A non-uniformity correction method for resistor arrays is given and a flood non-uniformity measurement method in the mapping ratio 1∶1 is analyzed according to the functional diagram of a non-uniformity measurement model. To improve the edge effect and non-ideal convergence due to image deterioration, a flood non-uniformity measurement method based on point spread function estimation is proposed. The simulation result shows that compared with the former method, this method can reduce the edge effect and has a better convergence when a greater smooth factor is existent.