遵循xDM标准的PGF压缩编码器优化设计

Optimal design of PGF compression encoder based on xDM standard

针对太阳观测中产生的极大数据流量,提出了一个遵循xDM标准的渐近式图形文件(PGF)压缩编码器对太阳观测图像进行实时压缩以节省存储空间和网络带宽。分析并裁减了在自然图像压缩和压缩速度方面都有很大优势的PGF压缩算法;按xDM标准要求的接口设计了一个PGF压缩编码器,并针对达芬奇硬件架构的特点在软件设计、C语言编程和线性汇编等多个方面进行了优化;最后,对压缩比、压缩时间和压缩信噪比等性能参数进行了在线实时测试。测试结果表明,优化后的PGF压缩编码器的压缩速度是原有编码器的18.7倍,完全满足太阳望远镜实时图像处理终端的要求。

A Progressive Graphic File（PGF） compression encoder based on xDM standard was presented for the real-time image compression of a solar image. The PGF compression algorithm with advantages of natural image compression and compression speed was analyzed and customized. According to the interfaces required by xDM standard, a PGF compression encoder was designed. Aiming at the features of the DaVinci hardware architecture, the PGF compression encoder was optimized on many aspects such as software design, C language program and linear assembly language program. Finally, a real-time online test was carried out for the performance parameters on compression ratio, compression time and SNR of the PGF compression encoder. The experimental result shows that the speed of the optimized PGF compression encoder is 18.7 times that of original one, which can fully meet the design requirements of the real-time image processing system of a solar telescope.