E T V I S I O N M A N U A L
4
1
Introduction and General System Description
ETVision
(ETV) is a lightweight wearable system for measuring binocular point of gaze 180 times per
second.
The wearable unit resembles an eyeglasses frame that can be worn by itself or over the participant’s
prescription eyeglasses. It contains miniature “eye cameras” that view each eye and a “scene camera”
that views the scene in front of the participant, and a microphone. An optional visor can be mounted
to front of the headgear.
A cable extending from the earpiece connects to a small Controller (slightly larger than a smart phone)
that easily fastens to an adjustable belt or can be held by the participant (or near the participant) in
some other way. The Controller holds a mico SD card for video and audio data recording, and
includes a rechargeable battery. It can also be powered directly from a DC power supply.
The
ETVision
system also includes a laptop PC that connects to the Controller in real-time via a LAN
cable or via WiFi. Alternately, the PC can read video and audio data from a microSD card previously
recorded by the wearable Controller. Note that by using the WiFi connection or recording to an SD
card for later data processing, the subject can be completely un-tethered while data recording takes
place.
An application running on the laptop PC uses the video images from the wearable cameras to compute
point-of-gaze with respect to a scene camera coordinate frame. The laptop can record the digital gaze
coordinates 180 times per second. This digital file also includes pupil diameter of each eye and other
feature detection measurements used as part of gaze computation.
In addition to recording a digital file, the PC application shows a real time display of the eye and scene
camera images and records these as wmv type video files. The 1280x720p scene image updates 30
times per second and includes a superimposed cursor showing the participant’s point of gaze in the
scene image. The scene video also includes audio from the head gear mic or a local mic. The eye
camera video displays include superimposed outlines and crosshairs to show proper recognition by the
system of eye image features.
The laptop PC can stream the 180 Hz, real-time, digital data to external devices via LAN, or stream
the real-time video scene image to external devices via LAN.
The Argus Science
ETAnalysis
application, usually included with the basic system, can be used to
play back and analyze gaze data recorded with
ETVision
. Detailed instructions for use of the
ETAnalysis
application are provided in a separate manual.
An optional addition to the basic system, called
ET3Space
, uses head position and orientation data
from one of several third party motion tracking devices to compute gaze with respect to a room fixed
coordinate system and to determine point-of-gaze on multiple surfaces in the environment. This
optional feature is described in a separate manual.