ETM图像地物反射率光谱反演

用搭载在卫星Landsat-7上的多光谱成像仪ETM记录的来自地气系统的辐亮度光谱图像，反演地物反射率光谱，在ETM 1波段，反射率反演的不确定度基本上保证在17%以内，2，3波段在10%以内，优于目前常用的简易算法。用反演的地物辐亮度光谱合成的sRGB真彩色图像，清晰度欠佳，未作经验调整时明显偏色，用于航天对地真彩色摄影这一反演精度还不够，但用于目视判读明显优于原图像。

The Ground Reflectance Spectrum Retrieval from ETM Images

Retrieval of ground reflectance spectrum from satellite sensor digital count requires knowledge of the atmospheric conditions. Images of spectral radiance from ground-atmosphere system recorded by the multi-spectral imager ETM which boarded Landsat-7 sensor can retrieve the ground reflectivity spectrum. The uncertainty of reflectance spectrum retrieval is no more than 17% at the band 1 of ETM, and less than 10% at the band 2 and 3 of ETM. It is superior to those arithmetics widely used at present. Retrieval of ground radiance spectrum from ground-atmosphere system can be used to synthesize the sRGB true color image, but the definition is not excellent. And it was proved that the color of the images can not reflect the actual nature of earth objects before being adjusted. And the accuracy of interpretation based on true color synthesized images is superior to those based on the source images. So the precision of such reflectance spectrum retrieval is not as good as expected if applied to the true color photography on the ground.