JPH0740742B2 - Motion detection circuit for television signals - Google Patents

Description

The present invention relates to a motion detection circuit for digital television signals.

[Conventional technology]

When digitizing a television signal, a high-efficiency coding method has been considered, which reduces the average value of the number of bits per pixel. An interframe coding method is known as one of them, and there is a motion correction method as the interframe coding method. This is to obtain positional relationship information (referred to as a motion correction amount or motion vector) between the current frame and the previous frame by motion detection, operate the image of the previous frame based on the motion correction amount, and It is to take measures between them.

An example of a motion detection circuit applicable to such an interframe coding method is described in US Pat. No. 4,278,996. This motion detection is called the gradient method, and as described below, the amount of motion is calculated using frame difference and tilt information (sampling difference in the horizontal direction, line difference in the vertical direction) for all pixels in the motion area. Is to seek.

FIG. 3A shows a digital video signal of the current frame corresponding to an image having a luminance gradient. In FIG. 3, the horizontal axis represents the horizontal direction of the image, the vertical axis represents the level, and each pixel of the signal of the current frame is represented by ◯.

FIG. 3B shows a digital video signal of the corresponding image in the previous frame, each pixel being indicated by a cross. Fig. 3B
From the position of to the position of FIG. 3A, an example in which the image moves to the right by two sampling intervals is illustrated. This amount of movement is generally represented by v1. FIG. 3C shows a digital video signal of the corresponding image in the previous frame, each pixel of which is represented by Δ. From the position of FIG. 3C to the position of FIG. 3A, there is shown an example in which the image is moved to the left by two sampling intervals. This amount of movement is generally represented by v1.

In the case of the above-described movement in the right direction, focusing on the area A surrounded by the inclined portions of the previous frame and the current frame in FIG. 3A, this area A is represented by A = v1 × h. Therefore, the motion amount v1 is obtained by v1 = A / h.

The area A can be represented by an integrated value of the frame difference ΔF. The frame difference ΔF is defined as “the pixel of the previous frame subtracted from the pixel of the current frame”. Here, the frame difference ΔF means a difference between the values of pixels at the same position in each frame, as is commonly used in the field of processing digital television signals. In the example of FIG. 3, in the case of rightward movement, the value of each pixel of the signal of FIG. 3B is subtracted from the value of each pixel of the signal of FIG. 3A. The frame difference ΔF shown is obtained. For example, from the pixel value x1 in FIG. 3A, the pixel value at the same position
By subtracting y1, the frame difference ΔF (= x1−y1
<0) is obtained. Similarly, even in the inclined portion where the inclination is negative, the frame difference ΔF (= x3−y3
> 0) is obtained.

Further, the height h is obtained by integrating the sampling difference ΔE of the inclined portion. Where sampling difference ΔE
Is defined as “the current sampling pixel minus the previous sampling pixel (that is, the pixel on the left side). In FIG. 3A, for example, for two consecutive pixels, x2−
A sampling difference ΔE is formed by x1. The third sampling difference ΔE formed from the video signal of the current frame
Shown in Figure E.

If the integrated value of the absolute value of the frame difference of the moving area is represented by Σ | ΔF | and the integrated value of the absolute value of the sampling difference is represented by Σ | ΔE |, the magnitude of the horizontal motion amount v1 is Required by.

| v1 | = Σ | ΔF | / Σ | ΔE | For the movement in the left direction, the frame difference ΔF is obtained in the same manner as described above, and the result is as shown in FIG. 3F. Since the sampling difference ΔE is obtained from the signal of the current frame, it is the same as that shown in FIG. 3E. Then, the magnitude of the movement amount can be obtained in the same manner as described above.

Here, when the polarity (sign) of the frame difference ΔF and the polarity (sign) of the sampling difference ΔE are examined, as shown in FIG. 3, the following relationship is established. In the case of rightward movement, the frame difference ΔF is negative and the sampling difference ΔE is positive in the positive slope portion, and the frame difference ΔF is positive and the sampling difference ΔE is negative in the negative slope portion. . That is, in the case of rightward movement, the frame difference ΔF and the sampling difference ΔE have opposite polarities (different signs).

