An algorithm for medical X-ray image enhancement based on human visual properties and improved PCNN image factorization is proposed. Using the improved image factorization algorithm

an image is decomposed into a set of image factors which are ordered from coarse to fine in details. Each factor is separately smoothed to obtain a gain matrix and then the matrix is adjusted adaptively according to whether its local contrast reaches the contrast threshold resulting from human visual properties. The enhanced image is reconstructed from the enhanced factors. Through simulations to different medical X-ray images

a better effect is achieved compared with common image enhancement methods.