具有AHB 介面之JPEG2000 編碼器系統設計

Abstract

由於JPEG2000是最先進的影像壓縮格式，我們實驗室也致力於開發高效能JPEG2000晶片，並提出比傳統小波離散轉換 (Discrete Wavelet Transform) 更有效率的 QDWT (Quad Discrete Wavelet Transform)。 QDWT的優勢在於可以比傳統DWT提早四分之三的時間將編碼資料送出至下級EBCOT (Embedded Block Coding with Optimized Truncation) 。我們也開發高效能的算數編碼器，採用三級管線的平行化架構達到1 CX-D pair/clock cycle 的輸入率。在本論文中會說明如何透過系統工作流程安排，分析系統內部每塊模組的工作時間，決定出效能最好的系統架構。 為了使我們開發的JPEG2000編碼器更具IP化，我們將其外掛一層AHB (Advanced High-performance Bus) Slave介面。AMBA (Advanced Microcontroller Bus Architecture)為ARM所制定的系統內部匯流排的溝通介面，是目前市面上最常被拿來使用的介面，因此，我們所設計的具有AHB介面的JPEG2000編碼器可應用於任何ARM-based的嵌入式系統。本論文的貢獻在於成功整合一顆具有平行化架構的JPEG2000 Coprocessor，並呈現此架構確實可以大幅提升JPEG2000的效能。此外，也成功的為JPEG2000 Coprocessor掛上AHB 介面，並使之與ARM CPU一起工作，完成整個JPEG2000的編碼流程。

Because JPEG2000 is the state-of-the-art image compression technology, our lab has made efforts in developing a high-performance JPEG2000 chip and developed QDWT (Quad Discrete Wavelet Transform) which is more efficient than the traditional DWT (Discrete Wavelet Transform) . QDWT only needs the quarter of compute time than the traditional DWT does to generate the coefficients to EBCOT (Embedded Block Coding with Optimized Truncation). We also develop a high-performance AC (Arithmetic Entropy Coder). The pipeline architecture is used in the AC and we only use three pipes to reach the input rate, 1 CX-D pair/clock cycle. We will explain that how to organize the best system architecture to achieve small area and high throughputs by arranging the system work flow properly and analyzing the timing of the individual modules. If the ASIC developed can be popular to be integrated into different systems, the IP issue should be addressed. We wrapped the JPEG2000 Encoder developed by our team in AHB (Advanced High-performance Bus) Slave interface. AMBA, which is drawn up by ARM, is an on-chip communication standard for designing high-performance embedded microcontrollers and is wildly used in the consumer electronic market now. So, the AHB-based JPEG2000 Encoder we developed could be applied in an ARM-based embedded system. The Contribution of this thesis is to integrate the QDWT, Pass Parallel EBCOT Tier1 and Pipeline AC as a JPEG2000 coprocessor and show this architecture really could improve the performance. Besides, wrap the JPEG2000 coprocessor in AHB slave interface and make it cooperate with ARM CPU to finish the coding procedures of JPEG2000.