JP2502694B2 - Video signal synthesizer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a composite screen image in which a main screen video signal and at least one or more child screen video signals are composited and a child screen is inserted in a part of the parent screen. The present invention relates to a video signal synthesizer that outputs a signal.

Conventional technology Conventionally, a screen in which a main screen video signal and a video signal of the same or different sub screen are combined and processed, and a sub screen is inserted in a part of the main screen in a digital television receiver, VTR with digital function, etc. There is one provided with a video signal synthesizing device that outputs a video signal (hereinafter referred to as a synthesizing screen).

In this type of video signal synthesizer, the synchronization of the parent screen image signal and the child screen image signal is irrelevant, and the phase and frequency are different. It is necessary to make adjustments. Furthermore, it is necessary to compress the sub-picture video signal on the time axis in order to reduce the size of the sub-picture in the composite picture. For the above reasons, the sub-screen video signal is digitally converted, sampled, and made into write data, then written to the memory based on the sync signal of the sub-screen video signal, and further based on the sync signal of the main screen video signal. Then, there is a conventional example in which the written data is read out and converted into analog to enable synchronization with the parent-child screen and compression of the child screen.

An example thereof will be described with reference to FIG.
In FIG. 3, reference numeral 1 is a small screen video signal input terminal, and 2 is a luminance signal / color signal separation circuit for separating a luminance signal component and a color signal component of the small screen video signal. A color signal demodulation circuit 3 demodulates the separated color signal into a baseband signal. 4 is for converting the separated luminance signal and demodulated baseband signal into digital signals and performing sampling processing.
An A / D converter, 5 is a memory circuit, 6 is digitally converted sub-screen data is written in the memory circuit 5 based on the sync signal of the sub-screen video signal, and further the sync signal of the main-screen video signal is referenced And a write / read control circuit for reading from the memory circuit 5. 7 is a D / A for converting the read digital data for the sub-screen to analog
A conversion circuit, 8 is a color signal modulation circuit for modulating the analog-converted baseband signal into a color signal, and 9 is a luminance signal / color signal mixture for mixing the analog-converted luminance signal and the modulated color signal. Circuit. 10 is a master screen video signal and a slave screen video signal are sequentially arranged so that the master screen video signal is arranged at the predetermined position of the master screen and the slave screen video signal is arranged at the position of the slave screen in the composite screen. Parent-child switching circuit for switching, 11 is a sync separation circuit for the parent screen video signal,
Reference numeral 12 is a sub-screen video signal sync separation circuit, 13 is a main screen video signal input terminal, and 14 is a composite screen video signal output terminal.

The operation of the video signal synthesizer configured as described above will be described below.

The sub-picture video signal input to the sub-picture video signal input terminal 1 is separated into a brightness signal component and a color signal component by the brightness signal / color signal separation circuit 2. The separated color signal component is demodulated by the color signal demodulation circuit 3 into a baseband signal.
Here, demodulating the color signal into a baseband signal means that when the sub-picture video signal is digitally converted and sampled, the sampling theorem shows that the lower the frequency component of the signal, the smaller the number of samplings within a certain period of time. As a result, the circuit scale of the digital processing unit becomes smaller,
It is necessary to make the frequency of the modulated color signal of the small screen video signal and the frequency of the modulated color signal of the main screen video signal equal when reducing the small screen in the composite screen. This is for two reasons that it is possible to avoid the complication of the digital processing unit and the increase of the circuit scale by demodulating the baseband signal once and then reducing it and modulating it again to the required frequency. Now, the luminance signal component of the sub-picture video signal separated by the luminance signal / color signal separation circuit 2 and the baseband signal of the color signal component of the sub-picture video signal demodulated by the color signal demodulation circuit 3 are synchronized separation circuit. The A / D converter 4 whose timing is controlled by the writing / reading control circuit 6 on the basis of the sync signal of the sub-picture video signal extracted by 12 is subjected to digital conversion, sampling processing, and written in the memory circuit 5.

