JPH02226988A - Video mixing circuit - Google Patents

Abstract

PURPOSE:To eliminate need for a line memory and to reduce cost by superimposing Y, R-Y, B-Y signals obtained through matrix conversion from external R, G, B signals onto a decoded video signal and color difference signals obtained from the decoded video signal and applying Y/C separation, scanning line interpolation and double speed conversion or the like. CONSTITUTION:A decoded video signal coming from a video input terminal T is separated of color signal C by a BPF 51 and demodulated into color difference signals R-Y, B-Y by a color demodulation circuit 52. On the other hand, external R, G, B signals are led from external R, G, B input terminals t1, t2, t3 to Y, R-Y, B-Y matrix conversion circuits 53, in which the signals are converted into the Y, R-Y, B-Y signals. Then a mixing circuit 54 mixes the decoded video signalled to the video input terminal T with the Y signal. Moreover, a mixing circuit 55 mixes the color difference signals R-Y, B-Y subjected to chroma demodulation by a color demodulation circuit 52 with the color difference signals R-Y, B-Y subjected to matrix conversion by the conversion circuit 53 respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for sequentially scanning a television video signal by interpolating scanning lines, in which an incoming composite video signal and an external R, such as a teletext or captain, etc., are used. This invention relates to a video mixing circuit that mixes CB multiplied signals.

In a display method in which a distorted television video signal is sequentially scanned by interpolating scanning lines, an incoming composite video signal and external R, C,
FIG. 3 shows a conventional video mixing circuit that superimposes the B signal.

In Fig. 3, the composite video signal coming from the input terminal T is filtered through a bandpass filter (hereinafter referred to as rBPFJ) (1).
The analog color signal component M/color demodulation circuit (3) consisting of a color demodulation circuit (2) and a color demodulation circuit (3) outputs color difference signals R-Y and B-Y. and the composite video signal and the color difference signal RY,
B-Y are converted into digital signals by analog/digital (hereinafter referred to as rA/DJ) conversion circuits (4), (5), and (6), respectively, and the video signal is processed by frame comb filters (8) and (9) according to the movement. ), the motion adaptive luminance signal separation circuit (7) consisting of a line comb filter (10) and a mixing circuit (11) removes the multiplexed color signal components, and calculates the color difference (for Similarly, frame comb filters (13) (14),
(17) (18) A motion adaptive color signal separation circuit (12) comprising line comb filters (15) (19) and mixing circuits (16) (20) removes the luminance signal mixed into the color signal.

Next, the luminance signal Y derived from the motion adaptive luminance signal separation circuit (7) is transferred to a motion adaptive scanning line interpolation circuit (21) consisting of a line interpolation circuit (22), a field interpolation circuit (23), and a mixing circuit (24). Scan line interpolation is performed.

The color difference signals R-Y and B-Y derived from the motion adaptive color signal separation circuit (12) are sent to the line interpolation circuits (26) (27).
Scanning line interpolation is performed by a scanning line interpolation circuit 25) consisting of a scanning line interpolation circuit 25). The luminance signal Y1, color difference signal R-Y, and B-Y subjected to scanning line interpolation are stored in line memories (28) and (29), respectively.
(30) Double speed conversion is performed by the double speed conversion circuit (40) consisting of digital/analog (hereinafter referred to as "r3/A")
The incoming video signal is converted into an analog signal by a conversion circuit (31) and sequentially scanned.

On the other hand, teletext led to the input terminal tl+F+t.

External R, G, and B signals from the captain, etc. are each converted into digital signals by an A/D conversion circuit (32), and then double-speed converted by a double-speed conversion circuit (33) each consisting of a line memory, and then converted to a D/A converter (33). The conversion circuit (34) converts the signal into an analog signal, and sequentially scans the external R, G, and B signals.

The luminance signal Y and the color difference signals R-Y, B-Y derived from the D/A conversion circuit (31) are sent to the R, B matrix circuit of the R2O,B matrix/switching circuit (35).
After being converted into G and B signals, the external R, G and B signals derived from the D/A conversion circuit (34) are switched and superimposed by the switching circuit, and the incoming video signal and external R, G are superimposed. , B signals are mixed and the color cathode ray tube (
36).

