一种基于相位相关法及数学形态学方法的眼底血管图像自动拼接方法

A Robust Method for Automated Retinal Vascular Images Mosaic Based on Phase Correlation Method and Mathematical Morphology

眼底图像的快速自动拼接是眼底血管图像定量分析的必要前提。首先运用数学形态学的‘开’运算从原始图像中分离出灰度分布高度不均的背景图像。经图像增强，采用相位相关法求出图像间的平移量。结果表明：本文方法具有错配率低、速度快。

Precise mosaic techniques are essential for quantitative evaluation of retinal images to make early detection of fundus anomalies feasible. Opening of a gray scale image by a gray scale structuring element(SE) can generate a background image. Image mosaic was achieved by subtraction this background image from the original image and then applying a phase correlation method to find translation difference. Because of the accuracy characteristics of the phase correlation method and the speed of the FFT hardware, this new algorithm can work very fast and accurately, compared to conventional techniques. The method was also characterized by an outstanding robustness against correlated noise and disturbances, such as those encountered with nonuniform illumination. The results confirm the robustness of the chosen approach.