High-accuracy measurement of rotational eye movement by tracking of blood vessel images

This study focuses on a technique for measuring the angle of rotational eye movement by tracking the conjunctival blood vessel ends of sclera, instead of grayscale iris patterns used in the existing techniques. It is because the blood vessel images of sclera have high grayscale contrasts. This technique especially recognizes the contour of the iris to detect the target conjunctival blood vessel end and use the degree of similarity by means of template matching to select automatically the blood vessel end to be tracked. The search region is limited by template matching to achieve low processing cost and high accuracy and resolution even when the background light varies.