JP2619120B2 - Video signal processing device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal processing apparatus, and in particular, records a color signal in the form of a line-sequential color signal, and interpolates the line-sequential color signal during reproduction. Later, the present invention relates to an apparatus applied to a video signal recording / reproducing apparatus for obtaining a video signal output.

[Conventional technology]

A video signal recording / reproducing device (hereinafter referred to as a VTR) includes a color signal and a luminance signal in order to avoid a deterioration in image quality due to interference between a color signal and a luminance signal of a video signal in recording and reproduction and to realize high image quality. There is a type that performs recording and reproduction after converting into a time division multiplexed signal (hereinafter, referred to as a TCI signal). In this case, two color signals P _B, the signal bandwidth of the P _R (corresponding to the horizontal resolution) is because it is less than half of the luminance signal Y, P _B, P _R
Halved the vertical resolution, that is, P _B , P _R
The Select Create a line sequential color signal P _B / P _R, time-division multiplexing the signal luminance signal Y and.

FIG. 12 shows the waveform of the TCI signal,
H indicates a horizontal scanning period of the video signal. The P _B , P _R , and Y signals are time-axis compressed for each scanning line, and are time-division multiplexed together with a negative horizontal synchronization signal indicating each scanning line unit.

FIG. 10 is a configuration diagram of a reproduction system signal processing circuit as a video signal processing device in a conventional VTR, where 1 is a magnetic tape, 2 is a magnetic head, and 3 is an FM signal reproduced by the magnetic head 2. Amplifier, a FM demodulator, 5
Is an A / D that converts the FM demodulated TCI signal to a digital signal
Converter 14 the luminance signal (hereinafter, Y signal hereinafter) from the TCI signal line sequential color signal (hereinafter, P _B / P _R signal hereinafter) TCI decoder to restore, 7 from P _B / P _R signals two color signals (hereinafter, respectively, P _B signal, referred to as P _R signal) color signal interpolation circuit for restoring, 8 converts the digital signal into an analog signal
D / A converter, 15 is a three primary color video signals Y, P _B, the P _R signals
A matrix circuit for converting R, G, B signals (hereinafter, referred to as G, B, R signals), and a synchronization adding circuit 10 for adding a synchronization signal conforming to a video signal standard to each output of the matrix circuit 15 .

FIG. 11 shows an example of the configuration of the color signal interpolation circuit 7;
6 and 17 are delay circuits for delaying the input signal by one horizontal scanning period.
8 is an addition circuit, 19 is a coefficient unit that multiplies the value of the input signal by 1/2,
Reference numeral 20 denotes a selector that selects and outputs an input signal. Then, P _B, is realized an interpolation filter for P _R by the above configuration.

FIG. 15 shows an example of the configuration of the matrix circuit 15. In the figure, 11a to 11g indicate the values of the input signals as 1,0.227, 0.477, and 0.477, respectively.
Coefficients for multiplying 1,1.826,1,1.576 and 12a, 12b, 12c are adders.

Next, the operation will be described with reference to the signal form diagrams shown in FIG. 13 and FIG. Figure 13 (a) is a diagram showing the form of the P _B / P _R signals TCI decoder 14. Here, the number of effective scanning lines in one field is n, and n is an even number. P _B in the figure, the numbers appended to the P _R represents the scanning line number. That, P _B / P _R signals, and P _B signal of the even number scan lines are constituted by P _R signals odd numbered scan lines. Parts other than the video information, such as the vertical blanking section and the horizontal blanking section, are at the 0 level of the color signal (representing achromatic color; hereinafter, referred to as the CB level).

The P _B / P _R signal is input to the color signal interpolation circuit 7 and
3 view (b), P _R signal shown (c), the is converted into P _B signal. Here, before the first scanning line at P _R signals, 1H period (CB +
P _R1) / 2 becomes signal appears, also the n in P _B signal
After the scan line, a signal of (P _Bn + CB) / 2 appears for 1H period.

On the other hand, from TCI decoder 14, FIG. 13 output P _B color signal interpolation circuit 7 as shown in (d), P P as _R with the corresponding scan line number is taken _B / P _R signals from 1H delay As a result, a Y signal is output. Here, P _B, in response to CB level P _R signals, the vertical and horizontal blanking portions have become black level (hereinafter, referred to as YB level).

