JP2007221257A - Digital broadcast receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital broadcast receiver capable of obtaining optimum image quality in response to respective display states with simpler processing when an MPEG video image and a graphics video image are overlappingly displayed at reception of a data broadcast program. <P>SOLUTION: The digital broadcast receiver comprises: an MPEG decoder 4 for decoding a video component to produce the MPEG video image; a BML browser 5 for decoding a data component to produce the graphics video image and a BML document and extracting a control signal from the BML document; a video image plane overlapping section 6 for overlapping the MPEG video image and the graphics video image to produce a display video signal; and an image quality adjustment means 7 that references a size of a display region of the MPEG video image indicated by the control signal so as to much more increase a degree of noise elimination in noise elimination processing and a degree of contour emphasis in contour emphasis processing as the size of the display region is greater. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a digital broadcast receiver having a browser function and capable of receiving a data broadcast program.

In digital broadcasting, video / audio data obtained by compressing a video / audio signal of a broadcast program by a compression method such as MPEG2, additional data including program information data including a program name for each program, broadcast start / end time, and the like are transferred. The data is multiplexed and transmitted in a stream format called a port stream. In Japanese digital broadcasting, data broadcasting programs are also broadcast in addition to the usual television programs composed of the video and audio data described above. The data broadcast program is composed of text data, still image file data, and the like, and these data are also multiplexed by a transport stream and transmitted.

    The digital broadcast receiving apparatus selects video data of a desired program from a transport stream in which each of the above data is multiplexed and transmitted, and a video obtained by MPEG decoding the selected video data (hereinafter referred to as MPEG video). Display to the user.

    If the desired program is a data broadcast program, video (hereinafter referred to as graphics video) obtained by decoding text data, still image file data, etc. with a BML browser may be displayed superimposed on the MPEG video.

In order to display the above-mentioned MPEG video and graphics video with better image quality, various image quality correction techniques have been proposed.
For example, according to the proposal described in Patent Document 1, the image quality adjustment data of the video signal is transmitted from the transmission side (broadcast station) together with the video signal, and the image quality is adjusted on the reception device side according to the received image quality adjustment data. It is said that optimal image quality can be obtained.
JP2005-142887

However, in the conventional example described in Patent Document 1, although the image quality can be adjusted as intended by the transmission side, each of the images that display the MPEG video and the graphics video in an overlapping manner, such as a data broadcast program, respectively. However, there is a problem that it is difficult to perform optimal image quality adjustment. Further, there is a problem that the image quality cannot be automatically adjusted unless the image quality adjustment data is sent. Furthermore, there has been a problem that the receiving device side needs to have a receiving device capability of the image quality adjustment data and a function of adjusting the image quality according to the received image quality adjustment data.

The present invention has been made to solve the above problems.
An object of the present invention is to adjust the image quality in accordance with the size of the display area of the MPEG video when the MPEG video and the graphics video are displayed in a superimposed manner when receiving a data broadcast program. It is an object of the present invention to provide a digital broadcast receiving apparatus that can obtain the optimum image quality according to simpler processing.

Therefore, in order to solve the above problems, the present invention provides the following apparatus.
Video component that is compression-coded video data, first data component that is graphics data including still image data and / or character data, a decoded video signal obtained by decoding the video component, and the first data component A data broadcast program content including a second data component including a control signal indicating the size and display position of the display area of the decoded video signal when the decoded graphics signal is superimposed on the display means and displayed on the display means Receiving means (1,2,3) for receiving;
Decoding means (4) for decoding the video component of the received data broadcast program content and generating the decoded video signal;
Of the received data broadcast program content, the first data component is decoded to generate the graphics signal, and the second data component is decoded to generate the control signal. )When,
Video superimposing means (6) for generating a display video signal by superimposing the decoded video signal and the graphics signal based on the control signal;
Image quality adjustment means for performing image quality adjustment processing on the display video signal by at least one of noise removal processing and contour enhancement processing, and refers to the size of the display area of the decoded video signal in the control signal The image quality adjusting means (7) for reducing the degree of the image quality adjustment processing as the size of the referenced display area is increased and the display area of the graphics signal is reduced.
A digital broadcast receiver characterized by comprising:

According to the digital broadcast receiving apparatus of the present invention, when an MPEG video and a graphics video are superimposed and displayed when receiving a data broadcast program, the image quality is adjusted according to the size of the display area of the MPEG video, It is possible to obtain an optimum image quality corresponding to each display state by simpler processing.

FIG. 1 shows an example of the configuration of the digital broadcast receiving apparatus of the present invention.
NIM1 (network interface module) has a signal processing function of a transmission system such as a tuner, digital demodulation, error correction, etc., and tunes to a broadcast wave of a desired channel among broadcast waves received by the antenna 10, The digital broadcast signal is demodulated and a transport stream (hereinafter referred to as TS) is output.

