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2017 IEEE Virtual Reality (VR) (2017)
Los Angeles, CA, USA
March 18, 2017 to March 22, 2017
ISSN: 2375-5334
ISBN: 978-1-5090-6648-3
pp: 213-214
Yuta Itoh , Keio Univ., Japan
Jason Orlosky , Osaka Univ., Japan
Kiyoshi Kiyokawa , Osaka Univ., Japan
Toshiyuki Amano , Wakayama Univ., Japan
Maki Sugimoto , Keio Univ., Japan
We present a method for focal distance estimation of a freely-orienting eye using Purkinje-Sanson (PS) images, which are reflections of light on the inner structures of the eye. Using an infrared camera with a rigidly-fixed LED, our method creates an estimation model based on 3D gaze and the distance between reflections in the PS images that occur on the corneal surface and anterior surface of the eye lens. The distance between these two reflections changes with focus, so we associate that information to the focal distance on a user. Unlike conventional methods that mainly relies on 2D pupil size which is sensitive to scene lighting and the fourth PS image, our method detects the third PS image which is more representative of accommodation. Our feasibility study on a single user with a focal range from 15–45 cm shows that our method achieves mean and median absolute errors of 3.15 and 1.93 cm for a 10-degree viewing angle. The study shows that our method is also tolerant against environment lighting changes.
Cameras, Three-dimensional displays, Lighting, Estimation, Measurement by laser beam, Solid modeling, Two dimensional displays

Y. Itoh, J. Orlosky, K. Kiyokawa, T. Amano and M. Sugimoto, "Monocular focus estimation method for a freely-orienting eye using Purkinje-Sanson images," 2017 IEEE Virtual Reality (VR), Los Angeles, CA, USA, 2017, pp. 213-214.
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