DSP performance comparison between lifting and filter banks for image coding

The lifting scheme is a very well-known computationally efficient alternative to the filter bank scheme for evaluating the discrete wavelet transform of signals and images. However, the actual computational saving is still a matter of debate. On one hand, theoretical results in the literature report an asymptotic upper-bound of two for very long wavelet filters. On the other hand, it is worth wondering to what extent the architecture of the processor used can actually bias this gain. In this paper we tackle this problem from an implementation perspective, and profile the execution time of the two algorithms on a digital signal processor. Both the real-valued and the integer versions of the wavelet transform are considered. The quantitative results are used to gain some insight on the way the processor architecture affects the algorithms.