提出了航天遥感相机的动态钳位方法, 该方法通过在相机的模拟前端对大气程辐射值进行减除, 实现场景信息的充分量化.建立了航天遥感相机成像链路模型, 分析了大气程辐射对图像灰阶范围的影响.研制了动态钳位相机, 实现了在相机硬件电路中减除模拟信号.在外场对动态钳位相机进行了实验验证, 实验中利用MODTRAN软件计算大气程辐射并转换为相机钳位值.实验结果表明: 本文方法可使相机低端信息得到充分利用, 图像灰阶范围能够提高62%; 在航天遥感相机中设计动态钳位能够利用低端量化信息, 用更多的量化位数来表示地物目标信息, 并可提高辐射分辨率, 保留更多图像的细节信息.

The dynamic clamping method of space remote sensing cameras was proposed to solve the above-mentioned problem. The method can realize adequately quantization of scene information by subtracting the value of atmospheric path radiation at the analog front end of camera. Imaging chain model for space remote sensing cameras was established first, and the effect of atmospheric path radiation on the image grey-scale area was analysed. Then, the dynamic clamping camera was developed, therefore the analog signal subtracted from the camera hardware circuit was implemented. Besides, experiments were carried out to test the dynamic clamp camera. And the value of atmospheric path radiation calculated by MODTRAN software was converted to value of camera clamp in experiments. Experiments results showed that, the low end information of camera can be fully used by this method, and the image grey-scale range increases by 62 percent. Thus low end quantitative information can also be adopted by designing dynamic clamping for space remote sensing cameras. Then the information of targets can be represented by more quantization bits, and the radiometric resolution is improved as well as more details information of image are remained.