Communication processing system with multiple data layers for digital television broadcasting

• US 6,026,164 A
• Filed: 08/27/1996
• Issued: 02/15/2000
• Est. Priority Date: 12/27/1994
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Shibaoka, Shuuichi, Hirota, Atsushi, Sakamoto, Noriya
• Primary Examiner(s): Barron, Jr., Gilberto
• Application Number:
  US08/702,607
• Time in Patent Office: 1,267 Days
• Field of Search: 380/10, 380/20, 348/385
• US Class Current: 380/217
• CPC Class Codes: H04N 19/30 using hierarchical techniques, e.g. scalability H04N19/63 takes precedence
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 21/234327 by decomposing into layers, e.g. base layer and one or more enhancement layers
• CPC Class Codes: H04N 21/23897 by partially encrypting, e.g. encrypting only the ending portion of a movie
• CPC Class Codes: H04N 21/43856 by partial decryption, e.g. decrypting a multiplex stream that has been partially encrypted
• CPC Class Codes: H04N 21/631 Multimode Transmission, e.g. transmitting basic layers and enhancement layers of the content over different transmission paths or transmitting with different error corrections, different keys or with different transmission protocols
• CPC Class Codes: H04N 7/1675 Providing digital key or authorisation information for generation or regeneration of the scrambling sequence pseudo-random number generators in general G06F7/58

Abstract

Video signals are encrypted so that only the privileged viewers can watch them. A layer coding unit divides video signals into two layers and encodes each layer. An encrypting unit encrypts the low-quality layer data items according to the setting signal from a secret level setting unit and supplies the encrypted signal to a combining unit. Another encrypting unit encrypts the high-quality layer data items according to the setting signal from a secret level setting unit and supplies the encrypted signal to the combining unit. Ideally the high-quality layer data items are encrypted at a secret level that is higher than the secret level used to encrypt the low-quality layer data items. The synthesized data from the combining unit is converted at a communication modem into communication data, which is transmitted to a reception apparatus.

Claims

1. A transmission apparatus comprising:

layer coding means for converting an image signal into a frequency domain signal by discrete cosine transform (DCT), dividing the frequency domain signal into m (m is an integer not less than

     2) layers in terms of frequency to generate m layer signals, and coding each of the layer signals;

encrypting means provided in correspondence to each of (m-1) layer signals of the layer signals obtained by the layer coding means in a frequency domain except for the lowest layer signal, for encrypting the (m-1) layer signals; and

multiplexing means for multiplexing the lowest layer signal in the frequency domain and the (m-1) layer signals encrypted by the corresponding encrypting means and outputting a resultant signal as a transmission signal.

2. A reception apparatus comprising:

separating means that receives a signal that is generated by converting an image signal into a frequency domain signal by discrete cosine transform (DCT), dividing the frequency domain signal into m (m is an integer not less than

     2) layers in terms of frequency to generate m layer signals, coding each of the layer signals, encrypting (m-1) layer signals obtained by the layer coding means excluding the lowest layer signal in a frequency domain and multiplexing the lowest layer signal and the (m-1) layer signals encrypted by the encrypting means, said separating means being used for separating the received signal into the lowest layer signal in the frequency domain and the encrypted (m-1) layer signals;

decrypting means provided in correspondence to each of the encrypted (m-1) layer signals for decrypting an encrypted layer signal that is separated from the lowest layer signal by the separating means;

layer decoding means provided in correspondence to each of the m layer signals for decoding each of the (m-1) layer signals decrypted by the corresponding decrypting means and the lowest layer signal separated by the separating means; and

inverse discrete cosine transforming means for selecting layer signals corresponding in number to a designated resolution from among the lowest layer signal and the (m-1) layer signals in higher layers, all individually decoded by the corresponding layer decoding means, the layer signals being selected from the frequency domain in ascending order starting from the lowest layer signal, and said inverse discrete cosine transforming means being further used for combining the selected layer signals and inverse discrete cosine transforming a resultant signal to generate an image signal which realizes the designated resolution.