The synchronizing signal of the parent screen image signal input to the parent screen image signal input terminal 13 is extracted by the sync separation circuit 11. The write / read control circuit 6 reads data from the memory circuit 5 at a predetermined timing based on the sync signal of the parent screen video signal, and the D / A converter 7 performs analog conversion. Here, at the output of the D / A converter 7, baseband signals of a luminance signal component and a chrominance signal component according to the size of the sub-screen in the composite screen are obtained. The baseband signal of the chrominance signal component of the child screen image signal is modulated by the chrominance signal modulation circuit 8 into a chrominance signal component having the same frequency as the chrominance signal component of the parent screen image signal and having a necessary phase, and the luminance signal / It is mixed with the luminance signal component by the color signal mixing circuit 9. From the luminance signal / color signal mixing circuit 9, a sub-screen video signal corresponding to the size and position of the sub-screen in the composite screen is obtained.
That is, the master screen video signal is output during the master screen period, and the slave screen video signal is output during the slave screen insertion portion of the composite screen, that is, during the slave screen insertion period, and the composite screen video signal is obtained from the composite screen video signal output terminal 14. Here, sync signal periods such as a horizontal blanking period and a vertical blanking period of the composite screen video signal are included in the parent screen period, and the sync signal of the parent screen video signal is used as the sync signal of the composite screen video signal.

However, in the above-described configuration, since the master screen period in the above-described composite screen includes the sync signal of the master screen and the color burst signal that is the reference of the color signal, the master screen image If the signal is a black and white signal, it means that there is no color burst signal within the horizontal blanking period of the composite screen video signal. Therefore, when the main screen video signal is a black and white signal, the output of the video signal synthesizing device having the above-described configuration becomes a black and white signal even if the sub screen video signal is a color signal. There is a problem in that even if the composite screen image signal is displayed on a color television or the like, the child screen is not colored.

In view of the above problems, the present invention provides a sub-screen image signal at a predetermined position depending on whether the sub-screen video signal is a black-and-white signal or a color signal even if the main-screen video signal is a black-and-white signal. Provided is a video signal synthesizing device capable of inserting a color burst signal, which is a reference of a color signal of a screen video signal, into a composite screen video signal as a color signal.

Means for Solving the Problems In order to solve the above problems, a video signal synthesizing apparatus according to the present invention includes a judging means for judging whether a parent screen image signal and a child screen image signal are color signals or black and white signals, respectively, and a parent screen image. When the signal is a black and white signal and the sub-screen video signal is a color signal, a color burst signal serving as a reference for the sub-screen video signal in the back porch portion of the horizontal blanking signal of the composite screen video signal according to the output of the discrimination means. Is provided with a means for inserting.

Operation Generally, a color burst signal is used to discriminate color signals and monochrome signals from video equipment such as color televisions and VTRs. According to the present invention, since the color burst signal can be inserted at a predetermined position of the composite screen video signal when the main screen video signal is a black-and-white signal and the child screen video signal is a color signal by the means described above, the composite screen can be displayed on these video devices. Inputting a video signal reproduces the color information of the small screen.

Embodiment A video signal synthesizing apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention.
In FIG. 1, 1,2,3,4,5,6,7,8,9,10,11,12,13,14 are sub-screen video signal input terminals, luminance signal / color signal separation circuit, color signal, respectively. Demodulation circuit, A / D converter, memory circuit, write / read control circuit, D / A converter, color signal modulation circuit, luminance signal / color signal mixing circuit, parent-child switching circuit, parent synchronization separation circuit, child synchronization The separation circuit, the parent screen video signal input terminal, and the composite screen video signal output terminal have the same operations as those in the conventional configuration of FIG. Reference numeral 15 denotes a color signal / black and white signal discrimination circuit which discriminates whether the main screen video signal and the sub screen video signal are color signals or black and white signals.
A burst signal insertion circuit 16 inserts a color burst signal at a predetermined position of the composite screen image signal according to the output of the discrimination result of the color signal / monochrome signal discrimination circuit 5. Reference numeral 17 is a reference oscillator for color signal modulation synchronized with the burst signal of the main screen video signal. The reference of the color burst signal inserted by the burst signal insertion circuit 16 according to the output of the determination result of the color signal / black and white signal determination circuit 15. And a reference signal having a frequency serving as a reference for the modulation operation performed in the color signal modulation circuit 8 are supplied to the burst signal insertion circuit 16 and the color signal modulation circuit 8, respectively. The operation of the video signal synthesizing apparatus configured as described above will be described below.