The Y, P _B, the P _R signals after being converted into an analog signal by the D / A converter 8, G by the matrix circuit 15, B, is converted to the R signal. Here, the conversion formula is as the following formula (1).

Note G For reference, B, matrix equation for converting the R signal Y, P _B, the P _R signals also note as an expression (2).

FIG. 14 shows the results shown in FIGS. 13 (b), (c) and (d).
This shows how the matrix circuit 15 converts the P _R , P _B , and Y signals 1H before the first scanning line into G, B, and R signals. Y, P _B, specific embodiment the diagram P _R signals (a), and is of (b), (c). That is, as described above, Y, P _B signal are each YB, CB level, P _R signal is assumed to be (CB + P _R1) / 2 becomes the result of the calculation, FIG. (C). Here, Y
The signal level 0-1 (0 black, 1 white) and to obtain a value of the signal level of P _B, P _R shall obtain a value of -0.5 to 0.5.

FIGS. 6D to 6F show the output of the matrix circuit 15, and as is apparent from FIG.
In the signal, there is a portion where the signal level has a negative value. FIG. 3G shows the R at the output of the synchronization adding circuit 10.
It shows a signal. As the synchronization signal, a ternary synchronization signal (having a value of ± 0.429 around the 0 level) is assumed. As described above, in the signal portion 1H before the first scanning line, a portion having a signal level equivalent to the negative electrode synchronization level may occur. A similar phenomenon can also occur in the signal portion 1H after the n-th scanning line, as is clear from FIG.

In the synchronization adding circuit 10, in addition to the horizontal synchronization signal shown in FIG. 14 (g), a vertical synchronization signal having at least a negative pulse portion wider than the horizontal synchronization signal in a part of the vertical blanking period is also provided. Add. The timing for adding a signal is supplied from the TCI decoder 14.

[Problems to be solved by the invention]

Since the VTR that obtains the video signal output after interpolation processing of the conventional line-sequential color signal is configured as described above, the VTR output may have the same signal level as the synchronization signal during periods other than the synchronization signal In addition, there is a problem that a malfunction of synchronization separation detection is induced in a video device such as a TV or another VTR which receives a VTR output as an input.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and can obtain a signal conforming to a video signal standard as an output of a device. It is an object of the present invention to obtain a video signal processing apparatus in which a signal level does not deviate from a predetermined level range in a period other than a synchronization signal when applied to a VTR that obtains

[Means for solving the problem]

A video signal processing device according to a first aspect of the present invention includes a color signal interpolation circuit, and obtains a video signal output after performing an interpolation process on an input color signal. The color difference signals subjected to R, G,
A matrix circuit for converting the signal into a B signal; and a selector for switching and outputting an R, G, B signal output from the matrix circuit and a signal corresponding to a blanking level of the R, G, B signal. , G and B signals are controlled during the vertical blanking period which does not include the horizontal blanking period, so that the selector outputs a signal corresponding to the blanking level of the R, G and B signals.

A video signal processing apparatus according to a second aspect of the present invention includes a color signal interpolation circuit, and obtains a video signal output after performing interpolation processing on an input color signal. A signal level comparison circuit for generating a control signal when the signal level falls below a predetermined level; and a control signal output from the signal level comparison circuit for switching between an interpolation filter output and a signal corresponding to an achromatic color level of a color signal. And a selector for controlling the selector to output a signal corresponding to the achromatic color level of the color signal at least during a period in which the luminance signal level is lower than a predetermined level.

A video signal processing device according to a third aspect of the present invention includes a color signal interpolation circuit, and performs the interpolation process in a video signal processing device that obtains a video signal output after performing an interpolation process on an input color signal. A vertical blanking period that does not include a horizontal blanking period of the color signal subjected to the interpolation processing, including a selector that switches and outputs a signal output from the color signal interpolation circuit and a signal corresponding to an achromatic color level of the color signal. Is to control the selector so as to output a signal corresponding to the achromatic color level.

[Action]

In the invention according to claim 1 of the present application, with the above configuration, the vertical blanking period that does not include the horizontal blanking period of the R, G, B signal is performed at the blanking level of the R, G, B signal. Is output.
During this period, the signal levels of the R, G, and B signals do not fall below the blanking level.

