In this paper a method for the fast determination of distortion-based optimal unequal error protection (UEP) of bitstreams generated by embedded image coders is described. The UEP problem is reduced to the more general problem of finding a path in a graph, where each path of the graph represents a possible protection policy and the best path is that one inducing minimal distortion. The problem is combinatorially complex and excludes a brute force approach. The solution is provided by applying heuristic information from the problem domain to reduce search complexity. In particular, we use graph search procedure A, well known in the field of artificial intelligence, to avoid exhaustive search. Numerical results show that this technique outperforms the methods presented in [1], [2], in terms of mean square error (MSE) distortion and computational complexity.
['Alessio Torquati', 'Maria Fresia', 'Fabio Lavagetto']
Determination of Optimal Distortion-Based Protection in Progressive Image Transmission: a Heuristic Approach