KR910005363Y1 - Chroma-key signal generator - Google Patents

Abstract

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Description

Chroma Key Signal Generator

1 is a circuit block diagram of a preferred embodiment according to the present invention.

2 is a circuit diagram of a preferred embodiment of the color selection circuit unit according to the present invention.

3 is a color signal vector display diagram for explaining a color selection circuit unit according to the present invention;

4 is a waveform diagram of each part of the present invention.

5 is a schematic diagram for explaining a chroma key device.

* Explanation of symbols for main parts of the drawings

10: color signal separation circuit unit 11: buffer

12 bandpass filter 13 clamp pulse generator

14 amplifier 15 blanking pulse generator

16: blankie circuit 20: color synchronization gate circuit

21: color synchronizing gate pulse generator 22: color synchronizing gate circuit

23: phase comparator 24: amplifier

25: integrator 26: voltage controlled oscillator

30: color selection circuit section 31: first stage abnormal circuit

32: second stage abnormal circuit 33: phase shift means

34: selection switch means 35: phase adjusting means

36: buffer 40: phase detection circuit

41: phase comparator 42: trap circuit

43: integrating amplifier 44: color saturation selection means

45: level comparator 46: mixer

The present invention relates to a chroma key signal generator, and more particularly, to a chroma key signal generator capable of obtaining a chroma key signal from a composite video signal.

As shown in FIG. 5, the chroma key device 3 generates a key signal to the chroma key signal generator 4 in response to a specific color among the color signals of the color video signal, and according to the key signal, two or more color video signals. It is a kind of image editing apparatus for synthesizing and editing two or more color image signals by driving the selection switch means 5 for selecting one of the two.

The conventional chroma key signal generator 4 generates a chroma key signal using the primary color signals red (R), green (G), and blue (B) output from the video camera 1. Since the primary color signal RG B cannot be obtained in a signal processing VTR or color TV, the chroma key signal generator cannot be used in combination with these signals.

Therefore, conventionally, since at least one video camera is required, there is a drawback that the use range is limited.

Accordingly, an object of the present invention is to provide a chroma key signal generator which can extend a range of use of a chroma key device by obtaining a chroma key signal from a composite video signal in order to solve the problems of the prior art.

In order to achieve the above object, the present invention provides a video editing apparatus for synthesizing the two video signals by selecting one video signal from two video signals in response to a specific color of one color video signal, wherein the color signal from one color video signal. A color signal separation circuit section for separating a signal, a color sync circuit section for detecting a color sync signal from the color signal, and generating a continuous color part carrier signal, and generating at least one color part carrier signal having a predetermined phase difference from the color part carrier signal and the signal; Among the signals, the phase of the selected signal is adjusted by comparing the phase of the color selection circuit unit for selecting a specific color signal with the phase of the color signal output from the color signal separation circuit unit and the specific color signal selected in the color selection circuit unit. Select the level of the generated signal Compared to a reference level corresponding to the color saturation and is characterized in that the hayeoseo provided with a phase detection circuit for generating a chroma signal makiyi.

The present invention constructed as described above uses a color image signal based on a color synchronization signal to generate a continuous color subcarrier signal having the same phase and frequency as the color synchronization signal, and within 360 ° with respect to the color synchronization signal. A phase shift means and a phase adjusting circuit selectable in any phase are used to detect a signal having the same phase by taking a phase comparison of the phase of the color subcarrier signal constituting the color signal among the input color image signal components, and comparing the phases. Even if a signal of the same phase is taken out, if a signal having a different magnitude is produced according to the saturation of the color, only the signal having the desired saturation is taken out and mixed with the synchronization signal to output a chroma key signal.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

In FIG. 1, the chroma key signal generator connects a color image signal (Fig. 4-a) supplied to an input terminal to a color signal separation circuit section 10 and a synchronization signal separator 50 through a coupling capacitor C6. .

The color signal separation circuit unit 10 passes only the color signal components of the color subcarrier signal (3.58 MHz) components of the composite color image signals input through the buffer 11 through the band pass filter 12 and is dropped during the filtering process. Clamp pulse generator 13 for compensating gain and symmetrical impedance and generating clamp pulse (Fig. 4c) by using a synchronous signal (Fig. 4b) supplied from the synchronous signal separator 50 as a trigger signal, for example, mono A clamp pulse (FIG. 4C) is supplied from the multivibrator to clamp the separated color signal (FIG. 4F) via an amplifier 14 which fixes the color signal to a constant level.

The clamped color signal (FIG. 4F) is a blanking pulse generator 15 which generates a blanking pulse (FIG. 4D) by using the synchronizing signal (FIG. 4B) of the synchronization signal separator 50 as a trigger signal, for example, two mono stages. Only the color signal having a stable phase is supplied to the phase detection circuit section 40 described later through the blanking circuit 16 which receives the blanking pulse (Fig. 4D) from the multivibrator and passes only the effective color signal period.

The clamped color signal (FIG. 4f) is also supplied to the color synchronization circuit section 20. FIG. The color synchronizing circuit unit 20 generates the color synchronizing gate pulse generator 21 generating the color synchronizing gate pulse (Fig. 4e) by using the color signal supplied as the synchronizing signal (Fig. 4b) of the synchronizing signal separator 50 as the trigger signal. For example, only the color synchronizing signal is extracted through the color synchronizing gate circuit 22 which receives the color synchronizing gate pulse (Fig. 4e) from the two-stage mono-multivibrator and passes only the color synchronizing signal, A phase locked loop (PLL) circuit that outputs a synchronous continuous color carrier signal (3.58 MHz), that is, a circuit composed of a phase comparator 23, an amplifier 24, an integrator 25, and a voltage controlled oscillator 26. Obtains the color carrier signal and supplies it to the color selection circuit unit 30.

