KR100499454B1 - Appratus for detecting caption data - Google Patents

Abstract

The caption data extracting apparatus is configured to generate a section signal for each section when a real eye signal of caption / KBP data is input, and outputs a section signal for each section, and a maximum value of the video signal input for each section determined by the section generator. A maximum comparator for determining a minimum value, a minimum comparator for determining a minimum value of a video signal input for each section determined by the interval generator, and a maximum comparator and a minimum value comparator each time a interval signal is input from the interval generator. Built-in caption or KBPS decoder consists of a storage unit for arithmetically averaging the highest and lowest output values in order, and a slice level determination unit that receives the interval slice levels stored in the storage unit to determine the final slice level. Apply the level of caption / KBPS data to one TV, VCR, STB, etc. To improve the performance of the data slicer, which has the effect that can operate more reliably.

Description

Caption data extraction device {Appratus for detecting Caption Data}

The present invention relates to a receiving apparatus for receiving a digital video signal, and more particularly, to a caption data extraction apparatus for extracting KBPS (Korea Broadcasting Program System) / caption data of a KBPS decoder.

The caption data is originated in the United States. When caption data is broadcast or a video tape is produced by inserting caption data in a VBI (Vertical Blanking Interval) section of the video signal, the caption decoder extracts the content and displays the contents on the screen.

The caption data is mainly information on the contents of the dialogue, weather, broadcast order, etc. currently being performed on the screen, and is particularly used for visually impaired people or learning foreign languages.

Caption specifications in the United States are set by the Federal Communications Commission (FCC), which mandates the inclusion of caption decoders in 13-inch and larger television sets that are traded, manufactured, and assembled in the United States.

In Korea, the transmission method, structure, and packet of caption data are prescribed by the Ministry of Information and Communication No. 1996-100.

KBPS inserts KBPS data into the VBI section of NTSC video signal and transmits it. The KBPS decoder extracts the information and displays the information on the screen. It contains detailed program information, classification information and cancellation program information.

The caption and the KBPS data differ only in the content of the inserted line and the inserted data, but the format of the signal itself has the same format as shown in FIG. 1.

The caption / KBPS data is divided into clock run-in (CRI), start bits, and details of data as shown in FIG.

A data slicer for extracting data from a general caption / KBPS data decoder includes a clock recovery unit 21, a slice level determination unit 22, and a data sampling unit 23 as shown in FIG.

The CRI portion of the caption / KBPS data consists of seven 503 sine waves of 503 kHz, and the phase of the CRI coincides with the point of signal transition in the data portion, i.e. from 0 to 1 or from 1 to 0.

The clock recovery section 21 extracts the 503 kHz component from the CRI section and uses the clock as the clock for the data sampling section 23 to extract data from the data section.

In addition, the slice level determination unit 22 determines the slice level in the CRI portion of the caption / KBPS data and outputs the slice level to the data sampling unit 23.

The data sampling unit 23 samples the data portion of the caption / KBPS data by using the clock extracted from the clock recovery unit 21. This sampled data is a value in which each bit is 0 or 1 compared with the slice level determined by the slice level determination section 22.

Here, there are two methods for determining the slice level of the slice level determiner 22, one of which uses a fixed slice level provided from the outside without a slice level determining function as shown in FIG.

In addition, another slice level determination method detects the highest value (A) and the lowest value (B) of the video signal in the CRI portion, and determines the arithmetic mean value (S = (A + B) / 2) of the highest value and the lowest value. Will output

Such a slice level determination method according to the related art has no problem with normal caption / KBPS data, but when a portion of the CRI is distorted or the video signal is severely distorted, the slice level cannot be properly determined to determine the value of each bit of data sampling. Because of this problem, the performance of the caption / KBPS decoder is degraded.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art, and an object thereof is to provide an apparatus for extracting caption data for accurate slice level determination.

A feature of the caption data extraction apparatus according to the present invention for achieving the above object is to divide the CRI interval into several smaller intervals in the video signal, obtain slice levels in each interval, and average the slice levels in each interval again to obtain the final slice. In determining the level.

The caption data extraction apparatus according to the present invention having the above characteristics will be described with reference to the accompanying drawings.

5 is a block diagram illustrating a configuration of an apparatus for extracting caption data of a KBPS decoder according to an embodiment of the present invention.

First, the caption data extraction apparatus of the KBPS decoder according to an embodiment divides the CRI into N sections from the moment when the CRI section display signal of the caption / KBPS data is input as shown in FIG. The interval generator 51 for outputting the maximum value, the highest value comparator 52 for determining the maximum value of the video signal input for each interval determined by the interval generator 51, and the interval generated by the interval generator 51. It consists of a minimum value comparator 53 for determining the minimum value of the video signal, and a first interval storage unit to an Nth interval storage units 541, 542, and 543, each time the interval end signal is input from the interval generator 51. A storage unit 54 and a storage unit 54 arithmetically averaging the highest and lowest values output from the comparison unit 52 and the lowest value comparison unit 53 and sequentially storing them in the section storage units 541, 542, and 543. The first section storage unit to the Nth section storage units 541, 542, and 543 of the The slice level determination unit 55 receives the stored section slice level and determines the final slice level.

