JPS631281A - Signal processing circuit - Google Patents

Abstract

PURPOSE:To prevent the malfunctions of movement detection and a YC separating circuit by providing a means which detects the non-reverse state of a color burst phase and a means which performs switching between adaptive signal processing in a time space and the signal processing in a space only to detect the phase non-reverse state of a color burst signal and setting the signal processing in the space only. CONSTITUTION:When a signal conforming to the standard of a NTSC signal is supplied, a color burst non-reverse state detecting circuit 106 detects that the phase of the color burst signal is inverted between frames. Then a switching circuit 110 is actuated so that the output of a movement-adaptive scan line interpolation circuit 105 is transmitted. While in case of a reproduction signal obtained in a special reproduction mode of a VTR or a VDP, the circuit 106 switches the circuit 110 so that the output of an intra-space scan line interpolation circuit 109 is transmitted. Then the video signals processed through an intra-space YC separating circuit 107, a RGB converting circuit 108 and the circuit 109 are sent to a time compressing/multiplexing circuit 111. As a result, signal processing is possible in a space area having the most intensive correlation. Thus the malfunctions of movement detection can be avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a signal processing circuit for color television blind signals, and in particular for NTS such as VTRJPVDp.
The present invention relates to a signal processing circuit suitable for processing a signal different from a C signal.

[Conventional technology]

There is a known technology that attempts to improve the image quality of current color television signals through signal processing on the receiver side.

For example, Achiba et al. 1: “New research and development trends at home and abroad”
, Television Studies 4R Magazine Vol.

56, No. 10 (1982). In this paper, a signal processing device that handles a color television signal in a three-dimensional space-time manner in which a time axis is added to the spatial coordinates of the vertical and horizontal axes of the screen is discussed. This ('i
A block diagram of the signal processing device is shown in FIG. This signal processing fct detects the movement of an image and adaptively performs various filter processes depending on the amount of movement. As examples of these adaptive filter processes, two filter processes, YC separation and scanning line interpolation, will be described in detail below.

First, a method of adaptive YC separation will be described.

As an example of a YC method for separating luminance signals and color signals from the current color television signal, Japanese Patent Laid-Open No. 58
- As shown in No. N5995, the movement of the subject is detected by the difference between the input and output of the frame memory, and when this movement is small, frame correlation is used to perform YC separation (hereinafter referred to as
It is called a frame comb filter. ), and when the movement is large, there is a filter that performs YC separation (hereinafter referred to as a line comb filter) using V-factor vertical correlation.

The YC separation method in the above conventional example can be expressed, for example, as shown in FIG. In this block diagram, the flow of video signals is shown by solid lines, and the flow of control signals is shown by broken lines.

The frame comb filter 305 has one frame memory 50
The input signal and output signal of 2 are each multiplied by 1 using a coefficient multiplier, the difference between the two is taken, and the output from the subtracter is passed through a band pass filter (hereinafter referred to as BpF) 308 to a mixer 31.
0.

Further, the output of the one frame memory 302 is supplied to the B P F 30B via the line comb filter 305,
Its output is provided to mixer 310. This mixer 51
At 0, the control value gK outputs a Frenaud signal CI separated by a line comb filter 304 for a still image, and a color signal C'L separated by a line comb filter 305 for a moving image. This control signal is combined with the motion detection and control circuit 303 from the 1 frame memory 3020 input signal and output signal.

Supplied 310 tons of mixer. Color signal C% output from mixer 310: Output of 1 frame memory 302 (ff
By subtracting f from the eccentric force delayed by the delay circuit 606 and dividing it into 0Jj by the subtractor 311V, the luminance intensity g
Obtained consideration Y312.

Next, an explanation will be given of an adaptive process for renumbering, which is a numbering method for dealing with deterioration in which line flickers and rough FD patterns are visible.

This method avoids the above-mentioned f problem by interpolating the foot movement on the receiving side and sequentially displaying the 1g image as a moving signal. For example, JP-A-58-
In the example seen in the 205577 Dimensions Publication, the movement of the image is detected, and when the movement is small, interpolation is performed between fields as a still image to create an interpolated scanning line, and when the movement is large, it is assumed that it is a moving image and the field is It performs motion-adaptive processing such as internal interpolation. The outline of this signal processing circuit will be explained using FIG. 4.

In Fig. 4, 401 is an input terminal, 402, 403
is the first. 404 is a set meal interpolation circuit, 405 is a motion detection circuit, 406 and 407 are the first field memory;
, a second time axis circuit, 408 a selection circuit, and 409 an output terminal.

