A SIMPLIFIED CALIBRATION METHOD FOR 3-DIMENSIONAL EYE-MOVEMENT RECORDINGS USING SEARCH-COILS

An algorithm is presented which allows the calibration of three-dimens ional eye movements in two magnetic fields with two search-coils in on e eye, whose relative orientation does not have to be known, Prior to recordings a calibration cube is placed in front of the eye to measure real and apparent crosstalk, produced by imprecisely oriented horizon tal or vertical magnetic fields, and to obtain a first approximation o f offset voltages, For calibration it suffices if one point is fixated and, in addition, spontaneous eye movements for 30-60 sec are perform ed. Additional fixation points can be used to improve the calibration. Position quaternions are applied for computing eye movement recording s from man and monkey and to determine Listing's plane.