JPS63262986A - Movement detecting circuit - Google Patents

Abstract

PURPOSE:To detect correct movement information by executing a Y/C separation respectively at a current sample point and a sample point delayed by one frame by a comb-line filter using a 1H delay circuit to obtain the movement information. CONSTITUTION:An input signal is delayed by the respective delay circuits 30a, 30b, 31 to obtain the current sample point, a sample point before one line, the sample point delayed by one frame and a sample point before one line therefrom. They are respectively added in addition circuits 20, 21, thereby, a luminance signal (Y signal) is taken, subtracted in subtraction circuits 22, 23, to take a chrominance signal (C signal). Since the Y, C signals 5, 7, 6, 8 are obtained according to the same circuit constitution, the leakage of the signal is the same, it is respectively subtracted in subtraction circuits 24, 25, thereby, the leakage is offset and a difference signal (movement information) is obtained according to outputs 9, 10. Thereby, the correct movement information can be detected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a motion detection circuit for a digital television (TV) that performs three-dimensional video signal processing.

[Conventional technology]

3 and 4 show conventional examples of this type of circuit, 1 is a video input signal, 12 is a detected motion signal, and 14 is a frame delay circuit that delays the signal by one frame (525 lines). , 27 is a subtraction circuit, 28 is a color signal extraction and polarity inversion circuit, and 29 is a low-pass filter for blocking the propagation of color signals.

Next, the operation will be explained.

First, to explain the example shown in Fig. 3, in the NTSC color television signal, the polarity of the color signal is inverted for each frame, so when the current input signal 1 and the signal delayed by 525H are subtracted by the subtracter 27, the output is The difference between the luminance signals and the color signal are extracted. These signals are then input to a low-pass filter 29 to remove the color signal, and the difference between the luminance signals, ie, motion information 12, is taken out to an output terminal.

In the example shown in FIG. 4, the color signal component of the signal delayed by 525H is extracted by a bandpass filter or the like 28, the polarity of which is inverted, and then subtracted from the current signal. According to this method, the color signals are canceled out and only the difference between the luminance signals, that is, the motion information is output.

Problems to be Solved by the Invention C] Since the conventional motion detection circuit is configured as described above, it has the following problems.

That is, in the example shown in FIG. 3, the color signal is removed by the low-pass filter 29, so if only the color signal moves, no motion information will be detected and the image will be regarded as a still image. Furthermore, there is a problem in that even when a luminance signal with a high frequency near the color signal moves, it is similarly regarded as a still image.

Further, in the example shown in FIG. 4, when extracting the color signal, the extraction is usually not performed accurately in edge portions or fine pattern portions of the image due to the mixing of high frequency components of the luminance signal into the color signal. For this reason, there is a problem in that the polarity of the color signal is not correctly inverted at the edge portion of the image, and a significant difference signal appears in the output even if it is a still image, causing it to be regarded as a moving image.

The present invention has been made to solve the problems of the above two methods, and aims to provide a motion detection circuit that can accurately detect motion information with the addition of a small amount of hardware.

[Means for solving problems]

The motion detection circuit according to the present invention uses a one-frame delay circuit to obtain a current sample point, a sample point one line before the current sample point, a sample point delayed by one frame from the current sample point, and a sample point one line before the current sample point. The luminance signal (Y signal) and one color signal (C signal) are separated from each other, and the difference is determined for each of the separated Y and C signals to obtain motion information.

[Effect]

In this invention, since Y/C separation is performed by a comb filter using an IH delay circuit, accurate Y/C
(Even if incomplete Y/C separation is performed at the edges of an image that changes in the vertical direction, which is a drawback of a rectangular filter, the current sample point and the sample point delayed by one frame will still be the same at each sample point.) Since the circuit configuration performs YC separation to obtain motion information, components caused by incomplete separation are canceled out and accurate judgment can be made.

[Example]゛ Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a motion detection circuit according to an embodiment of the present invention, in which 30a and 30b are 1-line delay circuits, 31 is a 524-line delay circuit, 20.21 is an addition circuit, 22. 23. 24゜25 is a subtraction circuit, 26
11 is a determination circuit that detects motion information from two difference signals;
indicates motion information.

