JPH06268913A - Closed caption signal receiver - Google Patents

Abstract

PURPOSE:To provide a closed caption signal receiver by which caption information is displayed without missing on a screen of a television receiver when a video image is displayed with extension by the television receiver having a zoom function. CONSTITUTION:A closed caption signal receiver decoding a caption signal superimposed on a video signal for a vertical blanking period as caption information is used for a television receiver with zoom function. The closed caption signal receiver executes compression rate setting processing when a video image of a cinema size with caption information added thereto is displayed on a picture tube 19 with magnification. In the compression rate setting processing, the compression rate to the caption information is set in response to the video display magnification and a display control circuit 15 compresses the caption information by the compression rate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in a television receiver provided with an enlarged display means for displaying an image while enlarging it on a screen, and includes a binarized signal during a vertical blanking period. The present invention relates to a closed caption signal receiving apparatus that extracts a caption signal from a video signal on which a caption signal is superimposed and decodes a binarized signal of this caption signal.

[0002]

2. Description of the Related Art There are various systems in which each information is transmitted by superimposing a binarized signal indicating information during a vertical line period of a video signal such as a television signal. , Japanese script, British Teletext (WST) extended to international specifications, and US closed captions.

For example, in the US closed caption system, a caption signal containing a binarized signal, which is caption information, is superimposed on 21 lines in a vertical blanking period of a video signal on the transmitting side, and this caption signal on the receiving side. Then, the binarized signal is extracted from the caption signal by subjecting the binarized signal to the decoding, and the binarized signal is decoded. The caption signal is added to the head of the caption signal, a clock run-in signal (CRI signal) for synchronizing the decoding of the binarized signal, and a star and bit following it.
It is composed of the following binary signal.

The caption information obtained by this decoding mainly consists of character information, and this character information is displayed on the screen in synchronization with the image.

A receiver is used for decoding the above-mentioned binarized signal, and this receiver receives a video signal on which a caption signal containing the binarized signal is superimposed during the vertical blanking period, and A caption signal is extracted from the video signal, and the binarized signal of this caption signal is decoded as caption information.

In recent years, wide screens having an aspect ratio of 6:19 have been adopted for television receivers, and accompanying this, cinema-size video software that allows a wide feeling to be enjoyed is provided.

When viewing cinema size software on a television receiver having a screen with an aspect ratio of 6:19, depending on the relationship between the size of the television receiver screen and the screen size of the software, as shown in FIG. Margins are formed above and below the screen of the television receiver, and a color close to a black level is displayed in this margin.

A television having a zoom display function which enlarges an image by changing the deflection rate and eliminates the upper and lower margins in place of the television receiver which displays the margins in a color close to a black level There is a John receiver.

However, the vertical scanning display period is 44H to 238H as the display area by the closed caption.
The horizontal scanning display period is typically 45μ.
Therefore, when enlarged display is performed, part of the caption information may be missing from the screen of the television receiver. In particular, as shown in FIG. 5, the display in the vertical direction is missing, and the display rate is about 75%.

[0010]

As described above, in the conventional closed caption signal receiving device, when the enlarged display of the image is performed on the television receiver, a part of the caption information may be lost. The caption information cannot be obtained accurately.

The present invention is a closed caption capable of displaying caption information without missing the caption information from the screen of the television receiver when the image is enlarged and displayed on the television receiver having a zoom function. An object is to provide a signal receiving device.

[0012]

The present invention is used in a television receiver provided with an enlarged display means for displaying an image on a screen while enlarging the image, and a binarized signal during a vertical blanking period. A closed caption signal receiving apparatus for extracting a caption signal from a video signal on which a caption signal including a video signal is superimposed and decoding the binarized signal of the caption signal as caption information, wherein the caption is displayed on the screen of the television receiver. A compression display unit for displaying the information while compressing it, and a compression ratio changing unit for detecting the expansion ratio of the expansion display unit and changing the compression ratio of the compression display unit according to the expansion ratio are provided.

[0013]

[Operation] In the closed caption signal receiving device of the present invention, a compression display means for displaying the caption information while compressing it is provided on the screen of the television receiver, and the enlargement ratio of the enlargement display means is detected. The compression ratio of the compression display means is changed according to the expansion ratio.

When an image is enlarged and displayed on the television receiver, the compression ratio of the compression display means is changed according to the enlargement ratio, so that the caption information is compressed by the compression means. It is displayed together with the enlarged image on the John receiver screen, and the caption information can be displayed on the screen without being lost.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a main part of a television receiver in which an embodiment of the closed caption signal receiving apparatus of the present invention is used.

