Abstract: A new coding and rate control method for JPEG2000 is proposed to improve its coding efficiency. Through modifying the coding order, the most important passes are coded first in a whole tile. Then, a simple data-stream truncation method is able to both terminate the coding in advance and approximate the optimal rate distortion. At the end, a feasible parallel implementation is proposed and it is to speed up JPEG2000 significantly. The improved algorithm makes JPEG2000 much more beneficial to applications with the restricted computing resource on board. The research satisfies the elementary requirements of image compression of Space Solar Telescope.

Key words: astronomy, image compression, SNR, rate control, parallel

摘要： 对JPEG2000算法提出了一种新的改进，以提高它的编码效率。通过修改编码顺序，使得在每个Tile中，数据按照其重要性降序编码。从而，码流截断方法也随之简化，并可以提前终止编码，而率失真效果仍接近最优。最后，给出一个可行的并行化方案，可大大缩短运行时间。改进后的JPEG2000更适用于计算资源有限的星上系统，满足了空间太阳望远镜的压缩需求。

关键词: 天文, 图像压缩, 信噪比, 率控制, 并行