Method for characterizing small-spot luminance in medical virtual reality headsets

Abstract

We present an experimental method that utilizes a conic probe attached to an integrating sphere for characterizing the small-spot luminance of virtual reality (VR) head-mounted displays (HMDs). This allows for the measurement of relative luminance in virtual scenes and the assessment of VR displays for visualizing grayscale medical images. We characterized the relative luminance of the VIVE Pro and Oculus Rift by displaying test patterns with a circular dark spot of varying diameter in the bright field and compared the probe performance with commercially available systems. Compared to a conventional flat-panel display, the results show a significant level of veiling glare in the HMDs using both a customized conic probe with improved optical performance and an advanced imaging photometer. We also found no significant change in the relative luminance response with the probe’s working distance for the HMDs due to their unique optical architecture for near-eye viewing conditions. Our results highlight the issue of high veiling glare in HMDs and the importance of small-spot luminance measurements to adequately evaluate the technical performance of HMDs for emerging medical applications.