A new registration method based on mutual information has been proposed for retinal fundus images, using genetic algorithms to solve transformation parameters.

Retinal images registration is an important step in retinal fundus diseases diagnosis and laser treatment in order to combine different retinal images information, such as fluoroscein angiography image (FA ) and red free image(RF).

The key process and difficulty to realize compute intelligent auxiliary diagnosis of retinal image is how to automatically ac- quire the pathological information.

The reasons of radiant distortion for retinal image are discussed based on the analysis of imaging system of ocular fundus, and the method of Homomorphic Filtering is used to calibrate the radiant distortion.