The 2:1 interlaced foot signal IN from the input terminal 401 and a signal delayed by one frame period are input to the motion detection circuit 405, and the absolute value of the interframe distortion signal is determined to detect the movement of the image. is being detected. As described above, the characteristics of the scanning line interpolation circuit 404 are controlled by the amount of movement of this image.

When creating an interpolated scanning line, since the input signal is interlaced scanned, the scanning of the field one field before and after a, - is performed by scanning the position of the scanning line to be interpolated in the current field. Therefore, these scanning line signals can be directly used as interpolated scanning line No. 100. However, such inter-field interpolation can only be performed for still images. For moving images, two images separated by a few seconds are superimposed, resulting in significant deterioration.

Therefore, if the amount of motion of the image detected by the motion detection circuit 405 is large (thus, when it is determined that it is a moving image, only the scanning line signal of the current field is used, and for example, the average of two consecutive scanning lines is taken). The above deterioration is avoided by creating an interpolated f-line signal.

As described above, in the conventional example, an interlaced scan signal is converted into a sequential scan signal without reducing the resolution of still images (and without causing deterioration such as afterimages with moving images). can be converted.

[Problem that the invention seeks to solve]

In this way, the above-mentioned American technology utilizes the fact that color (I!r components) are inverted between frames in still images for motion detection and YC separation.
RJPV D p T (, no matter where the signal is reproduced from, if you try to process it, the relationship that the color signal components are reversed between frames is lost, so motion detection etc. will malfunction, which may even lead to signal deterioration (possible). There was the issue of gender.

The purpose of the present invention is to solve the problems of the above-mentioned American technology and to
Motion detection even when signals from R9FDP are input
? It is an object of the present invention to provide a signal processing circuit that does not cause No. 13 deterioration without malfunctioning of a Yc' separation circuit.

[Means for solving problems]

The above purpose is to detect that the phase of the color burst signal within the horizontal NZ line erasure period is not inverted between frames in the Nyu I Hyakucho of VTR JPVDP at 7f, and to detect the non-inverted state of the color burst phase. and a means for switching between adaptive signal processing in time and space and signal processing in space only, and when it is detected that the phase of the color burst is non-inverted between frames, the adaptive signal processing is performed. This can be achieved by switching to only spatial signal processing.

[Effect]

For signals in which the phase of the color burst signal within the horizontal blanking period is not inverted between frames such as VTRJPVDp, the detection circuit detects a non-inverted state of the color burst signal. As a result, the detection circuit switches the signal processing circuit from adaptive signal processing in space and time to signal processing only in space, so there is no problem of motion detection malfunction, and in this case, the detection circuit switches the signal processing circuit from adaptive signal processing in space and time to signal processing only in space. No signal deterioration occurs due to signal processing.

[Implementation row]

An embodiment of the present invention will be described below with reference to FIG. The video signal is shown as a solid line, and the control signal is shown in pseudo-printing.

In FIG. 1, 101 is a color television signal, 1
02 is A11) summer converter, 106 is a motion adaptive YC separation circuit, 104 is an RGB conversion circuit, and 105 is a motion adaptive type running hill #! An interpolation circuit, 106 a color burst non-inversion detection circuit within the horizontal blanking period, 107 an intra-space YC separation circuit,
108 is a KGB conversion circuit, 109 is an intra-spatial scanning line interpolation circuit, 110 is a cutback circuit, 111 is a time compression and multiplexing circuit, 112 is a D/A converter, 113 is a cathode ray tube, 1
14 is a motion detection circuit. Here, the case of the NTSC system as a color television signal will be explained as an example.

In the iV T SC method, the color law carrier frequency, horizontal frequency, and frame frequency rfL number are fsc, fI,
When fr is assumed, there are the following two relationships.

fsc = ” ftt fit ftr = 525 fx 12 + From these two equations, the relationship between fsc and fr is determined and fsc = ””” X
525 fr=(integer+7) X fr (3+
becomes. Therefore, the temporary phase of the color sub-transport returns to its original state after two frames, and the phases of the color bursts within the horizontal blanking period between frames are inverted to each other.

Naturally, the signal sent from the broadcasting station satisfies equation (3), but the reproduction signal during special playback of the current VTR9VDP does not satisfy the relationship of equation (31).

Therefore, in the present invention, it is checked whether the relationship in equation (3) is satisfied, and if this condition is not satisfied, YC separation and scanning line interpolation in the space where the correlation is strongest in this case are used. The above is the basic idea of the present invention.

