JPS6170888A - Motion detecting circuit of color television signal - Google Patents

Abstract

PURPOSE:To realize the most suitable motion picture signal processing which uses motion information by obtaining motion information of a frequency component with a carrier chrominance signal of a compound color television signal as a center by a carrier chrominance signal band component of a difference signal with a signal for which two frame periods are delayed. CONSTITUTION:An NTSC color televison signal 1 is inputted in frame memories 2 and 3 of one frame capacity, the difference with a signal before one and two frame periods is calculated by substractors 4 and 7 and the low frequency component 5 is extracted. A carrier chrominance signal band component 8 is extracted from the output of the subtractor 7. A polarity of the carrier chrominance signal is returned to the original condition for two frame periods and in a static picture, the output of a BPF8 becomes zero. When any change occurs at the chrominance components, a significant signal, which is not zero, can be obtained from an absolute value circuit 9 and can be used as motion information for the chrominance components.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a motion detection circuit for a television signal, and particularly to a motion detection circuit for detecting motion of a subject included in a composite color television signal in which a color difference signal is superimposed on a luminance signal modulated at a subcarrier frequency. The present invention relates to a circuit for extracting motion information of a color signal portion of a color signal.

[Background of the invention]

In a composite color television signal, the Wi transmission signal polarity is inverted at each scanning edge, and is also inverted between the current scanning line and the scanning line one frame before. Therefore, when extracting object motion information contained in a television signal, a significant difference signal appears even in a still image because the simple inter-frame difference signal includes a carrier color signal component, and the correct moving area is detected. Could not be detected.

Figure 2(a) shows the configuration of the motion detection circuit used in the frame cyclic noise removal device.
The C color television signal is delayed by one frame period in the frame memory 12, and the color signal polarity inversion circuit 13 inverts the polarity of the carrier color signal to make it the same polarity as the input color television signal. 6 Subtracting from the signal If the absolute value of the subtraction result is taken by the absolute value circuit 15, a signal corresponding to the change in luminance or color difference signal between frames when the subject moves is obtained at the output terminal 11. 6 In the above configuration, The color M polarization inversion circuit 13 extracts the carrier color signal using, for example, a bandpass filter BPF and inverts its polarity. In this case, in edge portions or fine pattern portions of the image, high frequency components of the luminance signal may be mixed into the extracted carrier color signal, or a portion of the carrier color signal component may remain as the luminance signal. Therefore, the polarity of the carrier color signal is not correctly inverted at the edge portion of a still image, and the subtraction circuit 14
There was a problem in that a significant difference signal appeared in the output of , and it was considered that there was movement.

FIG. 2(b) shows a known motion detection circuit disclosed in Japanese Patent Laid-Open No. 58-130685. In the figure, a subtraction circuit 16 obtains an interframe difference signal, which is input to a low pass filter LPF 17, and its low frequency component is used as motion information. In this case, the still image is correctly determined to have no motion. However, if the subject moves, the luminance level of the subject is the same as that of the background, and only the color is different, then no significant signal will appear at the output terminal 11, and there is a problem that that part is also considered to be motionless.

FIG. 1(c) is a known example shown in Japanese Unexamined Patent Publication No. 58-130685. In the figure, a memory 18 with a capacity of 2 frames is installed, and a subtraction circuit 19 calculates the difference with a signal from 2 frame periods before, and outputs the absolute value as motion information. In this case, a still image is correctly determined to have no motion, but if a subject with strong contrast moves quickly, motion may not be detected because a signal from two frame cycles (67 ms) earlier is used. There is a problem.

[Purpose of the invention]

An object of the present invention is to solve the above-mentioned problems and provide a motion detection circuit that can accurately extract motion information of a subject in a composite color television signal.

[Summary of the invention]

In order to achieve the above object, the present invention provides motion detection for low frequency components of a luminance signal and motion detection for a carrier color signal band, and detects motion information in the carrier color signal band by NT.
It is characterized in that it is obtained from the difference signal between two frames of the SC signal.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG. In the figure, an NTSC color television signal input to input terminal 1 is input to frame memories 2 and 3 with a capacity of 1 frame connected in series, and the difference from the signal from 1 frame period and 2 frame periods ago is subtracted. Calculated by circuits 4 and 7. The inter-frame difference signal obtained by the subtraction circuit 4 is input to a low-pass filter (LPF) 5, and its low frequency component is extracted. The signal is input to a filter (BPF) 8, and its carrier color signal band component is extracted.

As already mentioned, the polarity of the carrier color signal returns to its original state every two frames, and in the case of a still image, the output of the BPF 8 becomes zero. If there is any change in the color difference signal, a non-zero significant signal is obtained from the absolute value circuit 9 and can be used as motion information for the Buddhist monk name. Therefore, the luminance signal obtained as the output of the absolute value circuit 6 By adding the motion information and the motion information for the color signal obtained as the output of the absolute value circuit 9 in the adding circuit 10, the output terminal 11 receives the NTS signal.
The motion information of the subject included in the C signal can be obtained.

〔Effect of the invention〕

According to the present invention, motion information of a frequency component centered on carrier color No. 41 of a composite color television signal is obtained from a carrier color signal band component of a difference signal with a signal delayed by two frame periods. This solves the problem of image quality deterioration in video signal processing due to a part of a still M image being regarded as a moving image or a part of a moving image being regarded as a still image. Image signal processing can be realized, and its performance will be greatly improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of an embodiment of a color television signal motion detection circuit according to the present invention, and FIG. 2 is a block diagram of a conventional motion detection circuit. 1... Input terminal, 2, 3, 12, 18... Frame memory, 4, 7, 10, 14, 16.19... Addition (subtraction) circuit, 5, 17... Low pass Filter, 6,9°15...Absolute value circuit, 8...Band pass filter, 1
1st 1riU Ton 21121

Claims (1)

[Claims] In a circuit for extracting motion information of a subject included in a composite color television signal, a frame memory capable of delaying the television signal by at least two frame periods and a subtraction circuit that takes the difference between the signal delayed by the frame memory. and a bandpass filter for extracting a frequency component centered on the carrier color signal of the composite color television signal, and a bandpass filter that extracts a frequency component centered on the carrier color signal of the composite color television signal, depending on the magnitude of the carrier color signal band component of the difference signal between two frame periods. A color television signal motion detection circuit characterized by extracting motion information of a color signal.