||Stankovic, V., Hamzaoui, R., Saupe, D.
||Fast algorithm for rate-based optimal error protection of embedded codes
||Embedded image codes are very sensitive to channel noise because a single bit error can lead
to an irreversible loss of synchronization between the encoder and the decoder. Sherwood and Zeger
introduced a powerful system that protects an embedded wavelet image code with a concatenation of a
cyclic redundancy check coder for error detection and a rate-compatible punctured convolutional coder for
error correction. For such systems, Chande and Farvardin proposed an unequal error protection strategy
that maximizes the expected number of correctly received source bits subject to a target transmission
rate. Noting that an optimal strategy protects successive source blocks with the same channel code, we
give an algorithm that accelerates the computation of the optimal strategy of Chande and Farvardin by
finding an explicit formula for the number of occurences of a same channel code. Experimental results
with two competitive channel coders and a binary symmetric channel showed that the speed-up factor
over the approach of Chande and Farvardin ranged from 2.82 to 44.76 for transmission rates between
0.25 and 2 bits per pixel.