JPH02281888A - Motion detecting circuit - Google Patents

Abstract

PURPOSE:To execute the motion detection of high detection accuracy being free from a detection omission by outputting a motion detecting signal of a luminance signal without eliminating its high frequency component at the time of input of a component luminance signal. CONSTITUTION:In a one-frame difference signal detecting circuit 5, an output signal of an analog/digital converter 4 is inputted to a one-frame memory 6 and a signal delayed by a one-frame period, and an input signal of the 1-frame memory 6 are supplied to a subtractor 7, and the one-frame difference signal is obtained. Subsequently, an output signal of the subtractor 7 is inputted to a variable type low-pass filter (variable type LPF) 8, and brought to filtering by making a passing band of the variable type LPF 8 variable in accordance with a form of the input signal. In this state, in the case a component signal is inputted, by setting the passing band of the variable type LPF 8 to a wide band, and outputting the one-frame difference signal as a motion detecting signal of a luminance signal, a high frequency component of the motion detecting signal of the luminance signal is also obtained. In such a way, the motion detection of high detection accuracy being free from a detection omission can be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a signal processing circuit for television signals, and in particular to a motion detection circuit that outputs a motion detection signal used as a control signal of a motion adaptive signal processing circuit. It is related to circuits.

[Conventional technology]

A signal processing circuit for television signals according to image movement is a very effective means for obtaining high image quality. For example, in a motion adaptive luminance signal/color signal separation circuit, NT
For still images, luminance and color signal separation (hereinafter referred to as
By performing YC separation processing using line correlation on moving images, the occurrence of dot interference, cross color, etc. can be suppressed. Further, in the motion adaptive scanning line interpolation circuit, by performing interfield interpolation for still images and intrafield interpolation for moving images, line flicker can be prevented and vertical resolution can be improved.

However, such a motion adaptive signal processing circuit can achieve the above effect if the motion of one image is detected accurately, but if the motion detection is not accurate, it may not be possible to perform video processing on a still image. Still image processing will be applied to the video, which will actually increase the interference. An example of such a motion adaptive signal processing circuit is disclosed in Japanese Patent Application Laid-Open No. 123280/1983.

Now, in the above proposed example, a circuit as shown in FIG. 2 is used as a circuit for detecting the motion of an image.

FIG. 2 is a block diagram showing a conventional example of a motion detection circuit.

In FIG. 2, 31 is a television signal input terminal;
35 is an output terminal for a control signal for controlling a motion adaptive signal processing circuit (hereinafter referred to as motion adaptive circuit), that is, a motion detection signal; 32 is for delaying the television signal from the input terminal 31 by one frame period; 1 frame memory, 3
3 is a subtracter that creates a difference signal between the input signal and output signal of the one-frame memory 32, and 34 is a low-pass filter (hereinafter referred to as LPF) that limits the band of the output signal of the subtracter 33.

In this conventional example, for example, an NTSC composite color television signal (hereinafter referred to as composite signal)
is delayed by one frame period by the one frame memory 32, and a one frame difference signal is created by the subtracter 33.

Here, if the 1-frame difference signal is zero, it is assumed to be a still image, and if it is not zero, it is assumed to be a moving image, so that movement of the image can be detected.

However, in a composite signal, the luminance signal components are in the same phase and the chrominance signal components are in opposite phases between frames.
Even in a still image, a significant l-frame difference signal is generated due to the color signal component. Therefore, the color signal component is removed by the LPF 34, and the output signal of the LPF 34 is used as a motion detection signal to control the motion adaptive circuit.

[Problem to be solved by the invention]

The motion detection circuit in this conventional example uses a composite signal as an input signal, for example, 5-VH3
Component color television signals such as
When a component luminance signal (referred to as a component signal) is input, even though there is no color signal component in the one-frame difference signal, if the band is limited by the LPF 34 at the subsequent stage, the high frequency of the motion detection signal of the luminance signal Components are removed, resulting in missed detection. As a result, there is a problem in that fine pattern movement corresponding to the high frequency component of the motion detection signal of the luminance signal is regarded as a still image, resulting in incorrect control of the motion adaptive circuit, resulting in image quality deterioration such as double images. Ta.

The purpose of the present invention is to solve the problems of the prior art described above,
An object of the present invention is to provide a motion detection circuit that can perform motion detection with high detection accuracy without causing detection omissions even when a component signal is input.

[Means to solve the problem]

In order to achieve the above object, the present invention includes a motion detection circuit that includes a selection circuit that inputs a composite signal and a component luminance signal, selects and outputs either one of them, and a selection circuit that selects and outputs one of them. a 1-frame difference signal detection circuit that inputs an output signal and outputs a 1-frame difference signal obtained as the difference between the output signal and a signal obtained by delaying the output signal by 1-frame period; A 1-frame difference signal is input, the 1-frame difference signal is band-limited, and outputted as a motion detection signal of a luminance signal, and the pass band at the time of band-limiting is variable depending on the selection state of the selection circuit. expression filter means;
It was made to consist of °.

