JPS6057793A - Movement detection circuit - Google Patents

Abstract

PURPOSE:To improve the accuracy of detection by obtaining a frame difference signal with the polarity inversion of a chrominance signal and detecting the movement from said difference signal and the high frequency component of a luminance signal. CONSTITUTION:The composite color television signal of the NTSC system inputted to an input terminal 6 is delayed by a frame memory 7, the polarity of a carrier chrominance signal is inverted by a chrominance signal polarity inverting circuit 8 and the same polarity as that of the input signal is obtained. The output of the inverting circuit 8 is fed to a subtraction circuit 10 to output the frame difference signal. Further, an input television signal is fed to a high frequency luminance signal extracting circuit 9, where the high frequency component signal of the luminance signal is extracted and the result is fed to a movement discrimination circuit 11. The discrimination circuit 11 changes the input/ output gain of the frame difference signal depending on the magnitude of the luminance signal and outputs the result as a movement information signal.

Description

[Detailed description of the invention] The present invention relates to a motion detection circuit for color television signals.

2. Description of the Related Art Interframe encoding devices, noise removal devices, and the like that use frame memories as television signal processing circuits are known. One of the major challenges in these devices is the extraction of motion information of nuclear objects. When the television signal is monochrome, if a frame memory is used to generate an interframe difference signal, motion information of 11 objects can be extracted based on the size of the signal. On the other hand, in the case of a composite color TV signal such as an NTSG signal in which color difference signals are frequency-multiplexed, the phase of the j-parallel color signals differs between adjacent frames, so correct motion information cannot be obtained from a simple frame-to-frame difference signal. is not obtained.

FIG. 1 is a block diagram showing an example of a conventionally known motion detection circuit for NTSC television signals.
The NTSC color television signal input to the input terminal 1 is delayed by one frame in the 7 reflex memory 2, and the polarity of the carrier color signal is completely inverted in the brown signal polarity inversion circuit 3 to make it the same polarity as the input television signal. , is calculated by the difference subtraction circuit 4 between both signals. As a result, a signal close to zero is obtained at the output terminal 5 when the subject is stationary, and when the subject moves, a signal corresponding to changes in brightness and color between frames is obtained.

In the above configuration, the color signal polarity inversion circuit 3 connects the bandpass filter BPF or line memory to BPFf, f:
The carrier color signal is extracted from the output of the comb filter used and its polarity is inverted. In this case, the h signal signal component is mixed into the extracted carrier color signal in the edges and fine pattern parts of the image, and some of the carrier color signal components are left in the luminance signal, resulting in imperfections. Now. Therefore, in the edge part of the still image, the polarity of the carrier color signal is not correctly inverted, and there is a significant difference in the output of the subtraction circuit 4. Also, compared to flat subjects, complex subjects with a lot of high-frequency components can cause a significant difference signal to appear more clearly due to slight movement or signal jitter. Another drawback was that correct detection was not possible.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a motion detection circuit that can accurately extract all image motion in a television signal without overcoming the above-mentioned problems.

According to the present invention, the phase of the chrominance signal is inverted in a circuit that determines the degree of motion contained in a color television signal in which the chrominance signal is frequency-multiplexed, thereby generating a frame difference signal of the σ full color television signal. A motion detection circuit is provided, comprising: means for detecting a signal of a high frequency component of a luminance signal; and means for detecting the entire degree of motion from the frame difference signal and the high frequency luminance signal. .

Further, according to the present invention, in a circuit for detecting the degree of motion in a composite color television signal in which a color signal is frequency multiplexed, a frame difference signal obtained by adding a frame difference signal of a luminance signal and a frame difference signal of a chrominance signal, All features include means for obtaining a signal, means for obtaining a signal of a high-frequency component of a luminance signal, and means for detecting the degree of movement from the weighted sum of the frame difference signal and the high-frequency luminance signal. A motion detection circuit is obtained.

Further, according to the present invention, in a circuit for detecting the full extent of motion contained in a television signal, there is provided a means for generating a frame difference signal of a luminance signal, a means for detecting a signal of a high frequency component of the luminance signal, and a means for detecting a signal of a high frequency component of the luminance signal, and a means for detecting a signal of a high frequency component of the luminance signal, There is obtained a motion detection circuit characterized in that it is equipped with means for detecting the degree of motion from the high-frequency luminance signal and the high-frequency luminance signal.

