JP2003244660A - Motion detection circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To generate a motion detection signal high in response at motion start and end. <P>SOLUTION: The motion detection circuit includes: a circuits 102, 103, 105, 106 for generating an inter-frame motion detection signal d12 from a signal s10 after one field of a current field and a signal s12 before one field; circuits 102 to 104, 107, 108 for generating an inter-frame motion detection signal d13 from a current field signal s11 and a signal s13 before two fields; circuits 102, 103, 109 to 112 for generating an inter-field motion detection signal from the current field signal s11 and the signal s12 before one field; a maximum value detection circuit 114 for generating a motion detection signal from motion detection signals d12, d13, d11; and a switch 113 for turning on/off an output of the motion detection signal d11 to the maximum value detection circuit 114 in response to the motion detection signal d12 or/and d13. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motion used for adaptively converting a moving part and a still part of an image in a device for converting an interlaced scanning line signal of a television into a non-interlaced scanning line signal. The present invention relates to a motion detection circuit that detects motion in an interlaced video signal and generates a motion detection signal.

[0002]

2. Description of the Related Art FIG. 4 is a block diagram of a conventional motion detection circuit, which is disclosed in, for example, Japanese Patent Laid-Open No. 2001-223995. In FIG. 4, 401 is an interlaced video signal input terminal, and 402, 403, 406, 40.
7 and 408 are field memories, 404 and 411 are subtractors, 405 and 412 are absolute value circuits, 409 is a line memory, 410 is an average value circuit, 413 is a switch, 414 is a maximum value detection circuit, and 415 is a motion detection signal output. It is a terminal.

In the conventional motion detecting circuit of FIG. 4, the interlaced video signal s40 input to the input terminal 401 is input.
Is input to the field memory 402, and the signal s41 delayed by one field is output from the field memory 402. The signal s41 is input to the field memory 403, and the field memory 403 outputs the signal s42 delayed by one frame.

Current signal s40 and one-frame delayed signal s42
Is input to the subtractor 404 to calculate the difference, the signal output from the subtractor 404 is converted into an absolute value by the absolute value circuit 405, and the absolute value circuit 405 outputs the inter-frame motion detection signal d42. The inter-frame motion detection signal signal d42 is delayed by one field in the field memories 406, 407, 408, and
Delayed inter-frame motion detection signals d43, d44 and d45 are output from 407 and 408, respectively. The inter-frame motion detection signals d42 and d43 are input to the maximum value detection circuit 414, and the inter-frame motion detection signals d44 and d45 are input to the switch 413.

The signal s41 is input to the line memory 409 and delayed by one line. The signal s41 and the signal obtained by delaying the signal s41 by one line in the line memory 409 are input to the average value circuit 410, and the average value of these signals is calculated to move the sample point to the same position as the current signal s40. Signal is generated. The difference between the current signal s40 and the signal output from the average value circuit 410 is input to the subtractor 411, the difference is calculated, and the signal output from the subtractor 411 is converted into an absolute value by the absolute value circuit 412, and the absolute value circuit 4
An inter-field motion detection signal d41 is output from 12. The inter-field motion detection signal d41 is sent to the switch 4
13 is input.

Since the inter-field motion detection signal d41 is generated by correcting the shift of the sampling points between fields as described above, when a still image signal having a high frequency in the vertical direction is input, Video that is not actually a video may be erroneously recognized as a video. Therefore, the switch 41
3, the delayed inter-frame motion signals d44, d45
Is turned on and the inter-field motion detection signal d41 is passed,
It outputs to the maximum value detection circuit 414. As a result, the inter-field motion detection signal d41 causes the maximum value detection circuit 414 only when the inter-frame motion detection is a moving image.
Entered in.

The maximum value detection circuit 414 outputs the maximum signal of the inter-frame motion detection signals d42 and d43 and the inter-field motion detection signal d41 controlled by the switch 413 to the output terminal 415 as a motion detection signal.

[0008]

However, in the conventional motion detection circuit as described above, since the motion detection is performed using only the signal delayed from the field in which the motion detection signal is generated, when the motion starts or There is a problem in that the responsiveness when the movement stops becomes poor and the image quality deteriorates.

