Patent ID: 6339658
Filing Date: 2002-01-15
Classification: H04N

Abstract:
A method of encoding a still image which improves the error resiliency of the resulting bitstream, comprising the steps of:decomposing a still image with a wavelet transform, choosing a scanning method with which to scan the wavelet coefficients produced by said decomposition, scanning the wavelet coefficients of a texture unit which is defined in accordance with said chosen scanning method, coding the wavelet coefficients of said texture unit to produce a bitstream, adding said bitstream to a packet which includes a data stream, all of the bits of the bitstream resulting from said coding of said texture unit becoming part of said packet's data stream, determining, in accordance with a first predetermined criterion, whether the packet associated with said data stream should be closed, repeating the steps of scanning and coding the wavelet coefficients of a texture unit to produce a bitstream and adding the resulting bitstream to said data stream for additional texture units until said first predetermined criterion for closing said packet has been met, constructing a packet header for said data stream, said packet header comprising: a resynchronization marker for enabling a decoder to resynchronize with the encoder producing said bitstream if synchronization is lost, and at least one index number, each of said index numbers identifying a respective one of the texture units in the packet header's associated data stream, for enabling a decoder to associate following packets with their correct position in the wavelet transform domain, and combining said packet header and its associated data stream to form a packet suitable for transmitting over a communication channel, the use of said encoding method providing independently decodable packets and thereby improving the error resilience of said bitstream by eliminating dependencies across the packets and isolating corrupted data to a single packet.