JPH06153163A - High definition video signal processing unit - Google Patents

Abstract

PURPOSE:To realize the function of preventing picture quality deterioration when a sub sample phase differs from motion vector correction with simple circuit configuration with respect to the high definition video signal processing unit employing a memory without motion vector correction and having inter- frame interpolation processing. CONSTITUTION:Sub sample phase information of a MUSE signal is extracted by a control signal detection circuit 18 and a frame alternate detection circuit 19 detects an alternate state for each frame of a sub sampling phase. A forced motion picture setting circuit 20 sets forcibly an output of a motion detection circuit 14 so as to replace a video signal interpolated by a still picture interpolation circuit 12 implementing at least inter-frame interpolation while employing a memory without motion vector correction when not in the alternate state with a video signal interpolated by a motion picture interpolation circuit 13 implementing in-field interpolation thereby preventing malfunction of the interpolation when not in the alternate state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-definition video signal processing device for restoring a high-definition television signal band-compressed by offset subsampling.

[0002]

2. Description of the Related Art The band of high-definition television signals is 20 MH
z or more, and band transmission must be performed by some method when transmitting using a satellite or the like. MUSE (Multiple Sub-Nyquist sampling Encoding), which compresses the signal band by multiple sub-Nyquist sampling, is an effective technique for significantly compressing the band of high-definition television signals.
The system is used (Ninomiya et al., "Satellite 1-channel transmission system for high-definition television (MUSE)", Technical Report of the Television Society of Japan, TEBS 95-2, pages 37 to 42).

In this MUSE system, offset subsampling is performed between fields and frames for a still region of an image, a process of sampling phase rounding is performed in four fields, and offset is performed between lines for a moving region. The image is transmitted by performing subsampling. Furthermore, for motion at a constant speed, such as when the camera is panning, image blurring becomes noticeable when processing is performed as a moving area, so the encoder detects the motion vector of the image and Where the signal of the previous frame is used at the time of interpolation, the motion vector is corrected by interpolating between frames even if the image is moving, using the signal whose position is corrected by the magnitude of this motion vector.

Further, the MUSE system is not compatible with the NTSC system which is the current standard television signal, and an expensive dedicated signal processing circuit (MUSE) is required to restore the original image from the signal transmitted by the MUSE system. Decoder) is required. Therefore, in order to easily receive the high-definition television signal with the current television receiver, the MUSE signal is demodulated only by the processing corresponding to the moving image processing of the MUSE decoder, and the current N
Video signal converter for converting to TSC signal (MUSE-N
TSC converters have been developed (eg "MUS
E / NTSC converter ", electronic technology 1989-4).

In these devices, since the signal transmitted as a still image in order to simplify the configuration is subjected to the interpolation processing only with the signal in the same field,
In the still image portion, image quality deterioration called aliasing distortion caused by offset subsampling between fields and frames occurred.

On the other hand, in the MUSE-NTSC converter, a high-definition video signal processing device has been proposed which removes aliasing distortion and improves image quality by performing processing between frames and between fields (for example, "MUSE"). −
Development of NTSC Converter "1991 Television Society Annual Meeting ITEC'91 14-9).

FIG. 5 is a block diagram of a conventional high definition video signal processing device. In FIG. 5, 101 is M
An input terminal for inputting a USE signal, and 102 is an interpolating process for a band-compressed MUSE signal by inserting sampling points of a signal delayed by one frame period into non-sampling points decimated by inter-frame offset subsampling. Inter-frame interpolation circuit for performing, 103 and 104 are field memories,
105 is a line memory, 106 is a field interpolation circuit for interpolating non-sample points from sample points in the same field, 1
Reference numeral 07 is a motion detection circuit, 108 and 109 are adders, and 110
Is a mixer, 111 is a scanning line conversion circuit for converting the number of scanning lines of a high-definition television signal into a current standard television signal, and 112 is an output terminal for outputting a current standard television signal.

The operation of the conventional high-definition video signal processing apparatus configured as described above will be described below. First, the MUSE signal input to the input terminal 101 is processed by the interframe interpolating circuit 102 so that it is not the current signal. A sampling point of the signal delayed by one frame period is inserted into the sampling point. The state of inter-frame interpolation will be described with reference to FIG.

