Three methods are proposed to enhance the targets in infrared images based on the analysis of the changes of the grey degree′s local mean contrast, local variance and local three dimonsional shape. Then the seed point is determined at the most possible location of the target by searching the point with the local maximum energy in the enhanced image. The seeded-region-grow algorithm is utilized to realize the separation of the target and the background and to extract the target from the background finally. Experimental results on a lot of real IR images with ocean and sky scenes show its effectiveness in detecting dot and spot targets in a single frame.