Closed-caption broadcasting and receiving method and apparatus thereof suitable for syllable characters

• US 6,256,072 B1
• Filed: 05/05/1997
• Issued: 07/03/2001
• Est. Priority Date: 05/03/1996
• Status: Expired due to Term

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Sang-Jin, Han, Sang-Rok, Yang, Jin-Hwa, Bae, Jum-Han
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): Lo, Linus H.
• Application Number:
  US08/851,077
• Time in Patent Office: 1,520 Days
• Field of Search: H04/N.708, H04/N.7084, H04/N.7087, 348/461, 348/465, 348/466, 348/468, 348/473, 348/474, 348/476, 348/477, 348/478, 348/479, 348/568
• US Class Current: 348/568
• CPC Class Codes: G09G 5/24 Generation of individual character patterns
• CPC Class Codes: G09G 5/30 Control of display attribute
• CPC Class Codes: H04N 21/4884 for displaying subtitles
• CPC Class Codes: H04N 5/44504 Circuit details of the additional information generator, e.g. details of the character or graphics signal generator, overlay mixing circuits
• CPC Class Codes: H04N 7/0357 for error detection or correction
• CPC Class Codes: H04N 7/0882 for the transmission of character code signals, e.g. for teletext circuits for the digital non-picture data signal H04N7/035
• CPC Class Codes: H04N 7/0885 for the transmission of subtitles

Abstract

A closed-caption broadcasting and receiving method and apparatus. According to the closed-caption broadcasting method and apparatus, additional information is inputted and the input of word information is checked. If the word information is inputted, it is selected, while if not, the additional information is selected. Thereafter, character information and control information of the selected information are inputted. A control code of 2 words is obtained by combining the control information with a mode control bit and a parity bit, and the character code of 2 words including a syllable character completion type code is obtained by combining the character information with a mode control bit and a parity bit. A digital-modulated caption signal is produced by inputting the control code and the character code, and is coded in a scanning line which does not affect a television video signal to be transmitted.

Claims

1. A closed-caption broadcasting method for a television image signal comprising the steps of:

receiving additional information unrelated to a video portion of said television signal;

checking whether word information related to a video portion of said television image signal has been received;

selecting said word information if said word information has been received, and selecting said additional information if said word information has not been received;

generating character information and control information from said selected information;

producing a control code of two words by combining said control information with a first mode control bit and a first parity bit, and a character code of two words including a syllable character completion type code by combining said character information with a second mode control bit and a second parity bit;

digitally-modulating said control code and said character code to generate a digital-modulated caption signal; and

coding said caption signal in at least one line of said television image signal which does not affect said television image signal to transmit said caption signal.

2. A closed-caption broadcasting method as claimed in claim 1, wherein each of said 2 words of each of said character and control codes is composed of 9 bits.

3. A closed-caption broadcasting method as claimed in claim 1, wherein said syllable character completion type code is a Hangul completion type KSC 5601 code.

4. A closed-caption broadcasting method as claimed in claim 1, wherein said at least one scanning line which does not affect said television image signal is one of a 262nd line of an odd field and a 525th line of an even field of said television image signal.

5. A closed-caption broadcasting method as claimed in claim 1, wherein said caption signal comprises:

a bit clock sync signal which is a first sine wave of a predetermined period, and has a frequency obtained by dividing a chrominance subcarrier of said television image signal at a predetermined rate;

a word start signal which is a second sine wave of one period, and has a frequency obtained by dividing said bit clock sync signal at a predetermined rate; and

an 18-bit data signal, being said control code or said character code, and modulated to a third sine wave having a frequency lower than said frequency of said bit clock sync signal and higher than said frequency of said word start signal.

6. A closed-caption broadcasting method as claimed in claim 5, wherein said data signal is modulated by a binary phase shift keying (BPSK) method.

7. A closed-caption broadcasting method as claimed in claim 5, wherein said frequency of said bit clock sync signal is obtained by dividing said frequency of said chrominance subcarrier by 4.

8. A closed-caption broadcasting method as claimed in claim 5, wherein said word start signal is obtained by dividing said frequency of said bit clock sync signal by 4.

