提高两点温度定标法精度的焦平面非均匀性校准技术研究

凝视红外成像系统中的探测器非均匀性校准(降低固有空间噪声)技术是一项处在探索过程中的关键技术.目前实用性较好的两点温度定标法的校准系数精度受读出噪声、信号动态范围、模数转换字长和运算噪声的限制,很难使焦平面探测器的空间残留噪声达到应有的精度.文中探索了一种二次参数补偿的两点温度定标方案,由基本公式得到的校准参数值,再依据现实信号动态范围进行实时精度补偿,使之更加接近于理论计算值,从而使非均匀性校准的系数精度得到较大幅度提高.这一方案可在不改变图像处理机硬件开销和软件运行负担的前提下完成对两点温度定标法精度的补偿.计算机仿真实验结果证明了该方法的有效性,可降低残留空间噪声50%以上.

IR FPA non-uniformity correction study based on the approach of modified two point temperature correction accuracy

Non|uniformity correction approach is one of the key technique in steering focal plane array imaging system. In practical application, due to the parameter accuracy of two point temperature correction is limited by readout circuit noise, dynamic range, analogue to digital converter word length and calculating noise, the performance of focal plane array detector is not the performance it should be. An approach of two point temperature correction parameter compensation is presented in this paper, it can compensate the parameter accuracy according to the real|time signal dynamic range, the parameter can be modified near to its theoretical value. In the condition of used image processor construction hardware and software, the approach we had can compensate the accuracy of two|point temperature correction. By the results of computer simulation, it is verified that the approach is effective and can decrease the level of rest spatial noise more than fifty percent. ;