[Operation] The selection circuit selects and outputs either the input composite signal or the component luminance signal. The one-frame difference signal detection circuit obtains a one-frame difference signal from the input output signal of the selection circuit.

The variable filter means band-limits the input one-frame difference signal and outputs it as a motion detection signal of a luminance signal. At this time, the pass band of the variable filter means changes depending on the selection state of the selection circuit.

That is, for example, when a composite signal is input and the selection circuit selects the composite signal, the variable filter means sets its pass band to a narrow pass band, and also sets the component luminance signal to a narrow pass band. Enter
When the selection circuit selects the component luminance signal, it sets a wider pass band than when inputting the composite signal.

As a result, when a composite signal is input, a motion detection signal of a luminance signal with color signal components removed is obtained from the variable filter means, and when a component luminance signal is input, a motion detection signal of a luminance signal is obtained from which the color signal component is removed. Frequency components are obtained. Therefore, when a component luminance signal is input, a motion detection signal of the luminance signal can be obtained without removing its high frequency component, and motion detection can be performed with high detection accuracy without any detection omissions.

(Example〕 An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is a block diagram showing a motion detection circuit as an embodiment of the present invention.

In Fig. 1, l is the input terminal of the composite signal, 2
is the component luminance signal input terminal, 3.18 is the selection circuit, and 4.20 is the analog/digital converter (hereinafter referred to as A).
DC), 5 is a one frame difference signal detection circuit, and 6 is 1
Frame memory, 7゜23 is a subtracter, 8 is a variable LPF
, 9.24 is a nonlinear conversion circuit, 10.25 is an absolute value unit,
11 and 26 are bit compression circuits, 12 is a color signal demodulation selection circuit, 13 is a band pass filter (hereinafter referred to as BPF),
Does 14.16 have an automatic color saturation system? 11 (hereinafter referred to as ACC) amplifier circuit, 15.17 a demodulation circuit, 19 a component color signal input terminal, 21 a 2-frame difference signal detection circuit, 22 a 2-frame memory, 27 a synthesis circuit, 2
1 is a noise removal circuit, 29 is a spatio-temporal processing circuit, and 30 is an output terminal for a motion detection signal.

A composite signal is input to input terminal 1, or component signals, such as a component luminance signal and a component color signal, are input to input terminal 2 and input terminal 19, respectively. When a composite signal is input, the selection circuit 3 selects the switch to the a side and outputs a composite signal, and when a component signal is input, the selection circuit 3 selects the switch to the b side and outputs a component luminance signal.

The output signal of the selection circuit 3 is converted from an analog signal to a digital signal by the ADC 4, and inputted to the one frame difference signal detection circuit 5 to obtain a one frame difference signal.

That is, in the one frame difference signal detection circuit 5, 80C4
A signal delayed by one frame period by inputting the output signal into the one frame memory 6 and the input signal of the one frame memory 6 are supplied to a subtracter 7 to obtain a one frame difference signal. The output signal of the subtracter 7 is input to the variable LPF 8 and filtered by varying the passband of the variable LPFB according to the form of the input signal.

Here, when a composite signal is input, a color signal component exists in the high frequency portion of the one frame difference signal in addition to the high frequency component of the motion amount detection signal of the luminance signal. Therefore, the passband of the variable LPFB is set to a narrow band to remove the color signal component.For example, in the NTSC system, the color signal has a center frequency of 9.58MHz and a bandwidth of 0.5 to 1.5M.
7, so at least this band can be removed as a pass band.

On the other hand, when a component signal is input, there is no color signal component in the 1-frame difference signal, so the variable L
The pass band of the PFB is set to a wide band, and the one frame difference signal is output as a motion detection signal of the luminance signal. Thereby, high frequency components of the motion detection signal of the luminance signal can also be obtained.

Note that the detailed circuit configuration of the variable LPFB will be described later.

The output signal of the variable LPF 8 is input to the nonlinear conversion circuit 9. In the nonlinear conversion circuit 9, the absolute value unit 10 includes a variable LPF.
The output signal from the absolute value unit 10 is subjected to bit compression by the bit compression circuit 11.

That is, the motion detection signal of the luminance signal input to the bit compression circuit 11 is converted into a composite signal,
If the component luminance signal is quantized with 8 bits, it is also 8 bits, so the bit compression circuit 1
In No. 1, the 8 bits are compressed to, for example, 4 bits to reduce the number of bits. Even in this case, the control of the motion adaptive circuit has 16 steps and can be performed sufficiently smoothly. Further, a small value of the input motion detection signal is regarded as noise, and bit compression is performed to set the output motion detection signal to O, thereby preventing false detection due to noise.

