Referring to the effect of the nonlinear response of detectors in Infrared Focal Plane Arrays (IRFPA) on the nonuniformity correction accuracy,an improved nonuniformity correction algorithm is presented based on Kalman-Filtering.The piecewise linear model of detector response is adopted in the algorithm.By use of the model,the nonuniformity correction algorithm based on Kalman Filter is extended and improved.The effect of the nonlinear response of detector on the nonuniformity correction accuracy is eliminated with this algorithm.Experimental result indicates that the improved algorithm acquires good effect of the nonuniformity correction.It can resolve the problems of detector bias and gain drift with time,as well as the influence of the detector nonlinear response on the nonuniformity correction performance in some degree.