Monocular focus estimation method for a freely-orienting eye using Purkinje-Sanson images

Yuta Itoh, Jason Orlosky, Kiyoshi Kiyokawa, Toshiyuki Amano, Maki Sugimoto

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Scopus citations


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.

Original languageEnglish (US)
Title of host publication2017 IEEE Virtual Reality, VR 2017 - Proceedings
PublisherIEEE Computer Society
Number of pages2
ISBN (Electronic)9781509066476
StatePublished - Apr 4 2017
Externally publishedYes
Event19th IEEE Virtual Reality, VR 2017 - Los Angeles, United States
Duration: Mar 18 2017Mar 22 2017

Publication series

NameProceedings - IEEE Virtual Reality


Conference19th IEEE Virtual Reality, VR 2017
Country/TerritoryUnited States
CityLos Angeles


  • Augmented
  • H.5.1 [Information interfaces and presentation]: Multimedia information systems - Artificial
  • Virtual realities

ASJC Scopus subject areas

  • Engineering(all)


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