The color selection circuit unit 30 supplies the supplied color part carrier signal to the phase shifting means 33 to output the input color part carrier signal and at least one color part carrier signal having a predetermined phase difference with respect to the phase of the signal. The signals are selected by the selection switch means 34, and then the selected signal is selected by the phase adjusting means 35 through phase fine adjustment to supply the selected signal to the phase detection circuit portion 40.

One embodiment of the color selection circuit section 30 is shown in FIG.

In FIG. 2, the phase shifting means 33 obtains a color carrier signal having an in phase (θ ₀ ) from the inputted color carrier signal at the emitter output terminal of the first or more circuits 31, and the phase of the color carrier signal. 120 ° phase difference (θ) at the emitter output terminal obtained by applying the collector output signal inverted by 180 ° to (θ ₀ ) to the base of the second stage or more circuit 32 via the capacitor C2 which is a phase 60 ° degree delay means. A first color subcarrier signal having ₀ ) is obtained, and a 120 ° phase difference (θ2) is now passed through the condenser C3, which is a phase delay of 60 °, to the collector output signal inverted by 180 ° with respect to the phase (θ1) of the one color subcarrier signal. Obtain a second color carrier signal with < RTI ID = 0.0 >

The color carrier signals of the phase θ ₀ generated as described above and the first and second color carrier signals of the phase θ1 (θ2) are supplied to respective terminals of the selection switch means 34.

The color carrier signal selected by the selection switch means 34 is supplied to the phase adjusting means 35, for example, the abnormal circuit, and in the abnormal circuit 38, the phase shift ψ = 2tna ^-1 (1 / 2π-fVR). ₂ · C ₄ ), the phase of the signal X (θ) is selected as θ = θm ± ψ (m = 0,1,2) according to the change of the resistance value of the variable resistor VR ₂ . For example, referring to FIG. 3, as shown in FIG. 2, when the selector switch means 34 selects a color carrier signal having a phase θ ₁ and adjusts the variable resistor VR2 to rotate 59 °, Green (G) of 3 degrees is selected as the specific color.

The signal having the specific phase thus selected is supplied to the phase detection circuitry 40 through the buffer 36.

The phase detection circuit unit 40 is configured to perform a phase comparison between the color signal supplied from the color signal separation circuit unit 10 and the feature color signal selected by the color selection circuit unit 30 to produce the maximum output for signals of the same phase. For example, a signal output through a phase comparator 41 composed of a multiplexer and a tuning circuit is supplied to the integrating amplifier 43 through the 3.58MHZ trap circuit 42. The integrating amplifier 43 integrates the input AC signal to obtain an average signal (Fig. 4G), amplifies it, and supplies it to the level comparator 45. The level comparator 45 compares the level of the supplied 4g signal with the reference signal supplied by the color saturation selector 44 (dashed line display signal in FIG. 4g), and has a predetermined or higher color saturation even if the signal has the same phase. When detected, the "H" output is sent out and this signal is output as a chroma key signal.

The chroma key signal (Fig. 4-h) is supplied to the mixer 46 to synchronize with the video signal and mixed with the synchronizing signal supplied through the variable resistor VR1 in the synchronizing separator 50. The chroma key is output as a control signal.

As described above, the present invention detects the same phase color signal input by comparing the phase of a specific color signal which is phase-selected based on the color synchronization signal obtained from the composite video signal with the input color signal, and has a predetermined color saturation even when the same phase color signal is input. Chroma key signals are generated only at the signal input, so that the video signals can be edited using the Chroma Key device without a video camera, for example, VTR and VTR, TV and VTR.

In addition, since the color signal separation circuit unit and the color synchronization circuit unit of the present invention overlap with existing VTRs and TVs, it is possible to adopt a chroma key function to the VTRs and TVs more simply and at low cost.

Claims (3)

An image editing apparatus for synthesizing a video signal by selecting one video signal among two or more video signals in response to a specific color of one color video signal, the color signal separation circuit unit 10 for separating a color signal from one color video signal; And a color synchronizing unit 20 which extracts a color synchronizing signal from the color signal and generates a continuous color subcarrier signal having the same phase and frequency, and at least one color subcarrier signal having a predetermined phase difference from the color subcarrier signal. A color selection circuit section 30 that selects a specific color signal by adjusting the phase of the selected signal among these signals, and a phase of a color signal output from the color signal separation circuit section 10 and a specific color signal selected by the color selection circuit section 30. And a phase detection circuit section 40 for generating a chroma key signal when detecting color signals of the same phase. Chroman makiyi signal generator that the yeoseo characterized. 2. The apparatus of claim 1, wherein the color selection circuit unit (10) comprises: a phase shift means (33) for outputting an input color part carrier signal, at least one color part carrier signal having a predetermined phase difference from the signal, and one of the color part carrier signals And a phase adjusting means (35) which selects one and selects and outputs a specific color signal by adjusting a phase of the selected color carrier signal. The phase comparator 40 of claim 1, wherein the phase detection circuit 40 compares the phases of two input signals and integrates a phase comparator 41 for generating a maximum output when the phases are the same and an output of the phase comparator 41. An integrated amplifier 43 for amplifying and outputting the obtained direct current, a color saturation selecting means 44 for outputting a reference signal proportional to the saturation degree, and a level comparator for generating a chroma key signal by comparing the direct current level with the reference signal level. And a mixer (46) for mixing the chroma key signal with the synchronization signal.