According to the motion detection circuit of the present invention, the motion detection sensitivity is lowered in the areas where motion detection is likely to malfunction, or in the areas where the high frequency components of the luminance signal are large, in the background TV signal, so that still images are accurately detected. It becomes possible to determine that the image is a still image.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a block diagram showing the configuration of a first embodiment of the motion detection circuit according to the present invention. N input to input terminal 6
The TSC system composite color television signal is stored in frame memory 7.
A brown signal polarity inversion circuit 8 inverts the polarity of the carrier color signal to make it the same polarity as the input television signal. The color signal polarity inversion circuit 8 outputs a television signal in which the input television signal and the carrier color signal have the same polarity and are delayed by one frame, and the difference between the two signals is calculated by the subtraction circuit 10 to obtain a frame difference signal. The signal is supplied to the motion determination circuit 11. Further, the human-powered television signal is supplied to a % area coverage signal extraction circuit 9, where a high frequency component signal of the luminance signal is extracted and supplied to a motion determination circuit 11.

The motion determination circuit 11 is configured such that the input/output gain of the frame difference signal can be changed depending on the magnitude of the brightness signal, and the frame difference signal subjected to gain 9 control is outputted as a Pih information signal.

FIG. 3 is a block diagram showing an example of the high frequency luminance signal extraction circuit 9. As shown in FIG. This circuit example has a configuration in which a high-frequency luminance signal is extracted using a Kushiya filter having a two-line memory and a high-pass filter 23. The composite TV signal M input to the input terminal 13 is delayed by one horizontal period at line memo') 14.15. The multipliers 16, 17, and 18 each have a coefficient of −1#−4 2 4 , and the respective multiplication outputs are added together by an adder 19 and supplied to the bandpass filter 21 . The band pass filter 21 has a characteristic of completely passing only the signal centered at the color subcarrier frequency f, and the carrier color signal is obtained as an output.
supplied to The signal output from the line memory 14 is delayed by a delay circuit 20 to match the delay of the carrier color signal, and is supplied to a subtracter 22. A subtracter 22 subtracts the carrier color signal from the composite color television signal to obtain a luminance signal, which is supplied to a high-pass filter 23. The high-pass filter 23 has frequency characteristics that allow only high frequencies to pass through, and the red frequency component of the luminance signal is obtained as an output, and the output terminal 24
is output as a high-band luminance signal.

FIGS. 4(a) and 4(b) are diagrams illustrating the input/output characteristics of the motion determination circuit 11 for side sounds. Figure 4 (8) is a diagram showing the entire relationship between the size X of the frame difference signal and the size y of the motion information signal, and the function of y = 7 (X) is in this case y =
kg (k indicates the slope). The magnitude k of the slope changes depending on the magnitude 2 of the high-frequency luminance signal, and
Figure (b) shows the relationship between the high-frequency luminance signal and the slope? show. That is, as the magnitude of the high-frequency luminance signal increases, the slope gradually becomes smaller than 1. That is, when the high-frequency luminance signal is large, the motion detection sensitivity is completely lowered by attenuating the magnitude of the frame difference signal to obtain the motion information signal.

A method for realizing the motion determination circuit 11 having the characteristics shown in FIG. 4 is to create a read-only memory ROM'f! in which all characteristics are written.
It can be easily constructed by inputting and pulling the frame difference signal and high-frequency luminance signal to the input address using C, and obtaining the motion information η at the output.

FIG. 85 is a block diagram showing the complete structure of a second embodiment of the motion detection circuit of the present invention. In this embodiment, the frame difference signal total luminance coefficient and the color signal can be calculated separately. The composite color television signal input to the input terminal 25 is sent to the subtracter 28. The signal is supplied to an adder 29, a frame memory 26, and a high-frequency luminance signal extraction circuit 27. frame memory 2
The signal which has been multiplied by one frame period y14L at 6 is supplied to a subtracter 28 and an adder 29. At the output of the reducer 28, a signal is obtained which is a combination of the frame difference of the 6.1 coefficient number and the carrier color AJ of the 2 coefficients, and is supplied to the iL filter 30. The filter 30 has all the frequency characteristics that pass at least low frequencies and blocks the area near the set transmission wave frequency f0, and the output of the filter 30 has a frequency characteristic of 1 representing the frame difference of the luminance signal.
When the number is obtained, it is supplied to the vessel 33.

