Hardware efficient multiplier‐less multi‐level 2D DWT architecture without off‐chip RAM

Abstract

This study presents a multi-level 2D discrete wavelet transform (DWT) architecture without off-chip RAM. Existing architectures use one off-chip RAM to store the image data, which increases the complexity of the system. For one-chip design, line-based architecture based on modified lifting scheme is proposed. By replacing the multipliers with canonic sign digit multipliers, a critical path of one full-adder delay is achieved. As per theoretical estimate, for three-level 2D DWT with an image of N × N size, the proposed architecture requires 123 adders, 66 subtracters, 167 registers, temporal memory of 7.5N words and input RAM of 3N bytes. The estimated hardware requirement shows that for the image size of 512 × 512 and three-level DWT, the proposed architecture involves at least 14.1% less transistor-delay-product than existing architectures.