Further, in the invention according to claim 2 of the present application, by configuring as described above, a signal corresponding to the achromatic color level of the color signal is output at least during a period in which the luminance signal level is lower than a predetermined level. Therefore, R, G, B
The signal level of the signal does not fall below the blanking level.

Further, in the invention according to claim 3 of the present application, the vertical blanking period not including the horizontal blanking period of the color signal subjected to the interpolation processing corresponds to the achromatic color level due to the above configuration. Therefore, the signal levels of the R, G, and B signals do not fall below the blanking level during the period.

〔Example〕

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

FIG. 1 is a block diagram of a video signal processing apparatus according to a first embodiment of the present invention, and particularly shows a reproduction signal processing circuit in a video signal recording / reproduction apparatus as an example. In FIG. 10, 1 to 5, 7, 8, and 10 are the same as those in FIG. Reference numeral 6 denotes a TCI decoder, and 9 denotes a matrix circuit. The TCI decoder 6 outputs a VB switching signal indicating a vertical blanking period to the matrix circuit 9.

FIG. 2 is a configuration example of the matrix circuit of FIG. In the figure, reference numerals 11 and 12 are the same as those in FIG. 13a is a selector, which outputs the output of the adder 12 at the preceding stage and the DCOV signal corresponding to the black level of the Y signal.
Switching is performed based on the VB switching signal.

Next, the operation of this embodiment will be described with reference to the signal form diagrams shown in FIGS.

The output of the D / A converter 8 is the same as that of the conventional device.
The signals are input to the matrix circuit 9 in the forms shown in FIGS.

In the matrix circuit 9, multipliers 11a to 11g and adders 12a to 12
After the matrix processing in c, the signal level, which has been a problem in the conventional device, is input to the selector circuit 13a with a negative value. A DCOV signal corresponding to the black level of the Y signal is connected to the other input terminal of the selector circuit 13a. The signal is selected by VB output from the TCI decoder 6.
Is performed on the basis of the switching signal, this signal is adapted to select a date only adder 12 outputs the presence of Y ₁ to Y _n in FIG. 13 (d), other periods selects DCOV . The VB switching signal is the same as the timing signal when the Y signal is restored and output from the TCI signal in the TCI decoder 6, and can be easily created.

The outputs of the selector circuit 13a are shown in FIGS.
As shown in (c), it is always at the YB level except during the effective scanning period. Therefore, the phenomenon that the signal level, which is a problem in the conventional device, becomes a negative value does not occur, and the signal level also becomes a negative value in the outputs G, B, and R of the present embodiment after the addition of the synchronization signal. Only the synchronization signal part.

In the above embodiment, the DC level corresponding to the black level of the Y signal is used.
Although an example using the OV signal is shown, as shown in FIG.
The selector 13b may connect the Y signal to G, B, R,
The same effects as in the above embodiment can be obtained.

Also, in this embodiment, a VTR is assumed as the video signal recording / reproducing device, but a video disc player may be used.
The same effects as in the above embodiment can be obtained.

FIG. 5 is a block diagram of a video signal processing apparatus according to a second embodiment of the present invention, and particularly shows a reproduction signal processing circuit in a video signal recording / reproduction apparatus as an example. In the figure, 1 to 5, 7 to 10 are the same as those in FIG. 21 is a ROM supplies a control signal indicating that the signal level of the Y signal is equal to or lower than a predetermined level to the selector 22 switches the P _B, P _R signals and CB by a control signal supplied from the ROM21 in the selector 22 Output. The Y signal is output from the TCI decoder 24 to the ROM 21.

Next, the operation of this embodiment will be described with reference to the signal form diagrams shown in FIGS. 6 and 13.

