JP2000069499A - Video signal processing circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a movement adaptation-type three-dimensional YC (luminance/color) separation operation and a picture still-operation and to reduce a frame memory. SOLUTION: The input of a first frame memory 111 is switched to a composite video signal and a luminance signal by a first selector 110. The input of a second frame memory 113 is switched to the output of the first frame memory 111 and a chrominance signal by a second selector 112. In the case of a picture still-operation, a fourth selector 121 switches a separated luminance signal and the output of the first frame memory. A fifth selector 123 switches the separated chrominance signal, and the output of a coefficient unit. The luminance signal from the first frame memory is returned to the input of the first frame memory through the fourth and first selectors. The chrominance signal from the second frame memory is phase-inverted by the coefficient unit 122. It is returned to the input of the second frame memory 113 through the fifth and second selectors. Then, the same luminance signal and the chrominance signal whose phase is inverted are still-operated for respective frames.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a video signal processing circuit for separating a composite video signal into a luminance signal (Y signal) and a chrominance signal (C signal), and more particularly to a motion adaptive three-dimensional YC separation circuit.

[0002]

2. Description of the Related Art In a television receiver, it is necessary to input a composite video signal in which a luminance signal and a chrominance signal are multiplexed and to separate the composite signal into a luminance signal and a chrominance signal. There is an original YC separation circuit. Conventionally,
Techniques for improving the quality of video signals using a frame memory include three-dimensional YC separation and frame NR (Noise Reduct).
ion) exists. Since these have almost reached the level of completion as technologies, new applications are currently being sought, and for example, an integrated system with a TBC (Time Base Corrector) is being studied. As such a motion-adaptive three-dimensional YC separation circuit, there is a technique described in JP-A-2-223290. In this technique, a line delay unit and a frame delay unit are provided, and YC separation is performed using a line correlation or a frame correlation. In addition, a switch circuit for forming a cyclic path for circulating the frame delay means at the time of reproducing a still image is provided, and YC separation is performed based on an output extracted from the cyclic path. Furthermore, there is also described a technique of performing three-dimensional YC separation by providing a plurality of frame delay means and setting a cyclic route to have a cycle of two or more frames.

However, in the technique described in the above publication, the composite video signal is circulated through all of the plurality of frame delay means, especially when performing three-dimensional YC separation by frame correlation. It is necessary to secure the amount of memory required for the frame configuration in the frame memory, and there is a problem that it is difficult to reduce the overall scale of the frame delay unit.

An object of the present invention is to provide a video signal capable of performing a motion adaptive three-dimensional YC separation operation and an image still operation, inverting a color signal phase during the image still operation, and reducing a frame memory. It is to provide a processing circuit.

[0005]

A video signal processing circuit according to the present invention receives a composite video signal, detects a frame signal and generates a frame timing pulse, a control signal input and the frame timing pulse. A first and second frame memories for delaying the composite video signal by one frame; a first selector for switching an input of the first frame memory; A second selector for switching an input of the two-frame memory, an inter-frame YC separation circuit for outputting an inter-frame separation color signal based on a frame correlation between the output of the first frame memory and the composite video signal, and the composite video signal Output in-field separation color signal from A YC separation circuit in the field, a third selector for selecting the inter-frame separation color signal and the in-field separation color signal, and outputting a luminance signal from the composite video signal and the color signal selected by the third selector. A fourth selector for switching between the output of the subtractor and the output of the first frame memory to output a luminance signal, a coefficient unit for inverting the phase of the output of the second frame memory, A fifth selector that switches between the selected color signal and the output of the coefficient unit and outputs the selected color signal as a color signal, wherein the first selector selects the composite video signal and the output of the fourth selector. Input to the first frame memory, the second selector selects the output of the first frame memory and the output of the fifth selector, and selects the output of the second frame memory. Configured to enter into Mumemori, the first to fifth selector,
The switching is controlled by the two timing signals.