3. A communication processing system comprising:

a transmission apparatus; and

a reception apparatus,

said transmission apparatus having;

layer coding means for converting an image signal into a frequency domain signal by discrete cosine transform (DCT), dividing the frequency domain signal into m (m is an integer not less than

     2) layers in terms of frequency to generate m layer signals, and coding each of the layer signals;

encrypting means provided in correspondence to each of (m-1) layer signals of the layer signals obtained by the layer coding means in a frequency domain except for the lowest layer signal, for encrypting the (m-1) layer signals; and

multiplexing means for multiplexing the lowest layer signal in the frequency domain and the (m-1) layer signals encrypted by the corresponding encrypting means and outputting a resultant signal as a transmission signal, and

said reception apparatus having;

separating means for receiving the transmission signal output from the transmission apparatus and separating the received signal into the lowest layer signal in the frequency domain and the encrypted (m-1) layer signals;

decrypting means provided in correspondence to each of the encrypted (m-1) layer signals for decrypting an encrypted layer signal that is separated from the lowest layer signal by the separating means;

layer decoding means provided in correspondence to each of the m layer signals for decoding each of the (m-1) layer signals decrypted by the corresponding decrypting means and the lowest layer signal separated by the separating means; and

inverse discrete cosine transforming means for selecting layer signals corresponding in number to a designated resolution from among the lowest layer signal and the (m-1) layer signals in higher layers, all individually decoded by the corresponding layer decoding means, the layer signals being selected from the frequency domain in ascending order starting from the lowest layer signal, and said inverse discrete cosine transforming means being further used for combining the selected layer signals and inverse discrete cosine transforming a resultant signal to generate an image signal which realizes the designated resolution.

4. A transmission apparatus comprising:

layer coding means for converting an image signal into a frequency domain signal by discrete cosine transform (DCT), dividing the frequency domain signal into m (m is an integer not less than

     3) layers in terms of frequency to generate m layer signals, and coding each of the layer signals;

encrypting means provided in correspondence to each of e (e is an integer not less than 2, m>

e) of the layer signals obtained by the layer coding means for encrypting the e layer signals, the e layer signals being selected in descending order starting from the highest one in a frequency domain; and

multiplexing means for multiplexing remaining (m-e) layer signals including the lowest ones that are coded by the layer coding means and the e layer signals encrypted by the corresponding encrypting means and outputting a resultant signal as a transmission signal.

5. A reception apparatus comprising:

separating means that receives a signal that is generated by converting an image signal into a frequency domain signal by discrete cosine transform (DCT), dividing the frequency domain signal into m (m is an integer not less than

     3) layers in terms of frequency to generate m layer signals, coding each of the layer signals, encrypting e (e is an integer not less than

     2) of the layer signals obtained by the layer coding means, the e layer signals being selected from a frequency domain in descending order starting from the highest one, and multiplexing remaining (m-e) layer signals including the lowest one that are coded by the layer coding means and the e layer signals encrypted by the encrypting means, said separating means being used for separating the received signal into the e layer signals including the highest one that are encrypted and the remaining (m-e) layer signals including the lowest one in the frequency domain;

decrypting means provided in correspondence to each of the encrypted e layer signals for decrypting an encrypted layer signal separated by the separating means;

layer decoding means provided in correspondence to each of the m layer signals for decoding each of the e layer signals including the highest one that are decrypted by the corresponding decrypting means and the remaining (m-e) layer signals including the lowest one and separated by the separating means; and

inverse discrete cosine transforming means for selecting layer signals corresponding in number to a designated resolution from among the e layer signals including the highest one and the remaining (m-e) layer signals including the lowest one, all individually decoded by the corresponding layer decoding means, the layer signals being selected from the frequency domain in an ascending order starting from the lowest one, and said inverse discrete cosine transforming means being further used for combining the selected layer signals and inverse discrete cosine transforming a resultant signal to generate an image signal which realizes the designated resolution.

6. A communication processing system comprising:

a transmission apparatus; and

a reception apparatus,

said transmission apparatus having;

layer coding means for converting an image signal into a frequency domain signal by discrete cosine transform (DCT), dividing the frequency domain signal into m (m is an integer not less than

     3) layers in terms of frequency to generate m layer signals, and coding each of the layer signals;

encrypting means provided in correspondence to each of e (e is an integer not less than 2, m>

e) of the layer signals obtained by the layer coding means for encrypting the e layer signals, the e layer signals being selected in descending order starting from the highest one in a frequency domain; and

multiplexing means for multiplexing remaining (m-e) layer signals including the lowest ones that are coded by the layer coding means and the e layer signals encrypted by the corresponding encrypting means and outputting a resultant signal as a transmission signal, and

said receptions apparatus having;

separating means for receiving the transmission signal from the transmission apparatus and separating the received signal into the e layer signals including the highest one that are encrypted and the remaining (m-e) layer signals including the lowest one in the frequency domain;

decrypting means provided in correspondence to each of the encrypted e layer signals for decrypting an encrypted layer signal separated by the separating means;