Referring to the operation of the caption data extraction apparatus of the KBPS decoder according to an embodiment of the present invention configured as described above, first, the section generator 51 is a caption / KBPS to the current video signal from an external timing circuit (not shown) From the moment of receiving the CRI display signal indicating the CRI part of the data, the CRI part is divided into N sections and the section end signal DIV_END is output for each section.

And, the highest value comparator 52 is initialized to the lowest value of the video signal whenever the interval end signal outputted from the interval generator 51 is input, and compares the highest value with the video signal in the next interval. Update again

The minimum value comparator 53 is initialized to the highest value that the video signal can have whenever the interval end signal output from the interval generator 51 is input, and renews the minimum value again by comparing the video signal with its lowest value in the next interval. do.

Each time the section end signal is input from the section generator 51, the storage unit 54 calculates an arithmetic mean of the highest and lowest values stored in the highest value comparator 52 and the lowest value comparator 53, and stores each interval. Store in wealth.

When the interval generation unit 51 divides the CRI portion of the caption / KBPS data into N intervals, there are N interval storage units 541, 542, and 543 of the storage unit 54.

The data of each section storage unit 541, 542, 543 moves to the right whenever the section ending signal is input.

Therefore, the arithmetic mean determination values of the highest value and the lowest value exist only in the first interval storage unit 541, and the other interval storage units 542 and 543 store interval slice levels moving from the left side.

The slice level determiner 55 determines the final slice level of the caption / KBPS data by adding interval slice levels stored in the N interval storage units 421, 542, and 543 and dividing by N.

If the CRI portion is divided into seven sections, slice levels S1 = (A1 + B1) / 2, S2 = (A2 + B2) / 2,... , S7 = (A7 + B7) / 2, and the final slice level is (S1 + S2 + S3 + S4 + S5 + S6 + S7) / 7.

In addition, FIG. 7 is a block diagram illustrating a configuration of an apparatus for extracting caption data of a KBPS decoder according to another embodiment of the present invention. In another embodiment according to the present invention, the section generator 51 may include the same as in FIG. The slice level is determined by dividing the CRI part into several sections, but the slice level in each section is calculated using the CRI accumulator 71 to add all the video signals in each section to calculate the average value of the video signal. Then use it as slice level in each section.

That is, the CRI accumulator 71 samples the video signal N times in each interval, and then adds each of the sampling data, and then the first interval storage unit 541 stores the value accumulated in the CRI accumulator 71. Divide by N to determine the slice level of each section.

When determining the final slice level of the slice level determination unit 55 of FIG. 5 or 7, the final slice level may be determined without ignoring all the slice levels in each section and ignoring the section slice level with high error probability.

For example, when the section generator 51 divides the CRI part into seven sections, the final slice level is determined using only the section slice level in five sections except the highest value and the lowest value among the seven section slice levels.

The caption data extraction apparatus of the KBPS decoder according to the present invention improves the performance of the data slicer which extracts the correct caption / KBPS data level from the distorted CRI signal by applying the caption or the TV, VCR, STB, etc. with the built-in KBPS decoder. It can work stably.

1 illustrates a signal format of general caption data.

2 is a block diagram for explaining the configuration of a caption data extraction apparatus of a general KBPS decoder;

3 is a view for explaining a slice level determination method according to an embodiment according to the prior art;

4 is a view for explaining a slice level determination method according to another embodiment according to the prior art;

5 is a block diagram illustrating a configuration of an apparatus for extracting caption data of a KBPS decoder according to an embodiment of the present invention.

FIG. 6 is a diagram illustrating slice determination when a section generator of FIG. 5 divides a section into seven parts. FIG.

7 is a block diagram illustrating a configuration of an apparatus for extracting caption data of a KBPS decoder according to another embodiment of the present invention.

Explanation of symbols for main parts of the drawings

51: interval generator 52: the highest value comparison unit

53: minimum value comparison unit 54: storage unit

55: slice level determiner 71: CRI accumulator

Claims (4)

A section generator for dividing the CRI portion into a plurality of sections and outputting a section signal for each section when a real eye indication signal of caption / KBP data is input; A maximum value comparator configured to determine a maximum value of the input video signal for each of the divided sections; A minimum value comparator configured to determine a minimum value of the input video signal for each of the divided sections; A storage unit for calculating slice levels of a corresponding section by arithmetically averaging the highest value and the lowest value output from the highest value comparator and the lowest value comparator each time the interval signal is input from the interval generator; And a slice level determination unit configured to receive a slice level of each section stored in the storage unit and perform arithmetic averaging to determine a final slice level. The method of claim 1, wherein the storage unit Caption data extracting apparatus comprising a section storage unit having the same number of sections divided by the section generator to store slice levels of the section. The method of claim 1, wherein the slice level determiner Caption data extraction apparatus, characterized in that the final slice level is determined by arithmetic average of the remaining slice levels except the highest value and the lowest value among the slice level for each section stored in the storage. A section generator for dividing the CRI portion into a plurality of sections and outputting a section signal for each section when a real eye indication signal of caption / KBP data is input; A CRI accumulator for sampling the video signal input for each section divided by the section generator and adding all the sampling data; A storage unit for dividing a value accumulated in the CRI accumulator by N every time an interval signal is input from the interval generator to obtain slice levels of the interval, and storing the slice levels in order; And a slice level determination unit configured to receive a slice level of each section stored in the storage unit and perform arithmetic averaging to determine a final slice level.

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