On the other hand, in the case of leftward movement, the frame difference ΔF is positive and the sampling difference ΔE is positive in the positive slope portion, and the frame difference ΔF is negative and the sampling difference ΔE is negative in the negative slope portion. Is. That is, in the case of leftward movement, the frame difference ΔF and the sampling difference ΔE have the same polarity (the same sign).

Therefore, the direction of motion can be known from the relationship between the polarities (signs) of the frame difference ΔF and the sampling difference ΔE. As one method for obtaining the amount of motion having a direction, the numerator is the integrated value of the frame differences of all pixels in the motion area including the positive and negative slopes, and the denominator is the integrated value of the absolute value | ΔE | of the sampling differences. In order to correspond the direction and the polarity of the amount of movement,
As the numerator (integrated value of frame difference) of this equation, when the sampling difference ΔE is positive (positive slope), the frame difference ΔE
F is added with a positive polarity and integrated, and when the sampling difference ΔE is negative (negative slope), the frame difference ΔF is added with a negative polarity and integrated.

Specifically explaining FIG. 3 by way of example, in the case of rightward movement, the polarity of ΔE is positive at a positive inclination,
The negative frame difference is added with a positive polarity and integrated, and at a negative slope, the polarity of ΔE is negative, so the positive frame difference is added with a negative polarity and integrated. After all,
The integrated value of the frame difference is negative in any of the positive and negative slopes, and the polarity of the motion amount obtained by dividing the integrated value by the integrated value of the absolute value of ΔE is negative (that is, indicating the rightward motion).

In the case of leftward movement, the positive frame difference is added with a positive polarity at a positive slope, and the negative frame difference is added with a negative polarity at a negative slope. It As a result, the integrated value of the frame differences becomes positive at any inclination, and the polarity of the obtained motion amount becomes positive (that is, indicates the leftward motion).

In the description of this specification, with respect to the above-described two integration methods of the frame difference, which are performed for each of the positive and negative slopes, adding the frame difference with a positive polarity is referred to as addition, and the integrated value of the frame difference is The addition of negative polarity with respect to is referred to as subtraction. Further, the meaning of each operation of addition operation and subtraction operation performed by an adder / subtractor described later is also the same.

In this way, the horizontal movement amount v1 having a direction can be obtained by the following equation.

v1 = Σ {ΔF · sign (ΔE)} / Σ | ΔE | However, the sign (ΔE) becomes 0 when (ΔE = 0),
When (ΔE ≠ 0), ΔE / | ΔE |.

The above idea can be applied to the two-dimensional motion as it is. That is, although the frame difference ΔF newly generated by the vertical movement is also added, since the value of the code (ΔE) is uncorrelated with the vertical movement, the frame difference ΔF generated by the vertical movement is changed to the horizontal direction. The effects of are offset. The vertical movement amount v2 is obtained by the following equation if the line difference ΔL is defined as “current line pixel minus previous line pixel”.

v2 = Σ {ΔF · code (ΔL)} / Σ | ΔL | FIG. 4 is a block diagram showing the configuration of a conventional two-dimensional motion detection circuit. In FIG. 4, a digital television signal is supplied to an input terminal 61. This digital television signal is supplied to a frame delay circuit 62 having a delay amount of 1 frame, a sample delay circuit 64 having a delay amount of 1 sampling period, and a line delay circuit 66 having a delay amount of 1 line.

Output from the frame delay circuit 62 from the input digital television signal by the subtractor indicated by 63 (pixels in the previous frame)
Is subtracted, and a frame difference ΔF is generated from the output of the subtractor 63. The subtracter indicated by 65 subtracts the output (pixel of the previous sample) of the sample delay circuit 64 from the input digital television signal, and the sampling difference ΔE is generated from the output of the subtractor 65. The output of the line delay circuit 66 (pixels on the previous line) is subtracted from the input digital television signal by the subtractor indicated by 67, and the line difference ΔL is generated from the output of the subtractor 67.

