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针对空间多光谱相机中CCD输出数据量大、谱段间冗余小和行频可变等导致常见基于矢量量化、预测和变换编码的整体压缩方案硬件实现困难的问题,提出了一种基于ADV212的空间相机图像压缩方案。依据ADV212工作原理和CCD图像特点,提出了Custom-specific工作模式,在该模式下,使用提出的图像帧和中断处理策略,并以流水线作业的方式实现单片ADV212处理8通道CCD图像;分析了影响图像压缩质量的2个参数,提出了(10,5)量化步长设置方法,使码率控制误差减小了16.385%;使用地检设备对ADV212压缩系统进行了试验验证。结果表明,压缩系统能快速稳定地工作,在压缩比指标2∶1～32∶1内,PSNR均在30dB以上,与传统方法相比,在正常工作压缩比为1bpp时平均PSNR提高了2.49dB。有效的解决了整体压缩方案硬件实现困难的问题。
Aiming at the difficulty of hardware implementation of common compression scheme based on vector quantization, prediction and transform coding, which is caused by the large amount of CCD output data, small redundant bands and variable line frequency in the space multispectral camera, Space camera image compression scheme. According to the operating principle of ADV212 and the characteristics of CCD image, a Custom-specific operating mode is proposed. In this mode, the proposed image frame and interrupt processing strategy are used, and a single-chip ADV212 processing 8-channel CCD image is realized by pipeline operation. Which affects the quality of image compression, proposes a method of setting the quantization step size (10,5), which reduces the rate control error by 16.385%. The verification of the ADV212 compression system is conducted by using the ground inspection equipment. The results show that the compression system can work quickly and stably with the PSNR over 30dB under the compression ratio index of 2: 1 to 32: 1. Compared with the traditional method, the average PSNR increases by 2.49dB at the normal operating compression ratio of 1bpp . Effectively solve the overall compression scheme hardware problems.