Here, a motion detection circuit for detecting a motion image based on the composite video signal and the outputs of the first and second frame memories, and whether the signal is capable of three-dimensional YC separation from the composite video signal And a non-standard detection circuit for detecting whether or not the third selector is switched based on the output of at least one of the motion detection circuit and the non-standard detection circuit. In this case, the timing generation circuit generates a first timing signal and a second timing signal that is delayed by one frame from the first timing signal, and uses the first timing signal to generate the first and second signals. And the fourth and fifth selectors are switch-controlled by the second timing signal. Alternatively, the timing generation circuit includes a first timing signal, a second timing signal delayed by one frame from the first timing signal, and a third timing delayed by one frame from the second timing signal. And a switching control of the first and second selectors with the first timing signal, and a switching control of the fourth and fifth selectors with the second timing signal. The third selector is switched and controlled based on a timing signal and at least one output of the operation detection circuit and the non-standard detection circuit.

According to the present invention, the input of the first frame memory is switched between the composite video signal and the luminance signal by the first selector, and the input of the second frame memory is switched between the output of the first frame memory and the color signal by the second selector. By switching, the first and second frame memories can be shared by the motion adaptive three-dimensional YC separation operation and the image still operation. Further, by switching the separated luminance signal and the output of the first frame memory by the fourth selector, and by switching the separated color signal and the output of the coefficient unit by the fifth selector, the first frame memory Can be returned to the first frame memory input via the fourth and first selectors, and the same luminance signal is output every frame, so that the still operation of the luminance signal can be performed. Also, the color signal output from the second frame memory is inverted by a coefficient unit for the color signal phase,
The input can be returned to the input of the second frame memory via the fifth and second selectors, and the same color signal is output with its phase inverted for each frame, so that the still operation of the color signal can be performed. Furthermore, first and second timing signals synchronized with a frame timing pulse generated by a frame detection circuit are generated, and the selector is controlled to be switched by this timing signal. Troubles can be avoided. At the same time, by providing a time difference of one frame between the first and second timing signals, the motion adaptive three-dimensional Y
Switching between the C separation operation and the image still operation can be performed. Further, it is not necessary to circulate the composite video signal in the second frame memory, and the memory capacity can be reduced.

[0008]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a first embodiment of the present invention. Here, an embodiment in which an image still is realized in a motion adaptive three-dimensional YC separation system is shown. In FIG. 1, a composite video signal is input from a port 101 and input to a first frame memory 111 via a first selector 110 to perform one-frame delay processing. The composite video signal input and the output of the first frame memory 111 are connected to an inter-frame YC separation circuit 1.
15 and outputs an inter-frame separation color signal (CF). The input of the composite video signal is input to an intra-field YC separation circuit 114, and an intra-field separation color signal (CL) is output. The output of the first frame memory 111 is input to the second frame memory 113 via the second selector 112, and further performs one-frame delay processing. Further, the input of the composite video signal, the output of the first frame memory 111, and the output of the second frame memory 113 are input to the motion detection circuit 116, and the frame correlation of the image is detected. Also, the composite video signal input is input to the non-standard detection circuit 117 to detect whether or not the input composite video signal is a signal that can be subjected to three-dimensional YC separation processing.

The output of the motion detection circuit 116 is as follows:
The output of the non-standard detection circuit 117 is synthesized by the OR circuit 118 and used as a control input of the third selector 119. The third selector 119 has an inter-frame separation color signal CF.
And the in-field separation color signal CL, and selects and outputs either one. The output of the third selector 119 becomes the separation color signal output of the motion adaptive three-dimensional YC separation. Further, the input of the composite video signal and the output of the third selector 119 are input to the subtractor 120, and the difference between the two is obtained. The output of the subtractor 120 is a motion adaptive three-dimensional YC
It becomes a separated luminance signal output for separation. Further, the subtracter 1
The output of 20 is used as the other input of the first selector 110 via the fourth selector 121. The output of the second frame memory 111 is used as the other input of the fourth selector 121, and the output of the fourth selector 121 is used as the luminance signal output. The output of the third selector 119 is supplied to the second selector 11 via a fifth selector 123.
2 is the other input. The output of the second frame memory 113 is input to the other input of the fifth selector 123 via a coefficient unit 122, and the output of the fifth
Output 3 is a color signal output.

