JPS62264789A - Picture synthesis device - Google Patents

Abstract

PURPOSE:To always keep the tinting of a master screen and a slave screen constant without causing deterioration in picture quality by applying ACC processing of a master composite video signal without Y/C separation and without deterioration in frequency characteristic in the ACC processing of the master composite video signal. CONSTITUTION:The master composite video signal is inputted from an input terminal 1 and fed to a variable frequency characteristic amplifier circuit 3. A burst extraction circuit 5 separates a burst signal of a chrominance carrier signal from the master composite video signal whose frequency characteristic is adjusted in the amplifier circuit 1 and gives the result to a detection circuit 4. The detection circuit 4 detects the amplitude level of the burst signal and controls the frequency characteristic of the amplifier circuit 3 depending on the detected level. As a result, the variable frequency characteristic amplifier circuit 3, the burst extraction circuit 5 and the detection circuit 4 act so as to bring the burst signal to a prescribed desired level, and the so-called ACC constitution is kept the level of the chrominance carrier signal constant without Y/C separation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image composition apparatus having a function of inserting another image into a part of an image.

There is an image composition device that inserts another image into a part of an image and displays two images on the same screen.

This function is called the Victeiya Inpicture function and is described below.
This is called the inP function.

[Conventional technology]

2. Description of the Related Art In recent years, based on advances in memory technology and digital technology, digital television receivers have been announced with the aim of providing higher image quality and multiple functions. The PinP function is a function adopted in many of these digital television receivers (Television Technology, December 1984 issue, pages 31-57, August 1985 issue, pages 19-23, etc.). Regarding the basic operation of P cnP, see Tokuko Sho 5L-9.
2015, etc., the odor temperature is discussed.

[Problem that the invention seeks to solve]

The conventional PLnP function described above is employed in television receivers. For this reason, the signal that drives the cathode ray tube is transferred from the video signal of the main screen to the video signal of the sub-screen (generally recorded in an image memory, etc.) in a part of the main screen, synchronized with the R screen, and transferred from the image memory. This was done by switching to another read video signal). Therefore, there is little focus on the problems that arise when the '-PinP function is realized by inserting the video signal of the sub-screen into the main screen at the standard composite video signal stage (for example, NTSC signal, PAL signal, etc.). It wasn't discussed. However, at the stage of the standard composite video signal mentioned above, Pi
nP does not require any changes to the television receiver, so you can use an adapter or video equipment other than the television receiver (
For example, this book is the most preferred method for realizing the PinP function with video tape recorders: VTR, video disc players: VDP, etc.), and in the future it will be used in video equipment other than these television receivers.
In order to realize P, it is necessary to solve the above problems.

One of these problems is level control (ACC) of the color carrier signal (hereinafter simply referred to as color signal) in the parent composite video signal.

Generally, in color television receivers, in order to prevent color changes due to color level fluctuations in the input composite video signal, it is necessary to control the gain of the color signal separated from the composite video signal so that the burst level remains constant (ACC). , After that, one wrapping 114 is performed. This is also the case with the pinP of the color television receiver mentioned above, and ACC and color demodulation can be performed after separating the color carrier signals of the parent and child video signals.

Even in PinP at the composite video signal stage, when it comes to child video signals, the color carrier wave is generally separated at the time of reduction, band limitation or color demodulation, so the above-mentioned method can be achieved by controlling the gain of the color carrier wave signal after separation. ACC can be performed in a similar manner. However, regarding the main signal, conventional AC
In C, it is necessary to separate the luminance signal and the chrominance carrier wave using a low-pass filter and a band-pass filter, respectively, perform ACC, and then mix the luminance signal and the chrominance carrier wave again, which generally causes deterioration of frequency characteristics (III !lF (luminance signal). Also, if you want to reduce the frequency characteristic deterioration when separating the luminance signal and color carrier signal, for example, 1H
There is a problem in that a comb filter using a delay line or the like is required, which increases the circuit scale.

The object of the present invention is to
The object of the present invention is to perform ACC of a parent composite video signal in a small circuit scale and with little deterioration of the frequency characteristics.

[Means for solving problems]

The above object is to provide a detection means for detecting the level of a color carrier wave from a parent composite video signal and a variable frequency characteristic amplification means capable of controlling the high frequency characteristics of the parent composite video signal including the frequency band of a single color carrier signal. According to the color carrier level detection means, the level of the color carrier signal is controlled by changing the high frequency gain in the frequency characteristic variable amplification means.

This is achieved by performing ACC.

