Perceived depth from subjects' position of actual or virtual objects presented in a virtual or a real space was measured. The objects presented were chosen from abstract forms, such as a sphere and a rectangle, and well-known concrete goods, such as a tennis ball and a postcard. The virtual objects were modeled and displayed on a CRT screen so that the subjects could view them as 3D objects through a liquid-crystal-shuttered glasses. Fifteen subjects expressed the perceived distance to objects verbally and seven responded by indicating the object position with their index finger. Every actual object was perceived to exist at a distance proportional to real one, but it was always underestimated. Nearer virtual objects were felt more distant than actual and farther ones were felt nearer than actual. These characteristics were explained by a two-channel model with the accommodation sensory channel and the convergence sensory channel under hypothesis that if the values obtained from the two channels differ, depth perception is compensated using the both values.