layer decoding means provided in correspondence to each of the m layer signals for decoding each of the e layer signals including the highest ones that are decrypted by the corresponding decrypting means and the remaining (m-e) layer signals including the lowest one and separated by the separating means; and

inverse discrete cosine transforming means for selecting layer signals corresponding in number to a designated resolution from among the e layer signals including the highest one and the remaining (m-e) layer signals including the lowest one, all individually decoded by the corresponding layer decoding means, the layer signals being selected from the frequency domain in an ascending order starting from the lowest one, and said inverse discrete cosine transforming means being further used for combining the selected layer signals and inverse discrete cosine transforming a resultant signal to generate an image signal which realizes the designated resolution.

7. A transmission apparatus comprising:

layer coding means for converting an image signal into a frequency domain signal by discrete cosine transform (DCT), dividing the frequency domain signal into m (m is an integer not less than

     2) layers in terms of frequency to generate m layer signals, and coding each of the layer signals;

secret level setting means provided in correspondence to each of the m layer signals generated by the layer coding means for generating an individual secret level setting signal;

encrypting means provided in correspondence to each of the m layer signals generated by the layer coding means for encrypting an individual layer signal in accordance with a secret level that is determined by a corresponding secret level setting signal output from the corresponding secret level setting means; and

multiplexing means for multiplexing the m layer signals each encrypted by the corresponding encrypting means and outputting a resultant signal as a transmission signal.

8. A transmission apparatus according to claim 7, characterized in that said secret level setting means provided in correspondence to each of the m layer signals sends the secret level setting signal to the corresponding encrypting means in a manner that the encrypting means corresponding to the highest layer signal in the frequency domain performs encryption at the highest secret level among the encrypting means for all the layer signals.

9. A transmission apparatus according to claim 7, characterized in that said secret level setting means provided in correspondence to each of the m layer signals sends the secret level setting signal to the corresponding encrypting means in a manner that the secret level at which the encrypting means performs encryption on each layer signal increases in order of ascending frequency level in the frequency domain.

10. A transmission apparatus according to claim 7, characterized in that said secret level setting means provided in correspondence to each of the m layer signals sends the secret level setting signal to the corresponding encrypting means in a manner that the encrypting means corresponding to the lowest layer signal in the frequency domain performs encryption at the lowest secret level among the encrypting means for all the layer signals.

11. A transmission apparatus according to claim 7, characterized in that said secret level setting means provided in correspondence to each of the m layer signals sends the secret level setting signal to the corresponding encrypting means in a manner that the secret level at which the encrypting means performs encryption on each layer signal decreases in order of descending frequency level in the frequency domain.

12. A reception apparatus comprising:

separating means that receives a multiplexed signal that is generated by converting an image signal into a frequency domain signal by discrete cosine transform (DCT), dividing the frequency domain signal into m (m is an integer not less than

     2) layers in terms of frequency to generate m layer signals, coding each of the layer signals, encrypting each of the layer signals obtained by the layer coding means in accordance with a secret level that is arbitrarily determined for each of the layer signals, and multiplexing the encrypted layer signals, said separating means being used for separating the received signal into the encrypted m layer signals;

decrypting means provided in correspondence to each of the encrypted m layer signals for decrypting an individual encrypted layer signal that is separated, in accordance with the corresponding secret level;

layer decoding means provided in correspondence to each of the m layer signals for decoding each of the m layer signals decrypted by the corresponding decrypting means; and

inverse discrete cosine transforming means for selecting layer signals corresponding in number to a designated resolution from among the m layer signals, all individually decoded by the corresponding layer decoding means, the layer signals being selected from the frequency domain in ascending order starting from the lowest layer, and said inverse discrete cosine transforming means being further used for combining the selected layer signals and inverse discrete cosine transforming a resultant signal to generate an image signal which realizes the designated resolution.

13. A reception apparatus according to claim 12, further comprising storage means connected to an input terminal of the separating means and used for recording and reproducing the multiplexed signal.

