JPH0440786A - System converting device - Google Patents

Abstract

PURPOSE:To obtain a standard television signal with the factor of picture quality deterioration owing to the band compression of a multiple sub-Nyquist sampling Encoding (MUSE) system removed by providing a filter to limit the high frequency component of the vertical frequency component of a signal from a mixing circuit, a scanning line number converting circuit and so on and executing system-converting. CONSTITUTION:A first moving picture processing circuit 4 to which a band- compressed high definition television signal is inputted to moving-picture-process, a first still picture processing circuit 3 to still-picture-process, a first filter 101 to limit the vertical high frequency component of a signal from a first mixing circuit 6, a first scanning line number converting circuit 110 to convert the signal from the first filter 101 into the number of scanning lines of a standard television signal and so on are provided. Then, the converting of the number of scanning lines is executed with using the high definition television signal obtained from the first mixing processing circuit 6 of a MUSE decoder. Thus, the signal with picture quality deterioration owing to the band compression of a MUSE system removed can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is a system conversion device for converting a high-definition television signal (MUSE system) band-compressed using the sub-Nyquist sampling system into a current standard television signal. It is related to.

Conventional technology The MU S
E (Multiple 5ub-Nyquis
t sampling Enc.

-ding) system has been proposed (Ninomiya, et al. ``High-definition TV satellite i-channel transmission system (MU 5E)
J Television Society Technical Report TEBS95237-42).

As described in the paper, this method compresses the band to about 1/4 and transmits it by performing 41 sub-Nyquist samplings on a wideband high-definition television signal in 4 fields. This band-compressed high-definition television signal (hereinafter referred to as the MUSE signal) is sent to the receiver's MUSE
The USE decoder uses intra-field, inter-field, and inter-frame interpolation to superimpose the four fields to restore the original wideband high-definition television signal.

In addition, when recording high-definition television broadcasts, you can use a MUSE-based VCR (Video Ca5sette Recorder).
er) or a wideband high-quality VCR. However, these VCRs are expensive, and it is thought that it will take a considerable amount of time for them to become popular in general households.

Therefore, for the time being, the standard television signal (N
An effective method would be to use a VCR compatible with the TSC system. For this purpose, a format conversion device is required to convert the MUSE signal into a standard television signal.

First, an outline of a MUSE type television receiver will be explained with reference to FIG. In Figure 3, 1 is M
An input terminal 2 for inputting the USE signal is an A/D conversion circuit for A/D conversion of the MUSE signal. 3 is a still image processing circuit connected to the A/D conversion circuit 2, and includes an interframe interpolation circuit 31 and an interfield interpolation circuit 32. 4
is a moving image processing circuit connected to the A/D conversion circuit 2, and includes an intra-field interpolation circuit 41. 5 is the same as A/D
A motion detection circuit connected to the conversion circuit 2 is connected to the mixing circuit 6 along with the still image processing circuit 3 and the moving image processing circuit 4. 7 is a TCI decoder connected to the mixing circuit.

In the conventional MUSE type receiver configured in this way, the MUSE signal input from the input terminal l is
The output signal is applied to the D conversion circuit 2, and the output signal is applied to the still image processing circuit 3, which includes an interframe interpolation circuit 31 with a frame memory, an interfield interpolation circuit 32 with a field memory, and a line memory. A moving image processing circuit 4 and a motion detection circuit 5 are configured of a field interpolation circuit 41 and a motion detection circuit 5.
are supplied respectively. The signal in the still image area is subjected to interpolation processing by the still image processing circuit 3 using the transmitted sample point information for four fields, and is supplied to one input of the mixing circuit 6. The signal in the video area is transmitted to the video processing circuit 4 using only the information of the sample points within that field.
The signal is subjected to interpolation processing and is supplied to the other input of the mixing circuit 6. The motion detection circuit 5 detects the amount of motion based on the correlation between one frame or two frames of the MUSE signal,
The mixing circuit 6 is controlled based on the detected amount of movement. The mixing circuit 6 performs mixing processing on the signals of the still image processing circuit 3 and the moving image processing circuit 4 according to the amount of motion from the motion detection circuit 5, and
I (Time-Compressed-Integr
ation) is supplied to the decoder 7. TCI decoder 7
Then, a decoding process is performed to return the time-base compressed and time-division multiplexed color signal to the original time base, and a high-quality television signal is output from the output terminal 8.

