JPH0451692A - Motion detection circuit - Google Patents

Abstract

PURPOSE:To optimize each motion detecting sensitivity of a luminance signal and a chrominance signal by raising the level of a color subcarrier frequency part by an emphasis circuit, and raising the motion detecting sensitivity of the chrominance signal. CONSTITUTION:A composite signal 2 supplied to an input terminal after being turned into a digital signal by an A/D converter is inputted to a 2-frame delay circuit 10 consisting of a frame memory, and two composite signals having the difference of two frames are supplied to a subtracter 12A, and a 2-frame difference signal is obtained at its output terminal. Then, this difference signal is supplied to the emphasis circuit 14, and it is outputted in form that the gain of its color subcarrier frequency part is raised. Further, the output signal of the emphasis circuit 14 is inputted to a first non-linear conversion circuit 16A, and the output signal of the first non-linear conversion circuit 16A is given the filtering of time space by a time space filter 18, and is inputted to a second non-linear conversion circuit 16B, and the removal of a noise and the decision of an area are executed, and a motion detection signal is obtained. Thus, each detecting sensitivity of the luminance signal and the chrominance signal can be optimized.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applied to a television receiver or the like by performing inter-frame processing on a still area and intra-field processing on a moving area for a composite video signal. This invention relates to a motion detection circuit that performs adaptive processing depending on the motion.

[Conventional technology]

In motion adaptive processing such as Y/C separation of television signals, so-called motion detection, which finds out which part of an image is moving, is important. If the two-frame difference signal is used, movement in both the luminance signal and the color signal can be detected. However, in the case of fast movement equivalent to 15Hz, even if there is no difference between two frames, there is movement between one frame, and 2
It cannot be detected using only the frame difference signal. Therefore, a one-frame difference signal is used, but the phase of the color subcarrier is inverted between frames, and the color subcarrier component is output. Therefore, the horizontal low-pass filter (L
PF) and removes the color subcarrier component, thereby detecting only the movement of the low frequency component in the horizontal direction of the luminance signal. The high frequency brightness signal in the horizontal direction is 15)
When the color signal moves at 1 Hz, it overlaps with the static part (OHz) of the color signal, and when the color signal moves at 15 Hz, it overlaps with the static part of the horizontal high frequency luminance signal.
Undetectable. Therefore, in the conventional motion detection circuit, the "motion signal generation circuit" disclosed in Japanese Patent Application Laid-Open No. 63-90988 is used.
As shown in , the movement of the luminance signal is detected using a difference of one frame and the difference of two frames, and the movement of the color signal is detected using a difference of two frames.

[Problem to be solved by the invention]

The amplitude of the chrominance signal is smaller than the amplitude of the luminance signal, and the chrominance signal also has a smaller amplitude than the luminance signal.

Therefore, in the conventional motion detection circuit, the motion detection sensitivity of the color signal is lower than that of the luminance signal.

For example, when there is a scene change in an anime or the like where the image changes significantly, only the color may change while the brightness remains the same. At this time, the change in color signal cannot be detected and Y/
If C separation is performed, dot interference will occur over the entire area where the color signal has changed.

Therefore, if the sensitivity is simply increased to increase the motion detection sensitivity of the color signal, the motion detection sensitivity of the luminance signal will also increase, making it susceptible to noise.

Therefore, an object of the present invention is to provide a motion detection circuit that can optimize the detection sensitivity of each of the luminance signal and color signal, is resistant to noise, and can appropriately remove dot interference.

[Means to solve the problem]

In order to achieve the above object, the present invention creates a two-frame difference signal of an input composite video signal, and is provided with an emphasis circuit that increases the gain of the color subcarrier frequency portion of this difference signal.

That is, according to the present invention, a difference signal between two frames of an input composite signal is created, and the difference signal is processed by a first nonlinear conversion circuit, a spatiotemporal filter, and a second nonlinear conversion circuit, thereby achieving noise removal and regional The motion detection circuit that performs the determination and obtains the motion detection signal is provided with an emphasis circuit that increases the gain of the color subcarrier frequency portion of the difference signal, and the output signal thereof is provided to the first nonlinear conversion circuit. A motion detection circuit is provided.

[For production]

In the motion detection circuit of the present invention, the gain of the color subcarrier, which is originally low in level, in the 2-frame-12 difference signal is increased, so the level of the color signal is optimized in relation to the level of the luminance signal. As a result, the motion detection sensitivity of the color signal can be increased without changing the motion detection sensitivity of the luminance signal.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. 1st
The figure is a block diagram showing a first embodiment of a motion detection circuit according to the present invention.

