Due to the complexity and relativity of image information

it may be present itself problems of vagueness and uncertainty when processing it. Rough sets theory is a new mathematical tool to deal with vagueness and uncertainty. It is a soft computing method and affords intellective information processing useful tool. The paper presents an image preprocessing algorithm that combines human visual properties with rough sets. According to rough sets theory

an image is segmented to different sub images according to condition attribute on human visual properties in the algorithm

and the contrast response of the sub images are transformed respectively. It can realize filtering noise when image enhanced.