On the other hand, motion detection using color signals is performed as follows.

That is, when a composite signal is input, the composite signal input from the input terminal 1 is input to the chrominance signal demodulation selection circuit 12, and first, the band is limited by the BPF 13 and the signal in the chrominance signal band is extracted. Next, the ACC amplifier circuit I
4 performs ACC so that the level of the burst signal included in the output signal of the BPF 13 is constant, and obtains an almost constant signal in which fluctuations in the color signal level due to the frequency characteristics of the transmission path are corrected. ing.

Thereafter, the demodulation circuit 15 performs color demodulation of the color signal, and outputs a signal obtained by dot-sequentially multiplexing two color difference signals (RY) and (B-Y). Incidentally, although the phase of the color subcarrier is inverted between frames, the demodulation circuit 15 operates to cancel this inversion. The chrominance signal band signal input to the demodulation circuit 15 includes high frequency components of the luminance signal in addition to the chrominance signal. Therefore, the high frequency component of the luminance signal is inverted between frames and output from the demodulation circuit 15.

When a component signal is input, the component color signal does not need to be separated from the luminance signal, so input terminal 1
The component color signal inputted from 9 is first level-corrected in an ACC amplifier circuit 16, and then color demodulated in a demodulation circuit 17.

In the selection circuit 18, similarly to the selection circuit 3, when a composite signal is input, the switch is set to the a side and the output signal of the demodulation circuit 15 is output, and when a component signal is input, the switch is set to the b side. The output signal of the selection demodulation circuit 17 is output.

The output signal of the selection circuit 18 is converted from a analog signal to a digital signal by the ADC 20, and the 2-frame difference signal detection circuit 2
1 to obtain a 2-frame difference signal. Here, instead of performing the analog/digital conversion of the color signal by placing the ADC 20 immediately after the selection circuit 18, for example, the ADC 20
0 immediately after input terminal 19, and A to BPF 13.
It may be configured to input the output signal of the DC4, or if the digital signal is inputted from each of the input terminals 1 and 2.19, the output signal of the ADC4 and 20
becomes unnecessary.

In the 2-frame difference signal detection circuit 21, the output signal of the ADC 20 is input to the 2-frame memory 22, and the signal delayed by 2-frame periods and the input signal of the 2-frame memory 22 are supplied to the subtracter 23, and the 2-frame difference is detected. Get a signal. Since the high frequency component of the luminance signal and the color signal are both in phase between signals separated by two frame periods, it can be determined that there is movement when the two frame difference signal is other than 0.

Thereafter, the two-frame difference signal is input to the nonlinear conversion circuit 24, and the same processing as that performed on the motion detection signal of the luminance signal is performed. That is, the absolute value unit 25 removes the positive and negative polarities, and the bit compression circuit 26 performs bit compression.

A combination circuit 27 combines the motion detection signal of the bit-compressed luminance signal and the motion detection signal of the chrominance signal.

Then, the output signal of the synthesis circuit 27 is transferred to a noise removal circuit 28.
to remove noise from the motion detection signal. The noise removal circuit 28 performs noise removal by utilizing the fact that the motion detection signal from the noise pixel has no correlation with the motion detection signal from the surrounding pixels, thereby preventing erroneous detection of motion due to noise.

The output signal of the noise removal circuit 28 is input to the spatio-temporal processing circuit 2g, so that motion that cannot be detected by a difference between one frame, such as a motion in a fast-moving image or an image with a fine pattern, is considered to be motion. , the amount of motion detected in the spatiotemporal direction is expanded.

Then, the output signal of the spatio-temporal processing circuit 29 is used from the output terminal 30 as a control signal for the motion adaptive circuit.

The detailed circuit configuration of the variable LPFB in this embodiment will be explained using FIG. 3.

FIG. 3 is a block diagram showing a specific example of the variable LPF in FIG. 1.

In FIG. 3, 36 is a narrowband LPF (hereinafter referred to as LP
37 is a broadband LPF (hereinafter referred to as LPF
38 is a selection circuit, 39 is an output terminal,
Other details are the same as in Figure 1.

A composite signal and a component luminance signal are input to the above-mentioned birch, and the selection circuit 3 selects one of them.

Thereafter, a one-frame difference detection circuit 5 comprising a one-frame memory 6 and a subtracter 7 obtains a one-frame difference signal.

Next, the one frame difference signal is converted to LPFN3 of variable LPF8.
6 to the LPFW37. In response to input of a composite signal, the LPFN 36 performs filter processing to remove color signal components present in addition to the motion detection signal of the luminance signal. At this time, as explained in FIG. 1, the passband of the LPFN 36 is, for example, 3.58±0.
It may be sufficient to block a band of 5 to 1.5 M7.

The LPFW 37 outputs a motion detection signal of a wideband luminance signal in response to input of a component signal.

