JPS63214094A - Movement detecting circuit - Google Patents

Abstract

PURPOSE:To reduce a rattling or a distortion as much as possible according to a high frequency component generated at the time of a still picture by separating a Y (luminance signal)/C chrominance signal) by a line comb-line filter, taking the difference between frames of the chrominance signal and using it as a moving signal. CONSTITUTION:A composite video signal inputted from an input terminal 1 is supplied to a 1H memory 2 and a subtracter 5. In the subtracter 5, the difference between lines is taken, thereby, the separated chrominance signal is fed to an absolute value circuit 9 via a BPF 7. The differential signal between lines before one frame is also fed to an absolute value circuit 10 via a BPF 8. The outputs of the absolute circuits 9, 10 are subtracted in a subtracter 11 and the differential signal between frames of the differential signal between lines is outputted. This differential signal between frames is added to a luminance moving signal in an adder 16 via an absolute value circuit 15 and outputted as the moving signal from an output terminal 17.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a motion detection circuit in a color television receiver.

Conventional technology Recent rapid advances in semiconductor technology such as IC and memory,
With the spread of digital signal processing to video signal processing systems,
Devices that digitally process video signals are being actively developed, and some are being commercialized.

Among these, color television receivers as consumer products that undergo digital signal processing in the baseband band are already on the market, and the development of televisions that aim to improve image quality through digital signal processing is progressing.

In order to improve image quality, Y/C separation (Y: luminance signal, C;
It is necessary to optimally process functions such as color signals), scan conversion, and noise reduction according to human visual characteristics, but these processes differ depending on whether or not the object is moving.

Processing that corresponds to the movement of an object is generally called motion adaptive processing, but in order to realize motion adaptive processing, motion detection must be performed. A general example of a method for detecting motion of a color television signal is disclosed in Japanese Patent Application Laid-Open No. 60-57792.

A conventional example will be explained below.

FIG. 3 is a block diagram showing an example of the configuration of a conventional motion detection circuit, in which 31 is an input terminal for a color television signal (hereinafter referred to as a composite video signal and is a digital signal after A/D conversion); 32 is a frame memory, 33.39 is an adder, 34 is a subtracter, 35 is a BPF (bandpass filter), 36 is an LPF (low pass filter), 37.38 is an absolute value circuit, and 40 is a motion signal output. It is a terminal.

Moreover, FIG. 4 is an explanatory diagram of the operation of FIG. 3, (al is a diagram showing the band of the composite video signal, (b) is a diagram showing each frequency amplitude characteristic of the LPF 36, and (C) is a diagram showing each frequency amplitude characteristic of the BPF 35. be.

In FIG. 3, the composite video signal input from the input terminal 31 is sent to an adder 33, a subtracter 34 and a frame memory 32.
supplied to The frame memory 32 delays the composite video signal by one frame (1/30 seconds) and outputs it to the adder 3.
3. Add to subtractor 34. The motion detection signal in the luminance signal is obtained by subtracting the difference between the composite video signal from the input terminal 31 and the previous frame composite video signal from the frame memory 32 in the subtracter 34, and subtracting the color signal component (the color signal is divided between frames. Since the phase is inverted (180@), when the difference is taken, the color signal component is reproduced (especially in still images). After passing through the LPF 36 with the characteristics shown in bl for the fourth time, It is obtained by performing absolute (E processing) in the absolute value circuit 38, and is added to the adder 39 as a luminance motion signal.

On the other hand, the motion detection signal in the color signal is generated in the adder 33 by the sum of the composite video signal from the input terminal 31 and the composite video signal from the previous frame from the frame memory 32 (the color signal has a phase inversion between frames). 180°), so the frame difference of the color signal is the frame sum.) is calculated, and after passing through BPF35 with the characteristics shown in Part 4 (C) to remove the low frequency component of the luminance signal, the absolute value is calculated. The signal is obtained by performing absolute value processing in the circuit 37, and is added to the adder 39 as a color motion signal. The adder 39 adds the luminance motion signal and the color motion signal, and outputs the motion signal to the motion signal output terminal 40 as a motion signal.
It is output from The motion signal obtained in this way is subjected to nonlinear transformation using a certain threshold value, and the motion signal is converted to Y/
It is added to C separation, scan conversion circuits, etc.

Problems to be Solved by the Invention However, in the above configuration, the problems shown in FIG. 4(b)
(Depending on the characteristics of the LPF and BPF of C1 and the frequency characteristics of the composite video signal, the color signal component may leak into the luminance motion signal or the luminance signal component may be mixed into the color motion signal, resulting in poor image quality. Even when a still image is recognizable, a significant motion signal is output, and optimal motion adaptive processing (Y/C separation, scan conversion, etc.) is not performed, resulting in an image with unnatural movement (jitteriness) or distortion. had.

In view of this, the present invention uses a one-frame difference between color signals separated by a line (one horizontal scanning line) comb as a color movement signal, thereby minimizing distortion in image quality in still images. The purpose of this invention is to provide a motion detection circuit that suppresses motion.