The present invention has been made in order to solve such a conventional problem, and provides a motion detection circuit capable of generating a motion detection signal having high responsiveness at the start and end of motion. That is the purpose.

[0010]

According to a first aspect of the present invention, there is provided a motion detection circuit which detects a motion in an interlaced video signal to generate a motion detection signal. First inter-frame motion detection signal generating means for generating a first inter-frame motion detection signal by taking a difference between one frame between the video signal and the video signal one field before the current field; A second 1-frame motion detection signal generating means for generating a second 1-frame motion detection signal by obtaining a 1-frame difference between the video signal of the current field and the video signal 2 fields before the current field. And the difference between the field of the video signal of the current field and the video signal of the field one field before the current field. Inter-field motion detection signal generation means for generating an inter-field motion detection signal, and motion detection signal generation for generating a motion detection signal using the first and second one-frame motion detection signals and the inter-field motion detection signal Means and control means for controlling the inter-field motion detection signal output to the motion detection signal generating means in accordance with the first or / and second one-frame inter-frame motion detection signal.

According to a second aspect of the present invention, in the first aspect, the control means outputs the inter-field motion detection signal to the motion detection signal generating means by the first or second one frame. It has a switch that is turned on / off according to the inter-motion detection signal.

According to a third aspect of the present invention, there is provided the motion detection circuit according to the first aspect, wherein the control means sets the output sensitivity of the inter-field motion detection signal output to the motion detection signal generation means to the first or / and the 2 has a sensitivity control circuit which adjusts according to the motion detection signal for 1 frame.

According to a fourth aspect of the present invention, in the motion detection circuit according to the first aspect, a difference between two frames of a video signal one field after the current field and a video signal three fields before the current field is obtained. A two-frame motion detection signal generating means for generating a two-frame motion detection signal, and a limiting means for limiting the first and second one-frame motion detection signals according to the two-frame motion detection signal. Further, the control means controls the inter-field motion detection signal according to the limited first or / and second inter-frame motion detection signal, and the motion detection signal generation means is limited to the above-mentioned restriction. The motion detection signal is generated using the first and second inter-frame motion detection signals and the inter-field motion detection signal.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. 1 is a configuration diagram of a motion detection circuit according to a first embodiment of the present invention. In FIG. 1, 101 is an interlaced video signal input terminal, 10
2, 103, 104 are field memories, 105, 10
7, 111 are subtractors, 106, 108, 112 are absolute value circuits, 109 is a line memory, 110 is an average value circuit, 1
13 is a switch, 114 is a maximum value detection circuit, and 115 is a motion detection signal output terminal.

In the motion detection circuit according to the first embodiment shown in FIG. 1, the interlaced video signal s10 input to the input terminal 101 is input to the field memory 102, and the video signal s11 of the current field is input from the field memory 102.
Is output. This signal s11 is the field memory 10
3 and the field memory 103 outputs a signal s12 delayed by one field from the current field signal s11.
Is output. This signal s12 is the field memory 10
4 and the field memory 104 outputs a signal s13 delayed by one frame from the current field signal s11.

The signal s10 and the signal s12 located one field before and after the current field signal s11 are subtracted by a subtractor 105.
The signal output from the subtractor 105 is converted into an absolute value by the absolute value circuit 106, and the inter-frame motion detection signal d12 is output from the absolute value circuit 106. Similarly, the current field signal s11 and this signal s11
From the signal s13 delayed by one frame to the subtractor 107, the difference is calculated, the signal output from the subtractor 107 is converted into an absolute value by the absolute value circuit 108, and the absolute value circuit 108 outputs the interframe motion. An inter-frame motion detection signal d13 delayed by one field from the detection signal signal d12 is output. Interframe motion detection signal signals d12 and d1
3 is input to the maximum value detection circuit 114 and the switch 113.

The signal s12 is input to the line memory 109 and delayed by one line. The signal s12 and the signal obtained by delaying the signal s12 by one line in the line memory 109 are input to the average value circuit 110, and the average point of these signals is calculated to determine the sampling point as the current field signal s1.
A signal that is moved to the same position as 1 is generated. The difference between the current field signal s11 and the signal output from the average value circuit 410 is input to the subtractor 111 and the difference is calculated. The signal output from the subtractor 111 is converted into an absolute value by the absolute value circuit 112, and the absolute value is calculated. The inter-field motion detection signal d11 is output from the circuit 112. The inter-field motion detection signal d11 is input to the switch 113.