9. A closed-caption broadcasting method as claimed in claim 5, wherein said sine wave frequency of said data signal is obtained by dividing said frequency of said bit clock sync signal by 2.

10. A closed-caption broadcasting method as claimed in claim 1, wherein said additional information is periodically transmitted by a predetermined amount.

11. A closed-caption broadcasting method as claimed in claim 10, wherein said additional information includes information on contents of said additional information.

12. A closed-caption broadcasting method as claimed in claim 11, wherein said contents information includes icon information representing characteristics of each contents information.

13. A closed-caption broadcast receiving method comprising the steps of:

detecting horizontal and vertical sync signals of a received television signal;

extracting a caption signal encoded in a last scanning line of said television signal by counting said horizontal sync signal in response to said detected vertical sync signal;

restoring digital data from said extracted caption signal;

detecting an error of said restored data;

decoding a control code and a character code of said restored data and discriminating whether said character code corresponds to additional or word information, wherein said additional information is unrelated to a video portion of said television signal and said word information is related to said video portion of said television signal;

receiving a command indicative of a caption word mode to display said word information or additional information mode to display said additional information;

storing said character code in an additional information memory if said character code corresponds to said additional information, while storing said character code in a word information memory if said character code corresponds to said word information;

pre-storing character data in a font ROM (read only memory), wherein said character data is based on a syllable character completion type code;

reading out said character code from said corresponding additional information or word information memory in response to selection of said caption word/additional information mode and reading out said character data from said font ROM by addressing said font ROM according to said read-out character code, and in response, storing said read-out character data in a display memory; and

converting said character data stored in said display memory into a video signal to display said video signal on a display screen in accordance with said control code.

14. A closed-caption broadcast receiving method as claimed in claim 13, further comprising the step of displaying said additional information on said screen, page by page.

15. A closed-caption broadcast receiving method as claimed in claim 14, further comprising the step of displaying a page of contents of said additional information on said screen in response to said additional information mode being selected.

16. A closed-caption broadcast receiving method as claimed in claim 15, further comprising icon-displaying on said screen whether additional information is received in response to said word information mode being selected.

19. A closed-caption broadcast receiving method as claimed in claim 13, further comprising the step of reading out said character data stored in said display memory frame by frame if said read out character data stored in said display memory is said additional information.

20. A closed-caption broadcast receiving method as claimed in claim 13, further comprising the steps of:

reading out said character data stored in said display memory frame by frame if said read out character data stored in said display memory is said additional information;

displaying said readout character data from said display memory frame by frame; and

erasing said displayed readout character data after a predetermined amount of time if further character data is not read out from said display memory.

21. A closed-caption broadcast receiving method as claimed in claim 13, further comprising the steps of:

reading out said character data stored in said display memory frame by frame if said read out character data stored in said display memory is said additional information;

displaying said readout character data from said display memory a page at a time;

receiving a designation from a user to hold a present display of said displayed character data, and holding a present page of said displayed character data on display; and

storing a next page of said read out character data from said display memory in a buffer while said present page of said displayed character data is held on display.

22. A closed-caption broadcast receiving method as claimed in claim 21, further comprising the step of automatically releasing the holding state of said present page of said displayed character data after a predetermined amount of time from a start of said holding of said present page of said displayed character data.

23. A closed-caption broadcast receiving method as claimed in claim 21, further comprising the step of performing an iconoscope display to indicate the holding state of said present page of said displayed character data after a predetermined amount of time from a start of said holding of said present page of said displayed character data.

28. A closed-caption broadcast receiving apparatus as claimed in claim 21, wherein said caption processing means performs an iconoscope display to indicate the holding state of said present page of said displayed character information after a predetermined amount of time from a start of said holding of said present page of said displayed character information.

