jpeg2000 tier2编码器的优化设计与实现-optimization design and implementation of jpeg 2000 tier 2 encoder.docx

ABSTRACT JPEG2000 is the new generation of static image compression standard, containing many excellent features. To achieve a better application of this compression standard, making it implemented with hardware, this paper made a deep study of the Tier-2 encoder, which is in charge of optimized truncation and code stream organization; schemes of hardware implementation are also proposed. An introduction to the Tier-2 algorithm defined in the JPEG2000 standard is made at first, including the PCRD-opt method, which is the recommend truncation method in the standard. Then the shortcomings of the PCRD-opt method is pointed out, followed by an optimized hardware-oriented solution, which replaces the division operation with lookup table, adopts a rate-distortion recording table , proposed by former researches and optimized by this paper according to the image characteristics for less hardware resources consumption, to achieve the truncation instead of the original algorithm. After that an introduction to the code stream format is made to interpret the concepts of packet, marker and marker segment. Then an implementation scheme of the whole coding system based on parallel Tier-1 encoder is proposed, followed by an introduction to the main operating process of each module. Due to the excessive hardware resources consumption, a new scheme based on serial Tier-1 encoder is proposed, which includes a pre-truncation module to accelerate the coding process. After the RTL coding, functional simulation and FPGA verification, the two schemes are compared in terms of compression time, image quality and resources consumption, results show that in spite of the minor image quality loss, the serial scheme can greatly reduce the resources consumption, and can significantly accelerate the compression speed under the effect of pre-truncation module. To upgrade the JPEG2000 theory to application level, this paper proposed a scheme of demonstration system, which can realize the process of