The frame difference ΔF is supplied to the two integrating circuits. One of the integrating circuits includes an adder / subtractor 71 and a register 72, and the adder / subtractor 71 is supplied with the frame difference ΔF and the output of the register 72. The other integrating circuit consists of an adder / subtractor 81 and a register.
The frame difference ΔF and the output of the register 82 are supplied to the adder / subtractor 81. The frame difference ΔF is supplied to the adder / subtractors 71 and 81 of these integrating circuits.

The adder / subtractor 71 is configured to perform one of addition and subtraction arithmetic operations according to the output of the control circuit 73. The sampling difference ΔE is supplied from the subtraction circuit 65 to the control circuit 73. When the sign of the sampling difference ΔE is positive, the addition operation is performed, and when the sign of the sampling difference ΔE is negative, the subtraction operation is performed. The control circuit 73 controls the adder / subtractor 71.

The adder / subtractor 81 is configured to perform one of addition and subtraction operation operations according to the output of the control circuit 83. The subtraction circuit 67 supplies the line difference ΔL to the control circuit 83. When the line difference ΔL has a positive sign, the addition operation is performed, and when the line difference ΔL has a negative sign, the subtraction operation is performed. The control circuit 83 controls the adder / subtractor 81.

The sampling difference ΔE is supplied to the conversion circuit 74, converted into an absolute value, and supplied to one input of the adder 75 for integration. The output of the adder 75 is supplied to the register 76, the output of the register 76 is supplied to the other input of the adder 75, and the integrated value of the absolute value of the sampling difference ΔE is taken out from the output of the register 76.

The line difference ΔL is supplied to the conversion circuit 84, converted into an absolute value, and supplied to one input of an adder 85 for integration. The output of adder 85 is fed to register 86
The output of 86 feeds the other input of adder 85
The integrated value of the absolute value of the line difference ΔL is taken out from the output of 86.

As described above, the horizontal motion v1 is obtained by adding or subtracting the frame difference ΔF in the motion area and dividing by the divider 77 by the integrated value of the absolute values of the sampling difference ΔE, and is output to the output terminal 78. This motion output v1 can be obtained.
Further, the vertical movement v2 is obtained by adding or subtracting the frame difference ΔF in the moving area by the divider 87 to obtain the line difference ΔL.
This motion output v2 can be obtained at the output terminal 88 by being divided by the integrated value of the absolute value of.

[Problems to be solved by the invention]

The motion detection by the gradient method described above has stationarity (ΔE
The continuity of the above is assumed, so an extreme value that does not satisfy this condition causes a decrease in accuracy as follows.

As shown in FIG. 5A, pixels a, b, c in the previous frame
When there is an extreme value consisting of, when one pixel moves to the left by one pixel in one frame (FIG. 5B), the frame difference ΔF becomes positive and the sampling difference ΔE becomes positive in the pixel b. Since the signs of both of them are the same, they are correctly detected as a movement to the left. On the other hand, when the extreme value shown in FIG. 5A moves to the right by one pixel (FIG. 5C), the frame difference ΔF becomes positive and the sampling difference ΔE becomes positive in the pixel b. Therefore, despite the movement in the right direction, it is erroneously detected as the movement in the left direction.

Further, when the extreme value is downward, the frame difference ΔF becomes negative and the sampling difference ΔE becomes negative regardless of whether the movement direction is left or right. Therefore, even if the true movement direction is the right direction, it is erroneously determined as the leftward movement.

Since a general television signal has extreme values everywhere, the decrease in the accuracy of motion detection due to the influence of the extreme values is a problem that cannot be ignored.

Further, the conventional motion detection circuit calculates the frame difference for all pixels in the motion area. Therefore, the processing speed of motion detection needs to be high. In order to solve this point, a simplified method is conceivable in which the motion detection is performed not for all the pixels but for a pixel (referred to as a representative point) positioned for every predetermined number of pixels. However, even in the case of motion detection using a representative point, the problem of deterioration of accuracy due to the extreme value as described above similarly occurs.