Since the inter-field motion detection signal d11 is generated by correcting the shift of the sampling points between fields as described above, when a still image signal having a high frequency in the vertical direction is input, Video that is not actually a video may be erroneously recognized as a video. However, the inter-field motion detection signal d11 is moving at a specific sample point even though there is motion only by observation between frames, such as a video in which a horizontal striped pattern moves in the vertical direction or a video in which a plurality of the same objects move. The above motion can be detected in a signal that does not seem to be detected and cannot be detected only by motion detection between frames. Therefore, the switch 113
Turns on to pass the inter-field motion detection signal d11 and output it to the maximum value detection circuit 114 only when it is determined that one of the inter-frame motion signals d12 and d13 has a value (there is motion).

The maximum value detection circuit 114 outputs the maximum signal of the inter-frame motion detection signals d12 and d13 and the inter-field motion detection signal d11 controlled by the switch 113 to the output terminal 115 as a motion detection signal.

As described above, according to the first embodiment, the current field signal s11, the signals s12 and s13 of the preceding two fields and the signal s1 of the subsequent one field s1.
0 is used to generate inter-frame motion detection signals d12 and d13, and an inter-field motion detection signal d11 is generated using the current field signal s11 and the signal s12 of the preceding one field, and these inter-frame motion detection signals are generated. d12, d13 and inter-field motion detection signal d
By generating the motion detection signal from 11, it is possible to improve the responsiveness of the motion detection at the start and end of the motion, and thereby suppress the image quality deterioration that occurs at the start and end of the motion.

Embodiment 2. 2 is a configuration diagram of a motion detection circuit according to a second embodiment of the present invention. In FIG. 2, FIG.
The same or corresponding parts are designated by the same reference numerals, and 213 is a sensitivity control circuit. This Embodiment 2
This motion detection circuit is the motion detection circuit of the first embodiment (see FIG. 1) in which a sensitivity control circuit 213 is provided instead of the switch 113.

The sensitivity control circuit 213 is the maximum value detection circuit 1
The output sensitivity of the inter-field motion detection signal d11 output to 14 is adjusted according to the inter-frame motion detection signal d12 and / or d12. That is, when the motion detection value of both or one of the inter-frame motion detection signals d12 and d13 is large, the output sensitivity of the inter-field motion detection signal d11 is increased, and when the motion detection value is small, the inter-field motion detection is performed. The output sensitivity of the signal d11 is reduced. The motion detection value of the inter-field motion detection signal d11 output from the sensitivity control circuit 213 to the maximum value detection circuit 114 changes in proportion to the controlled output sensitivity, and increases as the output sensitivity increases. The lower the sensitivity, the smaller it becomes. Thereby, smoother control can be performed as compared with the case where the switch 113 is used.

The maximum value detection circuit 114 outputs the maximum signal of the inter-frame motion detection signals d12a and d13a and the inter-field motion detection signal d11 whose sensitivity is adjusted by the sensitivity control circuit 113 as a motion detection signal. 115
Output to.

As described above, according to the second embodiment, instead of the switch, the output sensitivity of the signal output to the maximum value detection circuit 114 of the inter-field motion detection signal d11 is set to the inter-frame motion detection signal d12 or / and d12. By providing the sensitivity control circuit 213 that adjusts in accordance with the above, when the output of the inter-field motion detection signal d11 to the maximum value detection circuit 114 is switched in binary using a switch, the switch is turned on / off near the threshold value. It is possible to eliminate or reduce the image quality deterioration caused by the continuous OFF and the output of the irregular motion detection signal.

Embodiment 3. FIG. 3 is a configuration diagram of a motion detection circuit according to a third embodiment of the present invention. In FIG. 3, FIG.
The same or corresponding parts are designated by the same reference numerals, and 316 is a field memory, 317 is a subtractor,
Reference numeral 18 is an absolute value circuit, and 319 and 320 are sensitivity control circuits. The motion detection circuit according to the third embodiment is different from the motion detection circuit according to the first embodiment (see FIG. 1) in that a field memory 316, a subtractor 317, an absolute value circuit 318, and sensitivity control circuits 319 and 320 are further provided. It has a different structure.