Through the above processing, the MUSE signal is restored to the original wideband high-definition television signal.

Next, convert the MUSE system television signal into a standard television (N
TSC system) is displayed on the receiver, and the standard TV signal V
The operation of the converting device for recording on the CR will be explained with reference to FIG. Here, the conversion of the luminance signal will be explained. In FIG. 4, 1 is an input terminal for inputting the MUSE signal, 2 is an A/D conversion circuit, 100 is an aliasing interference removal circuit, 110 is a scanning line number conversion circuit, and 120 is an aspect conversion circuit, which are connected in this order. ing.

First, the input MUSE signal is supplied to the A/D conversion circuit 2, and its output signal is passed through the aliasing interference removal filter 10.
It is input to 0. The aliasing interference removal filter 100 removes aliasing interference of high-definition components in the vertical direction that occurs when scanning lines are thinned out. The signal from which the high-definition component in the vertical direction has been removed is thinned out by the scanning lines in the scanning line number conversion circuit 110, and is converted into 525 pixels of the current standard television signal.
Converted to the number of scanning lines in a book. For example, write/
This can be easily achieved by using a read-asynchronous memory or the like and writing to the memory at the signal rate of a high-definition television signal and reading it out at the signal rate of a standard television signal. The output signal of the scanning line number conversion circuit 110 is sent to the aspect conversion circuit 12.
0 and 43 NTS from 169 MUSE methods
Convert to C method. The conversion method is to display all the information as shown in FIG. 5 (FIG. 5A), or to display it with left and right gaps (FIG. 5B).

In addition, there is an EDTV system that aims to improve the image quality, and the goal is to widen the 169 resolution. As a method compatible with such a receiver, the aspect ratio conversion circuit 120 described above is not required.

The standard television signal converted as described above can be displayed on a standard television receiver or recorded using a VCR.

However, in the configuration described above, h4 U SE
Since the bandwidth is compressed using the sub-Nyquist sampling method, which goes through four fields, the aliasing components of the still image area appear as they are in the standard television signal, resulting in a deterioration in image quality. That is, in the conventional conversion device, the image quality deteriorates as flicker due to the aliasing component due to the inter-frame offset subsampling of the MUSE method.

Furthermore, in a receiver that converts a standard television signal into non-interlaced scanning and displays it, the aliasing component mentioned above appears as a jagged pattern in the vertical direction. (The upper vertical line is a vertical line with a phase difference for each scanning line.)

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide a system conversion device that prevents image quality deterioration caused by band compression in the MUSE system.

Means for Solving the Problems In order to solve the above problems, the system conversion device of the present invention includes:
A format conversion device that converts a high-definition television signal band-compressed by a sub-Nyquist sampling method that goes around once in four fields into a standard television signal, and at least the band-compressed high-definition television signal is manually processed to process a moving image. a first moving image processing circuit and a first still image processing circuit that processes still images; a first motion detection circuit that detects a motion amount based on interframe correlation of the band-compressed high-definition television signal; a first mixing circuit that controls the mixing ratio of output signals from the first video processing circuit and the first still image processing circuit based on the amount of motion detected by the detection circuit; and a vertical high frequency of the signal from the first mixing circuit. This device includes a first filter that limits the components, and a first scanning line number conversion circuit that converts the signal from the first filter into the number of scanning lines of a standard television signal.

Furthermore, the format conversion device of the present invention is a format conversion device that converts a high-definition television signal band-compressed by a sub-Nyquist sampling method that goes through one round in four fields into a standard television signal, and which converts at least a band-compressed high-definition television signal. a second filter for limiting the vertical high frequency components of the television signal; and a second filter for converting the signal from the second filter into the number of scan lines of a standard television signal. a scanning line number converting circuit, a second moving image processing circuit to which the scanning line number converted signal is input, processing a moving image and a second still image processing circuit processing a still image; A second motion detection circuit detects the amount of motion based on the inter-frame correlation, and the mixing ratio of the signals from the second video processing circuit and the second still image processing circuit is determined based on the amount of motion detected by the second motion detection circuit. and a second mixing circuit for controlling.

Function: With the above-described configuration, the present invention converts the number of scanning lines using the high-quality television signal obtained from the first mixing processing circuit of the MUSE decoder. Or you can get a stripped standard TV signal.

