JPH0846994A - Video selector device - Google Patents

Abstract

PURPOSE:To remove unnatural feeling of color reproducibility, at the time of reproducing a picture on a monitor by switching and selecting plural video signals, by newly adding a burst signal in the same level as a color burst signal in a selected video signal to the selected video signal. CONSTITUTION:In a video signal processing part 300, a color burst adding circuit 301 adds the color burst signal B from the Y and C signals of the video signals selected by a selector part to a video signal V generated by an NTSC encoder 14 and supplies it to a monitor 400. Then, a microcomputer 11 makes the burst adding circuit 301 take in a color burst signal BL extracted from the video signal selected by the selector each time of one vertical synchronizing period in accordance with a burst processing signal BS. The burst signal in the same level as the selected video signal is added like this so that a reproducing picture at the monitor obtains the reproducing picture with no unnatural feeling in spite of switching plural video signals.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video selector device, which is adapted to prevent discomfort in color reproducibility before and after switching.

[0002]

2. Description of the Related Art In an NTSC color video signal, a color burst signal is inserted in a back porch during a horizontal blanking period. In the color television receiver, the phase of the color subcarrier oscillator is matched with the color burst signal to demodulate the color signal.

The color video signal transmitted from the broadcasting station is
It propagates in the air, is received by the antenna of each home, and is guided to the color television receiver. The color burst signal level in the color video signal used for such television broadcasting may be slightly deviated from the level of the NTSC standard depending on the broadcasting station and program content. Further, the level of the color burst signal may be attenuated during the air propagation.

If the attenuated color burst signal is used as it is, the color reproducibility is deteriorated. Therefore, ACC (Automatic Chroma Adjustment: Automatic Ch
(romaControl) circuit detects the color burst signal level, and as the color burst signal level increases, the carrier color signal level also increases, so that the circuit gain can be changed so that the color density becomes constant. I have to.

On the other hand, video equipment has become widespread and includes video cameras, video tape recorders, laser disks,
There are various things such as video effectors. Among these video devices, there are models that digitalize signal processing for the purpose of improving image quality and increasing functions. Although a specific example will be described later, in a video device that performs digital signal processing,
In the signal processing process, the video signal (digital signal) from which the color burst signal has been removed is digitally processed, and the video signal (analog signal) after signal processing is added with the color burst signal at the NTSC compliant level later and output. ing.

Here, as an example of a video device in which the level of a color burst signal added later is a level conforming to NTSC, various image effects (multi-screen, multi-screen,
The configuration of a video effector that provides still image mosaic, solarization, wipe, etc.) will be described with reference to FIG.

As shown in FIG. 7, in the video effector, the NTSC decoder 1 produces color difference signals RY and BY from the luminance signal Y and the color signal C. Color difference signals R-Y, B-
Y is dot-sequentialized by the dot-sequential control analog switch circuit 4 via the prefilters 2b and 2c and the amplifiers 3b and 3c, further digitized by the A / D converter 5b, and written in the field memory 6. Further, the luminance signal Y is digitized by the A / D converter 5a via the prefilter 2a and the amplifier 3a, and is written in the field memory 7.

The sync separation circuit 8 separates the vertical drive signal VD and the horizontal drive signal HD from the luminance signal Y, and the sync signal generation circuit 9 generates the sync signal S and the clock signal C based on the signals VD and HD. To do. The write timing generation circuit 10 controls the dot sequential control timing in the dot sequential control analog switch circuit 4 and the write timing in the field memories 6 and 7.

The signals RY, BY and Y written in the field memories 6 and 7 are read out under the control of the microcomputer 11. By changing this reading method and reading order,
Various image effects can be obtained.

The read signals Y, RY, BY are D /
The analog signals are converted into analog signals by the A converters 12a, 12b, 12c and input to the NTSC encoder 14 via the post filters 13a, 13b, 13c. The read timing generation circuit 15 controls the read timing of the field memories 6 and 7.

The NTSC encoder 14 outputs signals Y, R-
An NTSC video signal V is created from Y and BY. In this case, the burst addition circuit 16 superimposes the color burst signal B having an NTSC-compliant level on the video signal V. The signal V + B is amplified by the amplifier 17 and output.