Next, the specific operation of the present invention will be explained using FIG. 1. First, when a signal based on the NTSC signal standard is input, the color burst non-inversion detection circuit 106 detects that the phase of the color burst signal is inverted between frames, and changes the switching circuit 110. It operates to pass the output of the adaptive scanning interpolation circuit 105. In this case, the operation will be the same as the configuration shown in FIG. 2, and adaptive signal processing in time and space will be performed, making it possible to output images in which the deterioration problem of the current broadcasting system has been improved.

- If a signal that does not meet the NTSC signal standard is input, such as a reproduced signal from a VTR or VDP during special Nyu mode, the color burst non-inversion detection circuit 106 detects the phase of the color burst signal between frames. is not inverted, and switches the switching circuit 110 to pass the output of the spatial scanning line interpolation circuit 109. Then, the video signal processed by the spatial YC separation circuit 107, the RGB conversion circuit 108, and the spatial scanning line 109 is sent to the time compression and multiplexing circuit 111 via the switching circuit 110, so that the spatial region with the strongest correlation is processing is possible. Therefore, there are no problems such as malfunction of motion detection or inability to perform signal processing between frames.

In addition, in the configuration shown in FIG. 1, the color burst non-inversion detection circuit 106 performs processing only in space and adaptive signal processing in space and time.
When the color burst non-inversion detection circuit 106 detects color burst non-inversion, the motion detection circuit 114 may be controlled to forcefully set the moving image mode to perform processing only in space.

In this way, the spatial YC separation circuit 107, RGB
There is no need to newly provide signal processing circuits for the conversion circuit 108 and the spatial scanning line interpolation circuit 109 (this simplifies the circuit).

Yet another embodiment is shown in FIG. The configuration in Figure 5 is the first
Parts that are the same as those in the figure and have the same functions are numbered the same as in Figure 1. The differences in Figure 5 from Figure 1 are as follows.

501 comb filter and 502, 5u3 A/D
This is an f conversion circuit. In other words, in FIG. 1, the spatial YC separation circuit 107 was composed of a digital circuit, but this fifth
An analog configuration may be used as shown in the figure.

Color burst non-inversion detection circuit 10 (S is intrapersonal g1
The operation of FIG.
It is similar to the figure. When the color burst non-inversion detection circuit 106 detects that the phase of the color burst signal is not inverted between frames of the input signal 101, the color burst non-inversion detection circuit 106 spatially switches the switching circuit 110 You can easily select the output of the interpolation circuit 109.

Suppose that the color television signal IQ1, which is an input signal, is switched in this way and is YC-separated by an analog comb filter 501, which is one of the YC separation circuits in the space.
/D converters 502 and 504 convert it into digital data. After that, the RGB conversion circuit 108 converts the Y and C signals into RGB signals, the spatial scanning line interpolation circuit 109 performs scanning line interpolation, and the signal is sent to the time compression and multiplexing circuit 111 via the switching circuit 110. It is possible to view a signal-processed image on the cathode ray tube 113 in a space similar to that shown in FIG.

Above, in FIG. 5, the case where a 4° analog line comb filter is used as the spatial YC separation circuit 107 has been explained, but as other embodiments of the present invention, a band pass filter, a low pass filter,・Those using digital line (rectangular filters, spatial adaptive YC separation filters that adapt these filters in space, etc.) as the spatial YC separation circuit 107 in FIG. 1 can be cited. As you can see, the open gate YC separation circuit 107 can be digital or analog.

Next, the iC color burst non-inversion detection (2) path 106 will be explained.

FIG. 6(α) shows an example of the color burst non-inversion detection circuit 106, in which 601 is a color television signal, 602
is a one-frame delay circuit, 603 is an addition circuit, 604 is an absolute value conversion circuit, 605 is an integration circuit, 606 is a comparison circuit, 6
07 is an output signal.

FIG. 6 FAI is a waveform diagram for explaining the operation of FIG. This is the case when there is no inversion between frames.

If the color burst -1-q is inverted between frames as shown by fil, the addition circuit 60 is added between frames.
3 to 7]13 becomes almost 0, and remains 0 even after passing through the absolute value converting circuit 604 and the integrating circuit 605. Even if the comparison circuit 606 compares the 1/0 with a predetermined 1/0, the output 607 becomes 0, indicating that the phase between frames of the color burst is reversed. On the other hand, when the phase of the color burst signal is not inverted between frames, for example when the phase is the same between frames, the output of the absolute value conversion circuit 604 becomes as shown by (Ill). When the comparison circuit 606 compares it with a predetermined 1 value, it outputs 1. This indicates that the phase of the color burst is not inverted between frames.

Further, even if the phase of the color burst is not inverted between frames but is shifted by an arbitrary phase, it can be detected by the same operation.

