JPH0583682A - High definition television signal decoder - Google Patents

Abstract

PURPOSE:To enable the decoding reproduction of a still picture with the higher definition only by changing the conventional high definition television signal decoder a little. CONSTITUTION:A changeover switch means 11 selects the input of a sample rate conversion circuit 3 in a high definition mode and the output in a MUSE mode, and supplies it to a field memory 4. A switching means 12 performs the inter-field insertion processing between the input and output of the field memory 4 to obtain a signal of 48.6MHz rate. In the high definition mode, the inter-field insertion processing is performed between the input and output of the field memory 4 to obtain a signal of 64.8MHz rate. A multiplier 13 multiplies a coefficient (1-K) by the output of the switching means 12 in the MUSE mode, and multiplies a coefficient '1' and the output together in the high definition mode. A multiplier 14 multiplies a coefficient K by the dynamic picture decoding output of a dynamic picture processing circuit 8 by the coefficient K in the MUSE mode, and multiplies a coefficient '0' and the output together in the high definition mode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to, for example, MUSE (mu
The present invention relates to a high-definition television signal decoder for demodulating a high-definition television signal such as an ltiple sub-nyquist sampling encoding method. The present invention relates to a high-definition television signal decoder which makes it possible to reproduce a higher definition image by slightly modifying the signal decoder.

[0002]

BACKGROUND OF THE INVENTION High definition television signals such as MUSE.
The signal undergoes sample rate conversion in the middle of encoding and decoding in order to prevent aliasing in the low frequency band below 4 MHz. Therefore, the band of the luminance signal in the MUSE signal is about 22 MHz.

For example, in the case of encoding a luminance signal, that is, a Y signal by the MUSE method, signal processing as shown in FIGS.

That is, an original signal having a frequency spectrum as shown in FIG. 5 is subjected to field offset subsampling to obtain a signal having a frequency spectrum as shown in FIG. The signal of the frequency spectrum of FIG. 6 is 48.6 MHz.
A signal having a frequency spectrum as shown in FIG. 7 is obtained by performing interpolation processing on the rate, and is further passed through a low pass filter having a cutoff frequency of 12 MHz. This signal is further 32.4MHz
The sample rate is converted into a signal having a frequency spectrum as shown in FIG. 8 and frame offset subsampling is performed to obtain a MUSE digital signal having a frequency spectrum as shown in FIG. By passing this MUSE digital signal through a low-pass filter of 8.1 MHz, the M spectrum shown in FIG.
Get USE analog signal.

The decoding process of the MUSE signal thus obtained may be carried out substantially reverse to the above.
FIG. 11 shows an example of the configuration of a conventional MUSE signal decoder.

FIG. 11 shows a MUSE decoder for decoding from the MUSE digital signal shown in FIG. The frame memory 1 is provided to the terminal T 1
Sequentially store MUSE digital signals at a 6.2 MHz rate. Switching means 2 is provided at terminal T 1
The MUSE digital signal of 6.2 MHz rate and the signal read from the frame memory 1 are alternately switched to perform interfield interpolation processing to obtain a signal of 32.4 MHz rate. This 32.4 MHz rate signal is converted into a 24.3 MHz rate signal by the sample rate conversion circuit 3. This 24.3 MHz signal is stored in the field memory 4. The switching means 5 alternately switches the signal of 24.3 MHz rate output from the sample rate conversion circuit 3 and the signal read from the field memory 4 to perform interfield interpolation processing,
A signal of 48.6 MHz rate is obtained. This 48.6MH
The z-rate signal is multiplied by (1-K) in the multiplier 7. Here, K is a motion detection signal (0 ≦ K ≦ 1). The moving image processing circuit 8 performs moving image decoding of the 16.2 MHz rate MUSE digital signal given to the terminal T. The video-decoded signal is multiplied by K in the multiplier 9. Multiplier 7
And the output of the multiplier 9 are added by the adder 10 to obtain M
It becomes a USE decode signal.

[0007]

On the other hand, it is desirable that the band corresponding to the vertical resolution determined by the number of scanning lines is 30 MHz or more as in the so-called "Hi-Vision Studio Standard". In particular, the current MUSE standard is insufficient for displaying works of art and the like in high-definition still images.

