An unobtrusive measurement method of the horizontal gaze angle

A horizontal gaze angle measurement device is introduced. By combining a photoelectric viewing device to measure the horizontal eye angle with a similar head angle measurement device, it is possible to measure the horizontal gaze angle without using a headrest. After discussion of circuit diagrams and measurement principles, it is shown that the measurements made with the device yield a reasonable precision. The mean absolute measurement error is below 1°. This inexpensive and unobtrusive device covers a visual field of about 20° and can be used in parallel with many tasks. Further, data on the successful application of the device in a driving simulation setting are discussed.