User manual

Introduction
© 2005-2008 SR Research Ltd.
9
1.3 System Specifications
1.3.1 Operational / Functional Specifications
Desktop and Arm Mounts
Tower
Mount
Primate
Mount
Base
System
Remote Option
(license required)
Average Accuracy
1
down to 0.15° (0.25° to 0.5° typical) 0.5° typical
Monocular: 250, 500,1000, 2000 Hz
Sampling rate
2
Binocular*:
250, 500, 1000 Hz
Monocular:
250, 500 Hz
End-to-End Sample Delay
3
M < 1.8 msec, SD < 0.6 msec @ 1000 Hz
M < 1.4 msec, SD < 0.4 msec @ 2000 Hz
M < 3.0 msec,
SD=1.11 msec
Blink/Occlusion Recovery
M < 1.8 msec, SD < 0.6 msec @ 1000 Hz
M < 1.4 msec, SD < 0.4 msec @ 2000 Hz
M < 3.0 msec,
SD=1.11 msec
Spatial Resolution
4
< 0.01° RMS @ 1000 Hz
< 0.02° RMS @ 2000 Hz
< 0.1° RMS
Eye Tracking Principle
5
Dark Pupil - Corneal Reflection
Pupil Detection Models
Centroid or Ellipse Fitting Ellipse Fitting
Pupil Size Resolution
0.2% of diameter TBD
Gaze Tracking Range
60° horizontally,
40° vertically
32 º horizontally,
25 º vertically
Allowed Head Movements
Without Accuracy Reduction
±25 mm horizontal or vertical
6
,
±10 mm depth
22x18x20 cm
(horizontal x
vertical x depth)
Optimal Camera-Eye Distance
Fixed at about 38 cm Between 40 - 70 cm
Glasses Compatibility
Good Excellent Good
On-line Event Parsing
Fixation / Saccade / Blink / Fixation Update
EDF File and Link Data Types
• raw eye position
• HREF position
• gaze position
• pupil size
• buttons
• messages
• digital inputs
Real-Time Operator Feedback
Eye position cursor or position traces.
Camera images and tracking status.
* Binocular Recording not available with the Arm Mount
1
Measured with real eye fixations at multiple screen positions on a per subject basis.
2
Availability of some sampling rates depends on the camera licensing. Values in Table are Color
Coded: EyeLink 1000 system; EyeLink 2000 system required
3
Time from physical event until first registered sample is available via Ethernet or Analog output.
Optional data filter algorithm adds one sample delay for each filtering level.
4
Measured with an artificial pupil.
5
Pupil-Only tracking mode is available for use in head fixed conditions.
6
Binocular tracking with Desktop Mount can reduce allowed head movement to approx. 25 mm
Horizontal and Vertical.