ADAPTIVE AND GRADUAL PROTECTION OF FIXED IMAGES WHICH ARE CODED IN WAVELETS

摘要

The invention relates to a method for secure distribution of fixed digital images according to a nominal format arising from digital coding in wavelets, represented by a stream consisting of at least one packet (relating to the organization of the binary sequence) containing at least one block including individual digitally coded elements according to a specific manner inside the stream concerned and used by all decoders able to retrieve or to decode it in order to display the image correctly. The inventive method comprises the following steps: a preparatory stage consisting in modifying at least one of said individual elements according to at least one substitution operation consisting in the extraction of said individual element, followed by the replacement thereof with dummy data; a stage of transmission of the main stream modified according to the nominal format, made up of blocks modified during the preparatory stage, and by a separate path of the main stream of additional digital information, enabling the original stream to be retrieved based on calculation on the target equipment according to the main stream and the additional information.