In this paper, two empirical studies, 'pointing task'and 'assembling task'are conducted in order to compare HMD with 40 inch projector as a display device for direct manipulation in a virtual workspace. In 'pointing task, 'it was shown that 40 inch projector was preferred to HMD with relatively small workspace, while HMD was preferred to 40 inch projector with relatively large workspace. In 'assembling task, 'it was shown that HMD was preferred to 40 inch projector even with small workspace.

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This article describes a sytem for the reconstruction of relics from the broken pieces by using Virtual Reality technology. The 3D shape and the texture of the broken pieces of a relics are first digitized with a laser range finder. Then a 3D surface model is built based on the digitized data of the relics in order to generate a virtual piece of the relics, which can be displayed and manupulated easily on a graphics workstation. The reconstruction of the relics is carried out in a Virtual Reality Environment where the operator performs the reconstruction job using the virtual piece with a stereo display and a data glove as the input device.

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We have developed an interactive multimedia system for the appreciation of three-dimensional art objects, such as porcelain and sculptures. With the system, the viewer is able to see a representation of the object from various directions as if holding it in his/her hands. He/she can enjoy the object images on high-quality HDTV (Hi-Vision) display, with supplementary andio and written information about the object. This system consists of (1) a video server, to store the HDTV images of the fine arts, which have been shot from various paths around the fine arts at 0.2 degree intervals ; (2) a specially designed manipulator to select a desired image from the server, and (3) an HDTV or stereoscopic HDTV display, and accompanying spectacles. The HDTV video server can randomly access data at a video rate (1/60 sec), so as to quickly respond to the operations of the manipulator. The experimental system has been tested by many artists and scientists for operability and effectiveness, and has been confirmed as useful for art galleries and other educational institutions.

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Virtual Reality technology provides a new methodology for human interface with realistic sensation, and has been received growing attention in the fields of human interface, computer graphics and computer vision. Reality of the virtual space is realized by generating photorealistic views in real time with computer graphic technology. One of key issues for the real time view generation problem is how to represent and display the 3-D virtual space efficiently with adapting human vision sensitivity. In this paper, we propose a novel and efficient approach for hierarchical modeling and view generation of the 3-D objects, in which the resolution of each level is determined according to the distance from the observer to the object based on the depth perception sensitivity of human vision. The object is then efficiently displayed with sufficient accuracy by selecting the appropriate level of the model based on the distance between the observer and the object. Experimental results demonstrate the efficiency and connectness of the proposed approach.

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Binocular fusional rage is measured under a condition that a subject shifts his gaze alternately between center and peripheral region of the random dot stereogram to clarify how the center and peripheral region of the presented image contribute. The result indicates that the peripheral region does not have an influence to the range of the fusional limit in uncross disparity condition. In cross disparity condition, both of the central and peripheral region have influence to the range of the fusional limit.

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States of atmospheric air have continuously been observed positive and negative ions distributions (0.0005〜0.01 microns) and densities, using ioncounter of Model KSI-1000. This report describes that the precursor of the Severe Hanshin Earthquake, the evaluation of spatial environment and the television image quality recorded on the ions densities data in January 1995.

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To contribute to ITU-R Recommendation, subjective evaluation of the relative timing of television sound and vision signals was carried out in Japan, Switzerland and Australia. ITU-R Working Party 11A predetermined experimental conditions, such as test material, camera type and viewing distance. The results show that the detectable thresholds are 45 ms for sound advance and 125 ms for sound delay relative to the vision signal ; and the acceptable threshold are 90 ms for sound advance and 185 ms for sound delay.

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