In FIG. 6, a thick circle mark ◯ indicates a pixel at a sampling point in each signal. Since the input MUSE signal, that is, the signal supplied to the terminal B of the inter-frame interpolation processing circuit 102 is thinned out every other pixel by the inter-frame offset sub-sampling as shown in B of FIG. The positions indicated by triangles Δ are non-sample points.

On the other hand, since the signal supplied to the terminal A is the signal interpolated between the frames one frame period delayed by the field memories 103 and 104 and the line memory 105, the pixel of A shown in FIG. It is a line. When the signal supplied to the terminal B is a non-sampling point, the interframe interpolation processing circuit 102 selects the signal supplied to the terminal A and outputs it from the terminal C. Therefore, as shown in C of FIG. 6, a signal interpolated by the current signal and the signal delayed by one frame is obtained from the terminal C.

The signal interpolated between frames is added by the adder 10
In fields 8 and 109, averaging processing is performed between fields, and interfield flicker components due to interfield offset subsampling are removed. A state of the averaging process between fields is shown in FIG. If the scanning line position of the output signal of the terminal C in FIG. 5 is the scanning line position C (n line) in FIG. 7, the scanning line positions of the points D and E in FIG. 5 are D (n-562) in FIG. Line) and E (n-563 line). Therefore adder 1
At 08 and 109, the averaging process is performed on the signals at the scanning line positions C, D and E.

The MUSE signal input to the input terminal 101 is also interpolated by the pixels in the same field by the field interpolating circuit 106. Mixer 11
At 0, the signal of the still image processing system subjected to inter-frame interpolation and field averaging and the signal of the moving image processing system subjected to field interpolation are adaptively mixed according to the motion amount detected by the motion detection circuit 107. It The scanning line conversion circuit 111 converts the high-definition television signal with 1125 scanning lines output from the mixer 110 into a current standard television signal with 525 scanning lines and outputs it from the output terminal 112.

[0013]

However, the interframe interpolating circuit for the stationary area having the above-mentioned structure is premised on that the subsample phase information is alternated for each frame when the motion vector correction is not performed. When the sub-sample phase is not alternated for each frame due to the motion vector correction under the control of the MUSE encoder side, a double image occurs due to the phase shift when the interpolation is simply performed using the signal of the preceding frame. However, there is a problem that image quality deterioration occurs.

In view of the above point, the present invention detects the alternating state of each frame of the sub-sample phase information even when a memory that does not perform motion vector correction is used in the interframe interpolation circuit, and when there is no alternation. The purpose is to prevent image quality deterioration by switching to the output signal of the field interpolation circuit.

[0015]

In order to achieve the above object, the present invention inputs a MUSE signal band-compressed by offset sub-sampling and uses a frame memory without a motion vector correction function from at least sampling points between frames. Still image interpolating means for interpolating non-sample points, moving image interpolating means for interpolating non-sample points from sample points in the field, and detecting image movement of the input signal using inter-frame correlation A motion detecting circuit, a mixer for mixing the output of the still image interpolating means and the output of the moving image interpolating means according to the detected motion, and a control signal detecting means for detecting the control signal included in the MUSE signal. , Input the sub-sampling phase information in the control signal detected by the control detecting means, and exchange the sub-sampling phase information for each frame. Frame alternation detection means for detecting the state, and means for switching the output of the still image interpolation means to the output of the moving image interpolation means by the alternation information detected by the frame alternation detection means regardless of the motion information from the motion detection circuit. It is a configuration provided with.

[0016]

According to the present invention, the still image interpolation means for interpolating a non-sample point from a sample point between frames by using a frame memory having no motion vector correction function in order to simplify the circuit structure by the above-mentioned structure. Then, when an MUSE signal with motion vector correction and irregular subsampling phase information is input, the alternating state of each frame of the subsampling phase information is detected, and when there is no alternation between frames, the motion detection circuit outputs By switching the output of the still image interpolating means to the output of the moving image interpolating means irrespective of the motion information, it is possible to prevent the image quality deterioration of the display image due to an erroneous interpolation signal.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a high quality video signal processing apparatus according to an embodiment of the present invention.

