从多波段图像中获取大气透过率的测量方法

Measurement of Atmospheric Transmittance From Multi-Spectral Image

提出了一种基于单帧多波段图像测量非气体吸收波段和弱气体吸收波段大气透过率的方法,可应用于相关光电工程中评估和修正大气衰减影响.首先,利用经过绝对辐射定标的图像采集设备获得辐射图像;其次,基于大气中图像退化光学模型与暗通道先验统计理论得到辐射图像暗通道对应的宽波段平均大气透过率;最后,结合特定波段消光系数和宽波段平均消光系数间的关系得到特定波段的大气透过率.实验对比分析表明:本文方法与能见度仪、激光雷达测量结果相关性较高,其中与能见度仪相比,相关系数在0.89和0.95之间,与激光雷达相比,相关系数在0.95和0.97之间;在1km近距离条件下与能见度仪、激光雷达测量结果平均相对偏差最高分别为9%和6%,在远距离条件下,与能见度仪测量结果相比,4km和6km平均相对偏差最高分别为15%和30%,与激光雷达测量结果相比,4km和6km平均相对偏差最高分别为9%和18%.

A method of measuring atmospheric transmittance from a single frame of multi-spectral image for non and weak absorption waveband was proposed, which can be applied to evaluate and correct atmospheric attenuation effect in optoelectronics engineering field. Firstly, a radiometric image can be acquired using the camera with absolute radiometric calibration; secondly, according to the optical model of image degradation in atmosphere and the dark channel prior statistical theory, average atmospheric transmittance of dark channel can be calculated from radiometric image; finally, the atmospheric transmittance of specific wavelength is calculated using the average extinction coefficient relation database of the specific wavelength and the dark channel waveband. The experimental comparison indicates that the correlations between the transmittances measured by the new method, visibility meter and lidar are good. For the new method and visibility meter, the correlation coefficients are between 0.89 and 0.95, and the average relative deviations are no more than 9%, 15%, 30% for 1km, 4 km and 6 km, respectively; while for the new method and lidar, the correlation coefficients are between 0.95 and 0.97, and the average relative deviations are no more than 6%, 9%, 18% for 1 km, 4 km and 6 km, respectively.