17. A closed-caption broadcasting apparatus for superimposing closed-caption information in a video signal and modulating an audio signal and said video signal to a television signal to transmit in the air a modulated television signal as a high frequency signal, said apparatus comprising:

word information input means for inputting word information related to a television scene;

additional information input means for inputting additional information unrelated to said television scene;

word information detecting means for detecting whether said word information has been inputted;

switching means for selecting one of said word information and said additional information in response to a detected signal of said word information detecting means;

character information input means for transmitting said word information or said additional information selected by said switching means as a 2-byte syllable character completion type code;

control information input means for inputting 7-bit control information for reception control of said closed-caption information of a closed-caption broadcast;

character code generating means for generating a data packet of an 18-bit character code by using an MSB (most significant bit) of each byte of said 2-byte syllable character completion type code as a caption word/additional information flag, replacing said MSB by a predetermined value in case of said additional information, and adding a parity bit to each byte;

control code generating means for generating a data packet of an 18-bit control code by dividing said 7-bit control information into upper 4 bits and lower 3 bits, creating an upper byte by adding to said upper 4 bits a first parity bit, first control code discriminating bits of 2 bits, and a first word/addition flag, creating a lower byte by adding to said lower 3 bits a second parity bit, a third parity bit, second control code discriminating bits of 2 bits, and a second caption word/additional information flag, and adding an additional parity bit to each of said created word bytes;

data packet modulating means for modulating said data packet generated by said character code generating means or said control code generating means by digital modulation to produce a caption signal;

synchronous counter means for receiving horizontal and vertical sync signals of said video signal and counting said horizontal sync signal, said synchronous counter means being reset by said vertical sync signal;

window signal generating means for receiving a counted value of the synchronous counter means and generating a window signal for selecting a predetermined line of each field of said video signal; and

switching means for selectively enabling transmission of said video signal and said caption signal in response to said window signal, to superimpose said caption signal in said video signal.

18. A closed-caption broadcast receiving apparatus for extracting a caption signal having data from a received composite video signal and decoding said extracted caption signal, said apparatus comprising:

a data extractor for extracting said caption signal from said composite video signal;

a sync separator for separating a sync signal from said composite video signal to produce vertical and horizontal sync signals;

a font ROM for storing character information corresponding to a syllable character completion type code;

a word information memory;

an additional information memory; and

caption processing means for analyzing said data of said caption signal extracted by said data extractor and detecting an existence of an error in said extracted data, said caption processing means detecting whether said extracted data is a character code for caption words related to a video portion of said composite video signal or a character code for additional information unrelated to the video portion of said composite video signal if said extracted data is identified as a syllable character completion type character code as a result of said data analysis, and storing in said word information memory said character code if said character code is for said caption words, and storing in said additional information memory said character code if said character code is for said additional information, said caption processing means reading out said character information from said font ROM, which is addressed by a value read out from said corresponding word information or additional information memory, as a new composite video signal.

24. A closed-caption broadcast receiving apparatus as claimed in claim 18, further comprising a display memory to store said read out character information from said font ROM, wherein said caption processing means reads out said read out character information stored in said display memory frame by frame if said read out character information stored in said display memory is said additional information.

25. A closed-caption broadcast receiving apparatus as claimed in claim 18, further comprising:

a display memory to store said read out character information from said font ROM, wherein said caption processing means reads out said readout character information stored in said display memory frame by frame if said read out character information stored in said display memory is said additional information; and

a display to display said readout character information from said display memory frame by frame;

wherein said caption processing means erases said displayed readout character information after a predetermined amount of time if further character information is not read out from said display memory.

26. A closed-caption broadcast receiving apparatus as claimed in claim 18, further comprising:

a display memory to store said read out character information from said font ROM, wherein said caption processing means reads out said readout character information stored in said display memory frame by frame if said read out character information stored in said display memory is said additional information; and

a display to display said readout character information from said display memory frame by frame;

an input unit to receive a designation from a user to hold a present display of said displayed character information, wherein said caption processing means holds a present page of said displayed character data on display in response to said designation; and

a buffer to store a next page of said read out character information from said display memory while said present page of said displayed character information is held on display.

27. A closed-caption broadcast receiving apparatus as claimed in claim 26, wherein said caption processing means automatically releases the holding state of said present page of said displayed character information after a predetermined amount of time from a start of said holding of said present page of said displayed character information.