14. A communication processing system comprising:

a transmission apparatus; and

a reception apparatus,

said transmission apparatus having;

layer coding means for converting an image signal into a frequency domain signal by discrete cosine transform (DCT), dividing the frequency domain signal into m (m is an integer not less than

     2) layers in terms of frequency to generate m layer signals, and coding each of the layer signals;

secret level setting means provided in correspondence to each of the m layer signals generated by the layer coding means for generating an individual secret level setting signal;

encrypting means provided in correspondence to each of the m layer signals generated by the layer coding means for encrypting an individual layer signal in accordance with a secret level that is determined by a corresponding secret level setting signal output from the corresponding secret level setting means; and

multiplexing means for multiplexing the m layer signals each encrypted by the corresponding encrypting means and outputting a resultant signal as a transmission signal, and

said reception apparatus having;

separating means for receiving the transmission signal and separating the received signal into the encrypted m layer signals;

decrypting means provided in correspondence to each of the encrypted m layer signals for decrypting an individual encrypted layer signal that is separated, in accordance with the corresponding secret level;

layer decoding means provided in correspondence to each of the m layer signals for decoding each of the m layer signals decrypted by the corresponding decrypting means; and

inverse discrete cosine transforming means for selecting layer signals corresponding in number to a designated resolution from among the m layer signals, all individually decoded by the corresponding layer decoding means, the layer signals being selected from the frequency domain in ascending order starting from the lowest layer, and said inverse discrete cosine transforming means being further used for combining the selected layer signals and inverse discrete cosine transforming a resultant signal to generate an image signal which realizes the designated resolution.

15. A communication processing system according to claim 14, characterized in that said secret level setting means, which is provided in the transmission apparatus in correspondence to each of the m layer signals, sends the secret level setting signal to the corresponding encrypting means in a manner that the encrypting means corresponding to the highest layer signal in the frequency domain performs encryption at the highest secret level among the encrypting means for all the layer signals.

16. A communication processing system according to claim 14, characterized in that said secret level setting means, which is provided in the transmission apparatus in correspondence to each of the m layer signals, sends the secret level setting signal to the corresponding encrypting means in a manner that the secret level at which the encrypting means performs encryption on each layer signal increases in order of ascending frequency level in the frequency domain.

17. A communication processing system according to claim 14, characterized in that said secret level setting means, which is provided in the transmission apparatus in correspondence to each of the m layer signals, sends the secret level setting signal to the corresponding encrypting means in a manner that the encrypting means corresponding to the lowest layer signal in the frequency domain performs encryption at the lowest secret level among the encrypting means for all the layer signals.

18. A communication processing system according to claim 14, characterized in that said secret level setting means, which is in the transmission apparatus provided in correspondence to each of the m layer signals, sends the secret level setting signal to the corresponding encrypting means in a manner that the secret level at which the encrypting means performs encryption on each layer signal decreases in order of descending frequency level in the frequency domain.

19. A digital television broadcasting system in which a broadcast signal is transmitted and received, said broadcast signal being generated by converting a television signal into a frequency domain signal by discrete cosine transform (DCT), dividing the frequency domain signal into m (m is an integer not less than 2) layers in terms of frequency to generate m encoded signals, and multiplexing the coded signals,

said digital television broadcasting system comprising:

a transmission apparatus for transmitting said broadcast signal; and

a plurality of unspecified reception apparatuses for each receiving said broadcast signal, wherein the transmission apparatus performs a scrambling process onto e (e is a natural number, m>

e) encoded signals that are selected from the m encoded signals in descending order starting from the highest-frequency signal, and multiplexes the scrambled signals and remaining (m-e) encoded signals including the lowest-frequency signal into the broadcast signal, and

each of the reception apparatuses extracts from the broadcast signal the e encoded signals including the highest-frequency signal and subjected to the scrambling process, performs a descrambling process onto the extracted signals, decodes the descrambled signals and the (m-e) remaining encoded signals including the lowest-frequency signal and unscrambled, combines decoded signals selected from among the decoded signals in ascending order starting from the lowest-frequency signal in the frequency domain in such a manner as to correspond in number to a designated resolution, and generates a television signal which realizes the designated resolution.

20. A transmission apparatus used in a digital television broadcasting system in which a broadcast signal is transmitted and received, said broadcast signal being generated by converting a television signal into a frequency domain signal by discrete cosine transform (DCT), dividing the frequency domain signal into m (m is an integer not less than 2) layers in terms of frequency to generate m encoded signals, coding each of the encoded signals and multiplexing the coded signals,

said transmission apparatus comprising scrambling means for performing a scrambling process onto e (e is a natural number, m>

e) encoded signals selected from the m encoded signals in descending order starting from the highest-frequency signal, said transmission apparatus being characterized by coding and multiplexing the e encoded signals including the highest-frequency signal and subjected to the scrambling process by the scrambling means and the remaining (m-e) encoded signals including the lowest-frequency signal to generate the broadcast signal.

