Abstract: Traditional X-ray image enhancement methods have the problem that enhanced image detail is not clear enough or too much noisy. Based on rigorous mathematical defined multi-scale geometric analysis method, Curvelet transform, a flexible non-linear enhancement function was presented. First of all, Curvelet transform was applied to the X-ray image, then, the fine Curvelet coefficients were mapped by the presented enhancement function, and finally the enhancement X-ray image was reconstructed from the amended Curvelet coefficients. The experiment results show that the Curvelet transform can effectively enhance the X-ray image edge contrast by presented enhancement function. The enhanced X-image has better visual effects with clear edge details and smaller noise compared with the traditional methods.

Key words: Image enhancement, Curvelet transform, Multi-scale geometric analysis, X-ray image