Measurement of rotational eye movement using conjunctiva blood vessel tracking

Much attention is now focused on the measurement of rotational eye movement as a technique for evaluating the sickness from excessive image viewing. Since the angle of rotational eye movement induced by the visual stimulus has small amplitude, a high degree of resolution and precision will be required. In the current mainstream method of obtaining the angle of rotational eye movement using an iris pattern, it has been difficult to ensure measurement with a tolerance of 1.0(degree) or less at all times due to changes in the deformation of the iris pattern. We wish to propose a method for high-speed and high-precision measurement of the rotational eye movement by a combination between the conventional method for measuring the rotational eye movement using the iris pattern and the conjunctival vessel extraction method where attention is paid to the conjunctival vessel end located on the outer edge of the iris as a site impervious to changes in the diameter of the pupil. In the step of evaluation, the vessel end position is measured by visual observation based on the image of rotational eye movement captured from three persons, and the tolerance of this system is calculated. It has been possible to take measurements with a precision of 0.24(degree) or less at a processing speed of 60(fps) or more, even when there is a change in the diameter of the pupil.