PROBLEM TO BE SOLVED: To provide a tracing system which eliminates the need for a headgear and is precise by using a diode laser so as to measure period and amplitude generated by interference between the luster of the cornea and red-eye reflection from the retina. SOLUTION: A unidirectional scan is made by a rotary polygon mirror 75 with the laser light beam emitted by the diode laser 71. The light beam reflected by the rotary polygon mirror 75 passes through a light beam forming optical element 76 to reach the eye 77 of a user. The light beam reflected by the user's eye 77 returns through the light beam forming optical element 76 and is reflected again by the rotary polygon mirror 75 to reach an optical detector 79 through a baffle 78. The output of the optical detector 79 is an AC signal and corresponds to the saw-tooth wave modulation of the original laser light beam. This detected AC signal is inputted to a signal processing circuit 80 to determine evaluation regarding where the user is seeing according to a statistical model.
SYSTEM AND METHOD FOR GAZE TRACING