In FIG. 1, reference numeral 11 is an input terminal for inputting a MUSE signal, 12 is a still picture interpolation circuit for inter-frame interpolation using a signal delayed by one frame period, and 13 is a sampling point in the field. An interpolating circuit for moving images for interpolating sample points, a motion detecting circuit 14 for detecting whether a still image or a moving image,
Reference numeral 15 is a sub-sampling phase control circuit that controls the phase of the pixel to be interpolated, 16 is a mixer that mixes the output of the still image interpolation circuit 12 and the moving image interpolation circuit 13, and 17 is a MU.
An output terminal for extracting a high-definition video signal obtained by restoring the SE signal, a control signal detection circuit 18 for detecting a control signal included in the MUSE signal, and a sub-sampling phase 19 for inputting sub-sample phase information in the control signal. A frame alternation detection circuit that detects an alternating state of each frame of information, and 20 is a forced moving image setting circuit that forcibly sets the motion information from the motion detection circuit 14 to a moving image.

Reference numeral 21 denotes an interframe interpolating circuit for performing interpolation processing by inserting sampling points of a signal delayed by one frame period into non-sampling points decimated by inter-frame offset subsampling according to the subsampling phase. , 22,
Reference numeral 23 is a field memory.

FIG. 2 is a block diagram showing the configuration of the frame alternation detection circuit 19 in FIG. Reference numerals 31 and 32 are 1-field delay circuits, and 33 is an EX-NOR circuit.

The operation of the high-definition video signal processing apparatus of the present embodiment constructed as described above will be described with reference to FIGS.

The MUSE signal (B in FIG. 6) input to the input terminal 11 is based on the sub-sampling phase information detected by the control signal detecting circuit 18 in the still image interpolating circuit 12 as in the conventional example. In accordance with the signal for controlling the phase of the pixel to be interpolated, which is obtained by the sub-sampling phase control circuit 15, the field memory 22, at the pixel position decimated by the inter-frame offset sub-sampling,
Pixels (A in FIG. 6) of the signal before one frame period delayed by 23 are inserted in the inter-frame interpolation circuit 21 to interpolate the sampling points one frame before into the non-sampling points of the current signal (FIG. 6). C).

On the other hand, the MUSE input to the input terminal 11
The signal is interpolated from sampled pixels in the field to non-sampled pixels in the moving image interpolation circuit 13 that performs field interpolation.

The motion detection circuit 14 detects the motion of the image by the signals before and after the field memory, and outputs the still image processing signal output from the still image interpolation circuit 12 and the moving image interpolation circuit 12. A moving image processing signal that has been processed in the field is mixed by a mixer 16 in accordance with the detected amount of motion, and a restored high-quality image without deterioration of image quality such as occurrence of double images in moving images. The video signal is obtained at the output terminal 17.

However, the motion vector correction is performed on the encoder side and the sub-sampling phase information (YS
S) becomes irregular and MUS input to the input terminal 11
When the sub-sampling phase of the E signal is shifted by 180 ° (BB in FIG. 4), if the frame memory composed of the field memories 22 and 23 is an inexpensive one that does not perform motion vector correction, the signal one frame before is simply used. Pixel (AA in FIG. 4) is inserted in the inter-frame interpolation circuit 21, the sample point of the current signal is interpolated with the sample point at the same position one frame before (CC in FIG. 4). Pixels are not in a "nested" relationship with each other for each frame, and when this is repeated, the pixels at the sampling points of the output signal are always the same, resulting in deterioration of image quality such as double image.

Therefore, the sub-sampling phase information (YS) of the luminance signal detected by the control signal detecting circuit 18 is detected.
The alternating state of each frame of (S) is detected by the frame alternating detection circuit 19 shown in FIG. 2 from the polarity of one frame before and after, and as shown in FIG. 3, the frame alternating detection result is "1". When there is no frame alternation, the compulsory moving picture setting circuit 20 compulsorily converts the motion information from the motion detection circuit 14 into a moving picture, so that the mixer 16 interpolates the still image incorrectly. The output of the moving picture interpolating circuit 13 is selected instead of the output of the circuit 12.

