激光与光电子学进展, 2017, 54 (3): 032802, 网络出版: 2017-03-08
航天遥感相机及参数优化方法
Optimization of Remote Sensing Camera and Its Parameters
遥感 航天遥感相机优化 互补金属氧化物半导体 测光相机 参数调整 大气程辐射去除 remote sensing optimization of remote sensing camera complementary metal-oxide-semiconductor transistor metering camera parameter adjustment removal of atmospheric radiation
摘要
为提高遥感图像质量,对航天遥感相机系统进行了优化,并提出一种航天遥感相机参数优化方法。在航天遥感相机中设计动态钳位电压值并在航天遥感相机前加装大尺度面阵测光相机,在航天遥感相机推扫某一区域前,测光相机通过低曝光参数和高曝光参数获取该区域图像,实测当前区域的高辐射亮度和低辐射亮度。将高辐射亮度与低辐射亮度的差值设为航天遥感相机的饱和亮度,解算航天遥感相机的曝光参数,并将实测低辐射亮度值设置为钳位电压值。随着卫星的转动,航天遥感相机采用上述曝光参数和钳位电压值完成该位置区域的成像,实现航天遥感相机参数自动调整。地面验证实验表明,通过优化航天遥感相机系统,可在成像前去除大气对灰度层次的影响,提高图像辐射分辨率。根据实验结果统计,图像的灰阶范围可提高80.7%,图像熵显著提升。该方法能够根据当前场景内容充分利用成像系统的动态范围,提高图像的灰度层次和图像质量。
Abstract
A method for optimizing the space camera system and its parameters is proposed in order to improve the quality of remote sensing images. First, a clamp voltage value is set in the space camera and a largescale array camera for light metering is installed besides the space camera. The image of a certain area can be obtained by metering camera with low and high exposure parameters before the space camera scans this area by the pushbroom mode, and the lowest and the highest luminance information of this area can be measured. Then, exposure parameters of the space camera can be calculated by setting the difference between the highest and the lowest luminance measured as the saturation luminance of the space camera. The value of clamp voltage is set according to the lowest measured luminance. Finally, when the space camera focuses on this area after orbiting to an appropriate position, the space camera images the area with the exposure parameters and the clamp voltage above, and thus the adaptive adjustment of the space camera parameters is realized. Ground experiment results show that the influence of atmosphere on the gray level is removed before imaging and the radiation resolution of the image is improved by optimizing the space camera system. According to the statistical results, the gray range of images increases by 80.7%, and the image entropy also increases significantly. This method makes use of the dynamic range of the imaging system sufficiently based on the current scene, and improves gray level and image quality of the image.
曹旗磊, 赵明, 董丽丽, 张明波, 许文海. 航天遥感相机及参数优化方法[J]. 激光与光电子学进展, 2017, 54(3): 032802. Cao Qilei, Zhao Ming, Dong Lili, Zhang Mingbo, Xu Wenhai. Optimization of Remote Sensing Camera and Its Parameters[J]. Laser & Optoelectronics Progress, 2017, 54(3): 032802.