In the paper, the relationship between response coefficients and two-points’correction coefficients for effective pixels is investigated, and the range of two-points’correction coefficients is found out. To economize hardware resource and ensure the appointed correction precision at the same time, an app roach for transforming NUC scheme from float operation to integer one is studied, and the relationship between precision loss and integer app roximation is discussed. Then the correction integer formula deduced from this app roach is implemented by FPGA ( field p rogrammable p raphic array). The experiment results using real IRFPA show the p roposed app roach is feasible.