JP2986194B2 - Video signal processing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a video signal processing provided with a motion adaptive luminance / color signal separation function and a noise reduction function.

(Prior art) Recently, video processing digital processing technology has advanced, and a motion-adaptive three-dimensional Y / C separation circuit is also used as a luminance / color signal separation (hereinafter referred to as Y / C separation) circuit in a television receiver. And video tape recorders.

In the motion-adaptive Y / C separation circuit, a moving image area of an input video signal is detected based on the magnitude of an inter-frame difference value. In the moving image portion, Y / C separation is performed using line correlation, and in the still image portion, Y / C separation is performed using a frame correlation picture. For example, in 1989, the development of LSI was reported at the National Convention of the Institute of Television Engineers of Japan (Miyazaki et al., "Development of 3D YC processing LSI, P215-P216.") In this example, the system clock was phase-synchronized with the IQ axis. 4fsc clock is used.

Also, it has been considered to perform noise removal (referred to as three-dimensional YNR) of a luminance signal using an input signal of a three-dimensional Y / C separation circuit as a luminance signal. In this method, a color (C) signal at the time of Y / C separation is considered as noise of a luminance signal, and is intended to be removed from the luminance signal. Therefore, uncorrelated noise between lines and uncorrelated noise between frames are removed according to the movement of the input luminance signal. As a system clock at the time of this noise removal, a clock of 910fh (fh: horizontal frequency) synchronized in phase with horizontal synchronization is used. This is so that, even for a signal whose time axis fluctuates, such as a reproduced luminance signal of a VTR, calculation between frames can be accurately performed following the fluctuation of the time axis.

As described above, if the Y / C separation circuit switches its operation clock, circuits such as an inter-frame arithmetic circuit and a motion detection circuit can also be used as a noise reduction device.

FIG. 2 shows a circuit capable of realizing Y / C separation and noise reduction by switching modes.

An input video signal or a luminance signal is supplied to the input terminal 10. The input video signal is a composite signal including a luminance signal, a color signal, a synchronization signal, and the like.

When the system is used as a Y / C separation circuit, an input video signal is introduced, and when the system is used as a noise reduction circuit, a luminance signal is introduced.

Input terminal 10 is analog digital (hereinafter referred to as A / D)
Connected to converter 11. The output data of the A / D converter 11 is transmitted to a burst phase lock circuit 12, a horizontal phase lock circuit 1
3, input to a 1H delay unit 15 having a delay amount of one horizontal period (hereinafter referred to as 1H), and a Y / C separation circuit 17 for a moving image.

When the input signal is a video signal, the burst phase lock circuit 12 generates a burst synchronization clock phase-locked to the burst signal. Horizontal phase lock circuit 13
Generates a horizontal synchronization clock signal that is phase-synchronized with the horizontal synchronization signal of the input signal. The burst synchronization clock and the horizontal synchronization clock are supplied to first and second input terminals of the switch 14. The switch 14 selectively derives a burst synchronization clock when the system is in the Y / C separation mode, and selectively derives a horizontal synchronization clock when the system is in the noise reduction mode.

On the other hand, the output of the 1H delay unit 15 is further input to the 1H delay unit 16. Then, the output of the 1H delay unit 15 and the output of the 1H delay unit 16 are input to the moving image Y / C separation circuit 17.

The video Y / C separation circuit 17 uses the correlation between lines to separate and derive color signals when the system performs Y / C separation,
When the system is in the noise reduction mode, noise is extracted. The output of the moving image Y / C separation circuit 17 is supplied to a band-pass filter (BPF) 18 and a limiter 19. The outputs of the bandpass filter 18 and the limiter 19 are supplied to one and the other input terminals of the switch 20. Switch 20 is
In the Y / C separation mode, the output of the band-pass filter 18 is selectively derived, and in the noise reduction mode, the output of the limiter 19 is selectively derived.

The output of the switch 20 is input to the subtractor 21. The output of the 1H delay unit 15 is also input to the subtractor 21. As a result, in the Y / C separation mode, the subtractor 21
The chrominance signal is removed from the output of the H delay device 15, and a moving image luminance signal can be obtained. In the noise reduction mode,
In the subtracter 21, a luminance signal from which a noise component has been removed can be obtained from the output of the 1H delay unit 15. The output of the subtracter 21 is input to one of the mixers 22.

 Next, the static image system will be described.

The output of the 1H delay unit 15 is input to the one-frame delay unit 23. One-frame delay unit 23 has a delay amount of 525H.
The output of the one-frame delay unit 23 is further input to the one-frame delay unit 24.

