JP2592871B2 - Color video signal transmission device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a color video signal transmission device, and more particularly to a so-called composite video signal obtained by multiplexing a luminance signal and a carrier chrominance signal, and a so-called component comprising a plurality of baseband signals. The present invention relates to a transmission device capable of transmitting a color video signal input in any form of a video signal.

2. Description of the Related Art Conventionally, in a device which can be applied to both input signal forms of a composite color video signal and a component color video signal, a composite signal is converted into a component and transmitted as a component signal, or It is necessary to convert the signal into a composite and transmit it as a composite signal.

The latter approach is relatively easy to implement,
On the other hand, since a part of the information of the original component signal is reduced, it is not suitable for transmitting a high-quality video signal.

[Problems to be Solved by the Invention] However, the former method requires a Y / C separation circuit that separates a multiplexed carrier chrominance signal and a luminance signal when a composite signal is made into components. Full Y / C
Separation requires a process of adaptively weighting and summing data obtained by a shape filter between frames, a shape filter between fields, a comb filter within a field, etc. according to the motion of the image. There is a disadvantage that the hardware scale becomes large, such as a circuit.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is possible to transmit a component color video signal and a composite color video signal to a common transmission path, without any deterioration of the video signal. It is an object of the present invention to provide a color video signal transmission device that can be configured with a circuit configuration.

Means for Solving the Problems In order to achieve the above object, the present invention provides a composite video signal comprising a luminance component signal and a plurality of color component signals; Input means capable of selectively inputting a component video signal composed of a signal and a component video signal; separating means for separating the composite video signal input by the input means for each of the component signals; and compression for each of the component signals. Compression means; a generation means for generating a control signal indicating whether the signal input by the input means is a composite video signal or a component video signal; and a video signal compressed by the compression means and generated by the generation means. And a transmission means for transmitting a control signal and a color video signal transmission apparatus. .

[Operation] With the above-described configuration, it is possible to transmit a composite video signal and a component video signal to a common transmission line regardless of input, and to perform highly efficient compression while suppressing deterioration of the video signal. it can.

Also, since the control signal indicating whether the input signal is a composite video signal or a component signal is transmitted, the signal input on the transmission side can be faithfully reproduced on the reception side.

[Example] Hereinafter, an example of the present invention will be described with reference to FIG.
(B) This will be described with reference to FIGS. 2 (A) to 2 (H). 1 (A) and 1 (B) show a transmitting device and a receiving device as one embodiment of the present invention, and FIGS. 2 (A) to 2 (H) show the spectrum distributions of signals of respective parts in FIG. It is.

In FIG. 1, the composite video signal input to the input terminal 1 is input to the A / D converter 3. The A / D converter 3 converts the input composite video signal to a frequency of 3 fsc or 4 fsc.
(Fsc is a color subcarrier frequency) and digitized.

FIG. 2A shows the spectrum distribution of the digital signal output from the A / D converter 3. Here, an NTSC television signal is taken as an example of an input composite signal. In the figure, reference numeral 14 denotes the spectrum of the luminance signal, reference numerals 15 and 16 denote the spectrum of the carrier chrominance signal, reference numeral 15 denotes the spectrum of the color difference signal on the I axis, and reference numeral 16 denotes the spectrum of the color difference signal on the Q axis.

The digital composite video signal output from the A / D converter 3 is supplied to a low-pass filter (LPF) 4 and a delay circuit 5. FIG. 2B shows the spectrum distribution of the signal output of LPF4. Now, cut off frequency of LPF4 is 2.5M
If the color difference signal in the carrier chrominance signal is set to about HZ and the color difference signal in the carrier color signal has a wide band, the I-axis color difference signal component is included in the low-frequency signal output from the LPF 4. However, the I-axis color difference signal component included in the low-frequency signal output from the LPF 4 is small in energy. The LPF 4 outputs a low-frequency signal as a pseudo-luminance signal (indicated by Y 'in the figure).
The signal is supplied to the A-side terminal of a and the subtractor 6.

