Digitally calibrated eye movement measurement system

A less expensive instrumentation alternative to record horizontal eye movements is presented in the form of a feasibility study. Currently, there are several techniques used to accurately measure eye position for research purposes. To implement these techniques, significant financial resources are required. The proposed technique costs less than $3000.00 and is based upon the limbus position technique. A linear charged coupled device (CCD) image array sensor and a biconvex lens are used to determine the position of the pupil. The self scanned CCD array is controlled by four analog clock signals generated from digital logic. The CCD video output signal is converted to a TTL compatible signal. The TTL signal is used to create a digital number based upon the limbus image formation upon the CCD pixels. This digital number is processed using standard signal acquisition techniques and is recorded on the hard drive disk of an IBM PC/AT compatible system. The C programming language is used to acquire the data and control calibration of the system. FORTRAN software is used to implement digital signal processing algorithms and estimate eye position.