JP3286379B2 - Video signal processing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal processing apparatus for performing Y / C separation of a composite video signal using a three-line logical operation processing circuit.

[0002]

2. Description of the Related Art Conventionally, a video signal processing apparatus for this kind of Y / C separation using a three-line logical operation processing circuit belonging to a non-linear filter is disclosed in Japanese Patent Laid-Open No. 1-220594 (H).
04N9 / 83), almost as shown in FIG.
It is configured as shown in FIG. The composite video signal of each line of the input terminal 1 which includes a luminance signal (Y) and chroma signal (C) a, the first is the two 1H delay circuits 2 and 3 by one line delay, a second Delayed video signal b,
c respectively.

Further, signals a, b, and c are supplied to three band-pass filters 4, 5, and 6 as frequency separation filters for extracting a chroma signal band, respectively. Chroma band signal d,
e and f are extracted and formed. These signals d, e,
f is depending on the band setting filter 4-6, usually, the filter 4-6 is set to a relatively wide band saw contains high-frequency components of the chroma signal and luminance signal, the signal e is the third consecutive lines
The signal of the center line, and the signals f and d
Before and after the line .

In order to match the polarities of the three consecutive chroma signals, the polarity of the signals d and f is inverted by sign inverting circuits 7 and 8, respectively. It is supplied to the line logical operation processing circuit 9. This arithmetic processing circuit 9 is configured as shown in FIG. 4, and the maximum value detection circuits 10 and 11 detect and select the greater one of the two signals e and g, e and h each time, and select the minimum value. The smaller of the levels of the two signals e and g, e and h at every moment is detected and selected by the circuits 12 and 13.

Further, output signals i, j of the maximum value detection circuits 10, 11 are supplied to a minimum value detection circuit 14, and output signals k, l of the minimum value detection circuits 12, 13 are supplied to a maximum value detection circuit 15. The detection circuit 14 detects and selects the smaller one of the two signals i and j at each moment, and the detection circuit 15 selects the larger one of the two signals k and l at the moment. Then, the detection circuits 14, 1
5 are added by the adder circuit 16. At this time, for example, if the signals e, g, and h all include a chroma signal having the same waveform and level, the output signals m and n have the same value. Since the signal is a line chroma signal, the output signal of the adder circuit 16 is a chroma signal of twice the input level.

Further, the output signal of the adder circuit 16 is attenuated by 1/2 by the attenuator circuit 17, and the input level chroma signal is separated and extracted by this attenuation. Then, the output signal of the attenuation circuit 17 forms the output signal p of the arithmetic processing circuit 9, and as shown in FIG. 3, this signal p is output from the chroma output terminal 18 as a chroma signal for each line.

Further, the output signal p is supplied to the subtraction circuit 19, and at this time, the composite video signal of the center line is used.
There signal b Ru is supplied to the subtraction circuit 19 is delayed by the delay circuit 20 to have the same delay amount as the output signal p.
Then, the subtraction circuit 19 subtracts and removes the output signal p from the output signal q of the delay circuit 20 to separate and extract a luminance signal from the composite video signal of each line.

The subtraction circuit 19 obtained by this separation and extraction
Is output from the luminance output terminal 21 as a luminance signal. Then, in the case of the configuration of FIG.
Is used to separate and extract the chroma signal using a band-pass filter.
Cross color and the like in the horizontal direction unlike in the case of C separation do not occur, and Y / C separation can be performed while preventing deterioration of the horizontal resolution.

[0009]

In the case of the conventional video signal processing apparatus shown in FIG. 3 , the arithmetic processing circuit 9 is used as a signal of a weather chart in which a blue isobar having a width of one line is drawn on a white background. only one line of the supplied three consecutive lines at the time of 1 line chroma state as including click <br/> Roma signal, as also described in the publication, in order to prevent anyone called color The chroma signal output of the arithmetic processing circuit 9 is suppressed as much as possible.

[0010] That is, three consecutive of 3 to 5
Signal lines a, b, only Hisashira-in signal b in one of the c comprises a chroma signal, the front and rear line of the signal c, a
Is only a luminance signal, only the output signal e of the output signals d to f of the filters 4 to 6 is a signal obtained by extracting a chroma signal, and the remaining output signals d and f are almost zero level (ground level). Level). Note that V in FIG.
Indicates the input level of the chroma signal.

At this time , the signals e, g, and h of three consecutive lines supplied to the arithmetic processing circuit 9 are the signals e, g of the central line.
Only becomes chroma signal, before, after the line of signal
h and g become almost no signal. At this time, the signal e is ± 1 /
To change the range of 2 · V, the positive half-wave large output signal m is approximately the signal e of the minimum value detecting circuit 14 of the arithmetic processing circuit 9
Becomes Kisano signal, the maximum value detecting circuit 15 becomes a negative half-wave magnitude of the signal of approximately the signal e.