In the motion detection circuit according to the third embodiment shown in FIG. 3, the signal s13 output from the field memory 104 is used.
Is input to the field memory 316, and the field memory 316 outputs a signal s34 that is one field delayed from the signal s13. Signal s10 and signal s
34 is input to the subtractor 317, the difference is calculated, the signal output from the subtractor 317 is converted into an absolute value by the absolute value circuit 318, and the absolute value circuit 318 outputs the two-frame motion detection signal d34. The two-frame motion detection signal d34 is input to the sensitivity control circuits 319 and 320.

The inter-frame motion detection signal (one-frame motion detection signal) d output from the absolute value circuit 106.
12 is input to the sensitivity control circuit 319 and is not input to the maximum value detection circuit 114 and the switch 113. Similarly, the inter-frame motion detection signal (one-frame motion detection signal) d13 output from the absolute value circuit 108 is input to the sensitivity control circuit 320, and is not input to the maximum value detection circuit 114 and the switch 113.

The sensitivity control circuit 319 is the maximum value detection circuit 1
The output sensitivity of the inter-frame motion detection signal d12a output to the switch 14 and the switch 113 is adjusted according to the inter-frame motion detection signal d34. The inter-frame motion detection signal d12a is a signal obtained by adjusting the output sensitivity of the inter-frame motion detection signal d12. That is, when the motion detection value of the inter-frame motion detection signal d34 is large, the output sensitivity of the inter-frame motion detection signal d12 is increased, and when the motion detection value is small, the output sensitivity of the inter-frame motion detection signal d12 is decreased. . The motion detection value of the inter-frame motion detection signal d12a changes in proportion to the controlled output sensitivity, increases as the output sensitivity increases, and decreases as the output sensitivity decreases.

Similarly, the sensitivity control circuit 320 adjusts the output sensitivity of the inter-frame motion detection signal d13a output to the maximum value detection circuit 114 and the switch 113 according to the two-frame motion detection signal d34. The inter-frame motion detection signal d13a is the inter-frame motion detection signal d1.
It is a signal in which the output sensitivity of 3 is adjusted. That is, when the motion detection value of the two-frame motion detection signal d34 is large,
The output sensitivity of the inter-frame motion detection signal d13 is increased, and when the motion detection value is small, the inter-frame motion detection signal d13
Decrease the output sensitivity of 13. Interframe motion detection signal d1
The motion detection value of 3a changes in proportion to the controlled output sensitivity, increases as the output sensitivity increases, and decreases as the output sensitivity decreases.

For a momentary motion in which the camera once shifts and then immediately returns to the original position, such as when the camera shakes slightly for a moment, motion detection is limited rather than detecting a large motion for a moment. The better the quality, the better. The two-frame motion detection signal d34 plays a role of limiting the inter-frame motion detection signals d12 and d13 from sensitively reacting to the above-described momentary motion. Inter-frame motion detection signals d12, d according to the inter-frame motion detection signal d34
By limiting the output sensitivity of 13, the inter-frame motion detection signals d12 and d13 are prevented from sensitively reacting to the above-mentioned momentary motion.

The switch 113 includes a sensitivity control circuit 319,
The inter-frame motion signal d12a whose sensitivity is limited by 320,
Only when it is determined that any one of d13b is a value (moving), the inter-field motion detection signal d1 is turned on.
1 is output to the maximum value detection circuit 114.

The maximum value detection circuit 114 is the sensitivity control circuit 3
Among the inter-frame motion detection signals d12a and d13a whose sensitivity is limited by 19, 320 and the inter-field motion detection signal d11 controlled by the switch 113, the maximum signal is output to the output terminal 115 as the motion detection signal.

As described above, according to the third embodiment, by limiting the inter-frame motion detection signals d12 and d13 in accordance with the inter-frame motion detection signal d34, the camera once shifts like a small blur for a moment. Good image quality can be obtained even when a video signal of only a momentary movement that immediately returns to the original position is input.

