JPH03229596A - Motion detection circuit - Google Patents

Abstract

PURPOSE:To correctly obtain the motion information of a subject by preventing two kinds of the motion information of a luminance signal and a chrominance signal from overlapping. CONSTITUTION:A comparator 12 decides whether the output of a first absolute value circuit 6 is a significant value or not, and a selector 13 selects either the output signal of the first absolute value circuit 6 or the output signal of a second absolute value circuit 9 according to the output of the comparator 12. A zone in which difference is detected by the output signal of the first absolute value circuit 6 overlaps the output of the second absolute value circuit 9. When the output of the first absolute value circuit 6 is significant, the selector 13 selects the output of the first absolute value circuit 6, and when the output of the first absolute value circuit 6 is 0 or a very small value close to 0, it selects the output of the second absolute value circuit 9.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a motion detection circuit that extracts motion information of a subject in an apparatus that reproduces an NTSC composite television signal through digital processing.

[Prior Art] FIG. 2 is a block diagram showing the configuration of a conventional motion detection circuit disclosed, for example, in Japanese Unexamined Patent Publication No. 61-70888. (2) is the input terminal of N arriving at the input terminal (1).
A first frame memory that receives the TSC signal and delays by one frame period, (3) is the first frame memory (
2) a second frame memory which takes the output signal of (2) as its input and delays it by one frame period; (4) which inputs the output signal of
) is a subtracter using human power.

(5) is a low-pass filter (hereinafter referred to as LPF) that manually inputs the output signal of the subtracter (4), and (6) is the t
, p F (5) is the first absolute value circuit which uses the output signal manually, (7) is the N which arrives at the input terminal (1).
TSC (subtractor which receives the output signal of No. 8 and the second frame memory (3) as input, (8) is the subtracter (8)
) input is the output signal of the bandpass filter (hereinafter referred to as B
PF), (9) is a second absolute value circuit which inputs the output signal of the above B P F (8), and (lO) is a circuit that receives the output signal of the first absolute value circuit (6) and the second absolute value circuit. Absolute value circuit (
9) is an adder which uses the output signal manually; (11) is the output terminal of the adder (lO);

Next, the operation of the above configuration will be explained.

The digital NTSC signal input to the input terminal (1) is manually input to the cascade-connected first and second frame memories (2) and (3) each having a capacity of one frame.
Subtractors (4) and (7) calculate the differences between the signals from a frame period before and two frame periods ago, respectively.

The difference signal between frames obtained by the subtracter (4) is L
The signal is input to P F (5), and a luminance signal component (x) with a low horizontal frequency as shown by the hatched passband in FIG. 3(a) is extracted. On the other hand, the difference signal between the two frames calculated by the subtractor (7) is manually input to the BPF (8), and the luminance signal with a high horizontal frequency as shown by the hatched passband in Figure 3(b) is signal component and color signal component (xi
) is extracted. Since the phase of the subcarrier of the color signal returns to its original state every two frames, in the case of a still image, the above B P F
The output of (8) is τ.

If there is any change in the high-frequency components of the color signal or luminance signal, a significant non-zero signal is obtained from the second absolute value circuit (9), and the 'vJ key for the high-frequency components of the color signal and luminance signal is It can be used as information.

Similarly, in the case of a still image, the output of L P F (5) is τ. If there is any change in the low frequency component of the luminance signal, a non-flat and significant signal is obtained from the first absolute value circuit (6) and can be used as motion information for the low frequency component of the luminance signal.

Therefore, by adding the motion information obtained as the output of the first absolute value circuit (6) and the motion information obtained as the output of the second absolute value circuit (9) in the adder (10), The motion information of the subject included in the NTSC signal is obtained at the output terminal (11).

[Problems to be Solved by the Invention] Since the conventional motion detection circuit is configured as described above, the motion information of the low frequency component of the luminance signal and the motion information of the modulated color signal overlap. There has been a problem in that it is difficult to accurately obtain movement information of the subject.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a motion detection circuit that can accurately obtain ah information of a subject.

