A Comparison of Folded Architectures for the Discrete Wavelet Transform

Abstract

The multi-level discrete wavelet transform (DWT) for multiresolution decomposition of a signal through the cascading of filter banks, employs a folded architecture to enhance hardware utilization. This work compares folded architectures for DWT based on three filter structures, the direct form filter, the linear systolic array, and the lifting structure. We generalize the design of these architectures in terms of DWT levels, filter taps and pipeline insertion in critical path. A figure of merit for assessing all the three architectures under different specifications is proposed. A detailed quantitative comparison among the architectures is presented with different combinations of specification. The result shows that variations in DWT levels, filter taps and pipeline insertions have different impacts on the three architectures. Overall, the folded architecture based on lifting structure gives the most desirable figure of merit and the one based on linear systolic array demonstrates the best scalability.