When the selection circuit 38 receives the composite signal, the selection circuit 38 selects the switch to the a side and outputs the output signal of the LPFN 36. Furthermore, when a component signal is input, the switch is set to the b side and the output signal of the LPFW 37 is output.

This makes it possible to realize a variable LPF that performs LPF processing with different passbands depending on whether the input signal is a composite signal or a component signal.

As described above, according to this specific example, the passband of the LPF that performs filter processing on the one-frame difference signal can be varied depending on the form of the input signal (composite signal/component signal). That is, when a component signal is input, since the l-frame difference signal does not contain color signal components, the pass band of the LPF is set to a wide band. As a result, the high frequency component of the motion detection signal of the luminance signal, which was removed together with the color signal component when inputting a composite signal, can be obtained when inputting a component signal, making it possible to obtain a motion detection signal with higher detection accuracy. There is an effect that it can be done.

Next, another specific example of the variable type LPFB in this embodiment will be explained using FIG. 4.

FIG. 4 is a block diagram showing an example of the variable LPF in FIG. 1.

This specific example is an example of a variable LPF that can perform LPF processing with sharper frequency characteristics when a composite signal is input by connecting LPFN (!: LPFW) in series.

In FIG. 4, 40 is a one frame difference signal input terminal;
1 is the LPFN, and the others are the same as in FIG. 3.

In FIG. 4, first, the l frame difference signal is sent to the LPFW37.
and performs wideband LPF processing corresponding to the case where a component signal is input. Furthermore, the output signal of the LPFW 37 is input to the LPFN 41 to perform narrowband LPF processing. This allows the l-frame difference signal to be directly transmitted to the LPFN4.
It is possible to obtain an output signal having a sharper frequency characteristic than that obtained by inputting the signal to the signal input signal 1.

In addition, by connecting LPFW37 and LPFN41 in series, L-E'FN41 can be configured with a simpler circuit configuration (for example,
Even if the LPFN 36 has fewer tap coefficients than the LPFN 36 shown in FIG. 3, it is possible to obtain an LPF characteristic with a narrow band similar to that of the LPFN 36.

The selection circuit 3 selects the output signal of the LPFN 41 when a composite signal is input, and selects the output signal of the LPFW 37 when a component signal is input, in the same way as in the specific example described above.

As described above, in this specific example, when a composite signal is input, two LPFs connected in series perform LPF processing with a sharper frequency characteristic than the LPF in the above-described specific example. This makes it possible to more accurately prevent color signal components from being mixed in, which has the effect of increasing motion detection accuracy.Also, to obtain the same effect as the specific example described above, This can be realized with a small circuit scale LPFN.

Next, another specific example of the variable LPF 8 in this embodiment will be explained using FIG. 5.

FIG. 5 is a block diagram showing another specific example of the variable LPFO in FIG. 1.

This specific example is an example of a variable LPF in which band characteristics can be switched with a small circuit scale by changing the tap coefficient of the LPF.

In FIG. 5, 42, 43, 44 are delay elements, 45.
46, 47, 48, 49 are coefficient multipliers with variable tap coefficients,
50 is an adder, and the other parts are the same as in FIG. 4.

In Fig. 5, the tap coefficients are set so that the 1-frame difference signal has a narrowband LPF characteristic when a composite signal is input, and a wideband LPF characteristic when a component signal is input. By setting tap coefficients to , a variable LPF can be realized.

Note that the specific setting of the tap coefficients can be easily performed by bit shifting the delayed signal, for example, by selecting coefficients for a combination of values that can be expressed by 2 to the N power.

As described above, in this specific example, the circuit scale can be reduced and power consumption can be reduced without configuring wideband and narrowband LPFs independently.

Next, another specific example of the color signal demodulation selection circuit 12 in this embodiment will be described with reference to FIG.

FIG. 6 is a block diagram showing another specific example of the color signal demodulation selection circuit in FIG. 1.

This specific example is an example of a color signal demodulation selection circuit that is intended to serve as both an ACC amplifier circuit and a demodulation circuit.

In FIG. 6, 51 is a selection circuit, 52 is an output terminal for a demodulated color signal, and the other parts are the same as in FIG. 1.

In this specific example, the selection circuit performs composite/component switching immediately after the BPF 13.

The composite signal is input to the BPF 13 to extract the color signal component, and then supplied to one input of the selection circuit 51. On the other hand, the component color signal is directly supplied from the input terminal 19 to the other input of the selection circuit 51. After selecting one of the color signal components of the composite signal and the component color signals in the selection circuit 51, the AC
The C amplifier circuit 14 performs level correction, and the demodulation circuit 15 performs color demodulation.

By doing this, in this specific example, the ACC amplifier circuit 1
4 and the demodulation circuit 15 can be used both when inputting a composite signal and when inputting a component signal, so a circuit equivalent to the color signal demodulation selection circuit 12 of FIG. 1 can be realized with a small circuit scale.

