Laboratory

The VIRG gaze laboratory is located in a traditional two-room usability lab with a one-way mirror between the rooms. The eye tracking equipment is set up according to the needs of each study, but when nothing special is going on, a Tobii T60 is set up and ready to be used for eye tracking. With the new mobile and low-cost trackers we increasingly take the tracking equipment where needed instead of bringing the study into the gaze lab.

Eye Tracking Equipment

Pupil Labs Tracker

Pupil Labs builds excellent head-mounted trackers with many possible camera configurations. The version we have is from late 2015 with 120Hz eye cameras and a Full-HD scene camera and one USB3 plug for connecting to computers. The software is open source, which allows interefacing and integrating with whatever other software is needed for any given project.

EyeLink 1000 Plus

With its 1000Hz sample rate and other high performance features the EyeLink 1000 allows us to study details of eye movements at a higher resolution than the other trackers we have. It has been used, for example, to investigate eye movement dynamics in gaze gestures.

Ergoneers Dikablis (Professional)

The Dikablis Professional is a binocular head-mounted 60Hz tracker with better mobility than our old EyeLink II. Attached to a windows tablet or a laptop it can stream gaze data over Wifi. With visible tags placed in the environment we can build setups where we can test gaze interaction in everyday environment. Conventional non-interactive eye tracking studies are also possible.

Tobii EyeX

The Tobii EyeX tracker is intended for gaming and other consumer products. It has a different programming interface than the more scientifically oriented Tobii trackers. For many of our interactive prototyping needs, however, it is more than adequate. The low price makes it possible to loan it to students and other collaborators without fear of trouble if an unit is lost or broken. Together with the ET1000 this tracker has by far the best price/performance ratio of all devices that we have seen.

Eye Tribe ET1000

Eye Tribe’s devices were available in early 2014 for developers at a very low price. Several of our researchers ordered them. The application scenarios are similar to Tobii X2-60, but the low price makes it possible to use as many devices as needed. The bright lights you can see in the photo are mostly infrared light that is invisible to the human eye, but is picked up by many digital cameras. All trackers listed on this page use similar illumination to see the eye clearly and to have trackable reflections on the surface of the eye. To the human eye the lighting is seen as a dark red glow that is often barely perceptible.

Tobii X2-60

The Tobii X2-60 is a bar-like device that you can attach to the lower border of a display (or a laptop or pretty much to anything). Our first X2-60 was acquired in 2014. It has a big head box and it is fairly robust regarding environment lighting and head movements (as long as they are not too fast). It is easier to transport for demos and on-site tracking sessions than the T60, for example.

Tobii T60

The Tobii T60 is integrated into a 17″ LCD monitor and it provides non-intrusive plug-and-play tracking of the eye movements and gaze direction. We have two of these units. One is usually in the lab, while the other sits on a cart that can be moved to wherever a tracker is needed. We use the T60 for most of the work we do nowadays. This includes a range of gaze related research, such as controlling a computer by gaze alone (playing games by gaze, drawing, text entry etc.), as well as research on gaze behavior (gaze paths, usability studies etc.).

History of eye tracking equipment at VIRG

As stated above, most of our work has used the Tobii T60. Over the years we have progressed through a series of tracking equipment. Some of the data on these devices is archived here.

Ergoneer’s Dikablis (Essential)

In 2014 while waiting for the shipping of the binocular model we used the older 30 Hz Dikablis Essential for a few prototypes. This tracker fit nicely over eye glasses and worked with our older computing hardware without USB 3 ports.

Tobii 1750

We got the Tobii 1750 eye-tracker in 2004 and updated it to a T60 in 2009. We have used the 1750, e.g., to study the usability of web search engines.

Specifications:
Sampling rate: 50Hz
Gaze position accuracy: 0.5 degrees
Freedom of head movement: 30 x 15 x 20 cm at 60 cm from the tracker
Features: binocular, long-lasting calibration
For more info about Tobii, see Tobii web pages.

SMI iView X

We got the SMI iView X remote tracker in 2002. We have used iView X, e.g., to study eye typing.

Specifications:
Sampling rate: 50Hz
Gaze position accuracy: 0.5-1 deg
Tracking resolution, pupil/cr: 0.1 deg
Operating distance subject-camera: 04.-1.0 m
Head tracking area: 40 x 40 cm at 80 cm distance
For more info about iView X, see SMI web pages.

iViewX is small enough to be placed beside the monitor.

The eye and the gaze path are illustrated in the iView X operator monitor. The system tracks the center of the pupil (black crosshair) and the corneal reflection (white crosshair). This photo was taken when the user was reading text.

EyeLink

We have had the head-mounted EyeLink since 1999. It has two cameras so it can monitor both eyes at the same time. We have used EyeLink, e.g., to study how people read foreign text, and for usability testing.

Specifications:
Sampling rate: 250 Hz
Gaze position accuracy: 0.5-1.0 deg average
Eye position tracking range: +/-30 deg horizontally, +/-20 dec vertically
Gaze position tracking range: +/-20 dec horizontally, +/-17 vertically (with head tracking)
Pupil size resolution: 0.1% (0.01 mm change detectable)
Working distance: 4-7 cm camera-to-eye distance. 40-140 cm display-to-eye working range.

In the left image, a user is reading text. The boundaries of the words are visualized in the operator monitor (right), together with two spots for the eyes.

Eyelink came with a cool glasshead rack for storing the head-worn part when not in use.

ASL 4250R+

We purchased the ASL tracker in 1996. The ASL tracker is a remote, floor-mounted, eye tracking device. We have used it, e.g., to study how people read menus, or how affective stimuli affects the pupil size.

This is the only eye tracker that has exploded in our lab. This happened when one of the fans that keep it cool was malfunctioning and the light bulb used for generating the infrared light overheated. As usual for the robust technology of the past decades, the tracker continued working just fine after the fan and the light bulb were replaced. After the newer trackers such as the Tobii 1750 were acquired, this tracker was used by the ESC group until it was finally archived as a museum piece in 2013.

Specifications:
Sampling rate: 60 Hz
Precision: 0.5 deg
Allowable head motion: +/-15 cm vertical and horizontal
Allowable eye movement: 40 deg horizontal, 35 deg vertical
Eyeglasses/contact lens: most are accepted
Eye to camera distance: 50-225 cm

The ASL eye tracker is placed under the monitor (left) in the usability lab. The operator can monitor the eye movements and make sure the eye and the pupil are tracked properly (right). Take note of the big gray box. All that (and the camera) is integrated in the tiny bar shaped body of the new trackers.