As shown in FIG. 1, the television receiver having a zoom function includes a video signal demodulation circuit 11 to which a video signal is input, a synchronous deflection circuit 12 and a caption data sampling circuit 13. The video signal demodulation circuit 11
The input video signal is demodulated and output as a video signal.

The synchronous deflection circuit 12 generates a deflection drive signal for driving the deflection coil 18 of the picture tube 19 based on the input video signal, and the display synchronization for the caption information is performed based on an instruction from the microcomputer 14 described later. Vertical deflection pulses and horizontal synchronization pulses are generated, and the deflection rate of the deflection drive signal is set.

The caption data sampling circuit 13 slices the caption signal superimposed on 21 lines in the vertical blanking period of the input video signal to extract a binarized signal included in the caption signal. To do.

The binarized signal extracted by the caption data extracting circuit 13 is given to the microcomputer 14 via the bus 24. The microcomputer 14 determines whether or not the input binarized signal is data of the information channel selected by the keyboard 16, and determines whether or not to execute the decoding process for the binarized signal according to the result of the determination. To decide. Input binary signal is keyboard 1
When the data matches the data of the information channel selected in 6, the decoding process for the binarized signal is executed together with the compression rate setting process. When the input binarized signal does not match the data of the information channel selected by the keyboard 16, the decoding process and the reception quality determination process for this binarized signal are not executed.

In the decoding process, the binary signal is decoded while checking the parity, and the decoded data is transferred to the bus 24.
To the display control circuit 15 and to the synchronous deflection circuit 12 to output a vertical synchronizing pulse for display and a horizontal synchronizing pulse. The display control circuit 15 generates caption information based on the decoded data, and outputs the caption information to the signal switching circuit 17 while synchronizing the caption information with the display vertical sync pulse and horizontal sync pulse from the sync deflection circuit 12.

The signal switching circuit 17 is a video signal demodulation circuit 11
Is a switch circuit for selecting one of the video signal from the display control circuit 15 and the caption information from the display control circuit 15, and the switch circuit outputs the caption information from the video signal every time the caption information from the display control circuit 15 is input. Switch to.

The caption information output from the signal switching circuit 17 is given to the picture tube 19, and the caption information is displayed on the picture tube 19 while being superimposed on the image corresponding to the video signal. The picture tube 19 has an aspect ratio of 9 :.
It has 16 screens.

In the compression rate setting process, the deflection rate corresponding to the video display magnification rate selected by the keyboard 16 is instructed to the synchronous deflection circuit 12, and the compression rate for the display of the caption information is set according to the video display magnification rate. To do.

The synchronous deflection circuit 12 generates a deflection drive signal having a deflection rate designated by the microcomputer 14, and the deflection coil 18 is driven by this deflection drive signal.
The compression rate set by the microcomputer 14 is given to the display control circuit 15, and the display control circuit 15 compresses the caption information at the set compression rate and then outputs it to the signal switching circuit 17.

The caption data extracting circuit 13, the microcomputer 14, and the display control circuit 15 cooperate with each other to form a closed caption signal receiving device.

Next, the operation of the closed caption signal receiving apparatus will be described with reference to the drawings. 2 is a diagram showing an example of the relationship between the display area of the cinema size image and the display area of the caption information on the screen of the television receiver of FIG. 1, and FIG. 3 is used for the television receiver of FIG. It is a figure which shows the relationship between the character before reduction of the caption information by the closed caption signal receiving device, and the character after reduction.

When the caption information is displayed on the picture tube 19 together with the image, the keyboard 6 is first operated, and the predetermined channel data is set by this operation.

Next, the caption data extracting circuit 13
The binarized signal included in the caption signal is extracted by performing the slicing process on the caption signal superimposed on 21 lines in the vertical blanking period of the video signal input at.

The binarized signal extracted by the caption data extracting circuit 13 is given to the microcomputer 14 via the bus 24. It is determined whether or not the binarized signal input by the microcomputer 14 is the data of the information channel selected by the keyboard 16, and from the result of the determination, the decoding process and the reception quality determination process for the binarized signal are performed. Whether or not to execute is determined. When it is determined that the input binarized signal matches the data of the information channel selected by the keyboard 16, the decoding process for the binarized signal is executed.

