A Novel Gray-Level Registration Algorithm for DSA Image Based on Subtraction Histogram

A novel gray-level registration algorithm for digital subtraction angiography (DSA) image based on subtraction histogram (the histogram of subtraction image) is firstly proposed in this paper. Due to gray-level distortion, the gray value of pixel in background region in subtraction image is shifted to a nonzero value, which is defined as gray value shift (GVS). The GVSs of all pixels in subtraction image can be calculated from the information contained in the subtraction histogram. The experiment results have shown that this algorithm can effectively reduce artifacts, and the visualization quality of vessels in subtraction image is significantly improved