The addition of the signals m and n causes the output signal of the adder circuit 16 to become a chroma signal having the input level V. Therefore, the output signal p of the arithmetic processing circuit 9 becomes half the input level (FIG. 5). V / 2).
Then , based on the subtraction of the chroma signal, a subtraction circuit 19 is provided.
Is a luminance signal including a chroma signal of level V / 2 as shown in FIG.

[0013] Therefore, when including the chroma signal only to one line of the three lines is not performed a complete Y / C separation, there is a problem that the dot interference is generated leaks chroma component to the luminance signal . The present invention improves a Y / C separation characteristic in a one-line chroma state in which only one of three lines includes a chroma signal in a video signal processing device that performs Y / C separation using a three-line logical operation processing circuit. Yo
It is intended to provide a specific configuration as described above.

[0014]

In order to achieve the above object, a composite video signal at an input terminal is line by line.
Two Is that output the first and second delayed video signals with a delay
H delay circuit, composite video signal at input terminal,
Apply frequency filter processing to each of the extended video signals,
Composite video of the center line formed by the delayed video signals
The composite of the image signal, the second delayed video signal, and the input terminal
G before and after the center line formed by the video signal.
Extracts the chroma band signal of each positive video signal
And generate three continuous lines of chroma band signals.
Frequency separation filter for chroma signal band extraction, before and after
Invert the polarity of each signal in the chroma band of the line
Two codes that make the polarity of the chroma band of the next three lines the same
Inverting circuit, center line chroma band signal and both codes
Chroma band before and after the line is inverted by the inversion circuit
The level judgment of the frequency of the signal, in one of the successive three lines
1 and line chroma detector circuit only central line detects a line chroma conditions including chroma signal, by switching the I that output signal to the detection output of the detection circuit, upon detection of 1 line chroma state, the output of the arithmetic processing circuit Instead of the signal
The central facilities signal of the one-dimensional frequency separation filter processing the composite video signal line, and chroma output switching circuit for output as the chroma signal of the center line, the center line co
Composite comprising a first delay subtraction circuit for separating and extracting the bright <br/> of signals of each line of the output signal by subtracting removed input terminal of the switching circuit from the video signal is a video signal, and 1 Rye
The chroma detection circuit is used to connect the center line chroma band signal and
Before and after the line is inverted by the sign inversion circuit.
Each signal in the chroma band is folded back from the negative component to the positive
And three absolute value circuits,
Three low-pass filters that integrate each output signal
And the chroma signal and the output signal of each low-pass filter.
Yes of No., free, and the level compared with the reference signal of the detection, the communication
By detecting the presence or absence of each chroma signal of the next three lines
Three comparison circuits that output binary-changing signals and each comparison circuit
Logic gate processing of the output signal of the circuit to detect the detection circuit
It is formed by a gate circuit for forming an output .

[0015]

[Action] When the video signal processing apparatus of the present invention configured as described above, 1 at line chroma conditions including Hisashira in only click <br/> Roma signal in one of the successive three lines, one line Chroma By the detection output of the detection circuit, the output signal of the chroma output switching circuit is changed from the output signal of the three-line logical operation processing circuit .
Switches to one-dimensional circumferential <br/> wavenumber separation filters were facilities signals into a composite video signal input of the central line.

Then, the output signal of the chroma output switching circuit is subtracted and removed from the composite video signal of the center line .
Thus, the luminance signal of each line is separated and extracted.

[0017] At this time, since the almost of the input level chroma signal I by the one-dimensional frequency separation filter processing the composite video signal of the center line is extracted, the separated and extracted luminance signal on the basis of the chroma signal leakage click Roma signal components almost rather name, when one line chroma state Y /
C separation characteristics are significantly improved. And 3 line logica
In addition to the arithmetic operation processing circuit, two 1H delay circuits and three clocks
A frequency separation filter for extracting the Roma signal band and two symbols
Signal inversion circuit, one-line chroma detection circuit, and chroma output
A switching circuit and an arithmetic circuit, and one line chroma
The detection circuit has three absolute value circuits and three low-pass filters.
Filter, a comparator circuit, and a gate circuit.
Only the center line contains one line chroma signal
The state is detected by a specific configuration using an absolute value circuit,
Y / C separation characteristics in one line chroma state
This type of video signal processing device with
Can be provided.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment will be described with reference to FIGS. In FIG. 1, the same reference numerals as those in FIGS. 3 and 4 denote the same components, and the differences from FIG.