Therefore, in order to be able to transmit and display a high-definition still image or the like, 30 MHz is required.
It is desirable to use a transmission method that can secure the above luminance signal band. However, for convenience of moving image transmission and the like, it is also necessary to ensure compatibility with the MUSE system.

The present invention has been made in view of the above-mentioned circumstances, and it is possible to reproduce still higher-definition still images by making a slight modification to the conventional high-definition television signal decoder. It is an object of the present invention to provide a high-definition television signal decoder that can be used.

[0010]

A high-definition television signal decoder according to the present invention includes interframe interpolation means for subjecting an input signal to interframe interpolation processing to obtain a signal having a data rate of 32.4 MHz. Sample rate conversion means for converting a sample rate of a signal having a data rate of 32.4 MHz obtained by the interpolating means to obtain a signal having a data rate of 24.3 MHz, and bypass means for bypassing the sample rate conversion means Is provided on the output side of the sample rate conversion means and the bypass means and has two operation modes. In the first mode, the signal is subjected to inter-field interpolation processing at a data rate of 24.3 MHz and 48.6 MHz. A signal with a data rate of .6 MHz is obtained, and in the second mode the signal is 32.4 MHz,
Inter-field interpolation means for performing inter-field interpolation processing at a data rate of 64.8 MHz to obtain a signal at a data rate of 64.8 MHz, moving picture processing means for decoding the input signal as a moving picture, and two operation modes are provided. Have, first
In the second mode, the output of the interfield interpolation means and the output of the moving image processing means are mixed according to the motion detection information, and in the second mode, the mixing means for outputting only the output of the interfield interpolation means, While the high-definition television signal is received, the bypass means is made inoperative, the interfield interpolating means and the mixing means are both set to the first mode, and the high-definition signal is received when the bypass means is enabled. It is characterized in that it is provided with a mode switching means for setting both the inter-field interpolation means and the mixing means to the second mode.

[0011]

In the high-definition television signal decoder according to the present invention, when decoding in the high definition mode, data of 32.4 MHz and 64.8 MHz are interpolated between fields of still image processing without performing sample rate conversion. Since it is performed at the rate, it is possible to decode and reproduce the high-definition still image information subsampled between fields and frames.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the configuration of a MUSE decoder having a high-definition still image decoding function according to an embodiment of the present invention. Before describing the MUSE decoder of FIG. 1 in detail, a high-definition still image encoding method in this embodiment will be described with reference to FIGS.

The original signal of a high-definition still image having a frequency spectrum as shown in FIG. 2 is subjected to field offset sub-sampling to obtain a signal having a frequency spectrum of 32.4 MHz as shown in FIG. The signal of FIG. 3 is subjected to frame offset sub-sampling to obtain a high definition still image digital signal of a frequency spectrum of 16.2 MHz rate as shown in FIG. The high definition still image digital signal of FIG. 4 is a signal substantially corresponding to the MUSE digital signal of FIG. When transmitting a high-definition still image, the high-definition still image digital signal of FIG. 4 is transmitted.

In this case, the high definition still image signal is roughly the same as the MUSE signal, but the Y signal is 64.8M.
Hz original sample is 1/2 between frames (32.4 MH
z), which is thinned out to 1/2 (16.2 MHz) between fields, and is a signal in which the direct current is folded because the sample rate conversion is not performed. Since the chroma signal (color signal) of the high-definition still image signal is similar to that in the MUSE method, the same processing as in the MUSE method may be performed.

The MUSE decoder of FIG. 1 is the MUSE of FIG.
The digital signal and the high definition still image digital signal of FIG. 4 can be decoded. That is, the MU of FIG.
The SE decoder is a decoder adapted to switch between the MUSE mode and the high definition still image mode. MUS
In the E mode, the same process as the conventional MUSE decoder shown in FIG. 11 is performed to decode the MUSE signal.
In high-definition still image mode, sample rate conversion of still images is not performed, and inter-field interpolation is 32.4 or 64.8M.
At a data rate of Hz, and the still image / video mix ratio is fixed to all still images, and subsequent processing is performed at 64.8 MH
Perform at z-rate.

