Tobii X2-30 eye tracker compact edition Technical specifications

Product Description

Tobii X2-30 Eye Tracker Compact Edition

Tobii X2-30 Eye Tracker Wide Edition

Tobii X2-60 Eye Tracker Compact Edition

Tobii X2-60 Eye Tracker Wide Edition

Product Description

Manual Version 1.0

01/2013

The information contained in this document is proprietary to

Tobii Technology. Any reproduction in part or whole without

prior written authorization by Tobii Technology is prohibited.

Products that are referred to in this document may be either

trademarks and/or registered trademarks of the respective

owners. The publisher and the author make no claim to these

trademarks.

While every precaution has been taken in the preparation of

this document, the publisher and the author assume no

responsibility for errors or omissions, or for damages resulting

from the use of information contained in this document or

from the use of programs and source code that may

accompany it. In no event shall the publisher and the author

be liable for any loss of profit or any other commercial

damage caused or alleged to have been caused directly or

indirectly by this document.

Content subject to change without notice.

Please check Tobii web site www.tobii.com for updated

versions of this manual.

Table of Contents

11 IInnttrroodduuccttiioonn .................................................................................................................................................................................................................................................................... 11

1.1 Overview...............................................................................................................................1

1.2 ApplicationsAreas..................................................................................................................2

1.3 asic Operating Principles ......................................................................................................2

22 TTeecchhnniiccaall SSppeecciiffiiccaattiioonnss .......................................................................................................................................................................................................................... 33

2.1 Tobii X2–30 Eye Trackers ........................................................................................................3

2.2 Tobii X2–60 Eye Trackers ........................................................................................................5

33 DDaattaa SSaammppllee OOuuttppuutt ........................................................................................................................................................................................................................................ 88

44 EEyyee TTrraacckkiinngg SSeettuuppss........................................................................................................................................................................................................................................ 99

4.1 Typical Tobii X2 Eye Tracker Screen Setups ..............................................................................9

4.1.1 Local Live Viewer ....................................................................................................9

4.2 Typical Tobii X2 Eye Tracker Physical Object Setup ..................................................................10

4.2.1 External video stimulus recording.............................................................................10

AAppppeennddiixx AA::GGlloossssaarryy..................................................................................................................................................................................................................................................1111

AAppppeennddiixx ::AAccccuurraaccyy aanndd PPrreecciissiioonn MMeeaassuurreemmeennttss..............................................................................................................................................1122

:1 Gaze Precision.....................................................................................................................12

:2 Gaze Accuracy ....................................................................................................................12

AAppppeennddiixx CC::CCoommpplliiaannccee IInnffoorrmmaattiioonn aanndd WWaarrnniinnggss..............................................................................................................................................1133

C:1 FCC Statement....................................................................................................................13

C:2 Industry Canada Statement....................................................................................................13

C:3 Standards ...........................................................................................................................13

C:4 Mounting Warning................................................................................................................13

C:5 Infrared Warning ..................................................................................................................14

1 Introduction

1.1 Overview

This document describes the features and functionality of the Tobii X2 Eye Trackers. The X2 Eye Tracker is a stand alone eye

tracker that can be used in various setups by attaching it to monitors, laptops or for performing eye tracking on physical objects.

The eye tracker requires some assembly before first time use and after transport.

The Tobii X2 Eye Tracker is an unobtrusive eye tracker for detailed research of natural behavior. Its large head movement box al-

lows the subject to move during recording while maintaining accuracy and precision. The Tobii X2 Eye Trackers offer maximum

flexibility with numerous software and stimuli set-up options.

The X2-30 and X2–60 Eye Trackers come in a Compact and in a Wide Edition, to meet you’re your specific needs:

•The CCoommppaacctt EEddiittiioonn is a smaller version of the eye tracker, measuring 184 mm (7.2’’) in length. It enables your portable

eye tracking lab or studies that require a small eye tracker to track:

–Laptops and smaller PC monitors up to app. 22’’ (up to 31° gaze angle)

–Mobile devices

–Small real-world interfaces

TToobbiiii XX22--3300 EEyyee TTrraacckkeerr CCoommppaacctt EEddiittiioonn mmoouunntteedd oonn aa llaappttoopp ((llaappttoopp nnoott iinncclluuddeedd))::

•The WWiiddee EEddiittiioonn, measuring 400 mm (15.7ʺ) in length, is designed for studies that require larger gaze angels (up to

37°). It enables studies that involve larger stimuli, being able to track interfaces such as:

–PC monitors up to app. 27’’

–TV screens

–Projections, simulators

–Large real-world interfaces

TToobbiiii XX22--3300 EEyyee TTrraacckkeerr WWiiddee EEddiittiioonn mmoouunntteedd oonn aa mmoonniittoorr ((mmoonniittoorr nnoott iinncclluuddeedd))::

Product Description v.1.0 - en-US 1 Introduction 1

1.2 Applications Areas

The modular system can be used both in screen and real-world test scenarios, making way for a very broad spectrum of studies.