A chroma output switching circuit 22 is provided at the subsequent stage of the arithmetic processing circuit 9, and supplies an output signal p of the arithmetic processing circuit 9 to a low level contact 221 of the switching circuit 22.
Is supplied to the output terminal 18 and the subtraction circuit 19.

A narrow band-pass filter 2 for extracting a chroma signal by subjecting the output signal b to frequency separation filtering.
3 and the output signal t of the filter 23 is
2 to the high-level contact 22h. A one-line chroma detection circuit 24 to which the output signals e, g, and h are supplied is provided, and the switching circuit 22 is connected to the contacts 22h and 22 by the high level and the low level of the output signal u of the circuit 24.
point to switch to l

[0021] Then, signals a continuous three lines, b, only Hisashira-in signal b in one of c is at 1 line chroma conditions, including the chroma signal, the output signal p of the arithmetic processing circuit 9 is input levels It becomes a half-level chroma signal, and this signal is supplied to the contact 221 of the switching circuit 22.

The output signal b of the delay circuit 2, which is a composite video signal of the center line, is also supplied to a filter 23, and a one-dimensional frequency separation filter process of the filter 23 separates and extracts a chroma signal from the composite video signal. This chroma signal is supplied to the contact 22 of the switching circuit 22.
h.

Further, the detection circuit 24 is configured as shown in FIG. 2, and the signals g, e, and h in the chroma band are converted into absolute values by the negative components being turned back to the positive electrodes by three absolute value circuits 25 to 27, respectively. After that, three low-pass filters 28-
30 and are respectively integrated.

By this integration, the level of the chroma signal of each of the three consecutive lines is detected, and the output signals of the filters 28 to 30 are supplied to three comparison circuits 31 to 33, and the presence or absence of the chroma signal of the reference level circuit 34 is provided. It is compared with a reference signal for detection. Then, the output signals of the comparison circuits 31 to 33 change their binary values depending on the presence or absence of the chroma signal, and go high ("1") when the chroma signal is detected, and go low ("0") when the chroma signal is not detected .

Further, the output signals of the comparison circuits 31 to 33 are supplied to the gate circuit 35 and subjected to logic gate processing .
The gate circuit 35 forms a signal that goes high only in the one-line chroma state in which the output signals of the comparison circuits 31 and 32 go low and the output signal of the comparison circuit 32 goes high. The signal u is the detection output signal 24.

The switching circuit 22 is switched by the signal u, and in the normal state where the signal u is held at the low level, the switching circuit 22 is held at the contact 221 and the output signal s is output from the arithmetic processing circuit 9. Since the signal p is formed and supplied to the output terminal 18 and the subtraction circuit 19 as a chroma signal, the Y / C separation is performed based on the output signal p of the arithmetic processing circuit 9 as in the conventional device of FIG. Done.

On the other hand, in the one-line chroma state in which the signal u is at the high level, the switching circuit 22 is switched to the contact point 22h, and the output signal s is formed by the output signal t of the filter 23. Is supplied to the output terminal 18 and the subtraction circuit 19.

At this time, the output signal p of the arithmetic processing circuit 9 becomes a chroma signal having a half of the input level as described with reference to FIG. 5, but the output signal t of the filter 23 obtained by the one-dimensional frequency separation filter processing. Becomes almost the input level chroma signal. Therefore, the output signal r of the subtraction circuit 19 obtained by subtracting the output signal t from the output signal q becomes a signal of substantially only a luminance signal without a chroma signal component, and this signal is supplied to the output terminal 21.

Since the output signal r is not a luminance signal including the chroma signal of the conventional device but is substantially a luminance signal, the chroma signal does not leak into the luminance signal even in the one-line chroma state, so that there is no so-called dot interference. / C separation can be performed.
The configuration of each unit such as the arithmetic processing circuit 9 and the detection circuit 24 is not limited to the embodiment.

[0030]

Since the present invention is configured as described above, the following effects can be obtained. One line (middle) in the center of three consecutive lines of the composite video signal
Central line) only when 1 line chroma conditions including chroma signal, the detection output of the one-line chroma detection circuit 24, the output signal of the output signal is three lines logical operation processing circuit 9 chroma output switching circuit 22, the central line One-dimensional frequency separation filter processing on the input composite video signal
It switched to facilities signals, the subtraction circuit 19 subtracts remove this signal from the composite video signal of the center line
The luminance signal of each line of the input terminal 1 is separated and extracted.