Next, another specific example of the color signal demodulation selection circuit 12 in this embodiment will be explained with reference to FIG.

FIG. 7 is a block diagram showing another specific example of the color signal demodulation selection circuit in FIG. 1.

This specific example is an example of a color signal demodulation selection circuit that performs BPF processing on component color signals as well.

In FIG. 7, 53 is a selection circuit, and the others are the 6th circuit.
Same as the figure.

First, one of the composite signal and the component color signal is selected by the selection circuit 53, and the BPF 13
After that, the ACC amplifier circuit 14 performs level correction, and the demodulation circuit 15 performs color demodulation, as in the specific example shown in FIG.

In this way, in this specific example, the component color signals also include B.
By performing PF processing, unnecessary components (for example, noise) existing in the low frequency part of the component color signal can be removed, so that the output terminal 52 has the same circuit scale as the specific example in FIG. 6 and is free of unnecessary components. Can output color signals.

Next, the two-frame difference signal detection circuit 21 in this embodiment
Another specific example will be explained using FIG.

FIG. 8 is a block diagram showing another specific example of the two-frame difference signal detection circuit in FIG. 1.

In this specific example, by outputting a one-frame difference signal when inputting a component signal, it is used as a motion detection signal of a color signal.
This is an example of a two-frame difference signal detection circuit that can obtain a motion detection signal that can represent fast motion.

In FIG. 8, 61 is an input terminal for a demodulated color signal; 54.
55 is a one-frame memory, 56 is a selection circuit, and 57 is an output terminal for a two-frame difference signal, and the other parts are the same as in FIG.

The demodulated color signal A/D converted by the ADC 20 is delayed by two frame periods in the one frame memories 54 and 55, and then sent to the selection circuit 5.
Enter 6. On the other hand, in response to input of a component signal, a signal delayed by one frame period is inputted from the one frame memory 54 to the selection circuit 56. Selection circuit 5
6 selects the switch to the a side when inputting a composite signal and outputs a signal delayed by two frame periods, and selects the b side when inputting a component signal and outputs a signal delayed by one frame period. After that, the subtracter 23 obtains a 2-frame difference signal and a 1-frame difference signal according to each input,
It is output from the output terminal 57.

That is, since the color signal component of the composite signal contains high frequency components of the luminance signal whose phase is inverted between frames, it is necessary to use the two-frame difference signal as the motion detection signal of the color signal. On the other hand, when the component color signal is input from the input terminal 19, the demodulated color signal input to the input terminal 53 does not contain the high frequency component of the luminance signal.
There is no problem in using the one-frame difference signal as the motion detection signal of the color signal.

In this way, in the specific example, when a component signal is input, a one-frame difference signal is output and used as a motion detection signal of a color signal, so a motion detection signal that can represent fast motion can be obtained.

Next, another embodiment of the present invention will be described using FIG. 9.

FIG. 9 is a block diagram showing a motion detection circuit as another embodiment of the present invention.

In this embodiment, in the process of detecting the amount of motion of the luminance signal,
When a component signal is input, by using a configuration that does not perform LPF processing on the one-frame difference signal, the motion detection signal of the luminance signal can be obtained without removing its harmonic components at all, resulting in high detection accuracy. Motion detection can be performed.

In FIG. 9, 58 is an LPF, 59 is a selection circuit, and 60
is a control circuit, and the other parts are the same as in FIG.

In this embodiment, except for the signal processing from the one-frame difference signal detection circuit 5 to the nonlinear conversion circuit 9,
This is the same as the embodiment shown in the figure.

The one-frame difference signal obtained by the l-frame difference signal detection circuit 5 is input to the LPF 58, and in response to inputting a composite signal, filter processing is performed to remove color signal components present in addition to the motion detection signal of the luminance signal. Alms, selection circuit 5
Enter 9. In addition, corresponding to the case where the component signal is input, the one frame difference signal is also input to the selection circuit 59 as a motion detection signal of the luminance signal.

The selection operation in selection circuit 59 is controlled by control circuit 60. Note that, as the control circuit 60, for example,
An input selection microcomputer (not shown) is used to control the selection circuit 3.

That is, the control circuit 60 selects the switch to the a side when the selection circuit 59 inputs the composite signal, and selects the switch to the L side.
The output signal of the PF 58 is output, and when a component signal is input, the switch is set to the b side and control is performed to output an l-frame difference signal.

However, even if a component signal is input, if the input component luminance signal is not a complete component luminance signal (for example, when a luminance signal obtained by line comb Y/C separation from a composite signal is input). If LPF processing is not performed, the color signal component mixed in the high frequency portion will be interpreted as motion even in a still image, causing erroneous motion detection.