However, in the conventional device described above, in order to double-speed convert the external R1G and B signals, there are three double-speed conversion circuits each consisting of an A/D conversion circuit, a line memory, and a D/A conversion circuit. This was necessary and the cost was high. In addition, external R, G,
Since the B signal is only subjected to double-speed conversion using a line memory and does not undergo three-dimensional processing using a frame memory, there are problems such as a drop in vertical resolution in still images, for example.

An object of the present invention is to provide a video mixing circuit that solves these problems.

According to the present invention, in a mixing circuit that superimposes external R, G, and B signals on a composite video signal, a first color signal demodulated from the composite video signal and the external R, G are combined.

a first mixing means for mixing a second color signal obtained by matrix-converting the B signal; and mixing the composite video signal and a luminance signal obtained by matrix-converting the external R, G, and B signals. A second mixing means is also provided.

Further, a motion detection means detects a motion from a video signal obtained by delaying the video signal superimposed by the second mixing means by a frame amount and a video signal before the delay, and a motion detection means detects a motion from the video signal superimposed by the second mixing means, and a luminance signal separating means for frame-delaying or line-delaying the signal according to the output of the motion detecting means, and subtracting the delayed signal from the original video signal to output a luminance signal; and the first mixing means; color signal separation means for outputting a color signal by subjecting the superimposed color difference signal to a frame delay or line delay according to the output of the motion detection means; and field interpolation of the outputs of both the separation means according to the output of the motion detection means. and/or scanning line interpolation means for performing line interpolation, and double speed conversion means for guiding the data before scanning line interpolation and the data after scanning line interpolation to a line memory circuit and converting the data at double speed.

Sho-■ The first mixing means mixes the first color signal demodulated from the incoming composite video signal and the second color difference signal obtained by matrix-converting the external R, G, and B signals. The above composite video signal and external R, G are mixed by a mixing means.

The B signal is mixed with a luminance signal obtained by matrix conversion.

Further, the movement of the image is detected by the motion detection means from the output of the second mixing means, and the outputs of the first and second mixing means are delayed by a frame in the case of a still image, and by a line in the case of a moving image. Separates the color signal and brightness signal, performs scanning line interpolation such as field interpolation and/or line interpolation depending on the movement of the image, and then doubles the speed of both the color signal and brightness signal using line memory to perform sequential scanning. ing.

The present invention will be described in detail below with reference to the embodiment shown in FIG.

In FIG. 1, (51) is a bandpass filter connected to the video input terminal T, and the color signal C derived from the bandpass filter is output to a color demodulation circuit that outputs color difference signals R-Y and B-Y. (52).

On the other hand, the external R, G, and B input terminals tI+F+t output a luminance signal Y and two color signals R-Y and B-Y.

It is connected to the R-Y, B-Y matrix conversion circuit (53).

(54) is a mixing circuit that switches the composite video signal from the video input terminal T and the luminance signal Y from the Y, R-Y, B-Y matrix conversion circuit (53), and (55) is a color demodulation circuit (52). The color difference signals R-Y, B-Y and Y,
This is a mixing circuit that switches the color difference signals R-Y and B-Y from the R-Y and B-Y matrix conversion circuit (53).
56) (57) (58) are the above mixing circuits (54) (
This is an A/D conversion circuit that converts the video signals RY and BY, which are the output signals of 55), into digital signals.

