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Proceedings Paper

A TV Camera System Which Extracts Feature Points For Non-Contact Eye Movement Detection
Author(s): Akira Tomono; Muneo Iida; Yukio Kobayashi
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Paper Abstract

This paper proposes a highly efficient camera system which extracts, irrespective of background, feature points such as the pupil, corneal reflection image and dot-marks pasted on a human face in order to detect human eye movement by image processing. Two eye movement detection methods are sugested: One utilizing face orientation as well as pupil position, The other utilizing pupil and corneal reflection images. A method of extracting these feature points using LEDs as illumination devices and a new TV camera system designed to record eye movement are proposed. Two kinds of infra-red LEDs are used. These LEDs are set up a short distance apart and emit polarized light of different wavelengths. One light source beams from near the optical axis of the lens and the other is some distance from the optical axis. The LEDs are operated in synchronization with the camera. The camera includes 3 CCD image pick-up sensors and a prism system with 2 boundary layers. Incident rays are separated into 2 wavelengths by the first boundary layer of the prism. One set of rays forms an image on CCD-3. The other set is split by the half-mirror layer of the prism and forms an image including the regularly reflected component by placing a polarizing filter in front of CCD-1 or another image not including the component by not placing a polarizing filter in front of CCD-2. Thus, three images with different reflection characteristics are obtained by three CCDs. Through the experiment, it is shown that two kinds of subtraction operations between the three images output from CCDs accentuate three kinds of feature points: the pupil and corneal reflection images and the dot-marks. Since the S/N ratio of the subtracted image is extremely high, the thresholding process is simple and allows reducting the intensity of the infra-red illumination. A high speed image processing apparatus using this camera system is decribed. Realtime processing of the subtraction, thresholding and gravity position calculation of the feature points is possible.

Paper Details

Date Published: 1 April 1990
PDF: 19 pages
Proc. SPIE 1194, Optics, Illumination, and Image Sensing for Machine Vision IV, (1 April 1990); doi: 10.1117/12.969833
Show Author Affiliations
Akira Tomono, ATR Communication Systems Research Laboratories (Japan)
Muneo Iida, ATR Communication Systems Research Laboratories (Japan)
Yukio Kobayashi, ATR Communication Systems Research Laboratories (Japan)

Published in SPIE Proceedings Vol. 1194:
Optics, Illumination, and Image Sensing for Machine Vision IV
Donald J. Svetkoff, Editor(s)

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