  TS is a program composed of various component signals such as video component signals, audio component signals, data component signals, etc., which constitute a plurality of television programs and data broadcast programs, and the program names and broadcast start / end times of each broadcast program. The stream is composed of additional data including information data, etc., and these are streams that are time-division multiplexed in units of transport packets (hereinafter referred to as packets) of 188 bytes.

  More specifically, a video component signal and an audio component signal constituting a television program are set in an elementary stream (ES) packet, a data component signal constituting a data broadcast program is set in a carousel packet, and a PAT (Program Association Table), PSI (Program Specific Information) such as PMT (Program Map Table), and program arrangement information (SI: Service Information) such as EIT (Event Information Table) including program name and program detailed information, Set in the additional data packet. A TS is a stream obtained by time-division multiplexing each of these packets. A TS in which data obtained by MPEG compression of a video component signal or an audio component signal is set in a packet is particularly called MPEG-TS. In the following description, it is this MPEG-TS that is referred to as TS.

  In the descrambler 2, when there is a TS that has been scrambled to prevent unauthorized viewing or recording of a pay program or the like, the descrambler 2 performs a process of descrambling the TS and returning it to a normal TS.

  The demultiplexer 3 extracts PSI such as PAT and PMT included in the TS, extracts video component signals and audio component signals related to the reception target program based on the information, and supplies them to the MPEG decoder 4. When the reception target program is a data broadcast program, a related data component signal is extracted and supplied to the BML browser 5.

  The MPEG decoder 4 decodes the video component signal and the audio component signal supplied from the demultiplexer 3, and outputs the decoded video signal (hereinafter referred to as MPEG video) and the audio signal. Since the audio signal is not related to the present invention, the following description is omitted.

  The BML browser 5 decodes the BML document included in the supplied data component signal, generates a graphics video according to the contents described in the BML document, and supplies the graphics video to the video plane superimposing unit 6. The graphics video is a video including any one of a video composed only of characters, a video composed only of still images, and a video composed of characters and still images.

  Further, in the case of a data broadcast program accompanied by an MPEG video decoded by the MPEG decoder unit 4 instead of being composed only of data components, the MPEG video is displayed at any position on the display screen and in what size. In some cases, the display position / size information that indicates whether or not is described in the BML document. In this case, the display position / size information is also supplied to the video plane superimposing unit 6.

  The video plane superimposing unit 6 superimposes the graphics video supplied from the BML browser 5 and the MPEG video supplied from the MPEG decoder 4 to generate a display video signal. At this time, when the above display position / size information is supplied from the BML browser 5, the display position and size of the MPEG video are controlled according to the display position / size information.

  The image quality adjustment processing unit 7 performs appropriate enhancement processing, noise removal processing, and the like on the display video signal generated by the video plane superimposing unit 6 to adjust the image quality so that the display video is optimal.

  Conventionally, the image quality adjustment performed by the image quality adjustment processing unit 7 is fixed, but in the present embodiment, the contents of the image quality processing are determined based on the display position / size information supplied from the BML browser 5. There is a feature to change. Details of this processing will be described later.

The OSD superimposing unit 8 further superimposes a menu screen, an electronic program guide, and the like that are displayed when the user makes initial settings on the display video signal.
The video display unit 9 is a CRT, a liquid crystal display, or the like, and displays the video signal supplied from the OSD superimposing unit 8.

FIG. 2 is a flowchart of image quality adjustment content change processing according to this embodiment. The flow of processing will be described below using the flowchart of FIG. 2 and the configuration diagram of FIG.
This image quality adjustment content changing process is a process performed by the digital broadcast receiving apparatus of this embodiment after selecting and receiving a data broadcast program of a desired channel. Therefore, the flowchart shows the flow of processing after this reception operation.

  When the received data broadcast program is displayed on the video display unit 9, the BML browser 5 decodes the BML document, and if the display position / size information of the MPEG video is described in the BML document, this information is displayed. Is supplied to the video plane superimposing unit 6. In the video plane superimposing unit 6, the MPEG video supplied from the MPEG decoder 4 and the display position / size of the MPEG video supplied from the BML browser 5 are added to the character / still picture graphics video supplied from the BML browser 5. It is superimposed on a predetermined area according to the information. At the same time, the display position / size information of the MPEG video is also supplied to the image quality adjustment processing unit 7 (step S101).

  In step S102, the image quality adjustment processing unit 7 refers to the size information in the display position / size information of the MPEG video supplied in step S101, and determines to change the image quality adjustment content according to the size information. I do. For example, as shown in FIG. 3, when the size of the MPEG video display area is ½ or more of the full screen display area, the process proceeds to step S103, and as shown in FIG. In other cases (less than 1/2), the process proceeds to step S104.