The output of the adder 29 is a signal that is a combination of the frame difference of the carrier color signal and twice the luminance (M number) and is supplied to the h filter 31. A signal representing the entire frame of the carrier color signal is obtained as an output, which is passed through a multiplier 32 with a coefficient of 1 and supplied to an adder 33. By changing the coefficient of the multiplier 32, the carrier color The gain of the complaint signal of the signal can be changed.The output of the adder 33 is a signal obtained by adding the phenome positive of the P9 signal and the frame difference of the carrier color signal, and is supplied to the motion determination circuit 34. The high-frequency luminance signal extraction circuit 27 is constructed in the same manner as shown in FIG. It has the same function as the motion determination circuit 11, and a motion 1 blue report signal is output to the output terminal 36.

FIG. 6 is a block diagram showing the configuration of an embodiment of the broom 3 of the motion detection circuit of the present invention. Since the luminance signal has a particularly large influence on motion detection, the color signal is ignored in order to simplify the hardware scale. Frame memory 38. High-frequency luminance signal extraction circuit 39. Subtractor 40
．． The filter 41.degree. motion determination circuit 42 is connected to the frame memory 26.degree. high frequency h1 degree signal extraction circuit 27.FIG. Subtractor 28. It has the same functions as the filter 30 and the motion determination circuit 34, and performs similar operations. That is, this corresponds to the case where the coefficient of the multiplier 32 in FIG. 5 is set to zero. FIG. 87 is a block diagram showing another example of the high-range luminance number a extraction circuit 39 of FIG. In order to easily detect high-band luminance signals without having to go around the entire line memory, all of the filters 63 are used to block signals near the zero frequency and near the idle transmission frequency.

The filter 63 includes delay circuits 44, 46, and 47 that delay the signal by one sampling period, a subtracter 45, and an adder 48. The absolute value of the high-frequency luminance signal obtained by the filter 63 is taken by an absolute value circuit 49, the average with the previous sample is taken by a delay circuit 50 with a delay of one sampling period and an adder circuit 51, and the signal is multiplied by 1 by a multiplier 69. is output.

FIG. 8 is a block diagram showing the configuration of a fourth embodiment of the motion detection circuit of the present invention. This embodiment shows a case where the present invention is applied to a monochrome television signal. The monochrome television (i) input to the input terminal 52 is supplied to the frame memory 5'3.subtractor 54° and to the delay circuit 56 and subtracter 57 of the high-frequency luminance signal extraction circuit 55. The frame difference signal is subjected to delay correction in a delay circuit 64 and then supplied to a motion determination circuit 61.A delay circuit 56, 58 that delays by one sampling period, a subtracter 57, 59, and a multiplier 65 with a coefficient of 7 perform delay correction on the frame difference signal. The constructed filter has a transfer function H(z) expressed by two transformations, which is given by the following equation.

The absolute value of the high-frequency luminance signal obtained at the output of the multiplier 65 is taken by an absolute value circuit 60, and the average with the previous sample is taken by a delay circuit 66, an adder 67, and a multiplier with coefficient i, and then output. The signal is supplied to the motion determination circuit 61. The motion determination circuit 61
It has the same function as the motion determination circuit 11 shown in the figure, and outputs a signal indicating the degree of motion from the frame difference signal and the high-frequency luminance signal and supplies it to the output terminal 62.

In addition, in FIG. 2, the color signal polarity inversion circuit 8 and the frame memory 7
It is possible to share the line memory required by the sieve coverage degree signal extraction circuit 9 by changing the position of the sieve area coverage signal extraction circuit 9. Alternatively, all of the red region luminance signals of the previous frame may be extracted and used to perform motion detection. In FIGS. 2 and 5, if there is a delay difference between the frame difference signal input to the motion determination circuit 11.34 and the high frequency y-temperature signal, this is completely corrected.

The high-frequency luminance signal used for motion determination is
A method of detecting the power of the signal component and using it, or a method of determining the average value of the amplitude of several samples before and after the high-frequency luminance signal component and using this, etc., may be used.

In the embodiments shown in FIGS. 2 and 5, the motion information signal obtained at the output terminal 12.degree. 36 is close to zero in the still image portion, and is a signal with an appropriate amplitude increase in the moving image portion. When classifying the image from stillness to motion according to the degree of motion, this output signal can be divided into magnitudes by comparing the vibration with some appropriate threshold values. Also this output signal'
It can be used in a noise removal circuit or the like that changes the processing algorithm by converting it into a variable coefficient k satisfying O≦k<1 by using kROM.