In FIG. 1, parts substantially similar to those in FIG. 11 are designated by the same reference numerals. Frame memory 1
Is a MUS of 16.2 MHz rate given to terminal T
E Digital signals or high-definition still image digital signals are sequentially stored. The first switching means 2 has a terminal T
The MUSE digital signal or the high-definition still image digital signal of 16.2 MHz rate and the signal read from the frame memory 1 are alternately switched to perform inter-field interpolation processing to obtain a signal of 32.4 MHz rate. ..

The sample rate conversion circuit 3 converts the 32.4 MHz rate signal obtained by the switching means 2 into two.
Convert to 4.3 MHz rate signal. The changeover switch means 11 selects either the input or the output of the sample rate conversion circuit 3 according to the reception mode. That is, this system has two reception modes of the MUSE mode and the high definition mode, and the changeover switch means 11
In the MUSE mode, the signal of the 24.3 MHz rate output from the sample rate conversion circuit 3 is selected and given to the subsequent stage, and in the high definition mode, the input of the sample rate conversion circuit 3 is selected and given to the subsequent stage. That is, in the high definition mode, the sample rate conversion circuit 3 is bypassed by the changeover switch means 11, and the signal of the 32.4 MHz rate obtained by the switching means 2 is directly transmitted to the subsequent stage.

The signal selected by the changeover switch means 11 is stored in the field memory 4. The operation of the second switching means 12 differs depending on which of the two receiving modes, that is, the MUSE mode and the high definition mode. In the MUSE mode, the switching means 12 alternately switches the output signal at the 24.3 MHz rate of the sample rate conversion circuit 3 selected by the changeover switch means 11 and the signal read from the field memory 4 to perform interfield interpolation processing. And 48.
Obtain a 6 MHz rate signal. In the high definition mode, the switching means 12 alternately switches the 32.4 MHz rate output signal of the switching means 2 selected by the changeover switch means 11 and the signal read from the field memory 4 to perform interfield interpolation processing. Do 6
Obtain a signal at the 4.8 MHz rate.

The multiplier 13 multiplies the output of the switching means 12 by a predetermined coefficient. In the MUSE mode, the multiplier 13 is 48.6M obtained by the switching means 12.
The above-mentioned coefficient (1-K) for the Hz rate signal (where K is a motion detection signal and satisfies 0 ≦ K ≦ 1)
And the switching means 12 in the high definition mode.
The signal at the 64.8 MHz rate obtained in step 1 is multiplied by a fixed value coefficient "1" (that is, the output of the switching means 12 is output as it is in the high definition mode).

The moving picture processing circuit 8 is supplied to the terminal T 1
The MUSE digital signal (or high definition still image digital signal) of 6.2 MHz rate is video-decoded.
The video decoded signal is multiplied by a predetermined coefficient in the multiplier 14. That is, in the MUSE mode, the multiplier 14 adds the above-mentioned coefficient K to the output signal of the moving image processing circuit 8.
(Motion detection signal) is multiplied, and in the high definition mode, the output signal of the moving image processing circuit 8 is multiplied by a coefficient "0" which is a fixed value (that is, in the high definition mode, the moving image processing circuit 8).
Block the output of).

The output of the multiplier 13 and the output of the multiplier 14 are added by the adder 15 to form a decoded signal. For the decoded signal, in the MUSE mode, the subsequent processing is performed at a rate of 48.6 MHz as in the conventional case, and in the high definition mode, the subsequent processing is performed at a rate of 64.8 MHz.

In this way, the MUSE mode and the high definition mode can be switched and decoded.
Then, in the MUSE mode, the conventional processing is performed. In the high-definition still image mode, the still image sample rate conversion processing is bypassed, and the inter-field interpolation is performed at the rates of 32.4 and 64.8 MHz. Then, the still image / moving image mix ratio is fixed to all still images, and the subsequent processing is performed at the 64.8 MHz rate.

The reason why the high definition information transmitted in the high definition mode is limited to the still image is as follows. (1) Since the high-definition information has a high-frequency folding back to the DC region, it is difficult to detect motion from the video signal. (2) For the same reason as (1) above, there is a possibility that the image quality deterioration due to a motion detection error becomes very large. (3) Still images have many applications that require high definition.