Therefore, in this case, the control circuit 60 controls the selection circuit 59
Forcibly selects the switch to the a side and performs LPF processing even when inputting component signals to prevent erroneous motion detection.

As described above, according to this embodiment, it is possible to switch whether or not to perform LPF processing on a one-frame difference signal depending on the format of the input signal (composite signal/component signal). In other words, when inputting a component signal,
Since the color signal component is not mixed in the 1-frame difference signal,
Do not perform LPF processing. As a result, the high frequency component of the motion detection signal of the luminance signal, which was removed together with the color signal component when inputting a composite signal, can be obtained when inputting a component signal, making it possible to obtain a motion detection signal with higher detection accuracy. There is an effect that it can be done.

In addition, if an incomplete component luminance signal is input when inputting a component signal, LPF processing is forcibly performed in the same way as when inputting a composite signal. can be prevented.

Next, another embodiment of the present invention will be described using FIG. 10.

FIG. 10 is a block diagram showing a motion detection circuit as another embodiment of the present invention.

This embodiment is a motion detection circuit having a color signal demodulation selection circuit, which corresponds to the case where the input component color signal is color demodulated.

In FIG. 10, reference numeral 61 is an input terminal for a component color signal subjected to color demodulation, and the other components are the same as in FIG. 1.

This embodiment is the same as the embodiment shown in FIG. 1 described above except for the signal processing within the color signal demodulation selection circuit 12.

The color signal demodulation selection circuit 12 in this embodiment performs the same color demodulation processing as in the embodiment of FIG. 1 on composite signals, and targets signals that have already undergone color demodulation on component color signals. Therefore, the color demodulation process is omitted and the signal is directly input to the selection circuit 18.

According to this embodiment, since the color signal demodulation selection circuit 12 does not include a color demodulation process for component color signals, the motion detection circuit is compatible with the case where a signal that has already been color demodulated is input as a component color signal. This makes it possible to output a motion detection signal with the same accuracy as the embodiment shown in FIG. 1 described above.

〔Effect of the invention〕

As explained above, according to the present invention, when a component signal is input, the one-frame difference signal obtained from the component luminance signal is filtered by setting it to a wider pass band than when inputting a composite signal. Suka,
Alternatively, by not performing any filter processing, the motion detection signal of the luminance signal can be obtained without its high frequency components being removed. Therefore, it is possible to perform motion detection with high detection accuracy and no detection omissions. In addition, if the motion detection signal obtained in this way is used as a control signal for the motion adaptive circuit, the motion adaptive circuit can be accurately controlled, thereby preventing image quality deterioration due to erroneous control and obtaining higher quality images. It has the effect of saying that it can be done.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a block diagram showing a conventional example of a motion detection circuit, and FIG.
A block diagram showing a specific example of the variable LPF in the figure,
FIG. 4 is a block diagram showing another specific example of the variable type LPF in FIG. 1, and FIG. 5 is a block diagram showing another example of the variable type LPF in FIG.
6 is a block diagram showing another specific example of the color signal demodulation selection circuit in FIG. 1; FIG. 7 is another specific example of the color signal demodulation selection circuit in FIG. 1. FIG. 8 is a block diagram showing another specific example of the two-frame difference signal detection circuit in FIG. 1, FIG. 9 is a block diagram showing another embodiment of the present invention, and FIG. FIG. 3 is a block diagram showing another embodiment of the invention. Explanation of symbols 1.2, 19, 31.40.61...input terminal, 3.
18.3B, 51, 53, 56.59... selection circuit,
4.20...Analog-digital converter, 5...1 frame difference signal detection circuit, 6,32.54.55...1
Frame memory, 7, 23. 33... Subtractor, 8...
・Variable LPF, 9, 24...Nonlinear conversion circuit, 10
．． 25... Absolute value unit, 11.26... Bit compression circuit, 12... Color signal demodulation selection circuit, 13... BPF
, 14.16... ACC amplifier circuit, 15.17...
- Demodulation circuit, 21...2 frame difference signal detection circuit, 2
2...2 frame memory, 27...composition circuit, 2nd...noise removal circuit, 29...spatiotemporal processing circuit, 3
o, 35.39, 52.57...output terminal, 34.5
8...LPF, 36.41...Narrowband LPF, 3
7... Wideband LPF, 42, 43.44... Delay element, 45.46.47, 48.49... Multiplier, 5
o... Adder, 60... Control circuit. Agent: Patent Attorney Akio Namiki! 5 Figure ■ L J Figure 32, H) 37 Figure 6 Figure 7 ■

Claims (1)