Although the function y −f (X) shown in FIG. 4(a) is a straight line, the frame difference signal
As shown in the figure, a non-linear characteristic may be used such that a frame difference signal below a certain value is regarded as noise and the motion information signal is output as zero. In FIG. 5, the frame difference signal is divided into a luminance signal component and a carrier color signal component. At this time, the motion detection sensitivities of both components do not necessarily need to match. Even if the movement is the same in brightness and color, the frame difference in the color signal tends to be larger than the frame difference in the brightness signal due to the leakage of the high-frequency moderation signal and signal jitter, so the frame difference signal tends to be larger than that in the color signal. It is desirable that the total gain of the chrominance signal be smaller than 1 to reduce the degree of motion detection based on this frequency component.

In the embodiment shown in FIG. 5, the motion information conversion circuit 35 is composed of an adder 33 and a motion determination circuit 34, but it can also be realized by a read-only memory ROM or the like.

For example, there are three types f, <(transition), /2 as shown in Figure 10.
It is also possible to realize a configuration that has the input/output characteristics of (X), fs<phantom, and adaptively switches depending on the magnitude of the high-band luminance signal.

According to the present invention, signals corresponding to motion information that can be easily distinguished between still images and moving images can be obtained for composite color television signals such as the NTSC system, and various types of processing can be performed using the motion information of the subject. Applicable to circuits.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a block diagram showing the configuration of a conventional motion detection circuit, FIG. 2 is a diagram showing a first embodiment of the present invention, and FIG. 3 is a block diagram showing the configuration of a conventional motion detection circuit. A block diagram showing a specific example of the luminance signal extraction circuit, FIGS. 4(a) and 4(b) show the motion determination circuit 11.
A diagram showing a specific example of zero input/output characteristics, FIG. 5 is the second example of the present invention.
6 is a block diagram showing a third embodiment of the present invention. FIG. 7 is a block diagram showing another example of the high-frequency luminance signal extraction circuit 39 used in the present invention. FIG. 8 is a block diagram showing the fourth embodiment of the present invention, and FIGS. 9 and 10 are diagrams showing other examples of input/output characteristics of the motion determination circuit 34. In the figure, 2.7, 26, 38.53... frame memory, 3, 8... color signal polarity inversion circuit, 4, 10,
22゜2B, 40, 45.54, 57.59... Subtractor, 11.34゜42.61... Movement determination circuit, 14
．． 15... line memory, 16.17.18.32.
65,68.69...n power, 20°56.58.4
4, 46.47, 50, 64.66...delay circuit, 1
9.29, 33.48.51.67...adder, 21
. . . Bandpass filter, 23 . . . High-pass communication filter, 30, 31° 41 . . . Filter, 9, 27, 39.
59... High frequency luminance signal extraction circuit, 35... Conversion circuit, 49.60... Absolute value circuit, 1.6, 13.25,
37.52 river input terminals, 5, 12, 24. 36, 43, 62... Output terminal metals are shown respectively. O 1 Fig. 2 (1 O 4 Fig. x Fig. 5 O 6 Fig.? 7 Fig. 5 Soo 8 Fig. O Fig. 9 x Fig. 10 Fig.

Claims (3)

[Claims] (1) In a circuit for detecting the degree of motion included in a composite color television signal in which color signals are frequency multiplexed, means for inverting the polarity of the color signal to obtain a frame difference signal of the composite color television signal, and A motion detection circuit comprising means for detecting a signal of a Takagi component of a signal, and means for detecting a degree of motion from the frame difference signal and the Takagi luminance signal. (2) In a circuit that detects the degree of motion included in a composite color television signal in which color signals are frequency multiplexed, a frame difference signal that is the sum of the frame difference signal of the luminance signal and the frame difference signal of the chrominance signal is used. 1. A motion detection circuit comprising: means for detecting a Takagi component of a luminance signal; and means for detecting a degree of motion from the weighted sum of the frame difference signal and the Takagi luminance signal. (3) means for obtaining a frame difference signal of a luminance signal in a circuit for detecting the degree of motion included in a television signal; a means for obtaining a total signal of the Takagi component of the luminance signal; and the frame difference 4
8. A motion detection circuit characterized by comprising means for detecting the degree of motion from No. 8 and a Takagi luminance signal.