Scheduling-scheme and parallel structure for multi-level lifting two-dimensional discrete wavelet transform without using frame-buffer

Abstract

In this paper, we have proposed a novel scheduling scheme for generating continuous input-blocks for the succeeding processing units of parallel structure to achieve 100% hardware utilisation efficiency (HUE) without block folding. Based on the proposed scheme, we have derived a parallel and pipeline structure for multilevel lifting two-dimensional discrete wavelet transform (DWT). The proposed structure involves regular data-flow and does not require frame-buffer, and calculates DWT levels concurrently. A theoretical comparison shows that the proposed structure for J = 2 involves 1.25 times more multipliers and adders, 2 N more registers than those of existing folded block-based structure and offers 1.25 times higher throughput, where N is the input-image width. Compared with similar existing parallel structure, the proposed structure requires the same number of multipliers and adders, 2.125 N less registers and offers the same throughput rate. Application specific integrated circuit synthesis result shows that the core of the proposed structure for 2-level DWT and image size (512 × 512) involves 41% less area-delay-product and 36% less energy-per-image than those of similar existing parallel structure.