FIG. 7 (C1 is another example of a color burst non-inversion detection circuit. In FIG. 7 (C1, 701 is a color burst signal, 702 is a phase comparison circuit, and 703 is a VCo.

704 and 705 are low-pass filters, 706 is a comparison circuit, 707 is a sample and hold circuit, and 707 is an output signal. A waveform diagram for explaining the operation of FIG. 7 (α) is shown in the same figure (bl iC). In FIG. 7, 2 (1) is the case where the phase of the color burst signal is inverted between frames, This is a case where the phase of the color burst signal is not inverted between frames.

In FIG. 7 (C1), the phase comparator circuit 702, VCζ 703, and low-pass filter 704 constitute a pLL circuit, which is designed to lock to the phase of the input color burst signal -8701. As shown in (11) of ¥1 (6), the CO output cuff 03 outputs the color burst signal 7.
If locked to 01, color burst toy g.
The phase difference between No. 701 and VCOC blade 05 should be maintained at 90°. At this time, the output of the phase comparator circuit 702 is like C1, so the low-pass filter 705 output is LD.
become that way. Then, 0 is output to the sample hold 707 output. - If the phase of the color burst becomes unlucky between frames, such as during special playback of final DP, the phase comparator circuit 702c/nororoki becomes like (111) of fil, and then the Lt low-pass filter 705 is When the signal is passed through and sampled and held, a B level signal (L') is obtained.

By the way, so far we have discussed an example of detecting only the state in which the phase of the color burst is not inverted between frames and switching between the signal processing that applies Tokiomi Kaimon and the spatial noise processing. [It should be noted that this signal does not necessarily have to be a switching signal for switching between adaptive signal processing within the 4r space-time and signal processing only within the space. In other words, other non-NTS
It may be used in combination with the C signal state detection signal. For example, the block diagram of FIG. 8 (C1 is an example of this.
l is a clock signal 801 that is locked to the burst, and a clock 1g signal 802 that is locked to the horizontal period signal.
are divided by N by frequency dividing circuits 8 [13 and 804, respectively, and then a frequency comparison circuit 805 determines whether the frequencies are equal or not, and this determination output and the color burst non-inversion detection output are mixed. It can also be used as a switching control signal for a switching circuit that switches between the adaptive signal processing circuit for time nitrogen opening and the spatial only signal processing circuit that has been described so far. As a method for this mixing, for example, the logical sum of the signals may be taken.

We then provide an acquisition description of the in-spatial scan line interpolator. Figure 9 (αI, +AI is a scanning line interpolation circuit in space, (α) is an example of repeatedly using the previous scanning distorted line as an interpolation scanning line, This is an example in which the average χ of the scanning line is used.

First, in FIG. 9 (αLK will be explained. μ), the scanning line interpolation circuit consists of an input scanning line 811 and a -H delay circuit 812. After that, the input scanning line is passed through time compression circuits 813 and 814, and multiplexed by a multiplexing circuit 815. and outputs an output signal 816 which has been subjected to scanning line interpolation.

Next, this operation will be explained using the waveform diagram of FIG. 9 (C1). First, the input scanning line 811 is sent as shown in FIG. The time compression circuit delays the input signal by 6 seconds and outputs it.
This is a circuit that outputs a signal whose time is compressed in half. Therefore, the output waveform of the time compression circuits 813 and 814 is obtained by time-compressing the shaping of the input signal.

The multiplexing circuit 815 switches these time-compressed signals every -H period. Then, a signal is obtained which is time compressed for the input scanning line 811 and interpolated to repeat the previous scanning line.

-7, the set meal Iwao darkening circuit in Fig. 9 1cl is connected to the input scanning line 8
11, OH delay circuit 817, 818, addition circuit 819
, and an upper coefficient circuit 820, similar to FIG. 9(α).

The signal is then connected to a multiplexing circuit 815 via time compression circuits 813 and 814.

This operation is similar to that shown in FIG. 9 (α), and will be explained using FIG. 1cl. The input scan a811, which is the current signal, is
The delay circuit 817 delays the iH period and sends it to the time compression circuit 813. The interpolated scan line signal is then input to the input scan line 811.
It is created by averaging the input scanning line 811 delayed by 1H by the iH delay line 81'7 and EN8 and the input scanning line 811 by an adder 819 and a 1-coefficient circuit 820. Thereafter, this signal is sent 9 to a time compression circuit 814 where it is time compressed. The outputs of the time compression circuits 815 and 814 are then sent to a multiplexing circuit 815.
If you switch, the average of the previous and subsequent scanning lines will be used as the interpolation scanning line. It is possible to get a signal.

