02-03-2011, 09:52 AM
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An Efficient Architecture for 2-D Lifting-based Discrete Wavelet Transform
I. INTRODUCTION
The two-dimensional discrete wavelet transform (2-DWT) is widely used in many image compression techniques,and adopted to be an ingredient in many image compression standards, such as JPEG2000[1],
The computation transform has been widely
implemented in very-large-scale integration (VLSI) to meetreal time requirement.
In this paper, an efficient line-based VLSI architecture for 2-D DWT using lifting scheme is proposed, which is mainly composed of one row DWT module and one column DWT module, working in parallel and pipeline fashion with 100%hardware utilization.
II. LIFTING DWT
It is composed of three basic operation stages:
Splitting
predicting
and updating operations
Block diagram of the lifting scheme.
• Split step: where the signal is split into even and oddpoints, because the maximum correlation between adjacent pixels can be utilized for the next predict step.
• Predict step: The even samples are multiplied by the predict factor and then the results are added to the oddsamples to generate the detailed coefficients.
• Update step: the detailed coefficients computed by the predict step are multiplied by the update factors and then the results are added to the even samples to get the coarse coefficients.