[Scope of Claims] 1. A first selection circuit that inputs a composite television signal and a luminance signal of a component television signal, and selects and outputs one of them; and the first selection circuit. a 1-frame difference signal detection circuit that inputs an output signal from and outputs a 1-frame difference signal obtained as a difference between the output signal and a signal obtained by delaying the output signal by 1 frame period; and the 1-frame difference signal detection circuit. From 1
A variable type that inputs a frame difference signal, band-limits the l-frame difference signal, and outputs it as a motion detection signal, and the pass band when band-limiting changes according to the selection state of the first selection circuit. A motion detection circuit comprising: filter means; 2. The motion detection circuit according to claim 1, wherein the variable filter means includes a first filter circuit which receives the one-frame difference signal, limits the band of the one-frame difference signal, and outputs the one-frame difference signal; a second filter circuit which inputs a frame difference signal, band-limits and outputs the one-frame difference signal, and has a wider passband than the first filter circuit when band-limiting; a second selection circuit that receives output signals from the first and second filter circuits, selects and outputs one of them depending on the selection state of the first selection circuit; A motion detection circuit characterized by: 3. The motion detection circuit according to claim 1, wherein the variable filter means includes a first filter circuit which inputs the one-frame difference signal, limits the band of the one-frame difference signal, and outputs the one-frame difference signal; a second filter circuit that inputs the output signal from the first filter circuit, outputs the output signal after band-limiting the output signal, and has a pass band narrower than that of the first filter circuit as a pass band when band-limiting; and the first
and a second selection circuit which receives the output signals from the second filter circuit and selects and outputs one of them depending on the selection state of the first selection circuit;
A motion detection circuit comprising: 4. In the motion detection circuit according to claim 1, the variable filter means includes a filter circuit that inputs the one-frame difference signal, limits the band of the one-frame difference signal, and outputs the one-frame difference signal; and a second selection circuit that receives the output signal and the one-frame difference signal, and selects and outputs one of them depending on the selection state of the first selection circuit. motion detection circuit. 5. In the motion detection circuit according to claim 1, when the input one frame difference signal is a digital signal,
The variable filter means is configured by connecting in series one or more one-sample delay circuits each having a delay time corresponding to at least one sample period of the one-frame difference signal, and receives the one-frame difference signal as input. , a delay circuit array that outputs the output signal from each 1-sample delay circuit, and the 1-frame difference signal or the output signal from each 1-sample delay circuit are input, multiplied by a coefficient, and output, and the multiplied coefficient is Two or more variable coefficient multipliers whose coefficient values are switched according to the selection state of the first selection circuit, and the output signals from each variable coefficient multiplier are respectively input, and the sum of these multipliers is calculated. A motion detection circuit comprising: an adder that outputs an output; 6. The motion detection circuit according to claim 2, 3 or 4, in which the second
A motion detection circuit comprising a control circuit for controlling the selection operation of the selection circuit. 7. The motion detection circuit according to claim 5, wherein the first
A motion detection circuit comprising: a control circuit for controlling a switching operation of coefficient values in the variable coefficient multiplier according to a selection state of the selection circuit. 8. A first selection circuit that inputs the composite television signal and the luminance signal of the component television signal, selects and outputs one of them, and inputs the output signal from the first selection circuit. a 1-frame difference signal detection circuit that outputs a 1-frame difference signal obtained as the difference between the output signal and a signal obtained by delaying the output signal by 1-frame period;
variable filter means inputting a frame difference signal, band-limiting and outputting the one-frame difference signal, and having a pass band when band-limiting changes according to the selection state of the first selection circuit; A first nonlinear conversion circuit inputs the output signal from the variable filter, nonlinearly converts the output signal, and outputs the output signal, and inputs the color signals of the composite television signal and the component television signal, respectively. A color signal demodulation selection means for outputting one of the demodulated signals, and an output signal from the color signal demodulation selection means are input, and the difference between the output signal and a signal obtained by delaying the output signal by two frame periods is calculated. a 2-frame difference signal detection circuit that outputs the obtained 2-frame difference signal; a second nonlinear conversion circuit that receives an output signal from the 2-frame difference signal detection circuit, nonlinearly converts the output signal, and outputs the resultant signal;
a synthesis circuit that receives output signals from the first and second nonlinear conversion circuits, synthesizes them, and outputs them;
A noise removal circuit inputs the output signal from the synthesis circuit, removes the noise component of the output signal, and outputs the signal; A motion detection circuit comprising: a spatio-temporal processing circuit that filters and outputs the filtered motion detection signal as a motion detection signal. 9. The motion detection circuit according to claim 8, wherein the variable filter means includes a first filter circuit that inputs the one-frame difference signal, limits the band of the one-frame difference signal, and outputs the one-frame difference signal; a second filter circuit which inputs a frame difference signal, band-limits and outputs the one-frame difference signal, and has a wider passband than the first filter circuit when band-limiting; a second selection circuit that receives output signals from the first and second filter circuits, selects and outputs one of them depending on the selection state of the first selection circuit; A motion detection circuit characterized by: 10. The motion detection circuit according to claim 8, wherein the variable filter means receives the one frame difference signal;