The delay circuit 5 is a delay circuit having a delay time corresponding to the time delay generated by the LPF 4, and the subtracter 6 subtracts the output signal of the LPF 4 from the output signal of the delay circuit 5, and outputs a high signal not separated by the LPF 4. Extract the area signal. The spectrum distribution of the high frequency signal obtained by the subtractor 6 is as shown in FIG. 2 (C). As shown in the figure, the luminance signal component 14 of 2.5 MHz or more and the I-axis color difference signal component in the carrier color signal. 15. Includes a color difference signal component on the Q axis.

The synchronous detection circuit 7 performs synchronous detection while including a luminance signal component of 2.5 MHz or more, and color-demodulates a high-frequency signal on the I axis and the Q axis. The two signals subjected to the color demodulation are supplied to the S-side terminals of the switches 18b and 18c as a pseudo I-axis color difference signal I 'and a pseudo Q-axis color difference signal Q'. The spectrum distributions of these signals are shown in FIGS. 2 (D) and 2 (E), respectively. The spectrum of the pseudo I-axis color difference signal I 'and the spectrum of the pseudo Q-axis color difference signal Q' are those of the high-frequency luminance signal. Is included.

On the other hand, the luminance signal, the I-axis, and the Q-axis color difference signals input to the terminals 10a, 10b, and 10c as component color video signals are supplied to A / D conversion circuits 11a, 11b, and 11c, respectively, and are converted into digital signals. It is supplied to the N-side terminals of the switches 18a, 18b, 18c.

Luminance signal Y, chrominance signal input to terminals 10a, 10b, 10c
The frequency spectra of I and Q are shown in Fig. 2 (F), (G),
(H) shown.

The switches 18a, 18b and 18c are connected to the S side when transmitting the composite signal input to the terminal 1, and to the N side when transmitting the component signal input to the terminals 10a, 10b and 10c. The signals output from the switches 18a, 18b, 18c are supplied to an image data compression circuit.

The image data compression circuit 8 receives the pseudo luminance signal Y 'and the pseudo color difference signals I' and Q 'or the luminance signal Y and the color difference signals I and Q, and performs data compression using the correlation (redundancy) of the image. Further, it is converted to TCI and output. This output signal is output as a transmission signal to a transmission path such as a magnetic recording / reproducing system or a communication path. Further, together with the output signal of the image data compression circuit 8, switching control data Dc indicating whether the input signal in the transmission system is a component signal or a composite signal is also output to the transmission path. This data Dc is output from the switch 18d interlocked with the switches 18a, 18b, 18c,
Switch if the input signal is a component signal
Since all 18a, 18b, 18c and 18d are connected to the N side, data Dc
Becomes "0", and when the input signal is a composite signal, the switches 18a, 18b, 18c and 18d are all connected to the S side, so that the data Dc becomes "1".

FIG. 1 (B) is a diagram showing a configuration example of a receiving device for receiving a signal transmitted to a transmission line by the transmitting device of FIG. 1 (A). The signal input from the transmission path is input to the image data decompression circuit 25, and the signals which have been time-division multiplexed are converted into three systems of signals. By performing the processing, the pseudo luminance signal Y 'and the pseudo color difference signals I', Q 'or the luminance signal Y'
And color difference signals I and Q.

The outputs of the image data expansion circuit 25 are switches 26a, 26b and 26c.
And if these are Y ', I', Q ', the switches 26a, 26a,
26b and 26c are switching control data Dc input via the transmission line.
To the S side, and in the case of Y, I, Q, switches 26a, 26b, 2
6c is connected to the N side.