In the decoding process, first, the binary signal is decoded while performing a parity check, the decoded data is given to the display control circuit 15 via the bus 24, and the vertical deflection pulse for display is supplied to the synchronous deflection circuit 12. And a horizontal sync pulse output instruction is given. Display control circuit 1
Reference numeral 5 generates caption information based on the decoded data, and this caption information is output to the signal switching circuit 17 in synchronization with the display vertical synchronizing pulse and horizontal synchronizing pulse from the synchronizing deflection circuit 12.

The signal switching circuit 17 switches from the video signal to the caption information each time the caption information from the display control circuit 15 is input, and the video signal and the caption information are alternately supplied from the signal switching circuit 17 to the picture tube 19. The caption information is displayed on the picture tube 19 while being superimposed on the image corresponding to the video signal.

When a cinema-size image to which the caption information is added is displayed on the picture tube 19, first, the image display enlargement ratio is selected by operating the keyboard 16.

Next, the microcomputer 14 performs the compression rate setting process in parallel with the decoding process. In the compression rate setting process, the deflection rate corresponding to the image display enlargement rate selected by the keyboard 16 is instructed to the synchronous deflection circuit 12,
The compression ratio for the display of the caption information is set according to the image display enlargement ratio.

In the synchronous deflection circuit 12, a deflection drive signal having a deflection rate designated by the microcomputer 14 is generated, and the deflection coil 18 is driven by this deflection drive signal. The compression rate set by the microcomputer 14 is given to the display control circuit 15, and the display control circuit 15 compresses the caption information at the set compression rate and then outputs it to the signal switching circuit 17.

The signal switching circuit 17 switches from the video signal to the caption information each time the caption information from the display control circuit 15 is input, and the signal switching circuit 17 alternately supplies the video signal and the caption information to the picture tube 19. The caption information is displayed on the picture tube 19 while being superimposed on the enlarged image.

As described above, when the image is enlarged and displayed on the picture tube 19, the compression rate for the caption information is set according to the enlargement rate. Therefore, the caption information is enlarged on the screen of the picture tube 19 while being compressed. It is displayed together with the video and can be displayed on the screen without losing the caption information.

For example, when the image display enlargement ratio is set so that the blank portion does not remain on the screen of the picture tube 19, as shown in FIG. 2, the caption display area fits within the screen of the picture tube 19 due to compression. Compressed characters are displayed in the caption display area. In this compressed character, as shown in FIG. 3B, different pixels are set in the first field and the second field of the same scanning line number. On the other hand, in the character before compression, the same pixel is set in the first field and the second field of the same scanning line, as shown in FIG.

Therefore, pixels are individually set in each of the first field and the second field of the same scanning line to achieve compression in the vertical direction. On the other hand, in the horizontal compression, the frequency of the display clock is doubled to halve the width of the display area.

[0040]

As described above, according to the closed caption signal receiving apparatus of the present invention, when the enlarged display of the image is performed on the television receiver having the zoom function, Caption information can be displayed without missing caption information.

[Brief description of drawings]

FIG. 1 is a block diagram showing a main part of a television receiver in which an embodiment of a closed caption signal receiving apparatus of the present invention is used.

FIG. 2 is a diagram showing an example of a relationship between a display area of a cinema size image and a display area of caption information on the screen of the television receiver of FIG.

FIG. 3 is a diagram showing a relationship between a character before reduction and a character after reduction of caption information by the closed caption signal receiving device used in the television receiver of FIG.

FIG. 4 is a diagram showing an example of a relationship between a display area of a cinema size image and a display area of caption information on a screen of a conventional television receiver.

FIG. 5 is a diagram showing an example of a relationship between a display area of a cinema size image and a display area of caption information on a screen of a conventional television receiver with a zoom function.

[Explanation of symbols]

 13 Caption Data Extraction Circuit 14 Microcomputer 15 Display Control Circuit 16 Keyboard 19 Picture Tube

Claims (1)

[Claims] 1. A television receiver provided with an enlarged display means for displaying an image on a screen while enlarging the image, wherein a caption signal containing a binarized signal is superimposed during a vertical blanking period. A closed caption signal receiving device that extracts a caption signal from a video signal and decodes a binarized signal of the caption signal as caption information, for displaying the caption information while compressing it on the screen of the television receiver. The closed caption signal receiving device, further comprising: a compression display means for detecting the enlargement ratio of the enlargement display means; and a compression ratio changing means for changing the compression ratio of the compression display means according to the enlargement ratio. .