In addition, as shown in FIG. 6, all pixels a, b, c,
Unlike the case where the motion detection is performed using d, when the representative point is used, the value of the slope (sampling difference) greatly differs depending on which pixel is selected, and thus the problem that the amount of motion greatly changes occurs.

For example, when the pixel b in FIG. 6 is used as the representative point, the sampling difference ΔE is obtained by (b−a), and even if the motion amount is obtained using this, no problem arises, but the pixel a When the pixel on the left side of is used as the representative point, the sampling difference ΔE becomes 0, and the amount of motion resulting from dividing the frame difference becomes infinite. In order to prevent this, if the amount of motion is not calculated at the representative point where ΔE is 0, the accuracy of motion detection will decrease.

Therefore, an object of the present invention is to provide a motion detection circuit which has a simple structure using representative points and which prevents deterioration of motion detection accuracy.

Another object of the present invention is to provide a motion detection circuit for a television signal capable of solving the problem of deterioration in the accuracy of motion detection due to an unsteady part such as an extreme value.

[Means for solving problems]

The present invention is a motion detection circuit in which a predetermined number of pixels of a digital television signal are used as representative points, and motions are detected using these representative points.

A first aspect of the present invention relates to a representative point, delay and calculation means 7 and 8 for generating a frame difference ΔF between a current frame and a previous frame, and inclinations of a plurality of pixels before and after the current pixel of an input digital television signal. Delay and calculation means 5,9,10,21,22 (2,3,4,6,11) for generating absolute value | ΔE | av (| ΔL | av) of the average value of ΔE1, ΔE2 (ΔL1, ΔL2) , 41, 42) and an integrating means 33, 34 (53, 54) for integrating the frame difference ΔF
And the outputs of the accumulating means 33, 34 (53, 54) are input. The absolute value of the average value of the inclination of the digital television signal | ΔE | av (| Δ
L | av) and a means 35 (55) for dividing by an integrated value.

A second aspect of the present invention relates to a representative point, delay and calculation means 7 and 8 for generating a frame difference ΔF between the current frame and the previous frame, and inclinations of a plurality of pixels before and after the current pixel of the input digital television signal. Delay and calculation means 5,9,10,21,22 (2,3,4,6,11) for generating absolute value | ΔE | av (| ΔL | av) of the average value of ΔE1, ΔE2 (ΔL1, ΔL2) , 41, 42) and an integrating means 33, 34 (53, 54) for integrating the frame difference ΔF
And the outputs of the accumulating means 33, 34 (53, 54) are input. The absolute value of the average value of the inclination of the digital television signal | ΔE | av (| Δ
L | av) means (35) for dividing by the integrated value, and means (2) for determining whether or not there is continuity of inclination with respect to the current pixel of the input digital television signal from a plurality of pixels in the vicinity of the current pixel.
6,27,28,29,30,31 (46,47,48,49,50,51) and means 23,32 (46,47,48,49,50,51) for prohibiting the motion detection at the representative point where the inclination is not continuous by this judgment output. 43, 52) and a motion detection circuit for a television signal.

[Action]

Since the motion detection is performed by the average value of the inclinations ΔE1 and ΔE2 (ΔL1 and ΔL2) before and after the current pixel, it is possible to prevent the amount of motion detection from largely changing due to the difference in the pixel taken as the representative point.

Further, for the pixel (extreme value) having no steadiness, the motion detection result is prohibited, so that it is possible to prevent the accuracy from being lowered due to the extreme value.

〔Example〕

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

In FIG. 1, reference numeral 1 is an input terminal for a digital television signal. This input digital television signal is continuous digital data sampled at a predetermined sampling frequency. Gate circuits 13 to 17 described later
By this, one sample (representative point) is extracted for each predetermined region, for example, 8 lines in the vertical direction and 32 samples in the horizontal direction, and the motion detection processing is performed.

