Abstract
Currentry, there are several types of Head Mounted Display (HMD) commercially available for virtual reality systems. The HMD uses two LCD displays to present the different image to each eye and enables a user to see stereo images. In order to display realistic images, the HMD is required to have the enough size screen which covers the whole visual field. In almost HMDs, however, the size of screen is not enough large because the use of the wider one will make the image resolution lower. As long as the NTSC display is introduced, there is a difficulty of overcoming this problem because of the restriction of the scanning lines. One of solutions for this is to introduce the Eye Movement Tracking Type HMD (EMT-HMD). Human eye can see the object precisely only at the area near to view point. With this in mind, the idea of EMT-HMD has been proposed which presents higher resolution images at the area near view point rather than the peripheral area. This paper describes the characteristics of human central vision useful to design such an image display system for EMT-HMD. In experiments, several grating Images with higher spatial frequencies at view point area were used. The images which have the various frequencies at the central and peripheral area, were presented to several subjects. Each subject was asked if he/she could recognize the difference of the resolution and required to answer the size of the high spatial frequency area at which the difference can not be recognized. From these experiments, the size of high resolution area was determined as a function of the difference of resolution. Based on these results, how to design the size of the high resolution area in EMT-HMD using NTSC display devices was provided.