29. A closed-caption broadcasting method for a television image signal comprising the steps of:

receiving additional information unrelated to a video portion of said television signal;

checking whether word information related to a video portion of said television image signal has been received;

selecting said word information if said word information has been received, and selecting said additional information if said word information has not been received;

generating character information and control information from said selected information;

producing a control code of two words by combining said control information with a first mode control bit and a first parity bit, and a character code of two words including a syllable character completion type code by combining said character information with a second mode control bit and a second parity bit;

digitally-modulating said control code and said character code to generate a digital-modulated caption signal;

coding said caption signal in at least one line of said television image signal which does not affect said television image signal to transmit said caption signal;

receiving said television image signal, and detecting horizontal and vertical sync signals of said received television image signal;

extracting a caption signal encoded in a last scanning line of said received television image signal by counting said horizontal sync signal in response to said detected vertical sync signal;

restoring digital data from said extracted caption signal;

detecting an error of said restored data;

decoding said control code and said character code of said restored data and discriminating whether said character code corresponds to said additional or word information;

receiving a command indicative of a caption word mode to display said word information or additional information mode to display said additional information;

storing said character code in an additional information memory if said character code corresponds to said additional information, while storing said character code in a word information memory if said character code corresponds to said word information;

pre-storing character data in a font ROM (read only memory), wherein said character data is based on said syllable character completion type code;

reading out said character code from said corresponding additional information or word information memory in response to selection of said caption word/additional information mode and reading out said character data from said font ROM by addressing said font ROM according to said read-out character code, and in response, storing said read-out character data in a display memory; and

converting said character data stored in said display memory into a video signal to display said video signal on a display screen in accordance with said decoded control code.

30. A closed-caption broadcasting apparatus for superimposing closed-caption information in a video signal and modulating an audio signal and said video signal to a television signal to transmit in the air a modulated television signal as a high frequency signal, said apparatus comprising:

word information input means for inputting word information related to a television scene;

additional information input means for inputting additional information unrelated to said television scene;

word information detecting means for detecting whether said word information has been inputted;

switching means for selecting one of said word information and said additional information in response to a detected signal of said word information detecting means;

character information input means for transmitting said word information or said additional information selected by said switching means as a 2-byte syllable character completion type code;

control information input means for inputting 7-bit control information for reception control of said closed-caption information of a closed-caption broadcast;

character code generating means for generating a data packet of an 18-bit character code by using an MSB (most significant bit) of each byte of said 2-byte syllable character completion type code as a caption word/additional information flag, replacing said MSB by a predetermined value in case of said additional information, and adding a parity bit to each byte;

control code generating means for generating a data packet of an 18-bit control code by dividing said 7-bit control information into upper 4 bits and lower 3 bits, creating an upper byte by adding to said upper 4 bits a first parity bit, first control code discriminating bits of 2 bits, and a first word/addition flag, creating a lower byte by adding to said lower 3 bits a second parity bit, a third parity bit, second control code discriminating bits of 2 bits, and a second caption word/additional information flag, and adding an additional parity bit to each of said created word bytes;

data packet modulating means for modulating said data packet generated by said character code generating means or said control code generating means by digital modulation to produce a caption signal;

synchronous counter means for receiving horizontal and vertical sync signals of said video signal and counting said horizontal sync signal, said synchronous counter means being reset by said vertical sync signal;

window signal generating means for receiving a counted value of the synchronous counter means and generating a window signal for selecting a predetermined line of each field of said video signal;

switching means for selectively enabling transmission of said video signal and said caption signal in response to said window signal, to superimpose said caption signal in said video signal;

a receiver for receiving said video signal superimposed with said caption signal;

a data extractor, connected to said receiver, for extracting said caption signal from said video signal;

a sync separator for separating a sync signal from said video signal to produce vertical and horizontal sync signals;

a font ROM for storing character information corresponding to said syllable character completion type code;

a word information memory;

an additional information memory; and

caption processing means for analyzing said data of said caption signal extracted by said data extractor and detecting an existence of an error in said extracted data, said caption processing means detecting whether said extracted data is a character code for caption words related to a video portion of said composite video signal or a character code for additional information unrelated to the video portion of said composite video signal if said extracted data is identified as said syllable character completion type character code as a result of said data analysis, and storing in said word information memory said character code if said character code is for said caption words, and storing in said additional information memory said character code if said character code is for said additional information, said caption processing means reading out said character information from said font ROM, which is addressed by a value read out from said corresponding word information or additional information memory, as a new video signal.