[Effect]

That is, in the detection means, after extracting a color carrier burst signal from the parent composite video signal, the level of the color carrier signal is detected by detecting the level of the burst signal, and this detection level K[,l; Then, the frequency characteristic variable amplifying means adjusts the gain of the high-frequency component of the composite video signal including the one-color carrier wave signal, and makes the color carrier level constant. For example, the burst signal level is 5d higher than the normal level.
If E is attenuated (increased), the gain of the high frequency component of the composite video signal is increased (decreased) so that the one-color carrier signal is increased (attenuated) by 5rtB. At this time, the high frequency component of the luminance signal also increases (or decreases) along with the color carrier signal, but generally,
In the propagation system, when the color carrier wave component attenuates (or increases), the high frequency component of the luminance signal also decreases and increases. Therefore, although the frequency characteristics of the luminance signal may be improved by the above processing, they will not be deteriorated.

Therefore, according to the above-mentioned ACC, there is no need to separate the luminance signal and color carrier signal as in the conventional case, no complicated separation circuit is required, and 7I! 1 without deterioration of d-wavenumber characteristics
The color carrier signal level can be kept at a constant level.

〔Example,〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a block diagram of a first embodiment according to the present invention. In Fig. 1, 1 and 2 are input terminals for a main composite video signal and a small composite video signal, respectively, 3 is a variable frequency characteristic amplifier circuit, 4 is a detection circuit, 5 is a burst extraction circuit, and 6 is an automatic phase control (APC) circuit. ) circuit, 7
The switch circuit 8 is a low pass filter (hereinafter referred to as LPF), 9 is a band pass filter (hereinafter referred to as BPF), 1
0 is the ACC circuit.

11 is a demodulation circuit, 12 is a recording circuit, and 15 is a control circuit.

14 is a modulation circuit. Further, FIG. 2 shows the frequency characteristics of the variable frequency characteristic amplifier, where the horizontal axis represents the frequency and the vertical axis represents the gain. The operation of this embodiment will be explained below using FIGS. 1 and 2.

The parent composite video signal is input from the input terminal 1 and supplied to the variable frequency characteristic amplification circuit 3. The burst extraction circuit 5 separates the burst signal of the color carrier signal from the parent composite video signal whose frequency characteristics have been adjusted in the variable frequency characteristic amplifier circuit 5 and supplies it to the detection circuit 4 . The detection circuit 4 detects the amplitude level of the burst signal by detecting the burst signal supplied from the burst extraction circuit, and controls the frequency characteristics of the variable frequency characteristic amplifier circuit 30 according to this detection level. At this time, if the detected burst level is lower than the desired level, in order to gain the high-frequency components of the parent video signal including the color carrier component, the frequency characteristics may be changed to have the frequency characteristics shown in 15 in Fig. 2, for example. 1, for example, as shown in 17 in FIG. Control to achieve the frequency characteristics. As a result, variable frequency characteristic amplifier circuit 3. Burst extraction circuit 5. The detection circuit 4 operates to keep the burst signal at a constant desired level and forms a so-called ACC loop, thereby keeping the level of the color carrier signal constant without Y/C separation.

Further, the child decoded video signal is separated into a luminance signal and a color carrier signal by the LPFB and EPF 9, and the color carrier signal is demodulated after adjusting the gain to a desired constant level by the ACC circuit 1o. The circuit 11 demodulates the color difference signals (R-y) and (B-y).

(However, unlike the main video signal, the ACC circuit 10
Circuitry similar to conventional color television receivers can be used. ) The luminance signal Y and color difference signal (R
-y) and (B-Y) are reduced in size and recorded in the recording circuit 12 whose recording and reading are controlled by the control circuit 13 so that the child video signal can be inserted into the parent video signal. Each signal recorded again.

Read out in synchronization with the main video signal. The readout color difference signal (
/? -y), (B-y) are APC circuit 6
In.

The luminance signal Y' is modulated again by the color carrier wave fzc phase-locked to the color carrier of the parent video signal and read out in the same way.
Add to. In this way, a reduced small composite video signal is obtained.

Further, the parent composite video signal subjected to ACC processing and the reduced composite video signal are supplied to a switch circuit 7 controlled by a control circuit 13. In switch 7,
According to a control signal supplied from the control circuit 15, the video signal is switched, a small composite video signal is inserted into the R composite video signal, and a PinP video signal is output.

According to the present embodiment whose operation has been explained above, 2.As described above, P*nP inserts a video signal at the composite video signal stage.
It is possible to perform ACC processing on the parent composite video signal without Y/c separation which causes deterioration of the odor 11 frequency characteristics.