The output of the color signal interpolation circuit 7 is the same as that of the conventional apparatus.
13 (b) and (c) are input to the selector 22. On the other hand, the Y signal is also input to the ROM 21 and, for example, when it is handled as 8-bit digital data of a video signal, the gradation is from 0 to 255, the white level having the highest signal level is 240, and the signal level is the highest. Low black level 70
If the digital data becomes a value of, for example, 80 or less, the output of the ROM 21 outputs such that the signal becomes "1" only in a section where the Y signal level is lower than the predetermined level as shown in FIG. 13 (e). Since only section becomes "1" by the output of ROM21 the selector 22 P _B, and select the CB both P _R, the section of "0" to select a color signal interpolation circuit 7, FIG. 6 (a), ( As shown in b), it is always at the CB level except during the effective scanning period. Therefore, in the present embodiment, the phenomenon that the signal level becomes a negative value, which is a problem of the conventional device in the matrix circuit, does not occur, and the output G, B, and R signals of the present embodiment after the addition of the synchronization signal do not occur. However, only the synchronizing signal portion has a negative signal level. Further, in this embodiment, since the selector control signal is generated in accordance with the luminance signal level using the ROM, the circuit can be simplified as compared with the case where the control signal is generated by a counter or the like.

In the above embodiment, the synchronization adding circuit is provided after the matrix circuit. However, a synchronization adding circuit may be provided between the selector circuits D / A converters.

In this embodiment, a VTR is used as a video signal recording / reproducing device.
However, a video disc player may be used, and the same effects as in the above embodiment can be obtained.

Further, in the present embodiment, the explanation has been made using the ROM as the signal level comparing circuit. However, the present invention is not limited to this, and other signal level comparing circuits can provide the same effects as the above embodiment.

FIG. 7 is a block diagram of a video signal processing apparatus according to a third embodiment of the present invention, and particularly shows a reproduction signal processing circuit in a video signal recording / reproduction apparatus as an example. In the figure, 1 to 5, 8 to 10 are the same as those in FIG. The vertical blanking period is indicated from the TCI decoder 25 to the selector 23 in the color signal interpolation circuit 26.
Outputs VB switching signal.

FIG. 8 is a configuration example of the color signal interpolation circuit 26 of FIG.
The interpolation filter consisting of 16 to 20 in FIG.
The description is omitted because it is the same as the figure. Reference numeral 23 denotes a selector, which switches the output of the preceding selector 20 and a signal indicating the CB level based on the VB switching signal.

Next, the operation of the present embodiment will be described with reference to the signal form diagrams shown in FIG. 9 and FIG.

The outputs P _B and P _R of the selector 20 in the color signal interpolation circuit 26 have the forms shown in FIGS. 13B and 13C as in the case of the conventional device. The above signal is input to the selector 23. The signal indicating the CB level is connected to the other input terminal of the selector 23. The selection of the signal is performed based on the VB switching signal output from the TCI decoder 25.
In FIG. 4D, the selector 20 is used only during a period in which Y _{1 to} Y _n exist.
And the polarity is such that the CB level is selected during the other periods. The above signal is the same as the timing signal when the Y signal is restored and output from the TCI signal in the TCI decoder 25, and can be easily created.

P _B, P _R output of the selector 23, i.e. the color signal interpolating circuit 26
P _B, P _R output Ninth view of (a), as shown (b), the
Except for the effective scanning period, it is always at the CB level. Therefore, in the present embodiment, the phenomenon that the signal level, which is a problem in the conventional device, becomes a negative value in the output of the matrix circuit 9 does not occur, and the outputs G, B, and Also in the R signal, the signal level has a negative value only in the synchronization signal portion.

In the above embodiment, an example in which a three-tap filter is used as the color signal interpolation circuit has been described. However, it is needless to say that the number of taps is not limited to three.

Further, in the present embodiment, the VT is used as the video signal recording / reproducing device.
Although R is assumed, a video disc player may be used, and the same effects as in the above embodiment can be obtained.

〔The invention's effect〕

As described above, according to the video signal processing device according to the invention of claim 1 of the present application, the video signal processing device including the color signal interpolation circuit and obtaining the video signal output after performing the interpolation processing on the input color signal, A matrix circuit for converting the luminance signal, and the color difference signal subjected to the interpolation processing into R, G, B signals, and the R, G, B signals output from the matrix circuit;
A selector for switching and outputting a signal corresponding to the blanking level of the R, G, B signal, wherein the vertical blanking period not including the horizontal blanking period of the R, G, B signal is the R, G, B Since the selector is controlled so as to output a signal corresponding to the blanking level of the signal,
There is an effect that a signal conforming to the video signal standard can be obtained as an output of the device.

