JPH0458693A - Receiver for band compression television signal - Google Patents

Abstract

PURPOSE:To reduce a noise component in a color signal properly and to enhance the picture quality without giving effect on a luminance signal system by interposing a noise reduction-means to a color signal still picture processing system and/or interposing a noise coring means to a color processing moving picture processing system. CONSTITUTION:A noise reduction section 31 is made up of an adder circuit 40 adding an input signal and a signal component of one preceding frame and forming an output signal, a one-frame delay circuit 41 delaying the sum signal by one frame, and a coefficient device 42 multiplying a signal subject to one frame delay with a prescribed number of multiple and giving the result as a signal component of one preceding frame to the adder circuit 40. A noise coring section 32 consists of an LPF 50, a subtractor circuit 51, a noise coring quantity setting circuit 52, and a subtractor circuit 53 subtracting a signal extracted from the noise coring quantity setting circuit 52 from the input signal. Through the configuration above, noise reduction processing for a color signal and a luminance signal is balanced and excellent picture quality is realized.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a band compression television signal receiving device,
For example, it can be applied to a MUSE decoder.

[Prior Art] In order to transmit a high-definition television signal of about 30 MHz for one channel of current satellite broadcasting, it is necessary to compress it to about 8 MHz. MUS is one method for compressing and transmitting high-definition television signals in this way.
There is an E method.

This MUSE method uses a band compression method as exemplified below. (1) The time axis of the color signal is compressed to 1/4 and multiplexed into the horizontal blanking period of the luminance signal. (
2) In static areas of the image, use dot-increment with inter-field, inter-frame offset sampling. (, 3) In the moving region of the image, dot interlacing with line-to-line offset is used. (4) Motion compensation keeps resolution degradation to a minimum during panning and tilting.

Therefore, the MUSE decoder requires a band expansion configuration compatible with these band compression techniques, and the conventional configuration is as shown in FIG. 4.

Approximately 8 [
A television signal according to the MUSE system demodulated to a baseband (Hz) is input to the MUSE decoder 10 shown in FIG.

In the MUSE decoder 10 , only a predetermined band component of the input television signal is passed through a low-pass filter circuit 11 and then provided to an input processing section 12 .

The input processing section 12 performs analog/digital conversion, de-emphasis processing, and the like. The signal after the de-emphasis processing is applied to the audio processing section 13, where audio components are extracted and audio processing is performed. Further, the signal after the de-emphasis processing is given to the control signal generator 14, and after being synchronously separated, various control signals (
timing signal) is formed. The video component of the signal after the de-emphasis processing is provided to an interframe interpolation/noise reduction section 15 and a motion detection section 16 .

The motion detection section 16 detects the motion of the signal after the de-emphasis processing and outputs the motion detection signal to each processing section as described below.

Since the input signal is subjected to dot interlacing by interframe offset sampling, the interframe interpolation/noise reduction unit 15 uses data from one frame before for dots that are compressed using frame memory and have no data. At the same time as interpolation, noise reduction processing is also performed.

A signal that has been subjected to such interframe interpolation processing and noise reduction processing is subjected to processing specific to luminance signals and color signals, and processing specific to moving images and still images.

The Y (R degree signal) still image processing unit 17 includes, for example, a low-pass filter circuit, a purlin frequency conversion circuit, an interfield interpolation circuit, etc., and the still image area is subjected to dot interlacing by interfield offset sampling. Correspondingly, for dots with no data, interpolation processing is performed using data from one field before. Y still image processing section 17
The output signal from is given to the adaptive combining section 18.

One Y video processing unit is composed of a sub-sample switch circuit, an intra-field interpolation circuit, a noise coring circuit, etc., and after returning the data from the inter-frame interpolation/noise reduction unit 15 to original frame data, The data of several dots adjacent in the vertical and horizontal directions are interpolated using a line's worth of memory, and then noise coring processing is performed. That is, since dot interlacing is applied to the moving region of the image by interline offset, two-dimensional interpolation is performed. The output signal from the Y video processing section 19 is given to the adaptive synthesis section 18.