(59) is a Y/C separation section. The above A/D conversion circuit (
The output terminal of 56) is the frame comb filter (60).
and a switching circuit (6) via a line comb filter (61).
2), and the output terminal of the switching circuit (62) and the output terminal of the A/D conversion circuit (56) are led to a subtracter (63) that outputs a Y signal. The above A/D conversion circuit (57
) The output terminals of (58) are frame comb filters (64) (67) and line comb filters (65), respectively.
(68) are connected to switching circuits (66) and (69) that output color difference signals RY and BY. (70)
is a scanning line interpolation section, and a field interpolation circuit (71) (7) is connected to the output terminal of the Y/C separation section (59).
4) (77), field/line interpolation circuit (72
) (75) (7B) , line interpolation circuit (73
) (76) (79) and switching circuits (80) (81) (82) connected to each of these circuits. (83) is a motion detection section. A/D conversion circuit (
56) directly to the subtractor (85),
The subtracter (85)
), and the output of the subtracter (85) is passed through a low-pass filter (
ROM (8B) via an absolute value circuit (hereinafter referred to as rABsj) (87)
).

The output of the ROM (88) is sent to the Y/C separator (59).
and switching circuits (62) (66) of the scanning line interpolation unit (70).
) (69) and (80) (81) (82). (89) is line memory (90) (
91) This is a double-speed conversion unit composed of (92), and the input terminals of each of the line memories (90), (91), and (92) are connected to the Y/C separation unit (59) and the scanning line interpolation unit (70), respectively. ) output terminal is connected. The above line memory (
The outputs of 90), (91), and (92) are led to an R, G, and B matrix conversion circuit (96) via D/A conversion circuits (93), (94), and (95), respectively.

The operation of the embodiment will be explained below.

A composite video signal obtained from radio waves from a VTR or broadcasting station that enters from the video input terminal T is separated into a color signal C by a B P F (51), and then converted into a color difference signal R-Y by a color demodulation circuit (52). , B-Y.

On the other hand, the other input of this system is teletext.

The external R, G, B signals obtained from the captain etc.
Y, RY from C, B input terminals jl+ b, ts.

The signal is guided to a BY matrix conversion circuit (53), where it is converted into Y, RY, and BY signals. Then, in the mixing circuit (54), the composite video signal led to the video input terminal T and the Y signal from the matrix conversion circuit (53) are mixed, and the mixing circuit (54)
In step 5), the color difference signals R-Y and B-Y chroma-demodulated by the color demodulation circuit (52) are converted into color difference signals R-Y and B-Y which are matrix-converted by the matrix conversion circuit (53), respectively.
Mixed with B-Y.

Next, the video signals are mixed by mixing circuits (54) and (55).

The color difference signals R-Y and B-Y are each sent to a double speed conversion circuit (56).
(57) Converted to a digital signal in (58).

The video signal converted into a digital signal by the A/D conversion circuit (56) is guided to a motion detection section (83). This motion detection section (83) detects the inter-frame difference between the immediately previous frame using a one-frame delay circuit (84) and a subtracter (85), and guides this detection signal to L P F (86) to After extracting only the area components, the absolute value is taken at AB S (87) and led to the ROM (88).
A motion coefficient signal corresponding to the motion of the video signal is output.

On the other hand, the video signal converted into a digital signal by the A/D conversion circuit (56) is passed through a frame comb filter (60).
) and the line comb filter (61), and a switching circuit (62) performs a switching operation in response to a motion coefficient signal derived from the motion detection section (83). ) is switched and the color signal C
Derive. Then, the subtracter (63) converts the composite video signal from the A/D conversion circuit (56) into the switching circuit (62).
) is subtracted from the color signal C to obtain a Y signal from which dot interference has been removed.

The color difference signals R-Y and B-Y converted into digital signals by the A/D conversion circuits (57) and (58) are respectively input to the frame comb filters (64) (67) and line (diamond filters (65) ( 68) to perform Y/C separation.

A switching circuit (66) (6) performs a switching operation according to a motion coefficient signal derived from the motion detection section (83).
9), both the above filters (64) (67) and (65)
(68 outputs are switched according to the movement of the image,
As a result, color difference signals R-Y, B- from which cross colors have been removed
Y is derived.

The Y, RY, and B-Y signals obtained from the Y/C separation section (59) as described above are sent to the scanning line interpolation section (70).
Each field interpolation circuit (71) (74) (77)
, field/line interpolation circuit (72) <75)
(78) and line interpolation port! (73) (76) (
79). And switching circuits (80) (81) controlled by the motion coefficient signal of the motion detection section (83).
Field interpolation circuit (71) (74) (77)
, In the video, line interpolation circuit (73) (76) (7
9).