Further, according to the video signal processing apparatus according to the invention of claim 2 of the present application, the video signal processing apparatus includes a color signal interpolation circuit and obtains a video signal output after performing interpolation processing on an input color signal. A signal level comparison circuit that generates a control signal when a certain level or less is reached,
A selector for switching and outputting an interpolation filter output and a signal corresponding to an achromatic color level of a color signal in accordance with a control signal output from the signal level comparison circuit; Since the selector is controlled so as to output a signal corresponding to an achromatic color level of a color signal, there is an effect that a signal conforming to a video signal standard can be obtained as an output of the apparatus.

Further, according to the video signal processing apparatus according to the third aspect of the present invention, the video signal processing apparatus includes a color signal interpolation circuit, and obtains a video signal output after performing interpolation processing on an input color signal. And a selector for switching and outputting the output of the color signal interpolation circuit and the signal corresponding to the achromatic color level of the color difference signal. The vertical blanking period not including the horizontal blanking period of the color signal subjected to the interpolation processing is Since the selector is controlled so as to output a signal corresponding to the achromatic color level, there is an effect that a signal conforming to a video signal standard can be obtained as an output of the apparatus.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a reproduced signal processing circuit of a video signal recording / reproducing device which is an example of a video signal processing device according to a first embodiment of the present invention, and FIG. 2 is a configuration example of a matrix circuit in the above embodiment. FIG. 3, FIG. 3 is a signal form diagram for explaining the operation thereof, FIG. 4 is a diagram showing a configuration example of another matrix circuit in the above embodiment, and FIG. 5 is a reproduction according to a second embodiment of the present invention. FIG. 6 is a block diagram of a signal processing circuit for explaining the operation of the above embodiment, FIG. 7 is a block diagram of a reproduced signal processing circuit according to a third embodiment of the present invention, and FIG. FIG. 9 is a diagram showing a configuration example of a color signal interpolation circuit in the example, FIG. 9 is a signal form diagram for explaining its operation, FIG. 10 is a configuration diagram of a conventional reproduction signal processing circuit, and FIG. FIG. 12 is a diagram showing a configuration example, FIG. 12 is a waveform diagram of a TCI signal, and FIGS. 13 and 14 illustrate the operation of a conventional device. Diagram showing the signal form for
FIG. 1 is a diagram showing a configuration example of a conventional matrix circuit. In the figure, 5 is an A / D converter, 6 is a TCI decoder, 7 is a color signal interpolation circuit, 8 is a D / A converter, 9 is a matrix circuit, 1
0 is a synchronization addition circuit, 11 is a multiplier, 12 is an adder, 13 is a selector, 21 is a ROM, and 22 is a selector. In the drawings, the same reference numerals indicate the same or corresponding parts.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-168792 (JP, A) JP-A-52-124821 (JP, A)

Claims (3)

(57) [Claims] 1. A video signal processing apparatus comprising a color signal interpolation circuit for obtaining a video signal output after performing an interpolation process on an input color signal, wherein a luminance signal and a color difference signal subjected to the interpolation process are represented by R,
A matrix circuit for converting into G and B signals; R, G and B signals output from the matrix circuit and the above R, G and B signals
A selector for switching and outputting a signal corresponding to the blanking level of the signal, wherein the vertical blanking period not including the horizontal blanking period of the R, G, B signal is the blanking level of the R, G, B signal. A video signal processing device for controlling the selector so as to output a signal corresponding to the video signal. 2. A video signal processing apparatus comprising a color signal interpolation circuit for obtaining a video signal output after interpolation of an input color signal, wherein a control signal is output when a luminance signal level falls below a predetermined level. A signal level comparison circuit to be generated, and a selector for switching and outputting an interpolation filter output and a signal corresponding to an achromatic color level of a color signal by a control signal output from the signal level comparison circuit, and having at least a luminance signal level. A video signal processing apparatus, wherein the selector is controlled to output a signal corresponding to an achromatic color level of the color signal during a period equal to or lower than a predetermined level. 3. A video signal processing device comprising a color signal interpolation circuit for obtaining a video signal output after performing an interpolation process on an input color signal, wherein a signal output from the color signal interpolation circuit performing the interpolation process and a color signal A selector for switching and outputting a signal corresponding to the achromatic color level of the color signal, and outputting a signal corresponding to the achromatic color level during a vertical blanking period not including a horizontal blanking period of the color signal subjected to the interpolation processing. A video signal processing device characterized by controlling the selector as described above.