In addition, after converting the number of scanning lines, video processing, still image processing, motion detection processing, and mixing processing are performed, so MU
It is possible to obtain a standard television signal in which image quality deterioration caused by band compression of the SE system is prevented, and it is also possible to reduce the circuit scale.

Example An embodiment of the present invention will be described below based on the drawings.

FIG. 1 is a block diagram showing the configuration of a system conversion device in a first embodiment of the present invention. In Figure 1, 1 is M
Input terminal for inputting USE signal, 2 is A/D conversion circuit,
3 is a first still image processing circuit, 4 is a first moving image processing circuit, 5 is a first motion detection circuit, 6 is a first mixing circuit, 7 is a TCT decoder, 8 is an output terminal for a high-definition television signal; It has the same configuration as the one in the figure. 101 is a first vertical low-pass filter connected to the first mixing circuit 6. +10 is the first
A scan conversion circuit, a 120 aspect ratio conversion circuit, and a fourth
The configuration is the same as that shown in the figure, and they are connected to the first vertical low-pass filter 101 in this order. The operation of the system conversion apparatus of this embodiment configured as described above will be described below. In FIG. 1, the MUSE decoding process is the same as that described in the conventional example, and its explanation will be omitted. The output signal of the first mixing circuit 26 is supplied to a first vertical low-pass filter 101 as a wave filter composed of a plurality of line memories and an arithmetic circuit, and the vertical high frequency component of the signal from the first mixing circuit 6 is limited. The aliasing interference component caused by thinning out the scanning lines is removed, and the first
The signal is supplied to the scanning line number conversion circuit 110. The first scanning line number conversion circuit 110 converts one frame from 1125 lines to 525 lines by thinning processing, and supplies the converted line number to the aspect ratio conversion circuit 120. The aspect ratio conversion circuit 120 performs aspect ratio processing for displaying on a 4:3 standard television as in the past, and sends out a standard television signal from the output terminal 130.

As described above, according to this embodiment, since the signal is a still image area signal before format conversion or a signal that has been subjected to interframe and interfield interpolation processing, aliasing due to interframe and interfield offset subsampling may occur. There is no such component, and the standard television signal obtained by converting the signal does not suffer from image quality deterioration such as flicker.

Further, according to the present invention, the high-definition television signal decoded by the MUSE decoder can be enjoyed using a high-definition television display or the like, and at the same time, a high-quality standard television signal can be obtained.

Furthermore, in the scanning line number conversion circuit for converting to a standard television signal, in this embodiment, it is converted to 525 lines/field, or 525 lines/field, and processed in 169 states. It can also be converted to a television signal compatible with the

FIG. 2 is a block diagram showing the configuration of a system conversion device in a second embodiment of the present invention. In Figure 2, l is M
Input terminal for inputting USE signal, 2 is A/D conversion circuit,
200 is a second vertical low-pass filter, 210 is a second scanning line number conversion circuit, 220 is a second still image processing circuit, 230 is a second moving image processing circuit, 240 is a second motion detection circuit, 250
is the second mixing circuit, 260 is the second TCI decoder, 270
This is a second aspect conversion circuit, which is connected in a different order from that in FIG.

The operation of the system conversion apparatus of this embodiment configured as described above will be explained below. A MUSE signal inputted from an input terminal 1 is applied to an A/D conversion circuit 2, and its output signal is supplied to a second vertical low-pass filter 200 as a wave filter composed of a plurality of line memories and an arithmetic circuit. A second vertical low-pass filter 200 removes aliasing interference of vertical high-frequency components caused by thinning out the number of scanning lines, and its output signal is sent to the second scanning line number conversion circuit 200.
0 and 1125. Converted from book to 525 books.

The output signal of the second scanning line number conversion circuit 210 is supplied to a second still image processing circuit 220, a second moving image processing circuit 230, and a second motion detection circuit 240. The second still image circuit 220 is 52
It is composed of a frame memory and a field memory of 5 lines/frame, performs interframe interpolation and interfield interpolation processing, and supplies it to one input of the second mixing circuit 250. The second moving image processing circuit 240 is constituted by a line memory, performs intra-field interpolation processing, and supplies it to the other input of the second mixing circuit 250. The second motion detection circuit 240 similarly performs differential processing between one frame and between two frames with 525 scanning lines, detects the amount of motion, and supplies it to the second mixing circuit 250.