The adaptive synthesis section 18 is given a motion detection signal from the motion detection section 16, and the adaptive synthesis section 18 selects the internal image as a still image area from the Y still image processing section 17 at a ratio according to this motion detection signal. The inserted signal and the Y video processing unit 1
9 and the interpolated signal as a moving image region are combined, and the combined signal is provided to the output processing section 20.

The C (color signal) still image processing unit 21 includes, for example, a time axis expansion circuit and an interframe interpolation circuit, and performs interframe interpolation and
After the color signal, which has been compressed to 1/4 during the horizontal blanking period of the signal from the noise reduction unit 15, is expanded by a factor of 4 on the time axis, the data of one field before is expanded to correspond to the dot interlace for the still image area. Interpolates dots with no data. The output signal from the C still image processing section 21 is given to the adaptive synthesis section 22.

The C video processing unit 23 includes, for example, a time axis expansion circuit, a frame interpolation circuit, etc., and after expanding the color signal by four times the time axis, which has been compressed to 1/4 during the horizontal blanking period in the input signal, Corresponding to dot interlacing in a moving image area, missing data is interpolated using dot data adjacent in the vertical and horizontal directions using a built-in memory for several lines.

The output signal from the C video processing section 23 is given to the adaptive synthesis section 22.

The adaptive synthesis section 22 is given a motion detection signal from the motion detection section 16, and the adaptive synthesis section 22 interpolates the still image area from the C still image processing section 21 at a ratio according to this motion detection signal. Processed signal and C video processing unit 29
Synthesize the interpolated signal as a video region from
The combined signal is given to the output processing section 20.

The output processing unit 20 performs low-frequency replacement, temporal filter processing, etc. on the luminance signal, performs line-sequential decoding, sampling frequency conversion, etc. on the color signal, and then performs matrix processing and digital/analog conversion. etc.,
The three primary color signals are applied to the low-pass filter circuit 24.

Thus, the three primary color signals R, G, and B filtered by this low-pass filter circuit 24 are output.

[Problems to be Solved by the Invention] As described above, in the conventional device, a noise reduction processing section (see reference numeral 15) and a noise coring processing section (see reference numeral 19) are provided to eliminate noise mixed in the transmission system. This is intended to reduce the effects of noise components and noise components caused by the employed encoding method (noise components associated with aliasing). Both the noise reduction processing section and the noise coring processing section process the luminance signal and the color signal together without distinguishing them.

However, the encoding methods of the luminance signal and color signal in the television signal given to the MUSE decoder are different. That is, compared to the luminance signal encoding method, the color signal encoding method has a characteristic that the aliasing component is included close to the DC component.

In this way, although the noise components are different, conventionally, the same noise coring processing and noise reduction processing have been performed on the luminance signal and the color signal.

As a result, noise components were more noticeable in color signals than in luminance signals. For example, it appeared as uneven color.

If the amount of noise coring is increased in an attempt to solve this problem, the noise component for the color signal can be reduced, but for the luminance signal, the original component that is not a noise component is also suppressed, resulting in deterioration of image quality. It is also possible to increase the amount of noise reduction, but in this case as well, the noise component to the color signal can be reduced, but
As for the luminance signal, the original component that is not the noise component is also suppressed, resulting in deterioration of image quality.

The present invention has been made in consideration of the above points, and it is an object of the present invention to provide a band compression television signal receiving device that can perform appropriate noise reduction processing on both color signals and luminance signals. It is something.

[Means for Solving the Problems] In the first to third aspects of the present invention, the luminance signal and the color signal are each subjected to dot interlacing by inter-field and inter-frame offset sampling in the still image area, In the moving image area, the present invention relates to a receiver for a compressed band television signal that receives and demodulates a compressed band television signal that has been subjected to dot inclacing due to line-to-line offsets.

