Eyehead Integration

Eye Head Integration With Head Mounted Optics

EYEHEAD™ integration is necessary to get digital data that specifies point of gaze with
respect to stationary objects in the environment. The EYEHEAD integration package, for
use with head mounted optics enables integration of eye and head position data to compute
real time point of regard. Required hardware includes a head tracking device, such as the
Ascension Flock of Birds or Laser Bird, Optotrak Certus, the Polhemus Fast Track or the
Intersense tracking system. All are supported by the ASL eye tracking system.

Eye Head Environment

The EYEHEAD™ “environment” consists of the head tracker transmitter and up to 20 surfaces
of interest. Typical surfaces include monitor screens, keyboards, poster displays, slide
screens, walls, etc. EYEHEAD data consists of the identification number of the scene surface
being viewed, coordinates of the gaze point on that surface, the distance of the eye from
the spot being fixated and pupil diameter. Note that this information does indicate what
the subject is viewing in the environment

Advantages To The ASL System When Combined With Head Tracking

• Computes the location of the gaze vector in true 3 dimensional space
• Determines intersection of gaze with multiple flat surfaces whose location, orientation and boundaries are known in true 3D space.
• Surfaces are easily specified to system using a laser pointing device (3 points define a surface)
• Can accurately superimpose a point of gaze cursor on the image from a stationary (non‐head mounted) scene camera. Most systems can only superimpose a cursor on a head mounted scene camera image.
• Better image than head mounted camera
• Less to wear on the head
• One less thing to set up and adjust
• System gives long term accuracy and does not require frequent recalibration.

EYEHEAD Environment While Playing The Piano

EYEHEAD™ integration combined with head mounted optics when playing the piano.

Sample EYEHEAD™ data
The raw data was gathered as a subject played an electric piano keyboard with a music book above the keyboard.The music stand was also the calibration surface and is scene plane 0.The piano keyboard was set up as scene plane 1.

ASL systems come bundled with our exclusive EYENAL™ analysis software, which will:

• Reduce data to a list of fixations
• Specify areas of interes
• Match fixations with areas of interest
• Compute statistics relating fixations to areas of interest
• Superimpose plot of fixation “scan path” over image viewed by subject