[0034]

As described above, according to the motion detecting circuit of the first and second aspects of the present invention, the video signal of the current field, the video signal of one field before and the video signal of two fields before and the field of one field after that. The first and second inter-frame motion detection signals are generated using the video signal of
An inter-field motion detection signal is generated using a video signal before the field, and a motion detection signal is generated from these one-frame motion detection signal and inter-field motion detection signal to detect motion at the start and end of motion. Is highly responsive, which has the effect of suppressing image quality deterioration that occurs at the beginning and end of motion.

According to the motion detection circuit of the second aspect, there is provided a switch for turning on / off the output of the inter-field motion detection signal to the motion detection signal generating means in response to the first or second inter-frame motion detection signal. With the provision, it is possible to improve the responsiveness of motion detection at the start and end of the motion, and thus it is possible to suppress the image quality deterioration that occurs at the start and end of the motion.

According to the motion detection circuit of the third aspect, the output sensitivity of the inter-field motion detection signal output to the motion detection signal generating means is adjusted according to the first or / and the second inter-frame motion detection signal. By providing the sensitivity control circuit, when the output of the inter-field motion detection signal to the motion detection signal generating means is switched between two values using the switch, the switch is continuously turned on / off near the threshold value. In addition, it is possible to eliminate or reduce the image quality deterioration caused by the output of the irregular motion detection signal.

According to the motion detection circuit of the fourth aspect, by limiting the first and second inter-frame motion detection signals in accordance with the inter-frame motion detection signal, when the camera shakes slightly for a moment, Even if a video signal of only a momentary movement that shifts once and then returns to the original position is input, good image quality can be obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a motion detection circuit according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a motion detection circuit according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a motion detection circuit according to a third embodiment of the present invention.

FIG. 4 is a configuration diagram of a conventional motion detection circuit.

[Explanation of symbols]

101, 401 interlaced video signal input terminal,
102, 103, 104, 316, 402, 403, 4
06, 407, 408 Field memory, 105, 1
07,111,317,404,411 Subtractor, 1
06, 108, 112, 318, 405, 412 absolute value circuit, 109, 409 line memory, 110,
410 average value circuit, 113,413 switch,
114,414 maximum value detection circuit, 115,415
Output terminal, 213, 319, 320 Sensitivity control circuit.

Claims (4)

[Claims] 1. A motion detection circuit for detecting a motion in an interlaced video signal to generate a motion detection signal, wherein one frame of a video signal one field after the current field and a video signal one field before the current field. A first inter-frame motion detection signal generating means for generating a first inter-frame motion detection signal by taking a difference between the video signals of the current field and the video signal two fields before the current field; Second one-frame motion detection signal generating means for generating a second one-frame motion detection signal by calculating the difference between the one-frame and the video signal of the current field and one field before the current field. An inter-field motion detection signal that generates an inter-field motion detection signal by taking the difference between the video signal and the field Signal generation means, a motion detection signal generation means for generating a motion detection signal using the first and second inter-frame motion detection signals and the inter-field motion detection signal, and output to the motion detection signal generation means. A motion detection circuit, comprising: a control means for controlling the inter-field motion detection signal according to the first or / and the second one-frame motion detection signal. 2. The control means has a switch for turning on / off the output of the inter-field motion detection signal to the motion detection signal generating means in response to the first or second inter-frame motion detection signal. Claim 1 characterized by the above.
The described motion detection circuit. 3. The control means adjusts the output sensitivity of the inter-field motion detection signal output to the motion detection signal generating means according to the first or / and the second inter-frame motion detection signal. The motion detection circuit according to claim 1, further comprising a control circuit. 4. A two-frame motion for generating a two-frame motion detection signal by taking a difference between two frames of a video signal one field after the current field and a video signal three fields before the current field. The control means further comprises a detection signal generating means and a limiting means for limiting the first and second inter-frame motion detection signals in accordance with the inter-two-frame motion detection signal. Or / and controlling the inter-field motion detection signal in accordance with the second inter-frame motion detection signal, wherein the motion detection signal generating means includes the limited first and second inter-frame motion detection signals, and 2. The motion detection circuit according to claim 1, wherein the motion detection signal is generated using the inter-field motion detection signal.