[0012]

By the way, as shown in FIG. 8, the video output signal V ₁ of the video player 25 is input to the video effector 21, and the video signal V ₁ ′ output from the video effector 21 and Color television receiver 22
The video selector 23 selects one of the video signals V ₂ output by the video selector 23 and sends the selected video signal to the monitor 24 to display it as a video.

In the system shown in FIG. 8, the color displayed on the monitor 24 by selecting the video signal V ₁ ′ is darker than the color displayed on the monitor 24 by selecting the video signal V _2. It may end up. This is because the level of the color burst signal in the video signal V ₁ ′ output from the video effector 21 is a level compliant with NTSC, while the video signal V ₂ output from the color television receiver 22. This is because the level of the color burst signal in <1> may be attenuated and become lower than the level according to NTSC.

As shown in the example of FIG. 8, a video selector generally receives a plurality of video signals, selects one of them and sends it to a monitor. As described above, when the type of the video signal is different, the level of the color burst signal may be different, and in this case, the color density displayed on the monitor is different, and switching is performed by the video selector. The color density changes each time, making the image difficult to see.

Such a phenomenon may also occur when the Y / C separated type video signal input via the S terminal input and the composite video signal are switched / selected by the video selector and displayed on the monitor. This is because the Y / C separation type video signal and the composite video signal may have different color burst signal levels.

In view of the above-mentioned conventional technique, the present invention does not have a difference in color density before and after switching and selecting a plurality of video signals of different types and sends them to a monitor, which causes a difference in color reproducibility. It is an object to provide a video selector device without feeling.

[0017]

The structure of the present invention for solving the above-mentioned problems includes a video selector section for selecting one video signal from a plurality of video signals by performing a switching operation, and the video selector section. A burst level detection unit for detecting the level of the color burst signal in the selected video signal, and the video signal selected by the video selector unit,
A new color burst signal is added, and a burst adding unit is also provided for adjusting the level of the newly added color burst signal to the level detected by the burst level detecting unit.

[0018]

In the present invention, one video signal is selected by the video selector section, and a new color burst signal is added to the selected video signal by the burst adding section. The level of the color burst signal added later is the same as the level of the color burst signal in the video signal when selected.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 and 2 show the circuit configuration of a video selector device according to an embodiment of the present invention. In both figures, points A, B, C, D, E, F and G surrounded by circles are the same points, and signal transmission is performed through each point. That is, for convenience of illustration, the circuit configuration of the embodiment is divided into two drawings (FIGS. 1 and 2).

The video selector device of this embodiment is roughly divided into the video selector section 100 and the burst level detecting section 200 shown in FIG. 1, the video signal processing section 300 shown in FIG. 2, the microcomputer 11, and the A / D conversion. It comprises a burst adder composed of a container 302 and a burst adder circuit 301, and a monitor 400.

First, an outline of the present embodiment will be described, and then detailed configurations and operations of respective parts will be described.

In the video selector section 100, two Y / C separated video signals Y ₁ / C ₁ and Y ₂ / C _{2 are provided.}
Also, one signal is selected from a total of four video signals of the two composite video signals V ₁ and V ₂ and sent to the video signal processing unit 300.

The burst level detecting section 200 detects the level of the color burst signal in the video signal selected by the video selector section 100.

The video signal processing section 300 is obtained by partially modifying the video effector shown in FIG. 7. The parts having the same functions as those in FIG. 7 are designated by the same reference numerals, and the duplicated description will be omitted. In the video signal processing unit 300, the color burst signal B is superimposed on the processed video signal V, but the color burst signal level is not the so-called standard NTSC-compliant level but the level detected by the burst level detection unit 200. There is. This is the point of the present invention.

The monitor 400 receives a video signal to which a color burst signal is added and displays an image. In this case, the level of the color burst signal is the same level as when selected by the video selector 100, so that there is no discomfort in color reproducibility, and the color does not become darker or lighter than the original color. .

If the level of the color burst signal before switching and the level of the color burst signal after switching are different when the signals to be selected are switched in the video selector section 100, the video signal processing section 300 The level of the color burst signal to be added later is gradually changed from the color burst signal level before switching to the color burst signal level after switching.

Next, the details of each part will be described.