The first aspect of the present invention is characterized in that a noise reduction means for performing noise reduction processing is inserted in the color signal still image area processing system.

A second aspect of the present invention is characterized in that a noise coring means for performing noise coring processing is inserted in the color signal moving image region processing system.

The third invention includes both the features of the first and second inventions.

[Operation] The first to third aspects of the present invention have been made in consideration of the fact that noise components are more noticeable in color signals than in luminance signals.

In the first aspect of the present invention, a noise reduction means for performing noise reduction processing is provided in the color signal still image area processing system, so that noise reduction is performed on the color signal still image area more than the luminance signal. This is what I did.

In the second aspect of the present invention, a noise coring means for performing noise coring processing is provided in the color signal video region processing system, so that noise coring processing is performed on the color signal video region more than on the luminance signal. This is what I did.

The third invention is a combination invention of the first and second inventions.

[Embodiment] Hereinafter, an embodiment in which the present invention is applied to a MUSE decoder will be described in detail with reference to the drawings.

FIG. 1 shows the overall configuration of this embodiment, and the fourth
Corresponding parts to those in the figure are indicated by the same reference numerals. Second
The figure is a block diagram showing the detailed configuration of the noise reduction unit 31 newly added in this embodiment, and FIG. 3 is a block diagram showing the detailed configuration of the noise coring unit 32 newly added in this embodiment.

In FIG. 1, in the MUSE decoder 30 of this embodiment, the processing system from the input terminal to the interframe interpolation/noise reduction unit 15 is the same as the conventional one.

Furthermore, the luminance signal processing system consisting of the Y still image processing section 17, the adaptive synthesis section 18, and the Y moving image processing section 19 is also the same as the conventional one. Further, the configuration of the output processing system including the output processing section 20 and the low-pass filter circuit 24, which processes the signal from the luminance signal processing system and the signal from the chrominance signal processing system, is also the same as the conventional one.

However, the color signal processing system is different from the conventional one. That is, a noise reduction section 31 whose detailed configuration is shown in FIG. 2 is provided between the C still image processing section 21 and the adaptive synthesis section 22, and a noise reduction section 31 whose detailed configuration is shown in FIG. A noise coring section 32 whose detailed configuration is shown in FIG. 3 is provided between the two.

That is, in the case of this embodiment, noise reduction processing is performed by the interframe interpolation/noise reduction unit 15, but for the still image area of the color signal, noise reduction processing is further performed by the newly provided noise reduction unit 31. I decided to perform a reduction process. Further, a signal subjected to noise coring processing by a noise coring unit (not shown) in the Y video processing unit 19 is sent to the C video processing unit 2.
In addition, a newly provided noise coring section 32 performs noise coring processing on the moving image region of the color signal.

This is done because noise components are more noticeable in color signals than in luminance signals.

Further, the reason why the noise reduction processing is performed on the still image area is that since there is a correlation between the signals, the noise reduction effect is better than that of the noise coring processing. On the other hand, in the case of a moving image region, since the correlation is weak, it is difficult to use noise reduction processing that assumes correlation.

As the noise reduction unit 31 used in this manner, for example, a conventionally known frame cyclic type as shown in FIG. 2 can be applied.

That is, an adding circuit 40 that adds an input signal and a signal component of one frame before to produce an output signal;
A one-frame delay circuit 41 that delays a frame and a coefficient multiplier 42 that multiplies the one-frame delayed signal by a predetermined value and supplies it to the adder circuit 40 as a signal component of one frame before can be applied.

In addition to the frame cyclic type noise reduction unit 31, there are line correlation type noise reduction units, but in this embodiment, the frame cyclic type is used as described above. This is because the motion detection unit 16 may erroneously detect a moving image area as a still image area, and in this case, if a line correlation type is applied, the edges of the image will become severely distorted. be.

Further, as the newly provided noise coring section 32, a conventionally known one as shown in FIG. 3, for example, can be applied.