On the other hand, the composite video signal input is input to a frame detection circuit 130 to generate a frame timing pulse FP. A control signal for controlling ON / OFF of the image still is input from the port 102, and a control signal input and an output of the frame detection circuit 130 are input to the timing generation circuit 131. In the timing generation circuit 131,
Generate two types of timing signals CTL1 and CTL2,
The timing signal CTL1 is used as a control input of the selector 110 and the selector 112, and the timing signal CTL1 is
2 is a control input of the selector 121 and the selector 123. The timing generation circuit 131 receives a control signal input as an input, and outputs a frame timing pulse FP
(D-type flip-flop) 131a having a clock input as a clock input, and a D-FF 131b having an output from the D-FF 131a as an input and a frame timing pulse FP as a clock input.
1a is a timing signal CTL1, and the DF
The output of F131b is a timing signal CTL2.

FIG. 2 shows an operation timing chart of the frame detection circuit 130 in the circuit having the above configuration. The composite video signal input includes a vertical synchronization signal (VSYNC) in addition to the video signal as shown in FIG.
The frame detecting circuit 130 separates the vertical synchronizing signal VSYNC from the composite video signal input by a known vertical synchronizing separating means as shown in FIG. 2B, and uses the field detecting means as shown in FIG. 2C. To generate a field detection signal. The frame timing pulse FP shown in FIG. 2D is generated by using a pulse generating means triggered by the falling edge of the field detection signal.

Next, FIG. 3 shows an operation timing chart of each part in the circuit of FIG. In the embodiment of FIG. 1, when the control signal input is at a low level, the motion adaptive three-dimensional YC
It is assumed that the operation is controlled so as to operate as separation, and to operate as an image still when the level is high. First, FIG.
From the control signal input of (b) and the frame timing pulse FP from the frame detection circuit 130 of FIG. 3A, two timing signals CTL shown in FIGS.
1, CTL2 is generated. By synchronizing these signals with the frame timing pulse FP, as will be apparent from the following description, it is possible to avoid a problem such as performing image still in the middle of the screen. Here, when operating as the motion-adaptive three-dimensional YC separation, the timing signals CTL1 and CTL2 are both at a low level, and the first and second frame memories 111 and 113 perform one-frame delay processing of the composite video signal, respectively. .

When there is a frame correlation, the luminance signal has the same phase before and after the one-frame delay, whereas the chrominance signal is inverted in phase. Input and first
By taking the difference between the outputs of the frame memory 111, an inter-frame separation color signal CF is generated. When there is a frame correlation, the YC separation between frames can perform separation with less noise. However, when there is no frame correlation in a moving image, or the relationship that the phase of a color signal is inverted before and after one frame delay. On the other hand, a non-standard signal that is not satisfied results in a separation with a lot of noise, so that YC separation between frames cannot be used, and it is necessary to switch to YC separation within a field. Therefore, the motion detection circuit 116 and the non-standard detection circuit 117 are used to detect the frame correlation of the image using a known motion detection means, and to convert the composite video signal into a three-dimensional YC signal using the known non-standard detection means. It detects whether the signal can be separated.

In the motion detection circuit 116, a composite video signal input, an output of the first frame memory 111,
The output of the second frame memory 113 is input. These have a relationship of a delay amount of 0 frame, 1 frame, and 2 frames. Since the signal delayed by two frames has the same phase for both the luminance signal and the chrominance signal, it has a feature that it is easy to detect whether or not it is a moving image. Further, in the OR circuit 118, the logical sum of the output of the motion detecting circuit 116 and the output of the non-standard detecting circuit 117 is obtained. The output of the OR circuit 118 indicates that the signal cannot be YC-separated between frames, and the third selector 119 switches the inter-frame separated color signal CF to the intra-field separated color signal CL. Then, the third selector 11
An output 9 is a separated color signal output of the motion adaptive three-dimensional YC separation, and a subtractor 120 subtracts the separated color signal from the composite video signal input to generate a luminance signal, which is used as a separated luminance signal output.