Means for Solving the Problems The present invention provides luminance signal motion detection means for detecting motion from the difference between an input composite video signal and a composite video signal delayed by one frame, and a luminance signal motion detection means for detecting motion from the difference between an input composite video signal and a composite video signal delayed by one horizontal scanning period. color signal motion detection means for detecting movement from the difference between the composite video signal and the difference between the composite video signal delayed by one frame and the composite video signal delayed by 1 frame + l horizontal scanning period; This is a motion detection circuit.

Effect of the Invention With the above-described configuration, the present invention uses a line comb to perform Y/C separation as a color signal motion detection method, and then takes a frame difference of the separated color signals and uses it as a motion signal. It is possible to suppress as much as possible the high-frequency components (Y) and l components of the luminance signal included in the color signal band when the image is displayed, and reproduce images with as much as possible the flicker and distortion caused by the Y and l components that occur during still images. do.

Embodiment FIG. 1 is a block diagram of a motion detection circuit according to an embodiment of the present invention, in which 1 is a composite video signal input terminal, 2.4 is an IH memory (H; 1 horizontal scanning period), 3 is a 524H memory, 5
, 6.11.12 is a subtractor, 7.8 is a BPF (band pass filter), 9.10, 14.15 is an absolute value circuit, 13 is an LPF (low pass filter), 16 is an adder, and 17 is a motion signal output terminal. FIG. 2 is a characteristic diagram of the Y/C separation used in this embodiment, in which the vertical axis represents the vertical spatial frequency (line/screen height), and the horizontal axis represents the normal frequency (MHz).

The operation of this embodiment will be explained below with reference to FIG.

First, a method of detecting motion of a luminance signal (motion detection) will be explained. This luminance signal dynamic detection method is the same as the conventional example, and will not be described here. The motion detection of color signals is as follows. A composite video signal input from composite video signal input terminal 1 is supplied to IH memory 2 and subtracter 5. Subtractor 5
Now, the line-to-line difference between the composite video signal before IH, which is the output of the IH memory 2, and the composite video signal from the composite video signal input terminal 1 is taken and added to the BPF 7. The second-order frequency characteristic at this time is shown by the diagonal line in the upper right corner of FIG. 2 (the diagonal line indicates the pass band). The line difference signal obtained in this way passes through the BPF 7 having the characteristics shown by the diagonal line on the lower right side of FIG. and added to the subtracter 11. On the other hand, the IH-delayed composite video signal from the IH memory 2 passes through a 524H memory with a 524H delay and is applied to the IH memory 4 and subtracter 6. :$
In the i-counter 6, the composite video signal delayed by one frame and I
The difference between the composite video signal of 1 frame + IH delay, which is the output of the H memory 4, is determined and supplied to the BPF 8. BPF
The output from 8 becomes a signal that passes only the double hatched area in FIG. 2 as before, and is subjected to absolute value processing in the absolute value circuit 10.
It is added to the subtracter 11. The subtracter 11 takes the difference between the absolute value circuits 9 and 10, that is, the one-frame difference in the absolute value of the color signal, and supplies it to the absolute value circuit 15.Finally, the adder 16 adds it to the luminance motion signal and outputs it as a motion signal. The motion signal is output from the motion signal output terminal 17. The motion signal is then subjected to nonlinear processing, etc., and then supplied to various motion adaptive processing circuits such as Y/C separation and scan conversion.

As described above, in this embodiment, after separating the color signal using a line comb as a motion detection means for the color signal, by taking the frame difference of the color signal, the luminance signal is increased within the color signal band. By reducing the mixing of area components, it is possible to reproduce images with less jitter and distortion, especially when the object is stationary.

In this embodiment, the motion signal output is treated as the sum of the luminance and color signals, but it is also possible to apply different non-linear transformations to each signal independently and in parallel.

As described in detail, according to the present invention, with a simple configuration, it is possible to reduce the deep motion of color signal motion detection, and in particular, it is possible to reproduce a good screen without flickering or distortion in still images. The value is great.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a motion detection circuit according to an embodiment of the present invention, FIG. 2 is a characteristic diagram of Y/C separation used in this embodiment, and FIG. 3 is an example of the configuration of a conventional motion detection circuit. FIG. 4 is an explanatory diagram of the operation of FIG. 3. 2.4...IH memory, 3...524
H memory, 7.8.35...BPF, 9.10
,14,15.37.38...Absolute value circuit, 1
3.36...LPF. Figure 2

Claims (1)

[Claims] A motion detection circuit for a color television receiver, comprising a luminance signal motion detection means for detecting motion from a difference between a composite video signal and a composite video signal delayed by one frame;
Color signal motion detection means for detecting movement from the difference between the composite video signal delayed by a horizontal scanning period and the difference between the composite video signal delayed by one frame and the composite video signal delayed by 1 frame + 1 horizontal scanning period. A motion detection circuit comprising: