| Summary: | 碩士 === 國立交通大學 === 電子工程系所 === 92 === The ability to have scalability in resolution as well as image quality is the main attractiveness of JPEG2000. DWT (Discrete Wavelet Transform) and EBCOT (Embedded Block Coding with Optimal Truncation) which are two major technologies enable it, however, are also the parts that demand huge storage and computations.
To reduce memory requirement, we combine five different computing orders of DWT with level-by-level or mixed-level and find that level-by-level optimal-z scan can reduce the temporal buffer in DWT as well as the buffer between DWT and EBCOT. We also adopt the new stripe-based computation order of EBCOT to further reduce 93.8% buffer size between DWT and EBCOT. The total buffer for the JPEG2000 encoder can be reduced to 66% of the original design. However, the stripe-based computing order will increase 14% more computation time. Thus, we proposed the zero-stripe skipping technique to skip the all-zero-bitplane. With this approach, we can eliminate this overhead and reduce 0.22% computation time further.
To reduce the computation complexity, we share the multipliers and adders of the two directional DWT kernels, so that 1/3 of the area of DWT module can be saved. For EBCOT, a pass-level parallelism is adopted to speed up 3 times of the traditional processing time and to reduce 2/3 memory accesses. The gate count of proposed context formation is 6.8% of others.
Finally, we proposed a plan to use one DWT module with three embedded block coders to integrate our JPEG2000 encoding system. It can achieve a throughput of 55.6 Msamples/sec at 100 MHz clock rate with lower cost and less memory requirement.
|
|---|
