Radially variant contrast measurement in virtual reality headsets using circular concentric ring patterns

Abstract

AbstractImage quality on virtual reality (VR) head‐mounted displays (HMDs) is radially variant on each eyepiece from the visual center (optical axis of the HMD) towards the periphery. The virtual image is blurred at the periphery of display field of view (FOV) resulting in contrast and resolution degradation. Conventional measurement methods adopted from flat‐panel display evaluation do not consider the spatially dependent image artifacts by additional optical components such as HMD lenses and thus may not be adequate to assess the VR image quality. We develop a new method using circular concentric ring patterns to measure the radially variant Michelson contrast on multiple VR HMDs. The results show that measured image contrast reduces towards the periphery of display FOV especially at high‐spatial frequencies. In addition, image quality on VR HMDs can be affected by the 3D position of the eye (or the camera) within the eyebox. Specifically, contrast is further degraded if the interpupillary distance (IPD) setting of the HMD does not match that of the user. It also varies with the entrance pupil location of the light‐measuring device. We propose an efficient method for image quality evaluation that can facilitate the regulatory evaluation of VR headsets.