Enhancement algorithm of X-ray blood vessel images

A new algorithm of enhancing blood vessels in X-ray photographs is proposed. The algorithm consists of the following two parts. In the first part, by using differential operators to detect the directionality, the edges of blood vessels can be accurately discriminated even in the case of blurred image. Both an edge and a region analysis are performed. The edge analysis makes clear the region segmentation. In the second part, the noise can be reduced by using the nonlinear gray level transformation. As the result of the transformation, the blood vessel is enhanced.