You can mount the eye tracker on a laptop, a PC monitor, an all-in-one PC, or even a tablet. Present your stimuli using a projec-

tion or TV. You can study real-world interfaces like a control panel, an ATM or a store shelf. The supplied mounting solutions sup-

port a variety of study designs.

•TToobbiiii XX22––3300 EEyyee TTrraacckkeerrss —The X2-30 Eye Trackers are designed for studies primarily aimed at determining precisely

where the participants are looking —the gaze point—rather than studying timing, duration of fixations or eye movements

such as saccades, for example.

•TToobbiiii XX22––6600 EEyyee TTrraacckkeerrss —The X2-60 eye tracker is designed for studies aimed at determining precisely where the

participants are looking and for studying and measuring eye fixations and other eye tracking metrics based on these.

1.3 Basic Operating Principles

During tracking, Tobii Eye Trackers use infrared diodes to generate reflection patterns on the corneas of the subject’s eyes.

These reflection patterns, together with other visual data about the subject, are collected by image sensors. Sophisticated image

processing algorithms identify relevant features, including the eyes and the corneal reflection patterns. Complex mathematics is

used to calculate the 3D position of each eyeball, and finally the gaze point on the screen; in other words, where the subject is

looking.

Tobii Eye Trackers are designed for use in indoor office environments.

21 Introduction Product Description v.1.0 - en-US

2 Technical Specifications

The characteristics of an eye tracker can be described in terms of gaze accuracy and gaze precision. Accuracy describes the an-

gular average distance from the actual gaze point to the one measured by the eye tracker. Gaze precision describes the spatial

variation between successive samples collected when the subject fixates at a specific point on a stimuli. More information re-

garding the accuracy and precision measurements can be found in

Appendix : Accuracy and Precision Measurements

. A glos-

sary can be found at

Appendix A: Glossary

2.1 Tobii X2–3 Eye Trackers

Table 2.1 Gaze Accuracy (Preliminary)

GGaazzee aaccccuurraaccyy1

TToobbiiii XX22--3300 EEyyee TTrraacckkeerr CCoommppaacctt EEddiittiioonn

((ffiirrmmwwaarree vveerrssiioonn 00..77..33))

TToobbiiii XX22--3300 EEyyee TTrraacckkeerr WWiiddee EEddiittiioonn

((ffiirrmmwwaarree vveerrssiioonn —— ppeennddiinngg))

iinnooccuullaarr MMoonnooccuullaarr iinnooccuullaarr MMoonnooccuullaarr

At ideal conditions 0.4 0.5 0.4 0.5

At 25° gaze angle 0.5 0.6 0.5 0.6

At 30° gaze angle 0.5 0.6 0.5 0.6

At 35° gaze angle N/A N/A Pending Pending

At 1 lux Pending Pending Pending Pending

At 300 lux 0.4 0.5 0.4 0.5

At 600 lux Pending Pending Pending Pending

At 1000 lux Pending Pending Pending Pending

White stimuli background Pending Pending Pending Pending

1. Accuracy under ideal conditions is measured in the centre of the head movement box with the subject fixed in a chinrest. Data is collected immediately after calibration, in a controlled laboratory

environment with constant illumination, with 9 stimuli points at gaze angles of ≤18º.

AAccccuurraaccyy aatt iiddeeaall ccoonnddiittiioonnss —— XX22––3300 CCoommppaacctt EEddiittiioonn ((PPrreelliimmiinnaarryy))

AAccccuurraaccyy aatt vvaarryyiinngg ddiissttaanncceess —— XX22––3300 CCoommppaacctt EEddiittiioonn ((PPrreelliimmiinnaarryy))

Product Description v.1.0 - en-US 2 Technical Specifications 3

Table 2.2 Gaze Precision (Preliminary)

GGaazzee pprreecciissiioonn

TToobbiiii XX22--3300 EEyyee TTrraacckkeerr CCoomm--

ppaacctt EEddiittiioonn

TToobbiiii XX22--3300 EEyyee TTrraacckkeerr WWiiddee

EEddiittiioonn

iinnooccuullaarr MMoonnooccuullaarr iinnooccuullaarr MMoonnooccuullaarr

Artificial Eye With Stampe filter 21Pending Pending Pending Pending

Without filter Pending Pending Pending Pending

Human Eye With Stampe filter 2 Pending Pending Pending Pending

Without filter 0.32 0.43 0.32 0.43

1. Stampe ( ehavior Research Methods, Instruments & Computers, 1993, 25 (2), pp.137-142) describes a noise reduction filter commonly used for eye tracking data. In these measurements, the

Stampe stage 2 algorithm has been applied.

