendicular to this is written. Just read it out.

Effects of the Invention According to the device of the present invention, since the image pickup tube scans in the longitudinal direction of the stripes of the color strife filter, color multiplexing is performed using a relatively low carrier wave, thereby increasing the signal-to-noise ratio. It also has good color reproducibility (9).
Furthermore, the brightness signal band can be widened and good horizontal resolution can be obtained, and the relative positions of the stripes and one numbering point on the scanning line are alternately arranged on the scanning line with the period of the horizontal scanning period due to scanning. Since the repetition pitch is shifted by 1/2, and the color demodulation output is mixed with the signal delayed by the second cycle and the non-delayed color demodulation (J), sampling aliasing distortion can be canceled out, and the color beat can be adjusted. It has the characteristics that it never occurs.

[Brief explanation of the drawing]

1 and 2 are respectively a block diagram of a first embodiment of the device of the present invention and a schematic diagram of a live filter for color filter 1 used in the device of the present invention, and FIG. 3 is for explaining the state of writing to the memory. , FIG. 4 is an input signal waveform diagram of the color demodulation circuit in the device of the present invention, FIG. 5 is a diagram for explaining aliasing distortion due to samples, and FIGS. FIGS. 8 and 9 are diagrams for explaining the block system diagram and scanning lines of the third embodiment of the present invention, respectively. FIGS. .

Claims (1)

[Claims] A color strife filter is arranged so that the longitudinal direction of its stripes is parallel (substantially parallel) to the scanning direction of the image pickup tube, and the relative position between the stripes and the sampling point on the scanning line of the image pickup tube is determined during the horizontal scanning period or The scanning lines are alternately shifted by 1/2 of the repetition pitch at a predetermined period such as a field period, and a color multiplexed signal is obtained in a direction perpendicular to the scanning direction to perform color demodulation, and the image pickup tube output or the color demodulated output is A color imaging device characterized by being configured to add a period-delayed signal and an undelayed signal.