JP2607537B2 - Television signal processing circuit - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television signal processing circuit, and more particularly, to a signal processing circuit for converting a composite color television signal of a current broadcast television standard into a progressive scanning signal.

[Conventional technology]

A conventional signal processing circuit for converting a composite color television signal into a progressive scanning signal is, for example, as described in JP-A-58-117788, a YC separation circuit having a frame memory,
A progressive scan conversion circuit for converting the output of a YC separation circuit into a progressive scan signal having a field memory and supplying the progressive scan signal to a display device to display a high-quality color image is known.

[Problems to be solved by the invention]

Recently, a new home-use VTR that can separate input / output without superimposing luminance and chrominance signals in the form of a composite color television signal has begun to appear on the market. The conventional signal processing circuit does not consider the input and output of the YC separation signal, and has a problem that high-quality recording and reproduction cannot be performed.

An object of the present invention is to solve the above-mentioned problems and to provide a television signal processing circuit capable of performing high-quality recording and reproduction using the above-mentioned new home VTR.

[Means for solving the problem]

The purpose of the above is to use a YC separation circuit with a frame memory.
The output terminal that can supply the separated signal to the outside, the input terminal that can input the YC separated signal, and the signal of this input terminal
This is achieved by providing a switching circuit for supplying a sequential scanning circuit having a field memory.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to FIG. In FIG. 1, a composite color television signal input to an input terminal 1 is separated into a luminance signal Y and a chrominance signal C by a YC separation circuit 2 having a frame memory. The YC-separated signal is input to a progressive scan conversion circuit 6 having a field memory via a switching circuit 5, and is converted from an interlaced scan signal to a double speed scan progressive scan signal.
Is output to On the other hand, in this embodiment, the output terminal 3 and the input terminal 4 are newly provided. An output signal of the YC separation circuit 2 is supplied to the output terminal 3, and a YC separation signal having a similar signal format is supplied to the input terminal 4 from the outside. The signal input to the input terminal 4 is input to the switching circuit 5 and is converted by the progressive scan conversion circuit 6 into a progressive scan signal.

In the circuit shown in FIG. 1, the high-quality Y and C signals obtained at the output terminal 3 are input to a VTR having separate input terminals and recorded. Also, the separated Y and C signals from the VTR are input to input terminal 4
, A high-quality progressive scanning signal free from interference such as cross color is obtained at the output terminal 7.

FIG. 2 shows a signal processing circuit of an EDTV receiver which converts a high-definition signal (having a high frequency component) into a frequency signal, mixes the signal with a current color television signal, and transmits the signal. 1 shows the configuration of the embodiment. In the figure,
Input terminal 1 has a baseband ED modulated by the EDTV system.
The TV signal is input, and the separation circuit 8 outputs a 0-4 MHz luminance signal Y _L.
And a low-frequency conversion signal Yh ′ of a high-definition signal of 4 to 6 MHz and a color signal C. Yh 'signal is 4-6M in demodulation circuit 9.
The luminance signal Yh is returned to the high-frequency luminance signal Yh of 0 Hz. The circuit after obtaining the Y and C signals is the same as that in FIG.

FIG. 3 is a more detailed block diagram of an embodiment in which the frame memory used for YC separation is shared for motion detection, noise elimination, and the like to achieve higher image quality. In FIG. 1, a composite color television signal input to an input terminal 1 is input to an A / D conversion circuit 12 via a switching circuit 11 (described later). Next, a noise reduction circuit 13 and a frame memory 14 perform frame cyclic noise removal, and the noise-reduced signal changes the separation mode according to the motion of the frame memory 14 and the image. Input to the circuit 22.
The motion adaptive YC separation circuit 15 calculates the mixing ratio between the inter-frame YC separation output using the input / output signal of the frame memory 14 and the inter-line YC separation output by using the motion coefficient K obtained by the motion detection circuit 22.
And outputs a Y signal and a C signal. Motion detection circuit
Reference numeral 22 denotes the output of the frame memory 14 and the movement of the subject included in the composite color television signal using the signal two frames before, which is further delayed by one frame period in the frame memory 21 via the switching circuit 20 (described later). Extract information,
Output the motion coefficient K.

The Y signal obtained by the motion adaptive YC separation circuit 15 is a switching circuit
The signal is input to a field memory 28 and a motion adaptive progressive scan conversion circuit 30 via a memory 26 (described later). The motion adaptive progressive scan conversion circuit 30 uses the motion coefficient K obtained by the motion detection circuit 22 to convert the signal of the interpolated scan line into the signal after scanning the previous field and the average value of the signals of the scan lines above and below the current field. And outputs a double-speed scanning sequential scanning signal.