At this time, the one-dimensional composite video signal
The frequency separation filter process, since almost chroma signal input level is extracted, most leaks not chroma signal, performs no Y / C separation dot interference in the separation extracted luminance signal on the basis of the chroma signal be able to.
In addition to the three-line logical operation processing circuit 9, two
1H delay circuits 2 and 3 and three chroma signal band extraction circuits
Frequency separation filters (bandpass filters 4 to 6);
Two sign inversion circuits 7 and 8 and a one-line chroma detection circuit
24, the chroma output switching circuit 22, and the arithmetic circuit 19
And a one-line chroma detection circuit 24
Three absolute value circuits 25-27, low-pass filter 28-
30, the comparison circuits 31 to 33 and the gate circuit 35
Only one line containing the chroma signal
The inchroma state is represented by a specific configuration using an absolute value circuit.
Can be detected. Therefore, in this type of video signal processing apparatus that performs Y / C separation using the three-line logical operation processing circuit 9, it is possible to provide a specific configuration in which the Y / C separation characteristics in the one-line chroma state are significantly improved. .

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of a video signal processing device according to the present invention.

FIG. 2 is a detailed block diagram of the one-line chroma detection circuit of FIG.

FIG. 3 is a block diagram of a conventional device.

FIG. 4 is a detailed block diagram of the three-line logical operation processing circuit of FIG. 3;

FIG. 5 is an explanatory diagram of a Y / C separation characteristic of the conventional device in a one-line chroma state.

[Description of Signs] 1 Input terminal 2, 3 1H delay circuit 4-6 Bandpass filter 7, 8 Sign inversion circuit 9 3-line logical operation processing circuit 19 Subtraction circuit 22 Chroma output switching circuit 24 1-line chroma detection circuit 25-27 Absolute value circuit 28-30 Low pass filter 31-33 Comparison circuit 35 Gate circuit

Claims (1)

(57) [Claims] 1. A continuous video signal formed by subjecting a composite video signal at an input terminal to delay and frequency separation filter processing.
A signal in the chroma band of the line is supplied to a three-line logical operation processing circuit, and a composite image of a central line among the three consecutive lines is obtained by a combination of operation processing of the maximum value and the minimum value of the operation processing circuit. the click Roma signal of the signal separated and extracted, separated luminance signal of each line of components <br/> JIT video signal of the input terminal from the composite video signal of the central line by subtracting removed output signal of the arithmetic processing circuit Y to extract
In the video signal processing device for / C separation, the composite video signal at the input terminal is delayed line by line.
Two IHs for outputting first and second delayed video signals
A delay circuit, a composite video signal at the input terminal, and the two delayed video signals
A signal is subjected to frequency filter processing, and the first
Composite of the center line formed by the delayed video signal
A video signal, the second delayed video signal,
Before the center line formed by the composite video signal,
Chroma band of each composite video signal of the rear line
The signal of the chroma band of the continuous three lines is extracted.
Frequency separation filter for extracting three chroma signal bands for generating
Filter and the polarity of each of the chroma band signals of the front and rear lines.
Reverse the polarity of the chroma band of the three consecutive lines to the same
Two sign inverting circuits, and a signal in the chroma band of the center line and the sign inverting.
Chroma band of the front and rear lines whose polarity has been inverted by the circuit
The level judgment of the frequency of the signal, among the three consecutive lines
The 1 and line chroma detector circuit only the central line detecting one line chroma conditions including chroma signal, by switching the I that output signal to the detection output of the detection circuit,
Upon detection of said one line chroma state, instead of the output signal of the arithmetic processing circuit, a signal obtained by facilities the one-dimensional frequency separation filter processing the composite video signal of the central line, and outputs a chroma signal of the central line A chroma output switching circuit, and a first video signal which is a composite video signal of the center line.
Subtracts and removes the output signal of the switching circuit from the delayed video signal
To separate and extract the luminance signal of each line of the input terminal
And a subtraction circuit, and the detection circuit is provided with a signal in a chroma band of the center line and the sign inversion.
Chroma band of the front and rear lines whose polarity has been inverted by the circuit
Each signal in the range is turned back from the negative component to the positive
Three absolute value circuits for converting values, and three absolute value circuits for integrating respective output signals of the absolute value circuits.
A low-pass filter, and an output signal of each of the low-pass filters and a chroma signal.
The level of the signal is compared with the reference signal of presence or absence of the signal.
The presence or absence of each of the three lines of chroma signals is
Three comparison circuits for outputting signals whose values change, and logic gate processing of the output signals of the respective comparison circuits to perform
And a gate circuit forming the detection output of the detection circuit.
A video signal processing apparatus characterized by comprising the.