Table 2.3 Eye Tracking Specifications (Preliminary)

TToobbiiii XX22--3300 EEyyee TTrraacckkeerr CCoomm--

ppaacctt EEddiittiioonn

TToobbiiii XX22--3300 EEyyee TTrraacckkeerr WWiiddee

EEddiittiioonn

SSaammpplliinngg rraattee130 Hz

(std. deviation ~ 3Hz)

30 Hz

(std. deviation ~ 3Hz)

TToottaall ssyysstteemm llaatteennccyy 48–67 ms 48-67 ms

TTiimmee ttoo ttrraacckkiinngg rreeccoovveerryy For blinks: immediate For blinks: immediate

HHeeaadd mmoovveemmeenntt2Freedom of head

movement at 70 cm

(width x height)

50 x 36 cm (20 x 14ʺ) 50 x 36 cm (20 x 14ʺ)

Operating distance

(eye tracker to subject) 40–90 cm (15.7–33.5ʺ) 50–100 cm (20–39ʺ)

RReeccoommmmeennddeedd ssccrreeeenn ssiizzee up to 22ʺup to 27ʺ

DDaattaa ssaammppllee oouuttppuutt Timestamp, eye position, gaze point,

pupil diameter, validity code

Timestamp, eye position, gaze point,

pupil diameter, validity code

1. As the Tobii X2-30 Eye Trackers have a variable and low sampling rate, they are not suitable for detailed studies of the onset or durations of fixations, saccades or other measures requiring high

temporal and stable sampling precision.

2. Freedom of head movement describes the volume in front of the tracker in which the user must have at least one of the eyes. The numbers are specified parallel/orthogonal to screen surface, as-

suming eye tracker is at 20 degree angle to screen.

Table 2. Eye Tracking Units (Preliminary)

TToobbiiii XX22--3300 EEyyee TTrraacckkeerr CCoommppaacctt

EEddiittiioonn

TToobbiiii XX22--3300 EEyyee TTrraacckkeerr WWiiddee EEddiittiioonn

EEyyee ttrraacckkeerr pprroocceessssiinngg uunniitt Embedded, no external eye tracking host

necessary

Embedded, no external eye tracking host

necessary

CCoonnnneeccttoorrss US 2.0 US 2.0

WWeeiigghhtt 200 g (7.1 oz) 250 g (8.8 oz)

SSiizzee 184*28*23 mm (7.2 * 1.1* 0.9’’) 400*28*23 mm (15.7 * 1.1* 0.9’’)

MMoouunnttiinngg ssoolluuttiioonnss Adhesive Mounting brackets for monitors,

laptops and tablets. Desk Stand Acces-

sory package for Tripod and desks

Adhesive Mounting brackets for moni-

tors, laptops and tablets. Desk Stand Ac-

cessory package for Tripod and desks

42 Technical Specifications Product Description v.1.0 - en-US

Table 2.5 Hardware package content (Preliminary)

TToobbiiii XX22--3300 EEyyee TTrraacckkeerr CCoommppaacctt EEddiittiioonn HHaarrddwwaarree

PPaacckkaaggee

TToobbiiii XX22--3300 EEyyee TTrraacckkeerr WWiiddee EEddiittiioonn HHaarrddwwaarree

PPaacckkaaggee

Tobii X2-30 Eye Tracker Compact Edition Tobii X2-30 Eye Tracker Wide Edition

3 x Adhesive mounting bracket kit (each kit contains 3 brack-

ets for different screen depths) for permanent installation.

6 x Adhesive mounting bracket kit (each kit contains 3 brack-

ets for different screen depths) for permanent installation.

Safety Instructions Safety Instructions

Installation Guide Installation Guide

Mounting tape kit Mounting tape kit

US extension cable N/A

Zipper bag Zipper bag

Tobii X2-30 Eye Tracker US memory stick containing the

Tobii Eye Tracker Installer.

Tobii X2-30 Eye Tracker US memory stick containing the

Tobii Eye Tracker Installer.