The C signal obtained by the motion adaptive YC separation circuit 15 is a demodulation circuit
The signal is demodulated into two types of color difference signals by 24, time-division multiplexed by a switching circuit 25, passed through a switching circuit 27 (described later), and separated by a separation circuit 29.
Line average type progressive scan conversion circuit separated into different color difference signals
Entered into 31. The sequentially scanned Y and color difference signals are returned to analog signals by a D / A conversion circuit 32, converted to three primary color signals of red, green and blue by a matrix circuit 33 and output to an output terminal 7.

In order to apply the present invention to the above circuit, the Y and C signals separated by the motion adaptive YC separation circuit 15 are converted back to analog signals by the D / A conversion circuit 23, and a high-quality signal without cross-color interference or the like is generated.
The Y and C signals are output to the output terminal 3.

On the other hand, of the Y and C signals input to the input terminal 4, the Y signal is switched by the switching circuit 11 and input to the A / D conversion circuit 12, and the noise is reduced by the cyclic noise removal circuit 13 by the frame memory 14. The data is input to the switching circuit 26. The C signal input to the input terminal 4 is demodulated into two types of color difference signals by an analog demodulation circuit 16 and input to an A / D conversion circuit 17. Thereafter, the signal is time-division multiplexed by the switching circuit 18, and a noise rejection circuit 19, a switching circuit 20, and a frame memory 21 constitute a frame cyclic noise elimination circuit.

When processing a signal from the input terminal 4, the switching circuits 11, 20, 26, and 27 are controlled as described above to share the circuit with the signal processing circuit from the input terminal 1. Although not shown, in the case of processing a composite color television signal from the input terminal 1, the clock is phase-locked to a burst signal, starting with the A / D conversion circuit 12, 4sc (sc: color subcarrier frequency) However, when processing the signal from the input terminal 4, 910h synchronized with the horizontal synchronization signal is used.
(H: horizontal scanning frequency). In the case of the processing mode of the input terminal 1, the frame memories 14 and 21 are provided with the switching circuit 2
0 constitutes a two-frame memory connected in cascade. In the case of the processing mode of the input terminal 4, two independent frame memories are provided, 14 stores a Y signal, and 21 stores a time-division multiplexed color difference signal. The motion detection circuit 22 performs motion detection using the frame difference and the two-frame difference of the composite color television signal in the case of the input terminal 1 mode, and performs the frame difference of the Y signal and the color difference signal in the case of the input terminal 4 mode. Is performed.

〔The invention's effect〕

According to the present invention, a high-quality progressive scanning signal is obtained by inputting a composite color television signal of a broadcasting standard, and a high-quality luminance signal and a chrominance signal are also obtained at another output terminal. Further, a high-quality sequential scanning signal can be obtained from the luminance signal and the chrominance signal separately input to the input terminal. Therefore, by connecting a new YC-separated input / output type home VTR to the luminance and color signal input / output terminals of the signal processing circuit, high-quality color images can be recorded and reproduced. There is an effect that it is possible to freely enjoy a high-quality color image by utilizing the image processing.

[Brief description of the drawings]

1, 2, and 3 are block diagrams of an embodiment of the present invention. 1,3,4,7 …… Input and output terminals, 2,8,15,29 …… Separation circuit, 6,
30,31 …… Successive scan conversion circuit, 9,16,24 …… Demodulation circuit, 1
2,17 A / D conversion circuit, 13,19 Noise removal circuit, 14,21
… Frame memory, 22… motion detection circuit, 23,32… D
/ A conversion circuit, 28 ... field memory, 33 ... matrix circuit.

Claims (2)

(57) [Claims] A first receiving means for receiving a composite color television signal;
An input terminal, a YC separation circuit for separating the composite color television signal into a luminance signal Y and a chrominance signal C, a progressive scan conversion circuit for converting an output signal of the YC separation circuit into a progressive scan signal, A television signal processing circuit having a first output terminal for outputting the progressive scanning signal converted by the conversion circuit, wherein the luminance signal Y and the color signal C output from the YC separation circuit are separated by YC. A second output terminal for outputting as it is, a second input terminal for receiving a luminance signal Y and a chrominance signal C separated from the outside by YC,
And a switching circuit for guiding the luminance signal Y and the chrominance signal C inputted to the input terminals of the television signal to the progressive scan conversion circuit. 2. The television signal processing circuit according to claim 1, further comprising a demodulation circuit for restoring a signal in a frequency band higher than a higher frequency band according to a current color television signal standard, wherein the luminance signal Y having an expanded frequency band and the color signal are reproduced. 2. The television signal processing circuit according to claim 1, wherein a signal C is output to said second output terminal.