21. A reception apparatus used in a digital television broadcasting system in which a broadcast signal is transmitted and received, said broadcast signal being generated by converting a television signal into a frequency domain signal by discrete cosine transform (DCT), dividing the frequency domain signal into m (m is an integer not less than 2) layers in terms of frequency to generate m encoded signals, coding each of the encoded signals and multiplexing the coded signals, said broadcast signal being outputted from a transmission apparatus which performs a scrambling process onto e (e is a natural number, m>

e) encoded signals selected from the m encoded signals in descending order starting from highest-frequency signal and codes and multiplexes the e encoded signals including the highest-frequency signal and subjected to the scrambling process and the remaining (m-e) encoded signals including the lowest-frequency signal to generate the broadcast signal,

said reception apparatus comprising;

separating means for separating the broadcast signal into the e encoded signals selected in descending order starting from the highest-frequency signal and subjected to the scrambling process and the remaining (m-e) encoded signals including the lowest-frequency signal and unscrambled;

descrambling means for performing a descrambling process onto the e encoded signals separated by the separating means;

decoding means for decoding each of the e encoded signals subjected to the descrambling process and the remaining (m-e) encoded signals; and

television signal generating means for selecting decoded signals from among the m decoded signals in ascending order starting from the lowest-frequency signal in the frequency domain in such a manner as to correspond in number to a designated resolution, combining the selected signals and generating a television signal which realizes the designated resolution.

22. A transmission and reception method for a digital television broadcasting system in which a broadcast signal is transmitted and received, said broadcast signal being generated by converting a television signal into a frequency domain signal by discrete cosine transform (DCT), dividing the frequency domain signal into m (m is an integer not less than 2) layers in terms of frequency to generate m encoded signals, coding each of the encoded signals and multiplexing the coded signals, said transmission and reception method comprising:

performing a scrambling process onto e (e is a natural number, m>

e) of the encoded signals selected in descending order starting from the highest-frequency signal, and coding and multiplexing the e encoded signals including the highest-frequency signal and subjected to the scrambling process and the remaining (m-e) encoded signals including the lowest-frequency signal to generate the broadcast signal, on a transmission side; and

extracting from the broadcast signal the e encoded signals including the highest-frequency signal and subjected to the scrambling process on the transmission side, performing a descrambling process onto the extracted signals, decoding the descrambled signals and the remaining (m-e) encoded signals including the lowest-frequency signal and unscrambled, combining decoded signals selected from among all the decoded signals in ascending order starting from the lowest-frequency signal in the frequency domain in such a manner as to correspond in number to a designated resolution, and generating a television signal which realizes the designated resolution.

23. A transmission method for a digital television broadcasting system in which a broadcast signal is transmitted and received, said broadcast signal being generated by converting a television signal into a frequency domain signal by discrete cosine transform (DCT), dividing the frequency domain signal into m (m is an integer not less than 2) layers in terms of frequency to generate m encoded signals, coding each of the encoded signals and multiplexing the coded signals, said transmission method comprising:

performing a scrambling process onto e (e is a natural number, m>

e) of the encoded signals selected in descending order starting from the highest-frequency signal, and coding and multiplexing the e encoded signals including the highest-frequency signal and subjected to the scrambling process and the remaining (m-e) encoded signals including the lowest-frequency signal to generate the broadcast signal.

24. A reception method for a digital television broadcasting system in which a broadcast signal is transmitted and received, said broadcast signal being generated by converting a television signal into a frequency domain signal by discrete cosine transform (DCT), dividing the frequency domain signal into m (m is an integer not less than 2) layers in terms of frequency to generate m encoded signals, coding each of the encoded signals and multiplexing the coded signals, wherein, on a transmission side, a scrambling process is performed onto e (e is a natural number, m>

e) encoded signals selected from the m encoded signals in descending order starting from the highest-frequency signal, and the e encoded signals including the highest-frequency signal that are subjected to the scrambling process and the remaining (m-e) encoded signals including the lowest-frequency signal are coded and multiplexed to generate the broadcast signal,

said reception method comprising;

extracting from the broadcast signal the e encoded signals including the highest-frequency signal and subjected to the scrambling process on the transmission side, performing a descrambling process onto the extracted signals, decoding the descrambled signals and the remaining (m-e) encoded signals including the lowest-frequency signal and unscrambled signals, combining decoded signals selected from among all the decoded signals in ascending order starting from the lowest-frequency signal in the frequency domain, in such a manner as to correspond in number to a designated resolution and generating a television signal which realizes the designated resolution.