当摄像机随载体作高速运动时,由于成像曝光时间、摄像机与目标间的纵向相对运动等因素使目标图像产生从中心到边缘的辐射状模糊,使系统有效视场减少,影响对目标的探测、识别和跟踪. 本文根据运动成像关系和光电探测器的信号积分机理,研究了摄像平台高速运动条件下,图像辐射状模糊的图像退化模型,对几种特殊图像的退化进行了分析;并针对实际离散成像过程,建立了图像退化模型,分析了影响辐射状退化的因素;提出了一种辐射状模糊图像的递推复原处理算法;计算机方法模拟的辐射状退化图像与实际图像一致,复原算法可有效地减轻相向运动所造成的图像辐射状模糊.

本文研究了热电型非制冷焦平面红外探测器在4 状态斩波调制下的信号响应,从理论上得到了响应信号的变化,数值模拟分析表明,响应信号的变化可以反映出景物入射辐射在双波段的差异,由此可望通过单一非制冷钛酸锶钡(BaxSr1-xTiO3 ,BST) 焦平面探测器,实现获取景物双波段信息的热成像系统.

对阿基米德斩波器及其工作状态进行了模拟,分析了探测器像元的曝光时间、曝光顺序、信号读出及其对后续信号均匀性处理的影响. 结果表明:探测器曝光的非均匀性与信号读出模式直接影响后续信号的均匀性处理,阿基米德螺旋线的参数、探测器几何尺寸、斩波器与探测器的相对位置等均影响探测器的曝光顺序和电荷均匀性. 在热成像系统总体设计以及电子处理系统设计时,必须综合考虑斩波器各参数的影响.

The improved scene-based adaptive nonuniformity correction (NUC) algorithms using a neural network (NNT) approach for infrared image sequences are presented and analyzed. The retina-like neural networks using steepest descent model was the first proposed infrared focal plane arrays (IRFPA) nonuniformity compensation method, which can perform parameter estimation of the sensors over time on a frame by frame basis. To increase the strength and the robustness of the NNT algorithm and to avoid the presence of ghosting artifacts, some optimization techniques, including momentum term, regularization factor and adaptive learning rate, were executed in the parameter learning process. In this paper , the local median filtering result of Xij (n) is proposed as an alternative value of desired network output of neuron Xij (n) , denoted as Tij (n) , which is the local spatial average of Xij (n) in traditional NNT methods. Noticeably, the NUC algorithm is inter-frame adaptive in nature and does not rely on any statistical assumptions on the scene data in the image sequence. Applications of this algorithm to the simulated video sequences and real infrared data taken with PV320 show that the correction results of image sequence are better than that of using original NNT approach , especially for the short-time image sequences (several hundred frames) subjected to the dense impulse noises with a number of dead or saturated pixels.

根据人眼视觉实验,对光电成像系统的性能评价方法进行了理论研究,证明了光电成像系统与人眼之间存在最佳匹配状态,分析了视场角、成像系统性能以及系统角放大率对匹配的影响,定量描述电视型成像系统的最佳观察距离和直视型最佳目镜焦距的客观现象,所得结果与实际基本一致。