Further, 5 and 7 are the Y signal and C signal separated by the comb filter at the current sample point. 6.8 is the Y signal and C signal separated at the same sample point of the previous frame.

Next, the operation will be explained. In this embodiment, the Y signal 5.6 and the C signal 7.8 are detected separately, and the difference 9 between these signals is determined (difference between the Y signals).

10 (C (difference in No. 8)) is detected, and if there is a significant difference in either or both of them, it is regarded as a moving image.

This will be explained in detail with reference to FIGS. 2(a) and 2(b).

Figure 2 shows time in the horizontal direction and TV screen in the vertical direction (vertical direction)
, and a, to a3. b+ to b indicate scanning lines of the previous frame and current frame. Furthermore, the scanning lines indicated by x in the figure are not used here.

Using the still image of FIG. 2(a) as an example, detection of the presence or absence of motion information regarding point bt will be described. The human input signal is delayed by each delay circuit 30a, 30b, 31, as shown in Fig. 2(a).
al + at * bI + b shown in is obtained. Then, a, and a2 are arranged, and b! A Y signal is extracted by adding the signals in an adder circuit 20.21, and a C signal is extracted by subtracting them in a subtracter circuit 22.23. At this time, if there is a change in the image in the region indicated by c-d, Y/C separation cannot be performed completely due to the drawbacks of the comb filter described above. That is, in the signals obtained at the outputs 5, 7, 6, and 8 of each adder circuit and subtracter circuit, the C signal leaks into the Y signal, or the Y signal leaks into the C signal. However, according to this embodiment, since the Y and C signals 5, 7 and 6, 8 are obtained by the same circuit configuration, the leakage of the signals is considered to be the same, and these signals are sent to the subtraction circuit 2.
By subtracting 4.25, the leakage is canceled out, and the output 9゜10 contains an accurate difference signal (motion information).
is obtained.

Next, using FIG. 2(b) as an example, we will explain motion information detection regarding the bt point in the case of a moving image.As shown in FIG.
If there is an image change in the c-d region, Y/C separation by al, a2, s, , b can be performed accurately, and Y
An accurate motion +R6 is obtained from the difference between the signal and the C signal (output 9.10 of the subtraction circuit 24.25).

〔Effect of the invention〕

As described above, according to the present invention, the current sample point, the sample point one line before the current sample point, the sample point delayed one frame, and the sample point one line before the current sample point are obtained using the one frame delay circuit, and these The luminance signal (Y signal) and color signal (C signal) are separated for each, and the difference is calculated for each of the separated Y and C signals to obtain motion information, so the drawbacks of conventional motion detection circuits are minimized. This can be eliminated by adding hardware, which has the effect of making it possible to accurately detect motion information.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a motion detection circuit according to an embodiment of the present invention, and FIGS. 2(a) and 2(b) show the relationship between scanning lines and frames on a TV screen for explaining the present invention in detail. 3 and 4 are diagrams showing conventional motion detection circuits, respectively. 1...Input signal, 20.21...Addition circuit, 22~
25... Subtraction circuit, 26... Movement determination circuit. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] (1) In a motion detection circuit that detects motion information of a subject included in a composite color television signal, the current sample point and the sample point one line before it, and the sample point one frame before the current sample point and its one line. a delay means for simultaneously outputting signals of previous sample points as first to fourth signals, and a first luminance signal for extracting a first luminance signal by adding the first signal and the second signal. and a second addition circuit that adds the third signal and the fourth signal to extract a second luminance signal, and subtracts the first signal and the second signal. a first subtraction circuit that extracts the first color signal; and a third subtraction circuit that extracts the first color signal;
a second subtraction circuit that extracts a second color signal by subtracting the first luminance signal and the second luminance signal; and a third subtraction circuit that subtracts the first luminance signal and the second luminance signal to remove leakage of the color signal. a third subtraction circuit that outputs a luminance signal; and a fourth subtraction circuit that subtracts the first color signal and the second color signal to output a third color signal in which leakage of the luminance signal is removed. A motion detection circuit comprising: a subtraction circuit; and a determination circuit that performs motion detection using the third luminance signal and the third color signal as motion information.