Perceptual Evaluation of Interpupillary Distances in Head-mounted Display Environments

Head-mounted displays (HMDs) allow users to explore virtual environments (VEs) from an egocentric perspective. In order to present a realistic view, the rendering system has to be adjusted to the characteristics of the HMD, e. g., the display’s field of view (FOV), as well as to characteristics that are unique for each user, in particular, the interpupillary distance (IPD). In the optimal case, the rendering system is calibrated to the binocular configuration of the HMD, and adapted to the measured IPD of the user. A discrepancy between the user’s IPD and stereoscopic rendering may distort the perception of the VE, since objects may appear minified or magnified. In this paper, we describe binocular calibration of HMDs, and evaluate which IPDs are judged as most natural by HMD users. In our experiment, subjects had to adjust the IPD for a rendered virtual replica of our laboratory until perception of the virtual replica matched perception of the real laboratory. Our results motivate that the IPDs which are estimated by subjects as most natural are affected by the FOV of the HMD, and the geometric FOV used for rendering. In particular, we found that with increasing fields of view, subjects tend to underestimate their geometric IPD.