Tobii X2-30 Eye Tracker user manual Tobii X2-30 Eye Tracker user manual

N/A X2 Wide Edition mounting aid

Table 2.6 Accessories (Preliminary)

TToobbiiii XX22--3300 EEyyee TTrraacckkeerr CCoommppaacctt EEddiittiioonn TToobbiiii XX22--3300 EEyyee TTrraacckkeerr WWiiddee EEddiittiioonn

Tobii X2 Eye Tracker laptop case Tobii X2 Eye Tracker laptop case

Tobii X2 Eye Tracker desk stand package:

•Tobii X2 Eye Tracker desk stand kit

•Digital angle gauge

•Measuring tape

Tobii X2 Eye Tracker desk stand package:

•Tobii X2 Eye Tracker desk stand kit

•Digital angle gauge

•Measuring tape

2.2 Tobii X2–6 Eye Trackers

Table 2.1 Gaze Accuracy (Preliminary)

GGaazzee aaccccuurraaccyy1

TToobbiiii XX22--6600 EEyyee TTrraacckkeerr CCoommppaacctt EEddiittiioonn

((ffiirrmmwwaarree vveerrssiioonn —— ppeennddiinngg))

TToobbiiii XX22--6600 EEyyee TTrraacckkeerr WWiiddee EEddiittiioonn

((ffiirrmmwwaarree vveerrssiioonn —— ppeennddiinngg))

iinnooccuullaarr MMoonnooccuullaarr iinnooccuullaarr MMoonnooccuullaarr

At ideal conditions 0.4 0.5 0.4 0.5

At 25° gaze angle 0.5 0.6 0.5 0.6

At 30° gaze angle 0.5 0.6 0.5 0.6

At 35° gaze angle N/A N/A Pending Pending

At 1 lux Pending Pending Pending Pending

At 300 lux 0.4 0.5 0.4 0.5

At 600 lux Pending Pending Pending Pending

At 1000 lux Pending Pending Pending Pending

White stimuli background Pending Pending Pending Pending

1. Accuracy under ideal conditions is measured in the centre of the head movement box with the subject fixed in a chinrest. Data is collected immediately after calibration, in a controlled laboratory

environment with constant illumination, with 9 stimuli points at gaze angles of ≤18º.

Product Description v.1.0 - en-US 2 Technical Specifications 5

Table 2.2 Gaze Precision (Preliminary)

GGaazzee pprreecciissiioonn

TToobbiiii XX22--6600 EEyyee TTrraacckkeerr CCoomm--

ppaacctt EEddiittiioonn

TToobbiiii XX22--6600 EEyyee TTrraacckkeerr WWiiddee

EEddiittiioonn

iinnooccuullaarr MMoonnooccuullaarr iinnooccuullaarr MMoonnooccuullaarr

Artificial Eye With Stampe filter 21Pending Pending Pending Pending

Without filter Pending Pending Pending Pending

Human Eye With Stampe filter 2 Pending Pending Pending Pending

Without filter 0.32 0.43 0.32 0.43

1. Stampe ( ehavior Research Methods, Instruments & Computers, 1993, 25 (2), pp.137-142) describes a noise reduction filter commonly used for eye tracking data. In these measurements, the

Stampe stage 2 algorithm has been applied.

Table 2.3 Eye Tracking Specifications (Preliminary)

TToobbiiii XX22--6600 EEyyee TTrraacckkeerr CCoomm--

ppaacctt EEddiittiioonn

TToobbiiii XX22--6600 EEyyee TTrraacckkeerr WWiiddee

EEddiittiioonn

SSaammpplliinngg rraattee 60 Hz

(std. deviation approx. 0.1Hz)

60 Hz

(std. deviation approx. 0.1Hz)

TToottaall ssyysstteemm llaatteennccyy 48–67 ms 48-67 ms

TTiimmee ttoo ttrraacckkiinngg rreeccoovveerryy For blinks: immediate For blinks: immediate

HHeeaadd mmoovveemmeenntt1Freedom of head move-

ment at 70 cm (width x

height)

50 x 36 cm (20 x 14ʺ) 50 x 36 cm (20 x 14ʺ)

Operating distance

(eye tracker to subject) 45–90 cm (15.7–33.5ʺ) 50–100 cm (20–39ʺ)

RReeccoommmmeennddeedd ssccrreeeenn ssiizzee up to 22ʺup to 27ʺ

DDaattaa ssaammppllee oouuttppuutt Timestamp, eye position, gaze point,

pupil diameter, validity code

Timestamp, eye position, gaze point,

pupil diameter, validity code

1. Freedom of head movement describes the volume in front of the tracker in which the user must have at least one of the eyes. The numbers are specified parallel/orthogonal to screen surface, as-

suming eye tracker is at 20 degree angle to screen.