For quasi-moving images and quasi-still images in between, switching is performed in the manner of field/line interpolation circuits (72), (75), and (7B), and scanning line interpolation is performed in accordance with the movement of the image.

FIG. 2 shows this situation. As shown in the second diagram, in the case of a still image with no movement in the human input signal, the field interpolation circuits (71) (74) (7, 7) are selected.
Data on the same line in the previous field is used as interpolation data. In the case of video, line interpolation circuit (73) (
76) (79) is selected, and interpolated data is created from the current line and the next line as shown in FIG. 2A. In the case of intermediate semi-still images and semi-moving images, as shown in Figure 2 B and C, interpolation data is generated by changing the coefficients added from the data of the current line of the current field, the data of the next line, and the data of the same line of the previous field. I'm making it.

As mentioned above, the Y/C separation unit (59) and the scanning line interpolation unit (
70), the luminance signal Y1 color difference signal R-Y, B-Y is subjected to Y/C separation and scanning line interpolation, and the luminance signal Y22 color difference signal R-Y, B-Y before scanning line interpolation is applied to the line. After being led to memories (90), (91), and (92) and subjected to double speed conversion, the D/A conversion circuits (93), (94), and (95)
) is converted into an analog signal by the R, G, B matrix conversion WA circuit (9G), and is further matrix-converted by the R, G, B matrix conversion WA circuit (9G). , B are derived.

Matasato■4! According to the present invention, after superimposing Y, R-Y, B-Y signals obtained by matrix conversion of external R, G, and B signals on a composite video signal and a color difference signal obtained from the composite video signal, Since C separation, 5 scanning line interpolation, 1x speed conversion, etc. are performed, external R, G,
There is no need for a line memory that performs double-speed conversion exclusively for the B signal, resulting in a significant cost reduction.
,G.

With regard to the B-idiom, three-dimensional field interpolation using a frame memory or the like can be performed, so that the vertical resolution can be significantly improved.

[Brief explanation of the drawing]

FIG. 1 is a boot diagram of an embodiment of the present invention, FIG. 2 is an explanatory diagram of the operation of FIG. 1, and FIG. 3 is a block diagram of a conventional example. (52)...Color demodulation circuit. (53)...Y, RY, B-Y matrix conversion circuit. (54) (55)...Mixing circuit. (60) (64) (67) ---Frame comb filter. (61) (65) (6B) Line comb filter. (62) (66) (69) --- switching circuit, (7
0)...-Scanning line interpolation unit. (83)--Motion detection section, (89)--Double speed conversion section. (90) (91) (92)---Line memory.

Claims (2)

[Claims] (1) In a mixing circuit that superimposes external R, G, and B signals on a composite video signal, a first color signal demodulated from the composite video signal and a first color signal obtained by matrix-converting the external R, G, and B signals are a first mixing means for mixing the two color signals; and a second mixing means for mixing the composite video signal and a luminance signal obtained by matrix-converting the external R, G, B signals. A video mixing circuit characterized by: (2) motion detection means for detecting motion from a video signal obtained by delaying the video signal superimposed by the video mixing circuit according to claim 1 by a frame amount and the video signal before the delay;
Luminance signal separation means for frame-delaying or line-delaying the video signal superimposed by the video mixing circuit in accordance with the output of the motion detection means, subtracting this delayed signal from the original video signal, and outputting a luminance signal. and a color signal separation means for outputting a color signal by subjecting the color difference signal superimposed by the video mixing circuit to a frame delay or a line delay according to the output of the motion detection means, and a color signal separation means for outputting a color signal, and a color signal separation means for outputting a color signal by delaying the color difference signal superimposed in the video mixing circuit according to the output of the motion detection means, A scanning line interpolation means that performs field interpolation and/or line interpolation according to the output of Features video mixing circuit.