That is, a low-pass filter circuit 50 and a subtraction circuit 51 for extracting high-frequency components to be subjected to noise coring processing.
And noise coring amount setting times to extract those whose high frequency component level is below a predetermined value &! 52, and a subtraction circuit 53 which obtains an output signal by subtracting the signal taken out from the noise coring amount setting circuit 52 from the input signal, thereby removing frequency components of the input signal having a predetermined frequency or higher and a level lower than a predetermined value. things can be applied.

Therefore, according to the above-described embodiment, the noise reduction section 31 and the noise coring section 32 perform noise reduction processing on the color signal more than on the luminance signal.
The noise reduction processing of the color signal and the luminance signal is balanced, and good image quality can be achieved. That is, it is possible to reduce the noise component of the color signal without reducing the original component of the luminance signal so as not to cause color unevenness.

In the above-described embodiment, the noise reduction section 31 is provided after the C still image processing section 21, but it may be provided between each section within the C still image processing section 21. For example, it may be provided before the interframe interpolation circuit.

Furthermore, in the above embodiment, the noise coring section 3
2 is provided after the C video processing unit 23, but
It may also be provided between each section within the C moving image processing section 21. For example, it may be provided before the frame interpolation circuit.

Further, in the above embodiment, the present invention is applied to a MUSE decoder, but the present invention is not limited to this, and can be applied to other devices that employ a similar encoding method. can also be applied. For example, at present, standards for high-definition television signals in the United States have not been clearly defined, but when applying them to satellite broadcasting, an encoding method similar to the MUSE method is likely to be adopted. The present invention can also be applied to a reception device for compressed band television signals.

[Effects of the Invention] As described above, according to the present invention, a noise reduction means is inserted into a color signal still image processing system, and/or a noise coring means is inserted into a color signal moving image processing system. Therefore, the noise component in the color signal can be appropriately reduced without affecting the luminance signal system, and the image quality can be improved compared to the conventional method.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment in which the present invention is applied to a MUSE decoder, FIG. 2 is a block diagram showing the detailed configuration of a noise reduction section added in this embodiment, and FIG.
The figure shows details of the noise coring section added in this example.
A block diagram showing the ll1ff4 configuration, Figure 4 is a conventional MU
FIG. 2 is a block diagram showing the configuration of an SE decoder. 21...C still image processing unit, 22...Adaptive synthesis unit, 2
3...C video processing unit, 30...MUSE decoder,
31... Noise reduction section, 32... Noise coring section.

Claims (4)

[Claims] (1) In the still image area, the luminance signal and color signal are subjected to dot interlacing using inter-field and inter-frame offset sampling, and in the video area, dot interlacing is applied using inter-line offset sampling. A band compression television signal receiving device for receiving and demodulating a compressed television signal, characterized in that a noise reduction means for performing noise reduction processing is inserted in a color signal still image area processing system. Signal receiving device. (2) In the still image area, the luminance signal and color signal are subjected to dot interlacing using inter-field and inter-frame offset sampling, and in the video area, dot interlacing is applied using inter-line offset sampling. A band compression television signal receiving device for receiving and demodulating a compressed television signal, characterized in that a noise coring means for performing noise coring processing is inserted in a color signal moving image region processing system. receiving device. (3) In the still image area, the luminance signal and color signal are subjected to dot interlacing using inter-field and inter-frame offset sampling, and in the video area, dot interlacing is applied using inter-line offset sampling. In a band compression television signal receiving device that receives and demodulates a compressed television signal, a noise reduction means for performing noise reduction processing is inserted in a still image area processing system for color signals, and a moving image area processing system for color signals is provided. 1. A receiver for a compressed band television signal, characterized in that a noise coring means for performing noise coring processing is inserted therein. (4) The receiver for a compressed band television signal according to claim 1 or 3, wherein the noise reduction means is of a frame cyclic type.