Table 2. Eye Tracking Units (Preliminary)

TToobbiiii XX22--6600 EEyyee TTrraacckkeerr CCoommppaacctt EEddiittiioonn TToobbiiii XX22--6600 EEyyee TTrraacckkeerr WWiiddee EEddiittiioonn

EEyyee ttrraacckkeerr pprroocceessssiinngg

uunniitt

Tobii X2-60 Eye Tracker external processing

unit

Tobii X2-60 Eye Tracker external processing

unit

CCoonnnneeccttoorrss US 2.0 US 2.0

WWeeiigghhtt 200 g (7.1 oz) 250 g (8.8 oz)

SSiizzee 184 x 28 x 23 mm (7.2 x 1.1 x 0.9ʺ) 400 x 28 x 23 mm (15.7 x 1.1 x 0.9ʺ)

MMoouunnttiinngg ssoolluuttiioonnss Adhesive Mounting brackets for monitors, lap-

tops and tablets. Desk Stand Accessory pack-

age for Tripod and desks

Adhesive Mounting brackets for monitors,

laptops and tablets. Desk Stand Accessory

package for Tripod and desks

Table 2.5 Tobii X2-60 Eye Tracker external processing unit

CCoonnnneeccttoorrss US 2.0, LAN and power connector

SSiizzee 116.6 x 112 x 39 mm (4.6 x 4.4 x 1.55’’)

WWeeiigghhtt 500 g (17.6 oz)

62 Technical Specifications Product Description v.1.0 - en-US

Table 2.6 Hardware package content (Preliminary)

TToobbiiii XX22--6600 EEyyee TTrraacckkeerr CCoommppaacctt EEddiittiioonn HHaarrddwwaarree

PPaacckkaaggee

TToobbiiii XX22--6600 EEyyee TTrraacckkeerr WWiiddee EEddiittiioonn HHaarrddwwaarree

PPaacckkaaggee

Tobii X2-60 Eye Tracker Compact Edition Tobii X2-60 Eye Tracker Wide Edition

3 x Adhesive mounting bracket kit (each kit contains 3 brack-

ets for different screen depths) for permanent installation.

6 x Adhesive mounting bracket kit (each kit contains 3 brack-

ets for different screen depths) for permanent installation.

Safety Instructions Safety Instructions

Installation Guide Installation Guide

Mounting tape kit Mounting tape kit

US extension cable N/A

Zipper bag Zipper bag

Tobii X2-60 Eye Tracker US memory stick containing the

Tobii Eye Tracker Installer.

Tobii X2-60 Eye Tracker US memory stick containing the

Tobii Eye Tracker Installer.

Tobii X2-60 Eye Tracker user manual Tobii X2-60 Eye Tracker user manual

Tobii X2-60 Eye Tracker external processing unit Tobii X2-60 Eye Tracker external processing unit

N/A X2 Wide Edition mounting aid

Table 2.7 Accessories (Preliminary)

TToobbiiii XX22--6600 EEyyee TTrraacckkeerr CCoommppaacctt EEddiittiioonn TToobbiiii XX22--6600 EEyyee TTrraacckkeerr WWiiddee EEddiittiioonn

Tobii X2 Eye Tracker laptop case Tobii X2 Eye Tracker laptop case

Tobii X2 Eye Tracker desk stand package:

•Tobii X2 Eye Tracker desk stand kit

•Digital angle gauge

•Measuring tape

Tobii X2 Eye Tracker desk stand package:

•Tobii X2 Eye Tracker desk stand kit

•Digital angle gauge

•Measuring tape

Product Description v.1.0 - en-US 2 Technical Specifications 7

3 Data Sample Output

Different applications can be connected as clients to the eye tracker to, e.g., gather eye gaze data in real-time and perform cali-

brations. Applications that can be used together with the eye tracker include the Tobii Studio™analysis software, third party anal-

ysis products such as E-Prime® or your own custom written software for analysis, gaze-contingent applications or eye control

applications. For more information on how to create your own applications, please refer to the Tobii Software Development Kit

(SDK) product description, version 3.0 or later.

elow is a list of data that can be accessed through the output of the eye tracker. In Tobii Studio™analysis software this data

can be accessed through a Data export function, and easily imported into a spreadsheet for further analysis. Please note that

some of the parameter names differs between what is delivered from the SDK and what is available in the Tobii Studio™data

export.

TTiimmeessttaammpp Timestamp in milliseconds stating the mid-exposure time when the sample was collected by the eye

tracker’s image sensors.

GGaazzeePPooiinnttXXLLeefftt Horizontal screen position of the gaze point for the left eye.

GGaazzeePPooiinnttYYLLeefftt Vertical screen position of the gaze point for the left eye.

CCaammXXLLeefftt Horizontal location of the left pupil in the camera image (0 is left edge, 1 is right edge).

CCaammYYLLeefftt Vertical location of the left pupil in the camera image (0 is top, 1 is bottom).

DDiissttaanncceeLLeefftt Distance from the eye tracker to the left eye. The distance is given in mm on a straight axis right out

from the eye tracker plane.

