Efficient VLSI Implementation of Modified Dual Tree Discrete Wavelet Transform Based on Lifting Scheme

In past few decades, dual tree discrete wavelet transform (DT-DWT) has become an open active research area for image processing applications. Nowadays; lifting based DT-DWT seeks more attention due to its lower computational complexity and shift invariance property. Nevertheless, VLSI implementation of lifting based DT-DWT further needs to be improved for low power and high speed image processing applications. In this article, an efficient VLSI implementation of modified lifting based DT-DWT is proposed. In proposed approach, two real valued lifting based filters are used to implement dual tree structure in which six high pass bands (i.e., two HH, two HL and two LH) and two low pass bands (LL) are obtained. Next, high frequency components (HH1 and HH2) as well as low pass bands (LL1 and LL2) are merged togetheras single sub bands HHm and LLm respectively. In synthesis section, the original image is recovered using LLm, HHm, and LH2and HL2 without considering the two high pass bands (HL1and LH1).Hence, the proposed approach greatly reduces the hardware requirements and consumes less power than the DT-DWT without affecting the image quality. Experiment was carried out and tested on various test images using Xilinx ISE and MATLAB R2010a. The experiment results inferred that the proposed approach is well suited for image compression.