The video selector section 100 has a first input section 101 having an S terminal T _1S to which the Y / C separated video signal Y ₁ / C ₁ is input and a terminal T _1V to which the composite video signal V ₁ is input. And Y / C separation type video signal Y ₂ / C ₂
Is input to the S terminal T _2S and the composite video signal V ₂
Is provided with a second input section 102 having a terminal T _2V to which is input. When the S terminals T _1S and T _2S have a pin input, the switches 101 _SW and 102 _SW are turned on, and the pin input via the point C means that the microcomputer 11 of the burst adding unit 300 has
It is transmitted to.

The video selector section 100 further includes a Y / V selection circuit 103, a C selection circuit 104, and a Y / C separation circuit 10.
5, a Y selection circuit 106 and a C selection circuit 107. Here, Y represents a luminance signal, V represents a composite video signal, and C represents a color signal. Then, a switching command from the microcomputer 11 is input to each of the circuits 103 to 107 via points D and E, and a selection / switching operation is performed. Each mode of the selection / switching operation will be described with reference to FIGS. It should be noted that FIGS. 3 to 6 show that a signal is transmitted along an arrow line indicated by a solid line.

When the S terminal T _1S is selected, as shown in FIG. 3, the Y / V selection circuit 103 selects the brightness signal Y ₁ , the Y selection circuit 106 selects the brightness signal Y ₁ , and the point A is selected. The luminance signal Y ₁ is sent to the burst adding unit 300 via the luminance signal Y ₁ . Further, the C selection circuit 104 selects the color signal C ₁ , the C selection circuit 107 selects the color signal C ₁ , and the color signal C ₁ is sent to the video signal processing unit 300 via the point B.

When the terminal T _1V is selected, as shown in FIG. 4, the Y / V selection circuit 103 selects the composite video signal V ₁ , and the Y / C separation circuit 105 sets the video signal V ₁ to the luminance signal Y. The color signal C is separated. The separated luminance signal Y is sent to the video signal processing unit 300 via the Y selection circuit 106 and the point A. The separated color signal C is sent to the video signal processing unit 300 via the C selection circuit 107 and the point B.

When the S terminal T _2S is selected, as shown in FIG. 5, the Y / V selection circuit 103 selects the brightness signal Y ₂ , the Y selection circuit 106 selects the brightness signal Y ₂ , and the point A is selected. The luminance signal Y ₂ is sent to the video signal processing section 300 via the luminance signal Y ₂ . The C selection circuit 104 selects the color signal C ₂ , the C selection circuit 107 selects the color signal C ₂ , and the color signal C ₂ is sent to the video signal processing unit 300 via the point B.

When the terminal T _2V is selected, the Y / V selection circuit 103 selects the composite video signal V ₂ and the Y / C separation circuit 105 selects the video signal V ₂ as the luminance signal Y, as shown in FIG. The color signal C is separated. The separated luminance signal Y is sent to the video signal processing unit 300 via the Y selection circuit 106 and the point A. The separated color signal C is sent to the video signal processing unit 300 via the C selection circuit 107 and the point B.

The burst level detecting unit 200 selects V / C.
Selection circuit 201, peak hold circuit 202, A / D conversion
It is composed of a container 203. The V / C selection circuit 201 is
S terminal T according to a command from the microcomputer 11_1S, T_2SIs selected
When the color signal C₁, C ₂Select Peak Hall
To the circuit 202, and the terminal T_1V, T_2VWhen is selected
Is a composite video signal V₁, V₂Select
It is sent to the hold circuit 202.

A burst gate pulse B _G is input to the peak hold circuit 202 from the synchronization signal generation circuit 9 of the video signal processing unit 300 via the point F. The burst gate pulse B _G is output during the period in which the color burst signal is added. Therefore, the peak hold circuit 202
Holds the peak values of the signals C ₁ , C ₂ , V ₁ and V ₂ during the period in which the burst gate pulse B _G is being output. This peak value becomes the burst level signal B _L indicating the level of the color burst signal. The burst level signal B _L is digitized by the A / D converter 203 and input to the microcomputer 11 via the point G.

The video signal processing unit 300 is constructed on the basis of the video effector shown in FIG. 7, and has a burst processing function (described later) of the microcomputer 11 for the apparatus shown in FIG.
, The function of the burst addition circuit 301 is changed, and an A / D converter 302 is added.