The second mixing circuit 250 controls the mixing ratio of the output signals of the second moving image processing circuit 230 and the second still image processing circuit 220 according to the amount of movement, and controls the mixing ratio of the output signals of the second moving image processing circuit 230 and the second still image processing circuit 220, and controls the mixing ratio of the output signals of the second moving image processing circuit 230 and the second still image processing circuit 220. A standard television signal is output from an output terminal 280 via an aspect ratio conversion circuit 270.

After converting the number of scanning lines as described above, still image processing,
By performing video processing and motion detection processing, high-quality standard television signals without aliasing interference can be obtained even in the case of still images. Furthermore, since still image processing is performed with the number of scanning lines approximately halved, the capacity of the frame memory and field memory can be halved. Therefore, it is possible to reduce the circuit scale.

Effects of the Invention As described above, according to the present invention, there is provided a video processing circuit that inputs at least a band-compressed high-definition television signal and processes a video, and a still-image processing circuit that inputs the band-compressed high-definition television signal and performs still image processing. a still image processing circuit that detects a still image processing circuit; a motion detection circuit that detects a motion amount based on the interframe correlation of the band-compressed high-definition television signal; and a motion detection circuit that detects a motion amount based on the interframe correlation of the band-compressed high-definition television signal; a mixer that controls the mixing ratio of the signals from the still image processing circuit; a filter that limits the high frequency components of the vertical frequency components of the signal from this mixing circuit; In order to perform system conversion by providing a scanning line number conversion circuit that converts the number of scanning lines of the signal, or after converting the number of scanning lines of the MUSE signal, video processing, still image processing, and motion detection processing are performed. Since the mixing process is performed, it is possible to obtain a standard television signal in which the cause of image quality deterioration caused by band compression of the MUSE method is removed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a system conversion device in a first embodiment of the present invention, FIG. 2 is a block diagram showing the configuration of a system conversion device in a second embodiment of the invention, and FIG. FIG. 4 is a diagram showing the configuration of a conventional MUSE system decoder, FIG. 4 is a diagram showing the configuration of a conventional MUSE system conversion device, and FIG. 5 is an explanation of the display method when converting from the MUSE system to the NTSC system. This is a diagram. 2... A/D conversion circuit, 3... First still image processing circuit, interpolation circuit, 5... First motion detection circuit, 6... First
Mixing circuit, 101... First vertical low-pass filter (wavelength filter for vertical high-frequency components), 110... First scanning line number conversion circuit, 200... Second vertical low-pass filter (wavelength filter for vertical high-frequency components); 210... Second scanning line number conversion circuit, 220... Second still image processing circuit, 230... Second moving image processing circuit, 240... Second motion detection circuit, 25
0...Second mixing circuit. 1 kidney

Claims (1)

[Scope of Claims] A format conversion device for converting a high-definition television signal band-compressed by a sub-Nyquist sampling method that goes through one cycle in 1st and 4th fields into a standard television signal, the system converting at least a high-definition television signal band-compressed. A first video processing circuit receives the input signal and processes a video signal; a first still image processing circuit receives the band-compressed high-definition television signal and processes a still image; a first motion detection circuit that detects the amount of motion based on inter-frame correlation;
a first mixing circuit that controls a mixing ratio of output signals from the video processing circuit and the first still image processing circuit; a first filter that limits vertical high frequency components of the signal from the first mixing circuit;
A format conversion device comprising: a first scanning line number conversion circuit that converts the signal from the first filter into the number of scanning lines of a standard television signal. A format conversion device that converts a high-definition television signal band-compressed by a sub-Nyquist sampling method that goes around in 2 or 4 fields into a standard television signal, the device converting at least vertical high frequency components of the band-compressed high-definition television signal. a second filter for limiting the number of scanning lines; a second scanning line number conversion circuit for converting the signal from the second filter into the number of scanning lines of a standard television signal; a second moving image processing circuit that processes a moving image using a signal converted to the number of scanning lines; a second still image processing circuit that also receives the signal converted to the number of scanning lines and processes a still image; a second motion detection circuit that detects the amount of motion based on the motion amount based on the second motion detection circuit; A system conversion device characterized by comprising a mixing circuit.