Corneal Topography Measurement In The Eye Locating And Tracking A Number Of Technical Studies

The human eye is the important sense organ. In many kinds of the inspecting-systemfor eyes, such as computer optometry, treatment of myopia through laser apparatus, statusidentifying system by information of the iris, corneal topographer and so on, people cannot ensure their heads and eyes absolute rest, which result in bad accuracy. Therefore, theocular position measurement and tracking system is important to guarantee theperformance of such apparatus mentioned above.The classification of eye movements is introduced, and then by comparing the existingmeasuring methods of the movement and the tracking systems, the way in eye trackingwhich is based on video image processing is presented. First, two cross-cut linear CCD arelocated to get the image of the pupil area, then the TLV990 act as Analog Front End toconvert analog signal to digital signal. At the same time, the high-speed MCU(MicroController Unit) and CPLD (Complex Programmable Logic Device) accomplish the dataprocessing and controlment. Through setting the counters to mark the boundary andcomparing the centre of the pupil with the optic axis, the MCU rectify the deviation bydriving the step-motors to ensure the pupil be in alignment with the optic axis, thusaccomplish eye-tracking.