FIG. 3 is a block diagram of a second embodiment according to the invention. In FIG. 3, reference numeral 18 denotes a variable gain amplifier circuit, and 19 is a variable gain amplifier circuit, and the same reference numerals as in the first embodiment are used, and the explanation thereof will be omitted. Further, in this embodiment, the parts other than those shown in FIG. 5 are the same as those in the first embodiment shown in FIG. 1, and the explanation thereof will be omitted. The operation of one embodiment of the present invention will be explained below with reference to FIG. First, the parent composite video signal S is
Supplied to LPFlB LPFlB attenuates high-frequency components including one-color carrier wave components. Also, variable gain amplifier 19
teeth.

The high-frequency component (S-5) of the composite video signal obtained by subtracting the signal S' after passing through the LPF from the signal S before passing through the LPF
), and according to the control voltage obtained by the detection circuit 4, the gain A of the high frequency component is adjusted and output. The gain-adjusted high-frequency components AC3-5') are added to the composite video signal after passing through the LPF again and output.

At this time, if the detected burst level matches the desired level, the gain A of the variable gain amplifier 19 becomes 1, and S'
+1.(S-5')-5 is output as a signal, and the frequency characteristic of the variable frequency characteristic amplifier circuit 3 is as shown in 16 in FIG. 2, for example. or.

When the detected burst level is lower than the desired level, the gain of the variable gain amplifier circuit 19 becomes greater than 1, and the frequency characteristics become as shown in FIG. 2, for example. vice versa,
When the detected burst level is higher than the desired level, the gain of the variable gain amplifier circuit 19 becomes less than 1, and the 1-frequency characteristic becomes as shown in FIG. 217.

As described above, the variable frequency characteristic amplifier circuit having the configuration shown in FIG. 3 operates in exactly the same way as that of the first embodiment. Therefore, the second embodiment also provides the same effects as the first embodiment.

FIG. 4 shows a third embodiment of the present invention.

In the third embodiment, the input signal of the burst extraction circuit in the second embodiment is changed from the output signal of the variable frequency characteristic amplifier circuit 5 to the output signal of the variable gain amplifier circuit 19. In this embodiment, the control loop naturally operates in a burst or constant manner at the output of the variable gain amplifier 19. Therefore, in general, an error occurs in the output of the variable frequency characteristic amplifier circuit 3 by an amount corresponding to the attenuated color carrier signal in the output of the LPllB. However, by designing LPllB so that the amount of attenuation of the color carrier signal in LP 118 is sufficiently large, the above error can be ignored. In this state, the present embodiment can obtain substantially the same effect as the above-described embodiment.

In the embodiments described above, the ACC processing of the child composite video signal is performed after Y/c separation as before. However, the ACC processing of the child composite video signal may also be performed by adjusting one frequency characteristic in the same manner as the parent composite video signal. This is effective in 1% of the cases where the small signal is converted into a composite signal from analog to digital (AID), separated into digital Y/c, decoded, and recorded in the memo+1. In this case, there is an effect of not only keeping the number of one color constant, but also keeping the doji noise of the number of one color constant.

〔Effect of the invention〕

According to the present invention, 1'C, Y/c separation is not performed in the ACC processing of the parent composite video signal, and as a result, the ACC of the parent composite video signal can be performed with a relatively simple circuit configuration and without a frequency characteristic diagram. Therefore, the coloring of the main screen and child screen can always be kept constant without deterioration of image quality.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a first embodiment of the image synthesis apparatus of the present invention, FIG. 2 is a frequency characteristic diagram of a variable frequency characteristic amplifier circuit, and FIG. 5 is a block diagram showing a second embodiment. FIG. 4 is a block diagram showing the third embodiment. 3・・・・・・・・・・・・・・・・・・・・・Variable frequency characteristic amplifier circuit 4・・・・・・・・・・・・・・・・・・・・・
・・・Detection circuit 5・・・・・・・・・・・・・・・
・・・・・・Burst extraction circuit・・・・・・・・・・・・
−・・・・・・・APC circuit 10・・・・・・・−
......APC circuit 12...
......-... Recording circuit 13...-
・・・・・・・・・・・・・・・Control circuit 15・16・1
7... Frequency characteristics 18... LPF
19・・・・・・・・・・・・・・・・・・・・・・・・Variable gain amplifier circuit agent Patent attorney Katsuo Ogawa C^1? 'I Evening 9C Condolence 3 times/'3

Claims (1)

[Claims] 1. In an image synthesis device that inserts a signal obtained by reducing the size of a second composite video signal into the first composite video signal to display two screens on the same screen, the color of the first composite video signal is A frequency characteristic adjusting means capable of controlling the gain of a high-frequency component including a carrier wave signal, and a detection means for detecting a color carrier wave level of the first composite video signal, and the frequency An image synthesis apparatus characterized in that the color carrier wave signal level of the first composite video signal is kept constant by controlling a characteristic adjustment means.