A first filter circuit for band-limiting and outputting the one-frame difference signal; inputting the output signal from the first filter circuit, band-limiting and outputting the output signal; A second filter circuit having a narrower pass band than the first filter circuit, and output signals from the first and second filter circuits are respectively input, and the selection state of the first selection circuit is determined. a second selection circuit that selects and outputs one of the motion detection circuits according to the motion detection circuit. 11. The motion detection circuit according to claim 8, wherein the variable filter means receives the one-frame difference signal;
A filter circuit that band-limits and outputs the 1-frame difference signal; an output signal from the filter circuit and the 1-frame difference signal are input; The second option selects and outputs either one.
A motion detection circuit comprising: a selection circuit; 12. In the motion detection circuit according to claim 8, when the input one frame difference signal is a digital signal,
The variable filter means is configured by connecting in series one or more one-sample delay circuits each having a delay time corresponding to at least one sample period of the one-frame difference signal, and receives the one-frame difference signal as input. , a delay circuit array that outputs the output signal from each 1-sample delay circuit, and the 1-frame difference signal or the output signal from each 1-sample delay circuit are input, multiplied by a coefficient, and output, and the multiplied coefficient is Two or more variable coefficient multipliers whose coefficient values are switched according to the selection state of the first selection circuit, and the output signals from each variable coefficient multiplier are respectively input, and the sum of these multipliers is calculated. A motion detection circuit comprising: an adder that outputs an output; 13. The motion detection circuit according to claim 9, 10 or 11, further comprising a control circuit that controls the selection operation of the second selection circuit depending on the selection state of the first selection circuit. motion detection circuit. 14. The motion detection circuit according to claim 12, further comprising a control circuit that controls a switching operation of coefficient values in the variable coefficient multiplier according to a selection state of the first selection circuit. Motion detection circuit. 15. The motion detection circuit according to claim 8, wherein the color signal demodulation selection means includes a filter circuit that receives the composite television signal, limits the band of the composite television signal, and outputs the composite television signal; a first amplifier circuit that inputs an output signal from the first amplifier circuit and outputs the output signal with a constant level; a demodulation circuit, a second amplifier circuit that inputs the color signal of the component television signal and outputs the color signal at a constant level; and an output signal from the second amplifier circuit, a second demodulation circuit that color-demodulates and outputs the output signal; and a color signal selection circuit that receives the output signals from the first and second demodulation circuits, selects one of them, and outputs the selected signal. A motion detection circuit comprising: 16. The motion detection circuit according to claim 8, wherein the color demodulation selection means includes a filter circuit that receives the composite television signal, limits the band of the composite television signal, and outputs the composite television signal; a color signal selection circuit that inputs an output signal and a color signal of the component television signal, selects and outputs one of them; and a color signal selection circuit that inputs an output signal from the color signal selection circuit and outputs the output signal; an amplifier circuit that outputs a constant level, and inputs an output signal from the amplifier circuit,
A motion detection circuit comprising: a demodulation circuit that performs color demodulation on the output signal and outputs the resultant signal. 17. The motion detection circuit according to claim 8, wherein the color demodulation selection means inputs the color signal of the composite television signal and the component television signal, and selects and outputs one of them. a color signal selection circuit that inputs the output signal from the color signal selection circuit, and a filter circuit that band-limits and outputs the output signal; and a filter circuit that inputs the output signal from the filter circuit and controls the level of the output signal. 1. A motion detection circuit comprising: an amplifier circuit that outputs a constant value; and a demodulator circuit that receives an output signal from the amplifier circuit, performs color demodulation on the output signal, and outputs the signal. 18. The motion detection circuit according to claim 8, wherein the color demodulation selection means includes a filter circuit that inputs the composite television signal, band-limits the composite television signal, and outputs the composite television signal, and an output from the filter circuit. an amplifier circuit that inputs a signal and outputs the output signal with a constant level; a demodulation circuit that inputs the output signal from the amplifier circuit, demodulates the output signal and outputs the color demodulation circuit; A motion detection circuit comprising: a color signal selection circuit that receives an output signal and a color signal of the component television signal, selects one of them, and outputs the selected signal. 19. The motion detection circuit according to claim 8, wherein the 2
The frame difference signal detection circuit includes a first frame memory that receives the output signal from the color signal demodulation selection means and outputs a signal obtained by delaying the output signal by one frame period;
a second frame memory which inputs the output signal from the frame memory and outputs a signal obtained by delaying the output signal by one frame period; and inputs the output signals from the first and second frame memories, respectively; a selection circuit that selects and outputs one of the chrominance signal demodulation and selection means, inputs the output signal from the color signal demodulation selection means, and the output signal from the selection circuit, and outputs a difference signal obtained as the difference between them; A motion detection circuit comprising: a subtracter that performs a motion detection circuit;