This input signal is supplied to the cascade connection of the line delay circuits 2 and 3 each having a delay amount of one line, and is also supplied to the sample delay circuit 4 having a delay amount of one sampling period. The sample delay circuit 5 is provided at the output of the line delay circuit 2.
And the sample delay circuit 6 is connected to the output of the line delay circuit 3. The sample delay circuit 9 is connected to the output of the sample delay circuit 5, and the frame delay circuit 7 is connected via the gate circuit 13.

Of the outputs of the sample delay circuit 5, the one passed through the gate circuit 13 is the current pixel of the representative point to be the object of motion detection. The output of the gate circuit 13 and the output of the frame delay circuit 7 are supplied to the subtraction circuit 8, the corresponding pixel of the previous frame is subtracted from the current pixel of the current frame with respect to the representative point, and the frame difference ΔF is output to the output of the subtraction circuit 8. Taken out.

The output of the sample delay circuit 9 is supplied to one input terminal of the subtraction circuit 10 via the gate circuit 14. This subtraction circuit 10
The output of the line delay circuit 2 via the gate circuit 15 is supplied to the other input terminal of the.

The output of the sample delay circuit 6 is supplied to one input terminal of the subtraction circuit 11 via the gate circuit 17, and the output of the sample delay circuit 4 via the gate circuit 16 is supplied to the other input terminal of this subtraction circuit 11. To be done.

These gate circuits 13, 14, 15, 16, 17 are controlled by a common representative point extraction signal from the terminal 18, and are turned on at the same time when the representative pixel current pixel S1 appears in the output of the sample delay circuit 5, The input pixel at that time is output.

Pixels near the current pixel S1 that is the representative point are line delay circuits 2,
3 and sample delay circuits 4, 5, 6 and 9 appear at each output. Second
The figure shows pixels in the vicinity of the current pixel S1. Pixel on input terminal 1
When S6 is supplied, the output of the line delay circuit 2 is 1
It is the pixel S2 before the line, and the output of the line delay circuit 3 is
The pixel S5 is two lines before, and the output of the sample delay circuit 4 is the pixel S4 one sample before. The output of the sample delay circuit 6 is the pixel S3 that is one sample before the pixel S5, and the output of the sample delay circuit 9 is the pixel S0 that is one sample before the current pixel S1.

Therefore, when the current pixel S1 is the representative point, the gate circuits 14 and 15 are
Is turned on, and the pixel S2 and the pixel S0 two samples before this are supplied to the subtraction circuit 10. The output of the subtraction circuit 10 is the sum of the two inclinations in the horizontal direction of the current pixel S1 and the pixels located before and after the current pixel S1. That is, the output of the subtraction circuit 10 is the sum of the sampling difference ΔE1 between the current pixel S1 and the pixel S0 one sample before and the sampling difference ΔE2 between the current pixel S1 and the pixel S2 one sample after (ΔE1 + ΔE2). is there. The output of the subtraction circuit 10 is supplied to the conversion circuit 21, converted into an absolute value, and further halved by the arithmetic circuit 22,
An average value | ΔE | av of the absolute values of the sampling differences is formed.

When the current pixel S1 is the representative point, the gate circuits 16 and 17 are turned on, and the pixel S4 and the pixel S3 two lines before this are supplied to the subtraction circuit 11. The output of the subtraction circuit 11 is the current pixel S1.
Is the sum of the inclination in the vertical direction between the pixel and the pixels located before and after it. That is, the output of the subtraction circuit 11 is obtained by adding the line difference ΔL1 between the current pixel S1 and the pixel S3 one line before and the line difference ΔL2 between the current pixel S1 and the pixel S4 one line after (ΔL1 +
ΔL2). The output of the subtraction circuit 11 is supplied to the conversion circuit 41, converted into an absolute value, and further calculated by the arithmetic circuit 42 as 1 /
The average value | ΔL | av of the absolute values of the line differences is formed.

