System and method of adaptive and progressive descrambling of digital image content

1. A method of distributing digital image content, comprising:

producing a scrambled modified digital image content, altered from the point of view of human visual perception, from an original digital image content by replacing at least a part of coefficients of the original digital image content by values different from original values, the original digital image content being in a nominal compressed format other than encrypted, said modified digital image content being of the same nominal compressed format as the original digital image content;

producing complementary information having a granular scalability structure which enables the decoder to obtain a reconstituted digital image content, said complementary information comprising the original replaced coefficients and corresponding locations in the original digital image content and at least one function containing at least one instruction;

transmitting the modified digital image content to a recipient;

transmitting the complementary information, as a whole or in part as a subset of the entire complementary information, to the recipient, the subset being determined based on a digital profile of the recipient and being adaptive and progressive as a function of said digital profile; and

reconstructing, at the recipient, said reconstituted digital image content from the modified digital image content and from the complementary information by replacing the modified coefficients from the modified digital image content by values contained in the complementary information at locations indicated by the complementary information.

2. The method according to claim 1 , wherein the modified digital image content is recorded on the destination equipment prior to transmission of the complementary information to the destination equipment.

3. The method according to claim 1 , wherein the modified digital image content and the complementary information are transmitted together in real time.

4. The method according to claim 1 , wherein the quantity of information contained in the subset corresponds to a scalability level determined as a function of the profile of the recipient.

5. The method according to claim 1 , wherein the type of information contained in the subset corresponds to a scalability level determined as a function of the profile of the recipient.

6. The method according to claim 1 , wherein the modifying complementary information contains at least one digital routine configured for executing said function.

7. The method according to claim 1 , wherein the complementary information is subdivided in at least two sub-parts.

8. The method according to claim 1 , wherein all or part of the complementary information is transmitted on a physical vector.

9. The method according to claim 1 , wherein the complementary information is transmitted on line.

10. The method according to claim 1 , wherein the digital images are I frames, or P frames, or B frames, or S frames.

11. The method according to claim 1 , wherein the nominal compressed format depends on wavelet-based technologies.

12. The method according to claim 1 , wherein at least one part of the profile is stored on the destination equipment.

13. The method according to claim 1 , wherein the type of information contained in the subset is updated as a function of the behavior of the recipient during the connection with the server, or as a function of user habits or as a function of data communicated by a third party.

14. The method according to claim 1 , further comprising a preliminary stage of analog/digital conversion in a structured format, the method being applied to an analog video signal.

15. A system for distributing digital image content, comprising a server containing means for broadcasting a modified digital image content according to claim 1 and a plurality of devices equipped with a descrambling circuit, wherein the server contains in addition a recorder for the digital profile of the recipient and an analyzer for the profile of each recipient receiving the modified digital image content, the recorder commanding the complementary information transmitted, as a whole or in part as a subset of the entire complementary information, to each of the analyzed recipients.

16. The method according to claim 6 , wherein the function transmitted to each recipient is personalized for each recipient in accordance with the session.

17. The method according to claim 6 , wherein the sub-parts of the complementary information can be distributed by the same media.

18. The method according to claim 7 , wherein the sub-parts of the complementary information can be distributed by different media.

19. The system according to claim 15 , wherein the subset (quality, quantity, type) of the complementary information is determined for each recipient as a function of the status of a profile at the time of the visualization of the digital images.