By the way, in the embodiments shown in FIGS. 1 and 5, we have explained the case where the set meal interpolation is performed and the horizontal frequency is twice that of the normal NTSC receiver. It is clear that the present invention is also effective when operating at the same horizontal frequency as an NTSC receiver.

By the way, so far we have described the case where the phase difference between color burst frames is used to detect VTRJPVDP. In addition, as a detection method for VTRs and FDPs, a method of looking at the phase difference in the horizontal Z period between frames may be used to switch between adaptive signal processing in space and time and signal processing only in space. An example of this is shown in FIG. 1st
In figure 0, 901 is a color television 4g-g-,
902 is a one frame delay circuit, 903 is a subtraction circuit, 90
4 is an absolute one-section circuit, 905 is an integration circuit, 906 is a comparison circuit, and 907 is a holding circuit. If the 1-frame delay circuit 902 is operated with a signal locked to the color burst signal, there is no relationship between the frequency of the burst signal and the horizontal synchronization and vertical synchronization frequencies in VTRs and VDPs. As shown in the figure (902 output of 61, the phase of the horizontal synchronizing signal is different from that of 901. Therefore, after this, subtraction is performed in the subtraction circuit 903, and absolute value conversion circuit 904
The absolute value is taken at , the integration circuit 905 integrates it, and the comparison circuit 9
06, it is compared with a predetermined value. If this value is held in the holding circuit 907, a VTR or the like outputs a signal of 1H level, and if the horizontal synchronization phase is not shifted between normal frames, a signal of ILI level is output. This detection signal may also be used.

〔Effect of the invention〕

According to the present invention, a VTR that does not satisfy the NTSC signal specifications
, even if a signal such as VDP special playback is input, it is automatically detected, and in this case, signal processing can be performed only in the space with the highest correlation, so processing without signal deterioration is always possible. effective.

[Brief explanation of the drawing]

Fig. 1 is a 10-step diagram showing an embodiment of the present invention, Fig. 2 is a block diagram explaining the prior art, and Fig. 3 is a motion adaptive type Y
FIG. 4 is a block diagram showing an example of a motion adaptive scanning line interpolation circuit, FIG. 5 is a block diagram showing another embodiment of the present invention, and FIG. 6 is a color burst non-inverting circuit. Figure 7 is a block diagram and waveform diagram showing an example of another color burst non-inversion detection circuit, and Figure 8 captures the course of the color burst non-inversion detection circuit. FIG. 9 is a block diagram and a temporary diagram for explaining the spatial 7I:iE line interpolation circuit, and FIG. 10 is an explanatory diagram of a circuit for detecting a phase shift in horizontal synchronization. 1u1...Color television signal 105...Motion adaptive YC separation 105...Motion adaptive scanning interpolation 106...Color burst non-inversion detection 107...Intra-space YC separation 109...Space Inner scanning line interpolation 110...5W 111...Temporal compression and multiplexing 113...CRT agent Patent attorney Masaru Ogawa Ogyu I Sen Figure 7 Oj Man 3 Figure Ushi 4 Figure 5 Figure S Figure 6 (i) (ii) (b) Figure 7 (i) LIIJ
(b)

Claims (1)

[Claims] 1. A motion detection circuit that detects image motion from a color television signal, and performs adaptive signal processing in the spatiotemporal domain according to the amount of image motion detected by the motion detection circuit. In the signal processing circuit of a color television receiver,
The signal processing circuit includes an adaptive signal processing means in the spatio-temporal domain, a signal processing means only in space, a detection means for detecting whether the color television signal is a non-standard signal, and among the above signal processing circuits, At least for signal processing that performs YC separation, there is a switching means for switching between an adaptive signal processing means in the spatiotemporal domain and a processing means only in space, and at least the detection means is in a non-inverted state of the color burst. The signal processing circuit is characterized in that the switching means switches so that only the processing means within the space is used while detecting the signal. 2. The signal according to claim 1, wherein the detection means is a detection means for detecting a non-inverted state in which the phase of the color burst signal of the color television signal is not inverted between frames. processing circuit. 3. The signal processing circuit according to claim 1, characterized in that an analog comb filter is used as the processing means only in space. 4. The detection means includes a delay means for delaying at least one frame period, an addition means for adding the input and output of the delay means, and means for comparing the signal passed through the addition means with a predetermined value. The signal processing circuit according to claim 1, characterized in that the signal processing circuit uses detection means. 5. The signal processing circuit according to claim 1, wherein the detection means is a detection means for detecting that the phase of the horizontal synchronization signal differs between frames.