The burst adding circuit 301 superimposes the color burst signal B on the video signal V generated by the NTSC encoder 14, and further, the burst processing signal B _S sent from the microcomputer 11 via the A / D converter 302. The level of the color burst signal B is adjusted accordingly. The microcomputer 11 takes in the burst level signal B _L every one vertical synchronization period (1 VD). Basically, the microcomputer 11 uses the color burst signal B added by the burst adding circuit 301.
Outputs a burst processed signal B _S having the same level as the burst level signal B _L. Therefore, the level of the color burst signal of the video signal selected by the video selector unit 100 and the level of the color burst signal B added to the video signal V output from the NTSC encoder 14 become equal.

Further the microcomputer 11 stores the burst level signal B _L before 1VD, burst level signal captured this B _L and 1VD previous burst level signal B _L
When the difference between and is larger than the preset value,
The value of the burst processing signal B _S is changed step by step every 1 VD so that the difference becomes small. Such a situation occurs when the signal selected by the video selector unit 100 is switched, but the level of the color burst signal B to be added is changed from the state in which the signal before switching is matched to the state in which the signal after switching is matched. , Because it will move in stages,
The reproducibility of color disappears.

The monitor 400 displays an image corresponding to the video signal V on which the level-adjusted color burst signal B is superimposed. In this case, the color depth of the image is the depth corresponding to the value of the color burst signal B. As described above, the level of the color burst signal B added later is equal to the level when selected by the video selector unit 100.
Even if a plurality of video signals are switched and selected, the reproduced image on the monitor 400 does not have a strange reproducibility.

The level of the color burst signal B added by the burst adding circuit 301 is set to the video selector unit 1
By changing the level regardless of the level selected at 00, it is possible to obtain a special effect such as a black and white screen (set the burst level to zero) or changing the color expression. Needless to say, the same function can be realized not only by NTSC but also by PAL system.

[0041]

As described above in detail with the embodiments, according to the present invention, when the video signals having different levels of the color burst signal are switched / selected and sent to the monitor, the level of the color burst signal to be added later is changed. , It does not give a strange feeling to the color reproducibility because it is adjusted to the level at the time of selection.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

FIG. 2 is a circuit diagram showing an embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a signal selection / switching state.

FIG. 4 is an explanatory diagram showing a signal selection / switching state.

FIG. 5 is an explanatory diagram showing a signal selection / switching state.

FIG. 6 is an explanatory diagram showing a signal selection / switching state.

FIG. 7 is a circuit diagram showing a video effector.

FIG. 8 is a configuration diagram showing a signal switching system.

[Explanation of symbols]

1 NTSC decoder 2a, 2b, 2c pre-filter 3a, 3b, 3c amplifier 4 point sequential control analog switch circuit 5a, 5b, 5c A / D converter 6, 7 field memory 8 sync separation circuit 9 sync signal generation circuit 10 write timing Generation circuit 11 Microcomputer 12a, 12b, 12c D / A converter 13a, 13b, 13c Post filter 14 NTSC encoder 15 Read timing generation circuit 16 Burst addition circuit 17 Amplifier 21 Video effector 22 Color television receiver 23 Video selector 24 Monitor 100 video Selector unit 101 First input unit 102 Second input unit 103 Y / V selection circuit 104 C selection circuit 105 Y / C separation circuit 106 Y selection circuit 107 C selection circuit 200 Burst level detection unit 201 V / C selection Road 202 peak hold circuit 203 A / D converter 300 the video signal processing unit 400 monitors B _G burst gate pulse B _L burst level signal B _S burst processed signal

Claims (2)

[Claims] 1. A video selector unit for selecting one video signal from a plurality of video signals by performing a switching operation, and detecting the level of a color burst signal in the video signal selected by the video selector unit. A new color burst signal is added to the video signal selected by the burst level detection unit and the video selector unit, and the level of the newly added color burst signal becomes the level detected by the burst level detection unit. A video selector device comprising a burst addition unit for adjusting to. 2. When the video signal selected by the video selector section is switched to another video signal, the burst level adding section sets the level of the color burst signal newly added to that of the video signal before switching. 2. The video selector device according to claim 1, wherein the color burst signal level is gradually changed to the color burst signal level of the switched video signal.