Further, as a signal source in this high definition mode, because it is a non-standard signal and has a great influence of noise non-linear distortion, it is not transmitted as an analog signal like the MUSE signal. , As mentioned above 1
You may make it interface directly as 6.2 MHz digital data.

The present invention is not limited to the MUSE signal decoder, but can be applied to any high-definition television signal decoder as long as it is a decoder for decoding a high-definition television signal having a substantially similar signal format. Can be applied.

[0026]

As described above, according to the present invention,
When decoding in the high definition mode, inter-field interpolation of still image processing is performed without performing sample rate conversion.
Making slight changes to conventional high definition television signal decoders by decoding and reproducing sub-sampled high definition still image information between fields and frames at a data rate of 4 MHz and 64.8 MHz. Only by itself, it is possible to provide a high-definition television signal decoder capable of reproducing still higher-definition still images.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a MUSE decoder according to an embodiment of the present invention.

2 is a frequency spectrum of an original signal of a high definition still image signal for explaining encoding of the high definition still image signal according to the embodiment of FIG.

3 is a frequency spectrum of a field offset subsampled signal of the original signal of the high definition still image signal of FIG. 2 for explaining encoding of the high definition still image signal according to the embodiment of FIG. 1;

FIG. 4 is a frequency of a high definition still image digital signal obtained by frame offset subsampling the field offset subsampled signal of FIG. 3 for explaining encoding of a high definition still image signal according to the embodiment of FIG. 1; It is a spectrum.

FIG. 5 is a frequency spectrum of an original signal for explaining MUSE encoding.

FIG. 6 is a frequency spectrum of a field offset sub-sampled signal of FIG. 5 for explaining MUSE encoding.

7 is a frequency spectrum of a 48.6 MHz rate signal obtained by performing interpolation processing on the signal of FIG. 6 for explaining MUSE encoding.

FIG. 8 shows a signal obtained by passing the signal shown in FIG. 7 through a 12 MHz low-pass filter to explain MUSE encoding.
It is the frequency spectrum of the signal sample rate converted to 2.4 MHz rate.

FIG. 9 is a MUS obtained by frame offset sub-sampling the signal of FIG. 8 for explaining MUSE encoding.
E is the frequency spectrum of the digital signal.

FIG. 10 is a diagram for explaining MUSE encoding.
MU which passed the signal of 8MHz to the low pass filter of 8.1MHz
It is a frequency spectrum of an SE analog signal.

FIG. 11 is a block diagram schematically showing a configuration of an example of a conventional MUSE decoder.

[Explanation of symbols]

1 ... Frame memory, 2, 12 ... Switching means, 3
... Sample rate conversion circuit, 4 ... Field memory, 8
... Moving picture processing circuit, 11 ... Changeover switch means, 13, 14
... multiplier, 15 ... adder.

Claims (1)

[Claims] 1. An interframe interpolating means for performing interframe interpolating processing on an input signal to obtain a signal having a data rate of 32.4 MHz, and a signal having a data rate of 32.4 MHz obtained by the interframe interpolating means. Convert the sample rate of 24.3
A sample rate conversion means for obtaining a signal of a data rate of MHz; a bypass means for bypassing the sample rate conversion means; and a sampling rate conversion means and an output side of the bypass means, which have two operation modes. In the first mode, the signal is subjected to inter-field interpolation processing at the data rates of 24.3 MHz and 48.6 MHz to obtain the signal of the data rate of 48.6 MHz, and in the second mode, the signal is set to 32.
Inter-field interpolation means for performing inter-field interpolation processing at a data rate of 4 MHz and 64.8 MHz to obtain a signal of a data rate of 64.8 MHz; moving picture processing means for decoding the input signal as a moving picture; and two operations In the first mode, the output of the inter-field interpolation means and the output of the moving image processing means are mixed according to the motion detection information, and in the second mode, only the output of the inter-field interpolation means is mixed. The mixing means for outputting and the bypass means are inoperative at the time of receiving a high-definition television signal, and the interfield interpolating means and the mixing means are both in the first mode, and the bypass at the time of receiving a high definition signal. And means for switching between the interfield interpolating means and the mixing means in the second mode. High-definition television signal decoder.