JPH05161063A - Video signal synthesizer - Google Patents

Abstract

PURPOSE:To prevent deterioration in picture quality at a border of a synthesized reproduced picture when an output synthesized video signal is reproduced. CONSTITUTION:A composite video signal S12 of a 1st video signal and a luminance signal S13 of a 2nd video signal are synthesized by a video signal mixing circuit (1) 18 with a key signal S23 cut off by a cutoff frequency at a filter (1) 15. Moreover, the composite video signal S12 of the 1st video signal and a chroma signal S14 of the 2nd video signal are synthesized by a video signal mixer circuit (2) 19 with a key signal S25 cut off by a cut-off frequency at a filter (2) 16. Thus, the discontinuity of the chroma signal is avoided to eliminate the brightness band.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a superimpose,
The present invention relates to a video signal synthesizing circuit used in a video signal processing device that performs chroma key and wipe processing.

[0002]

2. Description of the Related Art FIG. 2 shows the configuration of a conventional video signal synthesizing circuit. In the configuration of the video signal mixing circuit 1 shown in FIG. 2, 2 is a phase inverter for inverting the phase of an arbitrary key signal (keying signal) S ₁ , and 3 is a phase with the composite video signal S ₂ which is the first video signal. A multiplier for multiplying the phase-inverted arbitrary key signal S ₁ from the inverter 2 is shown. 4 luminance signal of the second video signal (Y signal) S ₃ and chroma signal (C signal) S ₄ an adder for outputting a video signal S ₅ obtained by adding, 5 any key signals S ₁ and the video signal S ₅ Reference numeral 6 denotes a multiplier for multiplying by and, and reference numeral 6 denotes an adder for outputting an output combined video signal S ₇ obtained by adding the video signals from the multipliers 3 and 5.

Next, the operation in this configuration will be described.
In the video signal mixing circuit 1, the composite video signal S₂And the second
Video signal (luminance signal S ₃, Chroma signal S_Four) In any
Arbitrary key signal S₁Video signals are synthesized using and output
Composite video signal S₇Is being output.

[0004]

However, in the video signal synthesizing circuit of the conventional example, only one video signal mixing circuit 1 performs the synthesizing process. That is, when performing image synthesis video signal containing much chroma signal components in any key signals S _1, the frequency band of the arbitrary key signal S ₁ is higher than the frequency band of the chroma signal, chroma boundary portion in the composite image There is a drawback that signal discontinuity occurs and the image quality deteriorates.

Further, the frequency band of the arbitrary key signal S ₁ is
If it is formed within the frequency band of the chroma signal, there is a drawback that the luminance band at the boundary portion of the composite video becomes narrow and the image quality deteriorates.

The present invention solves such a conventional problem, and provides an excellent video synthesizing apparatus capable of preventing deterioration in image quality of a boundary portion in a synthetic playback image when an output synthetic video signal is played back. With the goal.

[0007]

In order to achieve this object, a video synthesizing apparatus according to the present invention cuts off an input key signal at a frequency corresponding to a frequency band of a luminance signal of a second video signal. Filter, a second filter for blocking the key signal at a frequency corresponding to the frequency band of the chroma signal of the second video signal, and a key extracted from the input composite video signal of the first video signal through the second filter. Chroma signal component removing means for removing the chroma signal component by the signal,
First video signal mixing means for combining the composite video signal and the luminance signal of the first video signal with the key signal from the first filter, and the composite video signal and the chroma signal with the key signal from the second filter. Second image mixing means for

[0008]

Therefore, the video signal synthesizing circuit of the present invention synthesizes the composite video signal of the first video signal and the luminance signal and the chroma signal of the second video signal with the key signal which is cut off at the respective optimum frequencies. In order to eliminate the discontinuity of the chroma signal and prevent the brightness band from becoming narrow,
It is possible to prevent the image quality from degrading at the boundary portion of the composite reproduced image when the output composite video signal is reproduced.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a video signal synthesizing circuit of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of the embodiment. In Figure 1, 15 is a filter any key signal S ₁₁ is supplied (1), 16 denotes a filter (2) that any key signal S ₁₁ is supplied. Reference numeral 17 is a chroma signal component removing circuit that is supplied with the composite video signal S ₁₂ of the first video signal to remove only the chroma signal component, and 18 is a video signal mixing circuit (1),
Reference numeral 19 indicates a video signal mixing circuit (2).

Reference numeral 22 denotes a delay device which delays the arbitrary key signal S ₁₁ from the filter (1) 15 in order to match it on the time axis.
Reference numeral 23 denotes a delay device that delays the arbitrary key signal S ₁₁ from the filter (2) 16 in order to match it on the time axis.
Reference numeral 24 is a delay device that delays the luminance signal S ₁₃ of the second video signal to match it on the time axis, and 25 is a delay device that delays the chroma signal S ₁₄ of the second video signal to match it on the time axis. Shows.

Next, the chroma signal component removing circuit 17, the video signal mixing circuit (1) 18 and the video signal mixing circuit (2)
The configuration of 19 will be described in detail.

In the chroma signal component removing circuit 17, 3
1 is a bandpass filter (BPF), 32 is a delay device, 3
Reference numeral 3 indicates a multiplier. Further, 34 is a phase inverter, and 35
Indicates an adder.

In the video signal mixing circuit (1) 18, 4
Reference numerals 1 and 42 denote multipliers, 43 denotes a phase inverter, and 44 denotes an adder.

