A robust camera-based method for optical distortion calibration of head-mounted displays

Abstract

One of the problems in using head-mounted displays (HMDs) is that the virtual images shown through the HMDs are usually distorted due to their optical distortions. In order to correctly compensate the optical distortions through a predistortion technique, accurate values of the distortion parameters are required. Although several distortion calibration methods have been developed in prior work, these methods suffer a few critical limitations. In this paper, we proposed a method for robustly estimating the optical distortion parameters of both immersive and (optical) see-through HMDs, without the limitations of existing methods. The proposed method is based on photogrammetry and considers not only the radial distortion but also the tangential distortion. Its effectiveness was evaluated through an experiment conducted with two different types of HMDs, an optical seethrough head-mounted projection display and a commercially available non-see-through HMD. According to the experimental results, the proposed method showed significantly lower reprojection error than a previous method proposed by Owen et al. In addition, when both the radial and tangential distortions were considered, the proposed method was significantly more effective than when only the radial distortion was considered.

Light-Field Correction for Spatial Calibration of Optical See-Through Head-Mounted Displays

“…Our correction method considers an optical phenomenon that the optical elements distort incoming world light rays. In the same manner, the elements also distort virtual screens perceived by users into a nonplanar surface [20,21,27]. Even the assumption that we treat the virtual screen as a collection of 3D points floating in mid air is violated when the light sources are collimated as in retinal displays.…”

“…Future work directions involve: considering the distortion of the virtual screen [20,21,27] which is assumed to be planer in this paper, deepening the understanding of the eye-dependent parameters [28], investigating the possibility of automated frame-wise OST-HMD calibrations, establishing and refining ways to compare different calibration methods with both subjective [24] and objective error measurements, overcoming the latency issue which is also another dominant aspects directly affects to the spatial registration quality [37], and so on.…”

High dynamic range head mounted display based on dual-layer spatial modulation

“…All captured images were digitally pre-warped using these calibrated parameters before applying display calibration. Through two separate calibration steps, we adopted our existing camera-based HMD calibration method [14] to obtain the inverse homographic mapping transformation matrices,…”

“…The calibration steps also obtain the optical distortion coefficients induced to the images of the SLMs. The first three orders of radial distortion and two orders of tangential distortion coefficients were calibrated by using camera-based HMD calibration mentioned in [13,14]. Based on these calibrated parameters, a computational model is established for each of the SLM optical paths, through which a pixel displayed on one of the SLMs can be properly aligned with a corresponding pixel on the other SLM during the HDR image rendering process, to digitally correct alignment errors.…”

Division model‐based distortion correction method for head‐mounted displays

“…In a wide variety of application fields, including military, medical science, industry, and entertainment, HMDs work by presenting computer‐generated images in front of the viewers' eyes . However, one of the major problems that they suffer from is a geometrical distortion of the projected virtual image, leading to an uncomfortable visual effect or an inaccurate image information recognition . These distortions are more pronounced in the optical system of a wide field of view (FOV) HMD .…”