The pseudo color difference signals I 'and Q' output from the S-side terminals of the switches 26b and 26c are supplied to a balanced modulation circuit 27, and well-known quadrature two-phase modulation is performed in a digital signal state. At this time, the frequency of the carrier is fsc, and the reference clock of the frequency fsc from the clock generator 26 is supplied to the balanced modulation circuit 27.
The output signal of the balanced modulation circuit 27 is a digital high-frequency signal having a spectrum distribution as shown in FIG. It goes without saying that this high-frequency signal contains the high-frequency component of the luminance signal. This high-frequency signal is added to the pseudo-luminance signal as a low-frequency signal output from the S side of the switch 26a by the adder 28 to obtain the original composite digital video signal.

Composite digital video signal is 3fsc or 4fsc
Is converted into an analog signal by the D / A converter 29 which operates and output as a composite video signal.

On the other hand, the luminance signal Y and the color difference signals I and Q output from the N side of the switches 26a, 26b and 26c are converted into analog component video signals by the D / A converters 20a, 20b and 20c.
Output from 21a, 21b, 21c.

In the above-described embodiment, either the component signal or the composite signal is selected as the input signal, and when the composite signal is input, the pseudo component signals Y ', I', Q 'are obtained by a very simple process. These are handled in the same way as the component signals, thereby enabling transmission on the same transmission path.

As a system to which the above-described embodiment is applied, in particular, a camera-integrated VTR in which input of both a composite video signal and a component video signal is predicted is considered. When applied to a camera-integrated VTR, it can be said that this is an extremely suitable embodiment because it can contribute to downsizing and weight reduction of the device.

In the above embodiment, the case where the input signals as the component video signals are the luminance signal Y and the color difference signals I and Q has been described, but the three primary color signals of R, G and B are input as the component video signals. However, it is also possible to adopt a configuration in which after each of them is converted into a digital signal by an A / D converter, a luminance signal Y and color difference signals I and Q are obtained by a digital matrix circuit.

Also, we assumed a digital transmission path as the transmission path,
The same effect can be obtained by applying the present invention to a system that simultaneously transmits three signals to an analog transmission path.

Further, in the above-described embodiment, the NTSC television signal is used as an example of the video signal to be handled. Similar effects can be obtained by using the present invention for signal transmission.

[Effects of the Invention] As described above, according to the color video signal transmission apparatus of the present invention, when either a component color video signal or a composite color video signal is input, it can be transmitted to a common transmission path, Without degrading the signal at all,
In addition, the circuit configuration can be simplified.

[Brief description of the drawings]

1 (A) and 1 (B) are diagrams showing a configuration of an embodiment of the present invention, FIG. 1 (A) is a diagram showing a configuration of a transmitting device, and FIG. 1 (B) is a diagram showing a configuration of a receiving device. 2 (A) to 2 (H) are diagrams showing the frequency spectrum of the signal of each section in FIG. In the figure, 1 is an input terminal of a composite video signal, 3 is A /
D converter, 4 is a low-pass filter, 6 is a subtractor, 7 is a synchronous detection circuit that performs color demodulation, 8 is a data compression circuit, and 10a and 10a.
b, 10c are component video signal input terminals, 18a, 18
b and 18c are switches, respectively.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shin Shimokoriyama 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Soichi Kashida 770 Shimonoge, Takatsu-ku, Kawasaki-shi, Kanagawa Canon (56) References JP-A-1-141494 (JP, A) JP-A-55-86279 (JP, A) JP-A-62-230190 (JP, A) JP-A-60-55790 (JP JP, A)

Claims (1)

(57) [Claims] 1. A composite video signal composed of a luminance component signal and a plurality of color component signals, and a component video signal composed of the luminance component signal and a plurality of color component signals can be selectively inputted. Input means, separating means for separating the composite video signal input by the input means for each component signal, compression means for compressing each component signal, and whether the signal input by the input means is a composite video signal A color signal comprising: a generation means for generating a control signal indicating whether the signal is a component video signal; and a transmission means for transmitting the video signal compressed by the compression means and the control signal generated by the generation means. Video signal transmission device.