The signal on the input side and the signal on the output side of the one-frame delay unit 23 are input to the still image Y / C separation circuit 25. When the system is in the Y / C separation mode, the still image Y / C separation circuit 25 separates luminance and chrominance signals using correlation between frames. The separated still image luminance signal is input to the mixer 22. The separated still-color signal is input to one of the mixers 28 via the band-pass filter 26. The moving image color signal selected by the switch 10 is input to the other input terminal of the mixer 28.

When the system is in the noise reduction mode, the still image luminance signal is input to the mixer 22 after noise removal.

The motion detector 27 receives signals on the input side and the output side of the one-frame delay unit 23, and
The output signal from 24 is also input. This motion detector 27
Are supplied to the control terminals of the mixers 28 and 22. When the system is in Y / C separation mode,
The mixers 22 and 28 increase the ratio between the moving image luminance signal and the moving image color signal in the moving image portion, and increase the ratio between the still image luminance signal and the still image color signal in the still image portion. The luminance signal and the chrominance signal are led to output terminals 29 and 30, respectively. When the system is in the noise reduction mode, the noise reduced luminance signal is output to the output terminal.
Derived to 29.

(Problem to be Solved by the Invention) A problem in the above-described Y / C separation and noise reduction combined apparatus is time alignment between an output luminance signal and a color signal when noise reduction processing is performed.

In the case of Y / C separation, there is no problem because the luminance signal and the chrominance signal are similarly delayed, but in the case of noise reduction, only the luminance signal passes through the frame delay unit or the line delay unit.

In the above circuit, the luminance signal is delayed by 1H + α. 1H
Is caused by the main signal passing through the 1H delay unit 15. Α is a delay between the A / D converter 11 and the 1H delay device 15, and a Y / C separation circuit for moving images from the 1H delay device 15 to an output, a Y / C separation circuit for still images, a motion detector, This is a delay due to arithmetic processing by a mixer or the like.

As the above arithmetic processing becomes more complicated, α becomes larger, and may be about 2 μs or less.

Therefore, in order to match the time relationship between the luminance signal and the color signal before and after the three-dimensional noise reduction system, it is necessary to delay the color signal by 1H + α.

In order to obtain this delay, for example, a method using an A / D converter, a line memory (FIFO type), a D / A converter, and a method using a CCD delay line can be considered. But with these methods,
In any case, since the delay amount is special, that is, 1H + α, it is an expensive circuit to realize.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a video signal processing apparatus which can easily obtain a delay of a color signal and easily align a time between a color signal and a luminance signal.

[Constitution of the Invention] (Means for Solving the Problems) The present invention relates to an inter-frame operation unit for performing a luminance / color signal separation or noise reduction process by an inter-frame operation process of an input video signal; Signal is supplied,
In the Y / C separation mode, the delay amount for one horizontal period (= 1H),
In the noise reduction mode, a first delay device that is switched to a delay amount of (1H-α), a second delay device to which an output of the first delay device is input and that has a delay amount of 1H, Line-to-line arithmetic means for performing luminance / color signal separation processing by arithmetic processing using signals of three lines at respective terminals of the first and second delay units; and a second delay unit of the three line signals A noise extraction unit for extracting a noise component by a subtraction process between signals on the input side and the output side, and in the case of the Y / C separation mode, a color signal from the line-to-line calculation unit is selectively derived, and a noise reduction mode is selected. A selecting means for selecting and deriving a noise component from the noise extracting means; and a moving picture luminance signal for subtracting an output of the selecting means from an output of the first delay unit to obtain a moving picture luminance signal or a noise reduction luminance signal. Signal extraction means and the action from this means A system luminance signal, a mixer to which a still image system luminance signal from the inter-frame arithmetic unit is inputted, and a motion detection signal obtained by detecting a moving image portion of the input video signal. And a mixing means for adjusting and mixing the mixing ratio of the moving image luminance signal and the still image luminance signal of the device.

(Operation) By the above means, one of the 1H delay devices for Y / C separation is set as a variable delay device, and is set to 1H-α in the noise reduction mode.
This saves the amount of delay of the luminance signal. As a result, since the delay amount of the color signal of another system may be 1H, a general-purpose 1H delay device can be used, and an accurate delay is obtained, and the time alignment with the noise-reduced luminance signal becomes easy.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. The input terminal 100 receives an input video signal or a luminance signal. The input signal of this input terminal 100 is an analog-to-digital (A / D) converter
It is quantized at 101. The output of the A / D converter 101 is a burst phase lock circuit 102, a horizontal phase lock circuit 10
The variable delay device 105 is capable of changing the delay amount to 3, (1H−α) or 1H, and is input to the moving image Y / C separation circuit 17.