The sub-picture video signal input to the sub-picture video signal input terminal 1 is separated into a luminance signal component and a chrominance signal component by the luminance signal / color signal separation circuit 2, and the chrominance signal component is baseband by the color signal demodulation circuit 3. Demodulated into a signal. The baseband signals of the luminance signal component and the chrominance signal component are A / D converters whose timing is controlled by the writing / reading control circuit 6 on the basis of the synchronization signal of the sub-picture video signal extracted by the synchronization separation circuit 12. Digital conversion by 4,
The sampling process is performed and the data is written in the memory circuit 5. Further, the write / read control circuit 6 is based on the sync signal of the parent screen video signal extracted by the sync separation circuit 11.
Reads data from the memory circuit 5 at a predetermined timing, and the D / A converter 7 performs analog conversion. At the output of the D / A converter 7, a baseband signal of a luminance signal component and a chrominance signal component according to the size of the child screen in the composite screen is obtained, and the baseband signal of the chrominance signal component is the chrominance signal demodulation circuit 8
Is modulated into a color signal component having the same frequency as the color burst signal of the parent screen video signal and a required phase, and is mixed with the luminance signal component by the luminance signal / color signal mixing circuit 9. The luminance signal / color signal mixing circuit 9 obtains a sub-screen video signal according to the size and position of the sub-screen in the composite screen, and the parent-child switching circuit 10 outputs the sub-screen video signal during the main-screen period and the sub-screen during the sub-screen period. A screen image signal is output and a combined screen image signal is obtained.

Here, the master screen period includes the horizontal blanking period of the master screen video signal, and when the master screen video signal is a color signal or a black and white signal, a color burst is applied to the back porch of the horizontal blanking signal of the composite screen video signal. The signal is present / absent. The case where a color burst signal is present in the composite screen image signal is shown in FIG. 2 (a), and the case where it is not present is shown in FIG. 2 (b). When the parent screen image signal is a black and white signal and the child screen image signal is a color signal, there is no color burst signal in the combined screen image signal output from the parent and child switching circuit 10. In this case, the color signal / black and white signal discrimination circuit 15
The color burst signal is added by the burst signal insertion circuit 16 according to the output of the discrimination result of
A composite screen image signal to which a color burst signal as shown in FIG. 2 (a) is added is obtained at 14. At this time, the burst signal insertion circuit 16 is arranged so that the color burst signal to be inserted has the necessary phase at the same frequency as the reference signal obtained from the reference oscillator 17 for color signal modulation. It operates so that the color signal component of the video signal has the necessary phase at the same frequency as the reference signal obtained from the color signal modulation reference oscillator 17.

As described above, according to the present invention, a means for discriminating whether the parent screen video signal and the child screen video signal are a color signal or a black and white signal and the horizontal blanking signal of the composite screen video signal according to the output of the discrimination means. By providing a means for inserting a color burst signal in the pouch part, even if a composite screen video signal is output using a parent screen video signal that is a black and white signal and a child screen video signal that is a color signal, other video equipment, etc. The color information of the inset screen can be reproduced with.

Although the color burst signal in this embodiment is inserted into the composite screen video signal, it may be inserted into the parent screen video signal or inserted into the child screen video signal to switch to a predetermined position of the composite screen video signal. Also has the same effect.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a video signal synthesizing apparatus according to an embodiment of the present invention, and FIGS. 2A and 2B are signal waveform diagrams for explaining the video signal synthesizing apparatus having the configuration shown in FIG. FIG. 3 is a block diagram showing the configuration of a conventional video signal synthesizing apparatus. 1 ... Sub-screen video signal input terminal, 2 ... Luminance signal / color signal separation circuit, 3 ... Color signal demodulation circuit, 4 ... A / D converter, 5 ... Memory circuit, 6 ... Writing / reading Control circuit, 7 ... D / A converter, 8 ... Color signal modulation circuit, 9 ...
… Luminance signal / color signal mixing circuit, 10 …… Parent-child switching circuit, 11
...... Parent sync separation circuit, 12 …… Child sync separation circuit, 13…
… Parent screen video signal input terminal, 14 …… Composite screen video signal output terminal, 15 …… Color signal / black and white signal discrimination circuit, 16 ……
Burst signal insertion circuit, 17 ... Reference oscillator for color signal modulation.

Claims (1)

(57) [Claims] 1. A first video signal source, a second video signal source phase-synchronized with a synchronization signal of the first video signal, and a part other than a synchronization signal including a back porch of the first video signal. Means for substituting the section with the second video signal to create a third video signal; determining means for determining whether the first video signal and the second video signal are color signals or black-and-white signals respectively; When the first video signal is a black-and-white signal and the second video signal is a color signal, one of the third video signal and the second video signal, depending on the output of the discrimination means, is output. A video signal synthesizing device comprising means for inserting a color burst signal serving as a reference of the color signal of the second video signal into the back porch portion of the ranking signal.