红外焦平面阵列非均匀性的校正方法研究

Research on nonuniformity correction of infrared focal plane array

针对读出电路与探测器产生的非均匀性,并对递归最小二乘非均匀校正算法(RLS算法)进行扩展和改进,提高非均匀校正的精度和算法的收敛速度。首先对红外焦平面阵列的非均匀性进行建模仿真,根据建立的模型利用局部恒定统计法对读出电路产生的非均匀性进行校正,然后采用自适应中值滤波算法(RAMF算法)对图像进行预处理,从而提供给后续RLS算法具有较低噪声的图像,实现RLS算法对探测器的非均匀性校正。仿真结果表明提出的算法能够有效地抑制读出电路对校正精度的影响,消除图像的非均匀性,同时采用RAMF算法对图像的预处理过程,能够加快RLS算法的收敛速度,提高信噪比,获得较好的非均匀性校正效果。

For reducing the nonuniformity effect of readout circuit and detectors,a new improved recursive least square（ RLS） nonuniformity correction algorithm is presented to improve correction accuracy and convergent speed. Firstly,the nonuniformity of focal plane array detectors is modeled and simulated,and the nonuniformity from readout circuit is corrected by using the constant statistics method. Then,the images are preprocessed by using RAMF algorithm to provide lower noise images for RLS algorithm. The nonuniformity correction is achieved with RLS algorithm. The simulation results indicate that the proposed algorithm can effectively suppress the influence of readout circuit on the calibration accuracy,and eliminate the nonuniformity of the image. The pretreatment using RAMF algorithm can accelerate convergent speed of RLS algorithm,improve the signal- to- noise ratio,and acquire good NUC effect.