When the input signal is a video signal, the burst phase lock circuit 102 generates a burst synchronization clock phase-locked to the burst signal. Horizontal phase lock circuit 10
3 generates a horizontal synchronization clock signal phase-synchronized with the horizontal synchronization signal of the input signal. The burst synchronization clock and the horizontal synchronization clock are supplied to first and second input terminals of the switch 104. The switch 104 selectively derives a burst synchronization clock when the system is in the Y / C separation mode, and selectively derives a horizontal synchronization clock when the system is in the noise reduction mode.

On the other hand, the output of the variable delay device 105 is further input to the 1H delay device 106. Then, the output of the 1H variable delay device 105 and the output of the 1H variable delay device 106 are input to the Y / C separation circuit 107 for a moving image.

The video Y / C separation circuit 107 uses the correlation between lines to separate and derive a color signal when the system performs Y / C separation,
When the system is in the noise reduction mode, noise is extracted. The output of the moving image Y / C separation circuit 107 is supplied to a band-pass filter (BPF). The output of the band pass filter 108 is supplied to one input terminal of the switch 110.

The input and output of the 1H delay unit 106 are supplied to a subtractor 111. The noise component can be obtained from the subtractor 111 using the correlation between lines in the noise reduction mode. The output of the subtracter 111 is amplitude-limited by the limiter 112 and supplied to the other input terminal of the switch 110.

The switch 110 selectively derives the output of the bandpass filter 108 when the system is in the Y / C separation mode, and selectively derives the output of the limiter 112 when the system is in the noise reduction mode.

The output of the switch 112 is input to the subtractor 113. The output of the variable delay unit 105 is also input to the subtractor 113. Thus, in the Y / C separation mode, the subtractor 113 removes the chrominance signal from the output of the 1H variable delay unit 105 to obtain a moving image luminance signal. Further, in the noise reduction mode, the subtractor 113 can obtain a luminance signal from which the noise component has been removed from the output of the variable delay unit 105. The output of the subtractor 113 is input to one of the mixers 114.

 Next, the static image system will be described.

The output of the variable delay unit 105 is input to the one-frame delay unit 203. One-frame delay unit 203 has a delay amount of 525H. The output of the one-frame delay unit 203 is further input to the one-frame delay unit 204.

The signal on the input side and the signal on the output side of the one-frame delay unit 203, and the signal on the output side of the one-frame delay unit 204 are:
It is input to the still image Y / C separation circuit 205. When the system is in the Y / C separation mode, the still image Y / C separation circuit 205 separates luminance and chrominance signals using correlation between frames. The separated still image luminance signal is input to the mixer 22. The separated still-color signal is input to one of the mixers 208 via the band-pass filter 206. The moving image color signal selected by the switch 110 is input to the other input terminal of the mixer 208.

When the system is in the noise reduction mode, the still image luminance signal is input to the mixer 208 after noise removal.

The motion detector 207 receives the signals on the input side and the output side of the one-frame delay unit 203, and also receives the output signal from the one-frame delay unit 204. The motion detection signal obtained by the motion detector 207 is supplied to control terminals of the mixers 208 and 114. When the system is in the Y / C separation mode, the mixers 202 and 114 increase the ratio of the moving image luminance signal and the moving image color signal in the moving image portion, and increase the ratio of the still image luminance signal and the still image color signal in the still image portion. More. The luminance signal and the chrominance signal are led to output terminals 209 and 210, respectively. When the system is in the noise reduction mode, the noise-reduced luminance signal is output to the output terminal 209.

According to the above-described embodiment, by making the delay amount of the variable delay unit 105 variable, the delay amount is 1H in the Y / C separation mode, and is (1H-α) in the noise reduction mode. I have.

As a result, the time alignment between the luminance signal at the output terminal 29 and the color signal processed by another system in the noise reduction mode becomes easy.

Next, a description will be given of a delay time inside the circuit due to a change in the delay amount of the delay unit 105 in the noise reduction mode.

First, the signals Y 'and N input to the subtractor 113 must be temporally coincident. The signal N is delayed by the subtractor 111, the limiter 112, and the switch 110. If this is α1, the signal Y ′ needs to be delayed by that amount. Therefore, although not shown, a delay circuit of the delay amount α1 is provided between the delay unit 105 and the subtractor 113 in practice.

Further, the moving image luminance signal and the still image luminance signal, which are the inputs to the mixer 114, must be temporally coincident. Subtractor 11
Assuming that the delay amount of 3 is α2, the delay time of the still image luminance signal needs to be (α1 + α2). This delay amount (α
1 + α2) is secured by the processing time of the inter-frame operation.

