Study on the Difference of Reaching Cognition Between the Real and the Virtual Environment Using HMD and its Compensation

The purposes of this research are to investigate the information necessary for cognition of the VR environment using “Reaching” and to examine how to compensate the difference of cognition between the real and the VR environment. Therefore, this research conducts a task in VR to acquire cognition with the VR environment (Cognitive acquisition task) first. This task is one for a subject to be acclimated to VR environment. The important thing is that the subject's arms and hands and their actions are shown in VR environment using CG. Second, comparative experiment using Reaching is conducted. Cognitive acquisition task is conducted using simple action task related to reaching, such as stacking blocks and rolling spheres. In Reaching experiment, first, a subject estimate whether the subject can grasp a cylinder placed in front of the subject by just stretching arms in thought. After that, the subject grabs the cylinder and places it as far as possible. The results are investigated in the real and the virtual environment. In the real, it has been found that the longest distance to an object for a person to decide to be able to reach for and grab the object (CDDG) is about 1.1 times as long as the longest distance where a person actually can reach for grabbing the object (CRDG). The previous studies have shown that the ratio of CDDG and CRDG in VR is not 1.1 and its compensation is difficult. However, as a result of this research experiment, CDDGs in this research were the same value in the real and the VR environment. And in the case of VR with reduced environmental information, CDDG in VR was different from one in real. As the result, it was suggested that the difference in cognition could be compensated by including the necessary and sufficient environmental and user's information (CG model of user's body and user's movement) and an appropriate cognition could be realized even in the current VR environment.