The presence or absence of stationarity is checked at each representative point, and the motion amount is calculated only for the representative point having stationarity, that is, the representative point that is not an extreme value. This steadiness is achieved by using four pixels S0, S2, S3, S4 located on the left and right sides and above and below the representative point pixel S1.

The current pixel S1 is supplied from the gate circuit 13 as the input A of the comparison circuit 26, and the pixel S0 is supplied from the gate circuit 14 as the input B thereof. The pixel S2 is supplied from the gate circuit 15 as the input A of the comparison circuit 27, and the current pixel S1 is supplied as its input B. The output D of the comparison circuit 26 is (A> B), that is, (S1
> S0), it goes high and the output C of the comparison circuit 26
Becomes high level when (A <B), that is, (S1 <S0). The output D of the comparison circuit 27 is (A> B), that is, (S2> S).
At the time of 1), it becomes high level, and the output C of the comparison circuit 27 is
When (A <B), that is, (S2 <S1), the level becomes high.
Since the three pixels S0, S1, S2 are consecutive pixels in the horizontal direction, it is determined that the pixel S1 at the representative point has stationarity when (S0 <S1 <S2) or (S0>S1> S2). To be done.

When the size of 3 pixels is (S0 <S1 <S2)
When the output of the AND gate 28 becomes high level and the size of the three pixels is (S0>S1> S2), the AND gate 29
Output becomes high level. The outputs of the AND gates 28 and 29 are supplied to the OR gate 30. The output of OR gate 30 is AN
It is supplied to the D gate 23 and the AND gate 32.

The AND gate 23 has an average of absolute values of sampling differences.
ΔE | av is being supplied. On the other hand, the AND gate 32 is supplied with the frame difference ΔF from the subtraction circuit 8. Therefore, only in the case of the representative point having stationarity, the average value | ΔE | av of the absolute values of the sampling differences is supplied to the adder 24, and similarly, the frame difference ΔF is supplied to the adder / subtractor 33.

The adder 24 constitutes an integrating circuit together with the register 25, and the integrated value of | ΔE | av is obtained at the output of the register 25. The adder / subtractor 33 constitutes an integrating circuit together with the register 34, and
The integrated value of the frame difference ΔF is obtained at the output of 34. The adder / subtractor 33 is controlled so as to perform an addition operation when the output of the AND gate 28 is at a high level when the inclination is positive, and to perform a subtraction operation when the output of the AND gate 28 has a negative inclination where the output becomes a low level. To be done.

The movement in the horizontal direction is obtained by the divider 35 by adding or subtracting the frame difference ΔF in the movement area and dividing the sum by the absolute value of the average value of the sampling differences. A horizontal motion output is obtained at the output terminal 36 of the divider 35.
This motion output has its sign bit indicating the direction of motion,
The value indicates the amount of movement.

A configuration similar to the horizontal processing described above is provided in the vertical direction. As the input B of the comparison circuit 46, the current pixel S1
Of the current pixel S1 as the input A of the comparison circuit 46.
The pixel S4 after the line is supplied. The current pixel S1 is supplied as the input A of the comparison circuit 47, and the pixel S3 one line before the current pixel is supplied as the input B of the comparison circuit 46. The output C of the comparison circuit 46 and the output C of the comparison circuit 47 are AND gate 4
8 is supplied to the AND gate 49. Output C of comparison circuit 46
Becomes high level when (S4> S1), and its output D
Goes high when (S4 <S1). The output C of the comparison circuit 47 becomes high level when (S1> S3), and its output D becomes high level when (S1 <S3).

Therefore, the output of the AND gate 48 becomes high level when (S4>S1> S3), and the output of the AND gate 49 becomes (S4 <S1 <S
It becomes high level at 3). These AND gates 48 and
The output of 49 is supplied to the OR gate 50. The output of the OR gate 50 is supplied to the AND gate 43 and the AND gate 52.

The AND gate 43 displays the average value of the absolute values of the line differences | ΔL | av
Is being supplied. The frame difference ΔF is supplied from the subtraction circuit 8 to the AND gate 52. Therefore, the average value of absolute values of line differences | Δ
L | av is supplied to the adder 44, and similarly, the frame difference ΔF is supplied to the adder / subtractor 53.