A composite signal converted into a digital signal by an A/D converter (not shown) and applied to an input terminal is input to a 2-frame delay circuit 1O consisting of a 2-frame memory. The two composite signals having a two frame difference are processed by a subtracter 12A.
, and a two-frame difference signal is obtained at its output terminal. This difference signal is applied to the emphasis circuit 14, and is output in a form in which the gain of the color subcarrier frequency portion is increased. The emphasis circuit 14 includes a horizontal bandpass filter 20 that extracts the color subcarrier frequency from the difference signal;
It has an adder 22 that adds the output and the original difference signal. The output signal of the emphasis circuit 14 is input to a first nonlinear conversion circuit 6A. The output signal of the first nonlinear conversion circuit 16A is subjected to spatiotemporal filtering by the spatiotemporal filter 18, and the output signal of the first nonlinear conversion circuit IE is
It is input to iB. As shown in Japanese Unexamined Patent Publication No. 1-178189, the first nonlinear conversion circuit 16A, the spatiotemporal filter 18, and the second nonlinear conversion circuit 16B perform noise removal and regional determination to obtain a motion detection signal. .

In the first embodiment, the gain of the color subcarrier frequency portion is increased by the emphasis circuit I4, so that the detection sensitivity of the color signal can be increased without increasing the detection sensitivity of the luminance signal.

FIG. 2 is a block diagram showing another embodiment of the motion detection circuit according to the present invention. As in the first embodiment, the digital composite signal applied to the input terminal is input to a 1-frame delay circuit 2B consisting of a 1-frame memory. The two composite signals having a one frame difference are applied to a subtracter 12B, and a one frame difference signal is obtained at its output terminal. This 1-frame difference signal is applied to the LPF 30, and is output with the color subcarrier component removed. The output signal of the LPF 30 is input to the third nonlinear conversion circuit 16c.

On the other hand, the output signal of the 1-frame delay circuit 26 is input to the 1-frame delay circuit 28 consisting of another 1-frame memory, and two composite signals having a 2-frame difference are given to the subtracter 12A, and the 2-frame delay circuit 26 is sent to its output terminal. A difference signal is obtained. This two-frame difference signal is applied to the emphasis circuit 14, and is output in a form in which the gain of the color subcarrier frequency portion is increased. The configuration of the emphasis circuit 14 is similar to that of the first embodiment shown in FIG. Emphasis circuit 14
The output signal is input to the first nonlinear conversion circuit IBA.

The first nonlinear conversion circuit IBA and the third nonlinear conversion circuit 1[i
By changing the characteristics of C, it is possible to balance 1-frame differential motion detection and 2-frame differential motion detection. That is, it is possible to set a dead area and a nonlinear slope according to the respective properties of the 1-frame difference signal and the 2-frame difference signal, and it is possible to obtain the desired S/N ratio and sensitivity, respectively.

The outputs of the first and third nonlinear conversion circuits 16A and 1I3c are respectively given to the MIX circuit 32 and combined.

The output signal of the MIX circuit 32 is subjected to spatiotemporal filtering by the spatiotemporal filter 18, and is input to the second nonlinear conversion circuit 18B. Noise removal and regional determination are performed in the first and third nonlinear transformation circuits 18A and 16c, the spatiotemporal filter I8, and the second nonlinear transformation circuit 18B, and the resultant signal is output as a motion detection signal.

Like the first embodiment, the second embodiment also has the same effect because the gain of the color subcarrier frequency portion is increased for the two-frame difference signal.

〔Effect of the invention〕

As is clear from the above detailed explanation, according to the motion detection circuit of the present invention, the level of the color subcarrier frequency part is increased by the emphasis circuit, so that the motion detection sensitivity of the color signal is prevented while preventing false detection due to noise. It is possible to optimize the motion detection sensitivity of each of the luminance signal and color signal.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a first embodiment of the motion detection circuit of the present invention, and FIG. 2 is a block diagram of the second embodiment. 10, 26.28...1 frame delay circuit, 12A. 12B...Subtractor, 14...Emphasis circuit, 1
6A. 16B, 16c... Nonlinear conversion circuit, 18... Spatio-temporal filter, 20... Horizontal BPF, 22... Adder, 30... LPF. 32...MIX circuit. Figure 1 Inventor: Yasuyuki Yama

Claims (1)

[Claims] (1) A difference signal between two frames of the input composite signal is created, and the difference signal is processed by a first nonlinear conversion circuit, a spatiotemporal filter, and a second nonlinear conversion circuit to perform noise removal and regional determination. , in a motion detection circuit for obtaining a motion detection signal, an emphasis circuit is provided for increasing the gain of a color subcarrier frequency portion in the difference signal;
A motion detection circuit characterized in that the output signal is supplied to the first nonlinear conversion circuit.