PPuuppiillLLeefftt Size of the pupil (left eye) in mm. The distance and pupil size measurements are calculated to be as

close to real values as possible. However, individual differences in the eyes of subjects or the

strength of glasses/contact lenses will affect the size values. Shifts between the use of eye tracking

technique during a recording will also affect the pupil size value.

VVaalliiddiittyyLLeefftt The validity code indicates the system’s confidence in whether it has correctly identified which eye

is left and right for the specific sample. The validity is 0 if the eye is found and the tracking quality

good. If the eye cannot be found by the eye tracker the validity code will be 4. The value is for the left

eye.

GGaazzeePPooiinnttXXRRiigghhtt The horizontal screen position of the gaze point for the right eye.

GGaazzeePPooiinnttYYRRiigghhtt Vertical screen position of the gaze point for the right eye .

CCaammXXRRiigghhtt Horizontal location of the right pupil in the camera image (0 is left edge, 1 is right edge).

CCaammYYRRiigghhtt Vertical location of the right pupil in the camera image (0 is top, 1 is bottom).

DDiissttaanncceeRRiigghhtt Distance from the eye tracker to the right eye. The distance is given in mm on a straight axis out from

the eye tracker plane.

PPuuppiillRRiigghhtt Size of the pupil (right eye) in mm. The distance and pupil size measures are calculated to be as

close to real values as possible. However, individual differences in the eyes of subjects or the

strength of glasses/contact lenses will affect these values. Shifts between the use of eye tracking

technique during a recording will also affect the pupil size value.

VVaalliiddiittyyRRiigghhtt The validity code indicates the system’s confidence in whether it has correctly identified which eye

is left and right for the specific sample. The validity is 0 if the eye is found and tracking quality is

good. If the eye cannot be found by the eye tracker, the validity code will be 4. The value is for the

right eye.

83 Data Sample Output Product Description v.1.0 - en-US

4 Eye Tracking Setups

This chapter describes typical setup configurations that can be used with the Tobii X2 Eye Trackers. For specific information

about custom configurations or system requirements and recommendation, please contact your Tobii sales representative or To-

bii technical support. The System Requirements and Recommendations document can be downloaded at www.tobii.com.

Your particular needs might differ from these typical configurations. More detailed information is available in the Eye Tracker User

Manual provided with the product.

4.1 Typical Tobii X2 Eye Tracker Screen Setups

These basic setups are the simplest setups when using on screen stimuli, such as images, movies or web. To record the partici-

pant’s reactions, the conversation between the test leader and test participant, you need to connect an external user camera

and microphone to the computer running Tobii Studio. The setups below do not include the user camera and user sound.

SSiinnggllee SSccrreeeenn SSeettuuppss

Primary Screen

Stimulus

presentation

Primary Sc reen

Stimulus

presentation

Primary Sc reen

Stimulus

presentation

USB

VGA/DVI out

Comput er with

Tobii Studio or

oth er s upported software

Comput er with

Tobii Studio or

oth er s upported software

Comput er with

Tobii Studio or

oth er s upported software

VGA/DVI

out

LAN

USB

Tobii X2-60

Eye Tracker

exter nal pr ocessing unit

4.1.1 Local Live Viewer

The setup below is used when the test is to be supervised from a separate screen where the test leader can see the eye move-

ments of the subject in real time during testing.

LLooccaall LLiivvee VViieewweerr SSeettuuppss

Primary Screen

Stimulus

prese ntation

Secon dary Screen

Live Viewer

(optional)

VGA/DVI

out

USB

Computer with

Tobii Studio or

othe r suppo rted so ftware

Primary Screen

Stimulus Presentation

(Projected Screen )

Projector

Tobii X2 Eye Tracker

mou nted on a t ripod Computer with

Tobii Studio or

othe r suppo rted so ftware

USB

VGA/DVI

out

Secon dary Screen

Live Viewer

(optional)

Product Description v.1.0 - en-US 4 Eye Tracking Setups 9

4.2 Typical Tobii X2 Eye Tracker Physical Object Setup

When studying a stimuli that doesn’t have a screen or when studying an external device such as a mobile phone, a physical ob-

ject setup needs to be used where a video or web camera captures the image of the stimuli.

To record the participant’s reactions, the conversation between the test leader and test participant, you need to connect an addi-

tional camera and microphone to the computer running Tobii Studio. The setups below do not include the user camera and user

sound.

PPhhyyssiiccaall OObbjjeecctt SSeettuupp

Video Camera

Computer with

Tobii Studio or

other supported software

Calibration Grid

Tobii X2 Eye Tracker

mou nted on a t ripod

USB

4.2.1 External video stimulus recording

This setup is suitable when using a Tobii Eye Tracking system for eye tracking data analysis when the stimulus is presented from

a separate computer or other RG or VGA sources. This could include a computer game, a DVD player, or when stimulus is pre-

sented on a computer running a different operating system. The computer running Tobii Studio must be equipped with an addi-

tional video capture card.