On the other hand, when switching from the motion-adaptive three-dimensional YC separation operation to the image still operation, first, the timing signal CTL1 changes from low level to high level, and the first and second frame memories 111 and 113 As shown in FIGS. 3E and 3G, the input is switched from a composite video signal to a luminance signal and a chrominance signal. However,
During the period of FIG. 3, the first and second frame memories 111,
Since the output of 113 is still a composite video signal, it operates as a motion adaptive three-dimensional YC separation. When processed as it is for one frame period, the first and second
Since the outputs of the frame memories 111 and 113 are switched to a luminance signal and a color signal, the operation as the motion adaptive three-dimensional YC separation cannot be performed. Therefore, the timing signal CT
L2 is changed from the low level to the high level, the output of the fourth selector 121 is switched to the output of the first frame memory 111, and the output of the fifth selector 123 is switched to the output of the coefficient unit 122. Here, the first frame memory 111
Is returned to the input of the first frame memory 111 via the fourth selector 121 and the first selector 110, so that the same luminance signal is output every frame. A still operation is performed.

On the other hand, the color signal output from the second frame memory 113 is transmitted to the second frame memory 11 via a coefficient unit 122, a fifth selector 123 and a second selector 112.
Return to the input of 3. Here, the fifth line shown in FIG.
Considering the phase of the color signal output from the selector 123, the color signal phase must be inverted for each frame. Fifth
The output of the selector 123 becomes the input of the second frame memory 113 and is output in the next frame period. However, the color signal phase of the output of the second frame memory 113 is opposite to the originally required phase. I have. Therefore, coefficient unit 1
At -22, the color signal phase is inverted by multiplying by -1. By doing so, the same color signal is output with its phase inverted for each frame, and the still operation of the color signal is performed.

Next, when switching from the image still operation to the motion adaptive three-dimensional YC separation operation, first, the timing signal CTL1 changes from the high level to the low level,
3 and the inputs of the second frame memories 111 and 113 are shown in FIG.
As shown in (e) and (g), the luminance signal and the chrominance signal are switched to the composite video signal. However, during the period of FIG. 3, the outputs of the first and second frame memories 111 and 113 are still luminance signals and chrominance signals, so that they operate as image stills. Processing is continued for one frame period as it is, and when the period of FIG.
The output of 1 switches to the composite video signal and the output of 2
The output of the frame memory 113 is a luminance signal.
In this state, the output of the second frame memory 113 and the motion detection circuit 116 that receives the output from the second frame memory 113 do not perform the original operation as the motion adaptive three-dimensional YC separation. If there is no error detection, only erroneous detection can be easily performed, and it can be considered that the operation is substantially performed as motion adaptive three-dimensional YC separation. Therefore, the timing signal CTL2 is changed from the high level to the low level, the output of the fourth selector 121 is switched to the output of the subtractor 120, and the output of the fifth selector 123 is changed to the third selector 1
19, and returns to the motion adaptive three-dimensional YC separation operation. When the processing is further performed for one frame period, the output of the second frame memory 113 becomes a composite video signal, and the original motion adaptive three-dimensional YC separation operation is performed.

As described above, in the embodiment of FIG.
A first selector 110 is provided before the first frame memory 111.
Is provided to switch between the composite video signal and the luminance signal. Also, a second selector 112 is provided in a stage preceding the second frame memory 113 so that the second frame memory 113 is provided.
And the color signals are switched, so that the same frame memories 111 and 113 are stored in the motion-adaptive three-dimensional Y
This can be shared by the C separation operation and the image still operation.