As described above, according to this embodiment, when the motion vector correction is performed on the encoder side and the subsampling phase information (YSS) of the luminance signal becomes irregular, the frame of the subsampling phase information (YSS) is obtained. Prevents erroneous interpolation processing by detecting the alternation between the two and outputting the signal interpolated in the field for the moving image regardless of the motion information from the motion detection circuit when the alternation is not performed. You can

In this embodiment, by detecting the alternating state of the sub-sampling phase information for each frame, it is possible to prevent the malfunction of the interpolation processing due to the motion vector correction on the encoder side. Since the motion vector (horizontal, vertical) contained therein is standing, if any one of the motion vectors is standing, the forced moving image setting may be performed to prevent the malfunction of the interpolation processing.

However, in a device having a simple circuit structure such as a MUSE-NTSC converter, the sub-sampling phase information of the luminance signal can be taken out as a control signal which is not subjected to error correction with a simple structure. The control by detecting the alternating state of the sub-sample phase information for each frame as in the present embodiment can realize the prevention of the malfunction of the interpolation processing by the motion vector correction with a simpler configuration.

Further, in this embodiment, the alternating state of the sub-sampled phase information for each frame is detected, and the moving information from the motion detecting circuit is forcibly set to a moving image when there is no alternating between the frames. Although the signal from the moving picture interpolation circuit is output, a switch may be separately provided to output the signal from the moving picture interpolation circuit.

Further, the still image interpolating circuit is configured to perform only interframe interpolation, but a circuit for performing interfield calculation may be added as in the conventional example, and a conventional example is provided in the output stage. Similarly, a scanning line conversion circuit may be provided to convert to a current standard television signal, and the present invention is not limited to the embodiment.

[0032]

As described above, according to the present invention, in the high-quality video signal processing apparatus having the inter-frame interpolation function using the memory without motion vector correction, the alternating state of each sub-sampling phase is detected. Circuit to
By not interpolating between frames when there is no alternation, it is possible to prevent malfunction of interpolation processing with a simple configuration, and its practical effect is great.

[Brief description of drawings]

FIG. 1 is a block diagram of a high-definition video signal processing device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a frame alternation detection circuit for sub-sample phase information according to the same embodiment.

FIG. 3 is a timing chart for explaining the operation of the frame alternation detection circuit of the same embodiment.

FIG. 4 is a pixel configuration diagram for explaining the embodiment.

FIG. 5 is a block diagram of a conventional high-definition video signal processing device.

FIG. 6 is a block diagram of the same pixel

[Fig. 7] Same scanning line layout

[Explanation of symbols]

 11 MUSE signal input terminal 12 Still image interpolation circuit 13 Video interpolation circuit (field interpolation circuit) 14 Motion detection circuit 15 Sub-sampling phase control circuit 16 Mixer 17 High-quality video signal output terminal 18 Control signal Detection circuit 19 Alternating frame detection circuit 20 Forced video setting circuit 21 Interframe interpolation circuit 22,23 Field memory

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yoichiro Miki 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (3)

[Claims] 1. Still image interpolation means for inputting a MUSE signal band-compressed by offset sub-sampling and interpolating non-sample points from at least sample points between frames using a frame memory, and samples in a field. A moving image interpolating means for interpolating non-sampled points from the points, and a motion detection circuit for detecting the motion of the image of the input signal by using inter-frame correlation,
A mixer for mixing the output of the still image interpolation means and the output of the moving image interpolation means in accordance with the detected movement;
Control signal detection means for detecting a control signal included in the USE signal and sub-sample phase information in the control signal detected by the control detection means are input and the alternating state of each frame of the sub-sampling phase information is detected. Frame alternation detection means,
A means for switching the output of the still image interpolating means to the output of the moving image interpolating means irrespective of the motion information from the motion detecting circuit according to the alternating information detected by the frame alternation detecting means. High-quality video signal processing device. 2. The high-definition video signal processing apparatus according to claim 1, wherein the frame alternation detection means detects whether the polarities of one frame before and after one frame are the same or different in the subsampling phase information of the luminance signal. 3. The frame memory is a mere delay means having no motion vector correction function.
The described high-quality video signal processing device.