相机摆放方式对推扫成像试验的影响分析

Analysis on Effect of Camera Setting Way on Pushbroom Imaging Experiment

为了减小空间TDI CCD相机外场成像过程中相机摆放方式引入的误差,更准确地评价相机成像性能,提出了一种相机最佳水平摆放角、半径以及成像仰角的计算方法。建立了推扫成像的像移矢量数学模型,定义了像移矢量与水平摆放角、半径之间的函数关系,对工程近似进行了误差分析。建立了相机仰角与像移失配率之间的函数关系,提出了最佳仰角的计算方法。分析结果表明:在常规大气条件下,水平摆放角为0°,摆放半径为0,仰角为7°时,相机摆放方式对成像影响最小,成像结果最能客观反映相机性能。

In order to reduce the error resulted from the camera setting way in the TDI CCD spaceborne camera imaging experiments and to get a more accurate evaluation of the camera imaging performance, a computational method of the best setting angle, radius, and imaging elevation is proposed. Firstly, a mathematical model of image motion vector in pushbroom imaging is established, and a function among image motion vector camera setting angle and radius is defined. The error of engineering approximation is analyzed. Secondly, a function between camera elevation and image motion mismatch rate is established, and the computational method of the best elevation is proposed. The result shows that the camera setting way has the weakest impact on imaging quality, when the horizontal setting angle is equal to 0° , setting radius is 0 and the elevation is 7° in the normal atmospheric condition, and the performance of the camera can be reflected objectively by imaging experiment results.