Further, a fourth selector 121 is provided at a stage preceding the luminance signal output so that the separated luminance signal and the first frame memory 11 are output.
1 is switched, the fifth selector 123 is provided at a stage preceding the color signal output, and the output of the separated color signal and the output of the coefficient unit 122 are switched. Therefore, when operating as an image still, the first frame The luminance signal output from the memory 111 is transmitted to the fourth and first selectors 121 and 121,
Since the input is returned to the input of the first frame memory 111 via 110, the same luminance signal is output every frame, and the still operation of the luminance signal can be performed. Further, the color signal output from the second frame memory 113 is inverted by the coefficient unit 122 to obtain the fifth and second color signals.
Is returned to the input of the second frame memory 113 via the selectors 123 and 112 of the above, so that the same color signal is output with its phase inverted for each frame.
Still operation of a color signal can be performed.

Further, based on a frame timing pulse FP generated by the frame detection circuit 130 and a control signal input from the port 102, two types of timing signals CT
By generating L1 and CTL2 and synchronizing these signals with the frame timing pulse FP, it is possible to avoid a problem such as performing image still in the middle of the screen. Further, the timing signal CTL1 is used as a control input of the first selector 110 and the second selector 112, and the timing signal CTL2 is used as the control input of the fourth selector 121 and the fifth selector 123.
By providing a difference of one frame period between the timing signals CTL1 and CTL2, the switching between the motion adaptive three-dimensional YC separation operation and the image still operation can be performed.

Further, in the above embodiment, since the composite video signal for motion detection or the color signal is input to the second frame memory 113, it is not necessary to circulate the input composite video signal as it is, It is possible to reduce the amount of memory by thinning. Incidentally, in the technology described in the conventional publication, for example, 4 fsc (color sub-carrier frequency: about 3.58 MHz), 8 fsc
When sampling in bits, the required memory amount is 910 [datas / line] x 525 [lines / frame] x 8 [bit / data] x
It is 7,644,000 bits from 2 [frame]. In contrast, the first
In the embodiment, for example, by using a “1/3 thinning circuit” before the first frame memory 113 and a “restoration circuit” after the first frame memory 113, the memory amount of the second frame memory is reduced to 1/3.
This can reduce the amount of memory by about 2,548,000 bits.

FIG. 4 is a block circuit diagram of a second embodiment of the present invention. In the second embodiment, the timing generation circuit 231 is improved to further improve the timing signal CTL.
3 can be generated, and the timing signal CTL3 is input to the OR circuit 218, whereby the third selector 119
Is controlled to the in-field separation color signal CL.

FIG. 5 shows an operation timing chart of the second embodiment. In the figure, a motion adaptive three-dimensional Y
The operation in the case of operating as the C separation and the operation in the case of switching from the motion adaptive three-dimensional YC separation operation to the image still operation are the same as those in the first embodiment. At this time, even if the third selector 119 is controlled by the timing signal CTL3, the image still operation is not affected.

On the other hand, when switching from the image still operation to the motion adaptive three-dimensional YC separation operation, first, the timing signal CTL1 changes from the high level to the low level, and the inputs of the first and second frame memories 111 and 113 are changed. Then, the timing signal CTL2 changes from the high level to the low level, and the fourth and fifth selectors 12
The point that the outputs of 1,123 are switched and the operation returns to the motion adaptive three-dimensional YC separation operation is the same as in the first embodiment. Here, in the first embodiment, during the period of FIG. 3, it is assumed that the motion detection circuit 116 performs the motion-adaptive three-dimensional YC separation operation regardless of whether the motion detection circuit 116 is performing the original operation. On the other hand, in the second embodiment, FIG.
During the period of, the third selector 119 selects the intra-field separation color signal CL, so that it is not affected by the motion detection circuit.

