Evaluation of user-centric optical see-through head-mounted display calibration using a leap motion controller

Abstract

Advances in optical see-through head-mounted display technology have yielded a number of consumer accessible options, such as the Google Glass and Epson Moverio BT-200, and have paved the way for promising next generation hardware, including the Microsoft HoloLens and Epson Pro BT-2000. The release of consumer devices, though, has also been accompanied by an ever increasing need for standardized optical see-through display calibration procedures easily implemented and performed by researchers, developers, and novice users alike. Automatic calibration techniques offer the possibility for ubiquitous environment independent solutions, un-reliant upon user interaction. These processes, however, require the use of additional eye tracking hardware and algorithms not natively present in current display offerings. User dependent approaches, therefore, remain the only viable option for effective calibration of current generation optical see-through hardware. Inclusion of depth sensors and hand tracking cameras, promised in forthcoming consumer models, offer further potential to improve these manual methods and provide practical intuitive calibration options accessible to a wide user base. In this work, we evaluate the accuracy and precision of manual optical see-through head-mounted display calibration performed using a Leap Motion controller. Both hand and stylus based methods for monocular and stereo procedures are examined, along with several on-screen reticle designs for improving alignment context during calibration. Our study shows, that while enhancing the context of reticles for hand based alignments does yield improved results, Leap Motion calibrations performed with a stylus offer the most accurate and consistent performance, comparable to that found in previous studies for environment-centric routines. In addition, we found that stereo calibration further improved precision in every case. We believe that our findings not only validate the potential of hand and gesture based trackers in facilitating optical see-through calibration methodologies, but also provide a suitable benchmark to help guide future efforts in standardizing calibration practices for user friendly consumer systems.