In the video signal mixing circuit (2) 19,
Reference numeral 51 is a multiplier, and 52 is an adder for outputting the output composite video signal S ₂₀ .

Next, the operation of this configuration will be described.
The composite video signal S ₁₂ in the first video signal is supplied to the BPF 31 and the delay device 32 of the chroma signal component removing circuit 17. Also, the arbitrary key signal S ₁₁ is band-limited to the cut-off frequency corresponding to the chroma signal S ₁₄ by the filter (2) 16 and is used as the chroma signal component removing circuit 1 as the key signal S _{11 a.}
7 to the multiplier 33. In the chroma signal component removing circuit 17, the chroma signal component of the composite video signal S ₁₂ is B
The chroma signal component and the key signal S extracted by the PF31
_11a is multiplied by the multiplier 33 and supplied to the adder 35 through the phase inverter 34. Further, the composite video signal S ₁₂ is supplied to the adder 35 through the delay device 32, and the chroma signal S 12
The chroma signal component of the composite video signal S ₁₂ is removed in the ₁₄ band.

Therefore, the reproduced image at the boundary of the chroma signal S ₁₄ removed by the key signal S _11a does not become unnatural.

The video signal S ₂₂ from which the chroma component signal has been removed from the composite video signal S ₁₂ and the luminance signal S of the second video signal.
₁₃ is a multiplier 41 of the video signal mixing circuit (1) 18
And the multiplier 42.

Then, the arbitrary key signal S ₁₁ is band-limited by the filter (1) 15 at the cutoff frequency corresponding to the luminance signal S ₁₃ and the time axis is matched through the delay device 22, and this key signal S ₂₃ is a video signal. It is supplied to the multiplier 41 through the multiplier 42 and the phase inverter 43 of the mixing circuit (1) 18. The brightness signal S ₁₃ of the second video signal is applied to the multiplier 42.
Are supplied through the delay device 24. Then, the multiplier 41
And the output signal of the multiplier 42 is added by the adder 44.

As described above, in the video signal mixing circuit (1) 18, only the luminance signal S ₁₃ of the second video signal is synthesized, and the chroma signal S ₁₄ is not synthesized.

Therefore, the video signal mixing circuit (1) 18
When the frequency band of the key signal S ₂₃ supplied through the delay circuit 22 is higher than the band of the chroma signal S ₁₄ to also eliminates the influence of the chroma signal S ₁₄ of the second image.

Therefore, when the output composite video signal S ₂₀ is reproduced, the discontinuity of the chroma signal S ₁₄ at the boundary of the reproduced image does not occur, and the deterioration of the image quality is prevented.

The video signal S ₂₄ from the video signal mixing circuit (1) 18 is supplied to the adder 52 of the video signal mixing circuit (2) 19. Further, the chroma signal S ₁₄ of the second video signal is supplied to the multiplier 51 of the video signal mixing circuit (2) 19 through the delay device 25.

The arbitrary key signal S ₁₁ is the filter (2) 16,
The time axis is matched through the delay unit 23, and the band-limited key signal S ₂₅ corresponding to the chroma signal S ₁₄ is supplied to the multiplier 51 of the video signal mixing circuit (2) 19. Multiplier 5
The output signal of 1 is supplied to the adder 52, and is output as the output combined video signal S ₂₀ .

In the video signal mixing circuit (2) 19, only the chroma signal S ₁₄ of the second video signal is synthesized, and the luminance signal S ₁₃ is not synthesized.

Therefore, the video signal mixing circuit (2) 19
The frequency band of the key signal S ₂₅ supplied to the
Even if it is lower than the frequency band of ₁₄ , the luminance signal S of the second video signal
_It is possible to prevent the deterioration of the image quality at the boundary portion in the reproduced combined video that occurs when the frequency band of the key signal is lowered, since it does not affect the frequency.

[0027]

As is apparent from the above description, the video signal synthesizing circuit of the present invention optimizes the composite video signal of the first video signal and the luminance signal and the chroma signal of the second video signal respectively. Image quality degradation at the boundary of the composite playback image when playing back the output composite video signal because the key signal blocked at the frequency is combined to eliminate the discontinuity of the chroma signal and to prevent the luminance band from narrowing. Has the effect of being able to prevent

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration in an embodiment of a video signal synthesizing circuit of the present invention.

FIG. 2 is a block diagram showing a configuration of a conventional video signal synthesis circuit.

[Explanation of symbols]

15 Filter (1) 16 Filter (2) 17 Chroma signal component removal circuit 18 Video signal mixing circuit (1) 19 Video signal mixing circuit (2) S ₁₁ Arbitrary key signal S ₁₂ Composite video signal S ₁₄ Chroma signal S ₂₀ Output synthesis Video signal

Claims (1)

[Claims] 1. A first filter for blocking an input key signal at a frequency corresponding to a frequency band of a luminance signal of a second video signal, and the key signal corresponding to a frequency band of a chroma signal of the second video signal. A second filter that cuts off at a frequency to be used, a chroma signal component removing unit that removes a chroma signal component by a key signal extracted from the input composite video signal of the first video signal through the second filter, and the first filter. First video signal mixing means for synthesizing the composite video signal of the video signal and the luminance signal with the key signal from the first filter, and the composite video signal and the chroma signal from the second filter. A video signal synthesizing circuit comprising: second video mixing means for synthesizing with a signal.