The adder 44 constitutes an integrating circuit together with the register 45, and the integrated value of | ΔL | av is obtained at the output of the register 45. The adder / subtractor 53 constitutes an integrating circuit together with the register 54, and
The integrated value of the frame difference ΔF is obtained at the output of 54. The adder / subtractor 53 is controlled so as to perform addition operation when the output of the AND gate 48 is at a high level when the inclination is positive, and when the output of the AND gate 48 has a negative inclination where the output is at a low level. To be done.

The movement in the vertical direction is obtained by the divider 55 by adding or subtracting the frame difference ΔF in the movement area and dividing the sum by the integrated value of the absolute values of the average values of the line differences. This divider 55
A vertical motion output is obtained at the output terminal 56 of the. In this motion output, its sign bit indicates the direction of motion, and its value indicates the amount of motion.

〔The invention's effect〕

According to the present invention, when performing motion detection using a representative point, the average value of a plurality of points before and after the representative point is taken as a sampling difference or a line difference, so that a simple configuration using the representative point is used. In spite of this, it is possible to realize a motion detection circuit in which a decrease in the accuracy of motion detection is prevented.

For example, even when the pixel on the left side of the pixel a in FIG. 6 described above is used as the representative point, the sampling difference between this representative point and the pixel a contributes, so that the problem that the sampling difference becomes 0 can be avoided. Furthermore, when the value of the representative point is different from the original value due to noise, there is an advantage that the influence of this noise on the inclination is reduced and the accuracy can be improved.

Further, according to the present invention, since the motion detection in the non-stationary part such as the extreme value is prohibited, it is possible to solve the problem that the accuracy of the motion detection by the non-stationary part is lowered.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a schematic diagram used for explaining an embodiment of the present invention, and FIG. 3 is a schematic diagram used for explaining motion detection by a gradient method. Fourth
FIG. 5 is a block diagram of a conventional motion detection circuit, FIG. 5 and FIG.
The figure is a schematic diagram used for explaining the problems of the conventional motion detection circuit. 1: Digital television signal input terminal, 2, 3: Line delay circuit, 4,5,69: Sample delay circuit, 7: Frame delay circuit, 8,10,11: Subtraction circuit, 26,27,46,47 : Comparison circuit, 33,5
3: Adder / subtractor, 35,55: Divider, 36,56: Output terminal.

Claims (2)

[Claims] 1. In a motion detection circuit, wherein a predetermined number of pixels of a digital television signal are used as representative points, and motion detection is performed using these representative points. A delay and calculation means for generating a frame difference which is a difference between pixels, and a delay and calculation means for generating an average value of inclinations of a plurality of pixels before and after a current pixel of the digital television signal in a horizontal direction or a vertical direction, From the integration means for integrating the frame difference corresponding to the polarity of the inclination, and the means for outputting the motion amount by dividing the output of the integration means by the integrated value of the absolute values of the average values of the inclinations. A motion detection circuit for television signals, characterized in that 2. A motion detection circuit for detecting motion using a predetermined number of pixels of a digital television signal as a representative point, and in the motion detecting circuit using this representative point, the same position between the current frame and the previous frame with respect to the representative point. A delay and calculation means for generating a frame difference which is a difference between pixels, and a delay and calculation means for generating an average value of inclinations of a plurality of pixels before and after a current pixel of the digital television signal in a horizontal direction or a vertical direction, Integrating means for integrating the frame difference corresponding to the polarity of the inclination, means for dividing the output of the integrating means by the integrated value of the absolute values of the average values of the inclinations, and the present of the digital television signal. Judgment means for judging whether or not there is a change in the polarity of the inclination with respect to a pixel by using a plurality of pixels in the vicinity of the current pixel; Motion detecting circuit of a television signal, characterized in that it consists of a means for inhibiting movement detection in the representative point there is a change in the.