[0025]

As described above, according to the present invention, the input of the first frame memory is switched between the composite video signal and the luminance signal by the first selector, and the input of the second frame memory is switched by the second selector to the input of the first frame memory. By switching between the output and the color signal, the first and second frame memories can be shared by the motion adaptive three-dimensional YC separation operation and the image still operation. Further, by switching the separated luminance signal and the output of the first frame memory by the fourth selector, and by switching the separated color signal and the output of the coefficient unit by the fifth selector, the first frame memory Can be returned to the first frame memory input via the fourth and first selectors, and the same luminance signal is output every frame, so that the still operation of the luminance signal can be performed. Also,
The color signal output from the second frame memory is inverted by a coefficient unit for the color signal phase, and the color signal is inverted through the fifth and second selectors.
It can be returned to the input of the frame memory, and the same color signal is output with its phase inverted for each frame,
Still operation of a color signal can be performed. Furthermore, first and second timing signals synchronized with a frame timing pulse generated by a frame detection circuit are generated, and the selector is controlled to be switched by this timing signal. Troubles can be avoided. At the same time, by providing a time difference of one frame between the first and second timing signals,
Switching between the motion-adaptive three-dimensional YC separation operation and the image still operation can be performed. Further, there is no need to circulate the composite video signal in the second frame memory, and the memory capacity can be reduced.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram according to a first embodiment of the present invention.

FIG. 2 is a timing chart for explaining the operation of the frame detection circuit.

FIG. 3 is a timing chart for explaining the operation of each unit in FIG. 1;

FIG. 4 is a block circuit diagram according to a second embodiment of the present invention.

FIG. 5 is a timing chart for explaining the operation of each unit in FIG. 4;

[Explanation of symbols]

 110 First selector 111 First frame memory 112 Second selector 113 Second frame memory 114 In-field YC separation circuit 115 Inter-frame YC separation circuit 116 Motion detection circuit 117 Non-standard detection circuit 118 OR circuit 119 Third selector 120 Subtractor 121 fourth selector 122 coefficient unit 123 fifth selector 130 frame detection circuit 131 timing generation circuit 218 OR circuit 231 timing generation circuit

Claims (4)

[Claims] 1. A frame detection circuit that receives a composite video signal as input, detects a frame signal and generates a frame timing pulse, and a timing generation circuit that generates at least two timing signals from a control signal input and the frame timing pulse. A first and a second frame memory for delaying the composite video signal by one frame, a first selector for switching an input of the first frame memory, and a second selector for switching an input of the second frame memory; An inter-frame YC that outputs an inter-frame separation color signal from a frame correlation between the output of the first frame memory and the composite video signal
A separating circuit, an in-field YC separating circuit for outputting an in-field separating color signal from the composite video signal, a third selector for selecting the inter-frame separating color signal and the in-field separating color signal, A subtractor that outputs a luminance signal from the color signal selected by the third selector, a fourth selector that switches between the output of the subtractor and the output of the first frame memory and outputs the output as a luminance signal, A coefficient unit for inverting the phase of the output of the second frame memory; and a fifth selector for switching between the selected color signal and the output of the coefficient unit and outputting the selected signal as a color signal, wherein the first selector Selects the composite video signal and the output of the fourth selector and inputs them to the first frame memory, and the second selector The output of the first frame memory and the output of the fifth selector are selected and input to the second frame memory, and the first to fifth selectors perform switching control by the two timing signals. A video signal processing circuit characterized in that 2. The composite video signal and the first video signal.
And a motion detection circuit for detecting a motion image with the output of each of the second frame memories, and a non-standard detection circuit for detecting whether or not the composite video signal is a signal capable of three-dimensional YC separation, 2. The video signal processing circuit according to claim 1, wherein the third selector is switch-controlled based on at least one output of the motion detection circuit and the non-standard detection circuit. 3. The timing generation circuit generates a first timing signal and a second timing signal one frame later than the first timing signal, and uses the first timing signal to generate the first and second signals. 3. The switching control of a second selector, wherein the switching control of the fourth and fifth selectors is performed by the second timing signal.
3. The video signal processing circuit according to claim 1. 4. A timing generator, comprising: a first timing signal; a second timing signal delayed by one frame from the first timing signal; and a second timing signal delayed by one frame from the second timing signal. A third timing signal, and the first and second timing signals switch and control the first and second selectors, and the second and third timing signals switch and control the fourth and fifth selectors. 3. The video signal processing circuit according to claim 1, wherein the switching of the third selector is controlled based on a third timing signal and at least one output of the operation detection circuit and the non-standard detection circuit.