A proposal of new method for the depth accuracy in a virtual world

Stereoscopic displays, such as HMDs or lenticular screens, have a functional problem that is the disorder of the convergence and the accommodation. This disorder affects the depth accuracy. In this paper, we propose a new practical evaluation method of the depth accuracy in a virtual world, using by the stereoscopic display, and discuss a result of the evaluation. In this method, we focused the disorder of the convergence and the accommodation. To evaluate this disorder, we used HMD with our developed function, called the accommodative compensation. The accommodative compensation can regulate the depth position of the displayed image. In this evaluation, we used a subjective assessment method applying moving stimulus images, and showed stimulus images to subjects that changed the relationship of the convergence and the accommodation, by using the accommodative compensation function of the HMD. We quantitatively evaluated the effects of disorder of the convergence and the accommodation. The main index of the evaluation was the time difference of the ball manipulating actions at the ball game. We assume that such time differences indicate the tolerance of the perception of depth. Results suggest that the disorder may affect the depth accuracy.