A specific example of the image quality adjustment method is shown below.
Since the MPEG video generated by the MPEG decoder 4 is subjected to compression / decompression processing, specific block noise and mosquito noise are generated. Therefore, various noise removal processes such as a noise cut filter for removing these noises are performed on the MPEG video. Also, since an MPEG video is a natural image, a clear image can be obtained by performing an enhancer process that emphasizes the video contour by, for example, raising the contour edge of the image or raising the high frequency component of the image.

  On the other hand, the graphics video such as characters / still images generated by the BML browser 5 does not have the block noise and mosquito noise as in the above-mentioned MPEG video, so there is no need to perform noise removal processing. Rather, if the image is subjected to noise removal processing, the image quality often deteriorates. In addition, the graphics image is not a complex gradation expression like a natural image, and becomes an image with a relatively flat gradation expression. Therefore, the image quality often deteriorates even when enhancer processing such as processing for raising an edge or raising a high frequency component is performed.

  As described above, the display video signal output from the video plane superimposing unit 6 is an image in which MPEG video and graphics video having mutually opposite characteristics are superimposed. In this embodiment, the image having the larger image area is preferentially selected from the image areas of the two types of mutually contradictory images included in the display video signal, and the image quality adjustment suitable for the larger image is performed. It is characterized by that.

Based on the above description, the description returns to the flowchart.
In step S103, it is determined in step S102 that the MPEG video display area is larger than the graphics video display area, so image quality adjustment is performed in accordance with the MPEG video. Specifically, the noise removal processing and enhancer processing for removing the block noise and mosquito noise already described above are performed.

  In step S104, it is determined in step S102 that the MPEG video display area is smaller than the graphics video display area, so image quality adjustment is performed in accordance with the graphics video. Specifically, the noise removal processing for removing the block noise and mosquito noise already described above is not performed or the noise removal level is suppressed. Also, the enhancer process is not performed, or a process that suppresses the edge enhancement effect is performed.

In the embodiment described above, the MPEG video display area is ½ or more as an example, but this ratio may be changed depending on the contents of image quality adjustment.
In addition, although it is assumed that one of the two types of image quality adjustment patterns is switched, the image quality can be further optimized by increasing the number of patterns to be switched. Furthermore, further optimal image quality can be obtained by controlling the noise removal level of the noise removal process and the edge enhancement level of the enhancement process steplessly in accordance with the size of the MPEG video display area. In this case, the larger the MPEG video display area, that is, the smaller the graphics video display area, the greater the degree of noise removal in noise removal processing and the degree of edge enhancement in enhancement processing. Just do it.

In addition, the embodiment is an example in which the noise removal process and the enhancement process are performed at the same time, but it is possible to obtain a corresponding effect even if only one of these processes is performed.
As described above, according to this embodiment, when an MPEG video and a graphics video are displayed in an overlapped manner when a data broadcast program is received, the image quality is adjusted according to the size of the display area of the MPEG video. Thus, it is possible to obtain an optimum image quality corresponding to each display state by simpler processing.

Further, the present invention includes a program for causing a computer to realize the functions of the above-described apparatus. These programs may be read from a recording medium and loaded into a computer, or may be transmitted via a communication network and loaded into a computer.

It is a block diagram which shows one Example of this invention. It is a flowchart explaining operation | movement of one Example of this invention. It is an example of a screen with a large MPEG video display area. It is an example of a screen with a small MPEG video display area

Explanation of symbols

1 NIM
2 Descrambler
3 Demultiplexer 4 MPEG decoder 5 BML browser (signal generation means)
6 Video plane superposition unit 7 Image quality adjustment processing unit 8 OSD superposition unit 9 Video display unit 10 Antenna

Claims (1)

Video component that is compression-encoded video data, first data component that is graphics data including still image data and / or character data, a decoded video signal obtained by decoding the video component, and the first data component A data broadcast program content including a second data component including a control signal indicating the size and display position of the display area of the decoded video signal when the decoded graphics signal is superimposed on the display means and displayed on the display means Receiving means (1,2,3) for receiving;
Decoding means (4) for decoding the video component of the received data broadcast program content and generating the decoded video signal;
Of the received data broadcast program content, the first data component is decoded to generate the graphics signal, and the second data component is decoded to generate the control signal (5) )When,
Video superimposing means (6) for generating a display video signal by superimposing the decoded video signal and the graphics signal based on the control signal;
Image quality adjusting means for performing image quality adjustment processing on the display video signal by at least one of noise removal processing and contour enhancement processing, and refers to the size of the display area of the decoded video signal in the control signal The image quality adjusting means (7) for reducing the degree of the image quality adjustment processing as the size of the referred display area is increased and the display area of the graphics signal is reduced.
A digital broadcast receiver characterized by comprising:

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