Abstract: Variable integral time is an effective means to realize the high dynamic range (HDR) of infrared system. Unfortunately，it would lead to serious residual non-uniformity. The relationship between the correction parameters (gain and offset) of two-point non-uniform correction（NUC）and integral time is derived based on the infrared system response model. The result shows that the gain parameters are independent of integral time, and only the bias parameters change with integral time. The correctness of the above conclusions is confirmed by testing it against standard two-point NUC method. The result can provide a reasonable evidence for NUC of infrared system with variable integral time, which only updates the offset parameters but maintain same gain parameters.

Key words: ordnance science and technology, cooled infrared focal plane array, non-uniformity correction, two-point non-uniform correction, correction parameter, integral time, high dynamic range