Research On Eye-movement Image Processing And Tracking System

Excimer laser corneal refractive surgery has developed rapidly these years. It can correct refractive error by changing the shape of the corneal through laser ablation, and it has been proved to be a safe and effective method for refractive error correction. Locating the center of pupil area in human eye was fundamental to calculate ablation profile, and the accuracy of the location work has a major effect on curative effect.The paper first studied the existing eye–tracking system in the excimer laser aberration correction system, and then made some improvements on it based on real demands. Digital image processing was applied to make the locating work more accurate and some hardware was added to display the tracking work on video. Main research achievements of this paper are as following:1. The existing eye-tracking system in the excimer laser aberration correction system was studied. The general design of its improvement and detailed design of each module was carried out.2. The AVICap, which is a subclass of VFW (Video for Windows) hierarchy, was studied and it was the basis of video image acquisition.3. Several methods in digital image processing for calculating the pupillary center were presented and a comparative study on their calculated results was given, the best method was selected to apply in the system.4. The methods used to drive the step motor to coincide the pupillary center and excimer laser, were discussed. After the coincidence work, the operation of the eye-tracking system was displayed in video images.The improvement and development of the eye-tracking system advanced the reliability and predictability of the excimer laser corneal refractive surgery. It has been found that the pupillary center computed by image processing satisfied accuracy requirement and the speed to display the tracking work also met requirements.