[Means for Solving the Problems] A motion detection circuit according to the present invention provides an output signal of a first frame memory that delays an input signal by one frame period, and an output signal of a low frequency component of a luminance signal between one frame from the input signal. The absolute value of the difference is determined and the absolute signal is compared with the set value, and the height of the luminance signal is determined from the output signal of the second frame memory which delays the output signal of the first frame memory by one frame period and the input signal. The present invention is characterized in that the absolute value of the difference between two frames of the gamut component and the color signal component is determined, and one of the absolute value signal and the absolute value signal of the difference between one frame is selected.

[Operation] According to the present invention, the absolute value of the difference between one frame of the low frequency component of the luminance signal obtained from the input signal and the signal delayed by one frame period, and the input signal and the signal delayed by two frame periods. By selecting one of the high-frequency component of the luminance signal obtained from the signal obtained from the chrominance signal and the absolute value of the difference between two frames of the chrominance signal component, the duplication of motion information between the luminance signal and the chrominance signal is eliminated, and the subject's Movement information can be obtained accurately.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described based on the drawings.

FIG. 1 is a block diagram showing the configuration of a motion detection circuit according to an embodiment of the present invention.
) Since (11) is the same as the conventional example shown in FIG. 2, the same reference numerals are given to the corresponding parts and detailed explanation thereof will be omitted.

In FIG. 1, (12) is a comparator that compares the output signal of the first absolute value circuit (6) with a set value.

(13) is a selector which manually selects one of the signals from the output signal of the second absolute value circuit (9) and the input and output signals of the comparator (12) and outputs the signal at the output terminal (
11).

Next, the operation of the above configuration will be explained.

Since the operations (1) to (9) are the same as the conventional example,
The explanation will be omitted. The comparator (12) is a first absolute value circuit (
6) is a significant value, and selector (1
3) connects either the output signal of the first absolute value circuit (6) or the output signal of the second absolute value circuit (9) to the comparator (1).
Select based on the output of 2).

Generally, when a subject moves, in a region where a significant difference occurs between frames in the low frequency component (x) of the luminance signal, a significant difference also occurs in the color signal. Therefore, the area where a difference is detected in the output signal of the first absolute value circuit (6) is the area where the difference is detected in the output signal of the first absolute value circuit (6).
9) is duplicated in the output.

Furthermore, while the output of the first absolute value circuit (6) is difference data obtained only from the low frequency components of the luminance signal, the second absolute value circuit (6) which overlaps the output of the first absolute value circuit (6) Since the output of the absolute value circuit (9) is difference data obtained from two types of color signals subjected to orthogonal two-phase modulation, the output of the first absolute value circuit (6) is higher than that of the second This captures the speed of the subject's movement better than the output of the absolute value circuit (9), and is suitable as motion information.

For the above reasons, when the output of the first absolute value circuit (6) is a significant value, the selector (13) selects the output of the first absolute value circuit (6) and the first absolute value circuit. If the output of (6) is O or a very small value close to 0, the output of the second absolute value circuit (9) is selected. As a result, the activity information of the subject included in the NTSC signal is obtained at the output terminal (11).

[Effects of the Invention] As described above, according to the present invention, since the motion information of the luminance signal and the color signal are configured so as not to overlap, the motion information of the subject can be accurately obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a motion detection circuit according to an embodiment of the present invention, FIG. 2 is a block diagram showing the configuration of a conventional motion detection circuit, and FIG. 3 is a frequency characteristic diagram of a horizontal filter. . (1)...Input terminal, (2), (3)...Frame memory, (4), (7)...Subtractor, (5)...
・LPF, (6), (9)... Absolute value circuit, (1
1)...Output terminal, (12)...Comparator, (13)
···selector. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] (1) A motion detection circuit that extracts motion information of a subject included in an NTSC composite television signal by digital processing, which includes a first frame memory that delays an input signal by one frame period; a first absolute value means for calculating the absolute value of the difference between one frame of the low frequency component of the luminance signal from the output signal of the frame memory of the frame memory and the input signal; and the output signal of the first absolute value means is used as a set value. The comparator to be compared and the output signal of the first frame memory are
A second frame memory that is delayed by a frame period, and a second absolute value that calculates the absolute value of the difference between two frames of the high frequency component of the luminance signal and the color signal component from the output signal of the second frame memory and the input signal. A motion detection circuit comprising: a value means; and a selector for selecting one of the output signal of the second absolute value means and the output signal of the first absolute value means.