高分辨率测绘卫星遥感影像星上压缩质量评价

Evaluation of the effect of high resolution mapping satellite image onboard compression

针对高分七号测绘卫星模拟立体像对星上压缩是否满足测图应用需求的问题,本文从影响影像灰度、纹理、相关性等构像质量特征和DSM产品精度两方面进行影像压缩质量评价实验,开展了多种格网尺寸DSM的提取,通过比较不同压缩比下重建与原始影像生成DSM平均高程误差和高程中误差进行DSM产品精度分析。结果表明,对于星上JPEG-LS压缩算法,压缩比不大于4∶1时,压缩后影像灰度特征、纹理信息保持好,影像相关性大于0.997,重建影像峰值信噪比大于50,影像压缩质量好;随着压缩比的增加,DSM产品精度逐渐降低,压缩比不大于4∶1时,DSM高程中误差小于1 m,满足1∶10 000、1∶5 000数字高程模型高程中误差一级要求。本文相关结论可为高分七号星上压缩指标论证提供参考。

Aiming at the problem of whether the quality of on-board compression of GF-7 analog stereo remote sensing image met the requirements of mapping application,the evaluation of the effect of high resolution remote sensing image compression on the accuracy of image quality included gray level,texture and correlation and DSM products was tested in this paper. DSM based on different grid resolution were extracted from stereo image pairs,and the accuracy of DSM products was evaluated and validated according to the average elevation error and the root mean square elevation error.The result showed that:as to the JPEG-LS algorithm adopted in GF-7,when the compression ratio was less than 4∶1,the image features and texture information were kept well,the image correlation coefficient were greater than 0.997,the reconstructed image peak signal-to-noise ratio was greater than 50,and the image compression quality was good;With the increase of compression ratio,the accuracy of DSM products was decreasing,the root mean square error(RMSE) of DSM was less than 1 meters and the DSM generated by reconstructed stereo pairs could meet the first level requirement of 1∶10 000 and 1∶5 000 DEM specification. The conclusion of this paper could be used as a reference for the demonstration of the compression index of GF-7.