Note that if the external application runs on the Windows operating system, and it does not use 3D graphics accelera-

tion or it does not have a high processor load and high memory usage, it may be more suitable and less complex to in-

stead run this on the same computer as Tobii Studio and use the Screen Recording option in Tobii Studio.

For this setup, the image from the Tobii Studio computer has to be displayed on the screen during calibration (to display the cali-

bration points). The external stimulus computer, however, should be shown on the screen during the actual test. oth devices

must therefore be connected to the same screen. To switch between the inputs, use a switch or a screen that allows for multiple

input sources. The image shown on the screen must be sent to Tobii Studio to record the video stream and synchronize it with

the gaze data. If the stimulus is presented from an analogue video source, e.g., a VCR or an analogue video camera, a similar set-

up with slightly modified components can be used.

EExxtteerrnnaall VViiddeeoo SSttiimmuulluuss RReeccoorrddiinngg SSeettuupp

Primary Screen

Stimulus

presentation

Secondary Screen

Live Viewer

(optional)

USB

Video out

Video

capture VGA/DVI

out

VGA/DVI

out

DVD player, computer,

gamin g console, etc .

Computer with

Tobii Studio or

other supported software

Video capture

card

10 4 Eye Tracking Setups Product Description v.1.0 - en-US

Appendix A: Glossary

MMoonnooccuullaarr//bbiinnooccuullaarr Monocular data shown is based on data from each eye individually. inocular data is the average of

the two eyes.

GGaazzee pprreecciissiioonn Describes the spatial angular variation between a set of consecutive gaze samples. Gaze precision

can be measured under various conditions. For more details, see

Appendix : Accuracy and

Precision Measurements

GGaazzee aaccccuurraaccyy Describes the angular average distance from the actual gaze point to the one measured by the eye

tracker. Gaze accuracy can be measured under various conditions. For more details, see

Appendix

: Accuracy and Precision Measurements

SSaammpplliinngg rraattee Number of eye tracking data samples per second.

TToottaall ssyysstteemm llaatteennccyy The duration from mid-point of the eye image exposure, to when a sample is available via the API on

the client computer. This includes half of the image exposure time, plus image read-out and transfer

time, processing time and time to transfer the data sample to a client computer.

TTiimmee ttoo ttrraacckkiinngg

rreeccoovveerryy ffoorr bblliinnkkss

When a subject blinks, the eye tracker loses the ability to track eye gaze because the eye is covered

by the eye lid. If the pupil is occluded for only a short period, the system will regain tracking

immediately when the pupil becomes visible again, but only if the subject has maintained

approximately the same head position during the blink. Data during blinks are only lost when the

pupil is occluded, i.e. during the eye lid movement itself or when the eye is closed.

TTiimmee ttoo ttrraacckkiinngg

rreeccoovveerryy aafftteerr lloosstt

ttrraacckkiinngg

An eye tracker working in a natural user environment may occasionally lose track of the subject’s

eyes, e.g., when the subject completely turns away from the tracker. If a period of a few hundred

milliseconds elapses during which the eye tracker is unable to detect the eyes in close proximity to

where they were last detected, the eye tracker will start searching for the eyes within the entire head

movement box. The stated measurement is the typical time to tracking recovery in such a situation. If

the eye tracker is unable to detect the eyes of the subject even after about one minute, the system

will enter a “slow search”mode, leading to larger recovery times.

FFrreeeeddoomm ooff hheeaadd

mmoovveemmeenntt

Describes an area ( width x height in cm) where at least one eye is within the eye tracker’s field of

view.

OOppeerraattiinngg ddiissttaannccee Describes the range of distances (minimum and maximum) between the subject’s eyes and the

surface covering the eye tracker sensors at which eye tracking can be done while maintaining

tracking.

EEyyee ttrraacckkiinngg

pprroocceessssiinngg uunniitt

Gaze data calculations are performed by firmware embedded in the eye tracker or in a separate

processing unit.

Product Description v.1.0 - en-US A: Glossary 11

Appendix B: Accuracy and Precision

Measurements

Gaze accuracy and precision are typically measured in degrees of visual angle. One degree accuracy corresponds to an average

error of 12 mm (0.47’’) on a screen at a distance of 65 cm (27’’). Data is presented as monocular or binocular. Monocular data

is based on data from the subject’s dominant eye presented as monocular or binocular. Monocular data is based on data from

the subject’s dominant eye only. inocular data is the average of both eyes.

