基于仿射投影的弹载图像几何失真校正方法

Geometric Distortion Correction of Missile-borne Image Based on Affine Projection

针对图像末制导系统中,由弹体姿态变化引起的图像几何失真,提出了一种新的弹载图像几何失真的校正方法,并首先根据仿射投影不改变目标平行结构的特性,提出了以仿射投影图像为目标进行校正的思想;然后根据弹载摄像机成像特点,推导出了目标透视投影和仿射投影与弹体俯仰角之间的函数关系;最后利用该函数关系,通过合理的坐标系设置,结合惯导和图像信息来求得目标的校正图像。仿真实验结果表明,该方法能有效地校正由弹体姿态引起的图像几何失真,不仅有利于目标的精确定位,而且对惯导误差不敏感,计算量也较小。

In image-aided terminal inertial guidance system geometric distortion is induced in missile-borne image with varying missile attitude. The affine projection maintains the parallel structure of the objects,on which a method of geometric distortion correction of missile-borne image is proposed, and the affine projection is applied to the terminal corrected images. The function of the perspective target and its affine projection with the missile pitch is deduced based on the perspective geometry character of the missile-borne camera. That is used to achieve the terminal corrected image using the integrated information of the inertial navigation system （INS） and image by setting appropriate reference frames of the two systems. The results of simulation demonstrate that the method proposed is feasible to correct the geometric distortion induced by the missile attitude and increase the object position accuracy. Furthermore, the method is not sensitive to the INS error and consumes little time.