Web Posted on: January 4, 1999

QUICK GLANCE: EYE-TRACKING ACCESS TO THE WINDOWS95 OPERATING ENVIRONMENT

David Rasmusson
Robert Chappell
Melinda Trego
Mesa, AZ
URL: www.eyetechds.com
email: info@eyetechds.com

Introduction to Quick Glance

Access to the functionality of personal and local area network computer systems is proving ever more important in today's technological society. PCs' potential to increase productivity and enhanced communication is apparent, and proven in many fields: PC personal and working groups productivity tools, such as Microsoft's Office suit of products, are standard fair for computer users; and the advent of the world wide web has brought the ability to disseminate information in many forms to a wide audience irrespective of many traditional barriers. The development and application of adaptive devices have broken down further the barriers that have abated the disabled from benefiting from this technology.

One such development and application is the use of eye-tracking technology. In principle, an eye-tracker system determines the gaze point and length of gaze of the user. It can, therefore, indicate to the computer where on, and for how long thereupon, the computer monitor the user is looking, thus replacing the traditional PC mouse. Selections or, in the case of those systems running under the Windows95 operating environment, "clicks" can be made by a slow blink or other switching mechanisms. Together with companion software, such as on-screen keyboards and voice recognition software, an eye-tracker system becomes a completely hands-free method for computer use. This is an attractive alternative for those unable to operate the traditional mouse interface of a PC computer due to, say, restricted hand movements.

However, most eye-tracking systems on the market today have drawbacks: they may not run under the Windows95 operating system and Pentium platform; or they may require intrusive or expensive hardware; or they may be too costly for many individuals to purchase. This paper introduces EyeTech Digital Systems' product Quick Glance, an eye-tracking system that is free of these limitations. After the introduction of Quick Glance, the system will be demonstrated.

How Quick Glance Works

To measure the user's gaze point, Quick Glance examines the reflections from the user's eye which is illuminated by two low power infrared LEDs which are mounted on the computer's monitor. The reflected light is focused onto a simple image sensing camera, also mounted on the computer's monitor. The image of the eye upon which the camera is focused is captured at a fast and user determined rate by image capturing hardware provided with the system. By analyzing the position of the light reflections and the center of the pupil contained in the image, the RAM resident software determines the gaze point. Gaze point duration can also be derived. With that information, the software controls the location of the cursor according to the gaze point and its duration.

The Quick Glance System and Installation

The Quick Glance system consists of two (2) infrared LED light sources, a camera, a power supply and cabling, a PCI bus board, software and documentation. The camera and light sources are mounted on the computer's monitor with double-sided tape. (See figure 1.) They are plugged into the power supply which is itself plugged into a standard 110 volt electrical outlet. The video capture card (PCI bus board) is installed into an available computer slot and connected to the camera with a cable. The software is installed by running a software installation program that's similar to most Windows installation procedures.

Running Quick Glance

A user must conduct a calibration of his eye's gaze point for the Quick Glance system. This calibration is a one-time event lasting about one minute. Quick Glance's calibration has proven robust enough in several situations that if a user is unable to conduct the calibration, often someone else's calibration can be employed without reducing performance materially.

Quick Glance can then be used to access all the wonderful multitasking features of the Windows95 operating environment and associated software.

Restrictions

Strong infrared sources, such as sunlight or incandescent lights, from certain angles will cause the system to fail to track properly. Florescent lights, however, have never proved a problem. Also, users wearing glasses is not usually a problem, although the user may have to tilt them slightly to move reflections away from his eye's pupil. We have found that some contact lenses interfere with tracking.

A Quick Glance At Quick Glance Facts

Method: Infrared video imaging, pupil center and corneal reflection.

Features: Gaze point calculation and duration; Windows95 cursor control.

Mounting: Camera and 2 infrared LEDs mounted on monitor; nothing on user.

Sampling: User can adjust sampling from 1 to about 15 frames per second.

Applications: All applications needing gaze point determination or gaze point duration.

Figure 1. (Back to text.)