If the sum of the delay times of the mixer 114 and the A / D converter 101 is α3, the delay amount τy of the luminance signal in the noise reduction mode is τy = (1H−α) + (α1 + α2 + α3). Here, when the delay amount (1H-α) of the delay unit 105 is set so that α = (α1 + α2 + α3), τy = 1H, and the delay time in the noise reduction mode is 1H.

Next, a method of changing the delay amount of the delay unit 105 is described. For example, a reset signal of an address is generated by a counter using a RAM, and the input / output delay of the RAM can be changed by changing the cycle of the counter. .

The input signal in the noise reduction mode is only the luminance signal, and it is necessary to keep the time relationship between the luminance signal and the color signal in a predetermined relationship by delaying the color signal by the luminance signal delay time τy due to the noise reduction processing. . At this time, τy = 1H + α
In order to delay the color signal, it is necessary to use (1) an A / D converter and a line memory, and (2) a special CCD having a delay amount (1H + α). Requires expensive and complicated circuits.

However, if the delay unit 105 is made variable and τy = 1H as in this embodiment, the color signal may be delayed by 1H, so that it is possible to use a simple general-purpose circuit and implement it inexpensively.

Further, when this system is used in a home VTR, and used as a motion adaptive Y / C separation circuit during recording, and as a motion adaptive noise reduction circuit during reproduction, a subtractor 111 is used during reproduction.
By using this system, it is also possible to obtain a crosstalk removal process using a line correlation for a color signal. In this case, the 1H delay unit 106 for noise reduction
High utility value because it can be shared for / C separation.

Also, in a system such as a home VTR that processes a luminance signal and a chrominance signal separately, a difference between the color and luminance on the display screen may occur due to a difference in delay time between the luminance signal and the chrominance signal. If the delay device 105 is configured to be variable as in this embodiment, the user himself can adjust the system clock unit while watching the screen. Further, in this embodiment, the calculation between lines in the noise reduction mode,
Although the inter-frame operation is of the non-cyclic type, at least one of the operations may be of the cyclic type.

[Effects of the Invention] As described above, according to the present invention, the delay of the color signal is easily obtained, and the time alignment between the color signal and the luminance signal is facilitated.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, and FIG. 2 is a circuit diagram showing a luminance / color signal separation circuit which is a premise of the present invention. 101: A / D converter, 102: Burst phase lock circuit, 1
03 …… Horizontal phase lock circuit, 104 …… Switch, 105 ……
Variable delay unit, 106 1H delay unit, 107 Y / C separation circuit for video, 109, 206 Band-pass filter, 110 Switch, 111 Subtractor, 112 Limiter 113 Subtractors, 114, 208... Mixers, 203, 204... 1-frame delay units, 205.

Continued on the front page (72) Inventor Toshiyuki Namioka 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Inside the Home Appliances Research Laboratory, Yokohama Toshiba Corporation (72) Inventor Toru Miyazaki 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Stock (72) Inventor, Yasuo Takahashi 8th, Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture, Japan Toshiba Yokohama Office, Electric Appliance Research Laboratory (72) Inventor: Tomoya Otsuki Tokyo Metropolitan Port 3-3-9, Shimbashi-ku, Toshiba Audio-Video Engineering Co., Ltd. (72) Inventor Masanori Sumiyoshi 3-3-9, Shimbashi, Minato-ku, Tokyo Toshiba Audio-Video Engineering Co., Ltd. (56) References JP-A-1-40887 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H04N 9/79-9/898

Claims (1)

(57) [Claims] 1. An inter-frame operation means for separating luminance / color signals or noise reduction processing by an inter-frame operation process of an input video signal, wherein said input video signal is supplied and in a Y / C separation mode. A first delay unit that is switched to a delay amount of one horizontal period (= 1H), and a delay amount of (1H-α) in the noise reduction mode; an output of the first delay unit is input, and a delay of 1H is input. A second delay unit having a quantity, an inter-line operation unit for performing a separation process of a luminance / color signal by an operation process using signals of three lines at respective terminals of the first and second delay units, A noise extracting means for extracting a noise component by subtracting a signal between an input side and an output side of a second delayer out of the three lines of signals; Selects and derives a color signal. Selecting means for selecting and deriving a noise component from a noise extracting means; moving picture luminance signal extracting means for subtracting the output of the selecting means from the output of the first delay unit to obtain a moving picture luminance signal or a noise reduction luminance signal And a mixer to which the moving image based luminance signal from the means and the still image based luminance signal from the inter-frame calculating means are input; a moving image portion of the input video signal is detected to obtain a motion detection signal; A video signal processing device comprising: a mixing unit that adjusts and outputs a mixing ratio of a moving image luminance signal and a still image luminance signal of the mixer based on the detection signal.