Aiming at the characteristic (low contrast and heavy noise) of the infrared image under the sea-sky background,an complex image processing algorithm based on image filtering,image locality enhancement and super-resolution reconstruction is presented,and the tone mapping algorithm is improved.An infrared digital image processing system for sharp display has been designed.Experiment results show that this system is stable and reliable,and can improve infrared image quality.It also has better real time performance and can meet the engineering requirement.