B:1 Gaze Precision

Precision measurements are done using artificial eyes to eliminate artifacts from human eye movements. Tobii specifies precision

both with and without noise reduction filters. All measurements are done at the default sampling rate of the eye tracker and at

the optimum distance between the eye tracker and the subject. Precision is calculated as root-mean-square (RMS) of

successive samples.

As the distance from the eye tracker influences precision, measurements are also taken at various distances. Data from these

measurements is binocular.

B:2 Gaze Accuracy

Accuracy under ideal conditions is measured in the center of the head movement box with the subject fixed in a chinrest. Data is

collected immediately after calibration, in a controlled laboratory environment with constant illumination, with 9 stimuli points at

gaze angles ≤18º. Measurements are done on 20 test subjects without lenses, glasses or droopy eyelids. Accuracy for one

subject is calculated as the mean of several data samples for several stimuli points across a screen. The accuracy figure

presented is the mean accuracy from all subjects.

Good accuracy is difficult to achieve at large gaze angles, but is important when testing large stimuli. For instance, the upper

corner of a 23’’ screen with the test subject at a distance of 65 cm (26’’) from the eye tracker corresponds to a 32º visual angle

from the center of the eye tracker unit. Consequently, measurements are also presented for stimuli presentations at large gaze

angles.

When luminance of the stimuli or the illumination in the lab changes, the size and shape of the pupil is affected. Unless

compensated for, this may cause a significantly reduced accuracy. Testing the influence of surrounding light and stimuli

luminance on accuracy is done in a laboratory environment with controlled light conditions. Stimuli points are presented on a

black background so as not to influence ambient light conditions. Testing is also done with ambient light at a level deemed

‘normal’office lighting where the background is changed to white with black stimuli points. The results from a test in which the

background was changed has been referred to as Drift in previous Tobii product description documents.

As with precision, the distance from the eye tracker influences accuracy. When testing this influence, calibration is done with the

subject in the center of the head movement box (i.e. at a distance of 65 cm) and measurements are done thereafter.

Measurements are performed with the test subject at precise and specific distances relative to the eye tracker, measured along

the axis of the tracking sensors. Data from these measurements is binocular.

12 : Accuracy and Precision Measurements Product Description v.1.0 - en-US

Appendix C: Compliance Information and

Warnings

All Tobii X2 Eye Trackers are CE-marked, indicating compliance with the essential health and safety requirements set

out in European Directives.

C:1 FCC Statement

This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) this device may not

cause harmful interference, and (2) this device must accept any interference received, including interference that may cause

undesired operation.

Modifications not expressly approved by Tobii could void the user’s authority to operate the equipment under FCC

rules.

This equipment has been tested and found to comply with the limits for a Class digital device, pursuant to part 15 of the FCC

Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This

equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with the

instructions, may cause harmful interference to radio communications.

However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful

interference to radio or television reception, which can be determined by turning the equipment off and on, the user is

encouraged to try to correct the interference by one or more of the following measures:

•Reorient or relocate the receiving antenna.

•Increase the separation between the equipment and receiver.

•Connect the equipment into a wall outlet on a circuit different from that to which the receiver is connected.

•Consult the dealer or experienced radio/TV technician for assistance.

C:2 Industry Canada Statement

This Class digital apparatus complies with Canadian ICES-003.

Cet appareil numérique de la classe est conforme à la norme NM -003 du Canada.

C:3 Standards

The Tobii X2 Eye Trackers complies with the following standards:

•IEC/EN62471, Photobiological Safety of Lamps and Lamp Systems

•EMC Emission: EN 61000-6-3:2001 including EN 55022:1998/A1/A2 Class , FCC part 15, Class

•EMC Immunity: EN 61000-6-1:2007

•FCC part 15, Class

C:4 Mounting Warning

The Tobii X2 Eye Trackers should be mounted according to instructions for approved mounts . However, should the

device for any reason harm or damage someone or something due to falling or other. Neither Tobii nor any of its

representatives will be responsible or liable for any damages or injuries which may arise. The mounting of the Tobii X2

Eye Trackers is done entirely at the user’s own risk.

The double sided tape supplied with the adhesive Magnetic Mounting Plates is designed to permanently attach the

bracket to the monitor/laptop. Attempting to remove the bracket after attaching it using the supplied tape can result in

damages both to the monitor/laptop and the bracket.

Product Description v.1.0 - en-US C: Compliance Information and Warnings 13

C:5 Infrared Warning

When activated, the Tobii X2 Eye Trackers emits pulsed infrared (IR) light. Certain medical devices are susceptible to

disturbance by IR light and/or radiation. Do not use the Tobii X2 Eye Trackers when in the vicinity of such susceptible

medical devices as their accuracy or proper functionality could be inhibited.

14 C: Compliance Information and Warnings Product Description v.1.0 - en-US

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Tobii Technology A

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