A THREE DIMENSIONAL VISOR DISPLAY SYSTEM FOR THE POSTURAL STABILITY ANALYSIS Biomechanics of Posture and Seating

A new measurement system was developed to quantify the effect of alteration to the visual feedback information on the human body sway. A three dimensional visor display was proposed to provide the human eyes with the stereoscopic vision depending on his head motion. A pair of CCD cameras and a pair of liquid crystal displays were used to show wide images with binocular parallax to the test subject. The head motion on the frontal plane was measured on-line by using the image processing unit for the video signal obtained from the CCD cameras, and an ultrasonic distance sensor was used to measure the rotation of the head on the horizontal plane. In the experiments. the subject tracked a visual reference signal with his head rotation. The results from the experiments revealed that the vestibular information contradictory to the visual information increased body sway.