The measuring system is a set two devices. One is a brand new eye mark recorder EMR-8 by NAC Inc. The other is a display device of a DOS/V computer with a liquid crystal glasses system SB300 by SOLIDRAY Co. Ltd.

The eye mark recorder is divided into 5 parts: a head unit assembled in a baseball cap, a controller, an eye mark detecting unit, a software for eye movements analysis and an AC adapter. The head unit is a 1/4 inch colour CCD camera for recording a visual field and its weight is almost 300 gr. The eye mark detecting unit uses 1/3 inch CCD, its measuring scope is within 40 deg. The detecting method is pupil/cornea reflection and the detecting rates are 60 Hz (monocular) and 30 Hz (binocular). The controller has detection power of less than 0.2 deg, its outputs are images of visual field, signals of pupil image, and RS-232C serial data (XY co-ordinates, diameters of pupil, numbers of frames). By the supplied software, one can obtain a graph of eye marks, a graph of diameters of pupil in a time series, results from fixation points analysis, a graph of conversion angles in a time series, etc.

The display system is divided into 4 part: a DOS/V computer, a vertical synchroniser (SB300T), active liquid crystal glasses (SB300G) and a graphic software developed by us. The SB300T has signal inputs such as a frame sync (TTL), a composite video (RS-343A compatible), or separate horizontal and vertical sync, NTSC/PAL, a vertical sync. The SB300G has a more than 26% transmittance, a less than 0.5 ms close time, a less than 2.8 ms open time. Especially, we produced the graphic software for the 3-D virtual display. The software is written in the language C by use of the Open GL graphic library. A picture for the left eye can be displayed in the upper half of the CRT, and a picture for the right eye can be displayed in the lower half of it. The synchroniser makes each picture twice as large in its vertical size and then it can display the right picture when the right shatter of SB300G is opened, and can display the left picture when the left shatter is opened. Available pictures are moving images from CCD cameras and stored computer graphic images.

When each picture has visual disparity, we can recognise the picture in the virtual 3-D space. By the system, we can compare eye movements in the virtual vision and in the real vision.