Road vehicles -- Measurement and analysis of driver visual behaviour with respect to transport information and control systems

This document defines key terms and parameters applied in the analysis of driver visual behaviour focused on glance and glance-related measures. It provides guidelines and minimum requirements on equipment and procedures for analysing driver visual behaviour including assessment of TICS to: — plan evaluation trials; — specify (and install) data capture equipment; and — validate, analyse, interpret and report visual-behaviour metrics (standards of measurement). The parameters and definitions described below provide a common source of reference for driver visual behaviour data. It is applicable to on-road trials (e.g. field operational tests or naturalistic studies), and laboratory-based driving studies. The procedures described in this document can also apply to more general assessments of driver visual behaviour. Data collected and analysed according to this document will allow comparisons to be performed across different TICS applications and experimental scenarios.

Véhicules routiers -- Mesurage et analyse du comportement visuel du conducteur en relation avec les systèmes de commande et d'information du transport

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Publication Date
25-Aug-2020
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INTERNATIONAL ISO
STANDARD 15007
First edition
2020-08
Road vehicles — Measurement and
analysis of driver visual behaviour
with respect to transport information
and control systems
Véhicules routiers — Mesurage et analyse du comportement visuel
du conducteur en relation avec les systèmes de commande et
d'information du transport
Reference number
ISO 15007:2020(E)
ISO 2020
---------------------- Page: 1 ----------------------
ISO 15007:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 15007:2020(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

3.1 Basic terms ................................................................................................................................................................................................. 1

3.2 Terms for metrics .................................................................................................................................................................................. 5

3.2.1 Basic direct metrics ....................................................................................................................................................... 5

3.2.2 Glance derived metrics ............................................................................................................................................... 5

4 Trial planning and evaluation ................................................................................................................................................................ 7

4.1 General ........................................................................................................................................................................................................... 7

4.2 Trial planning ........................................................................................................................................................................................... 8

4.2.1 General...................................................................................................................................................................................... 8

4.2.2 Roadway/traffic specification .............................................................................................................................. 8

4.2.3 Vehicle specification ..................................................................................................................................................... 8

4.2.4 TICS specification ............................................................................................................................................................ 8

4.2.5 Participant selection ..................................................................................................................................................... 8

4.2.6 Participant training........................................................................................................................................................ 8

4.2.7 Data exclusion .................................................................................................................................................................... 8

4.3 Steps for data acquisition and data processing .......................................................................................................... 9

4.4 Experimental conditions, tasks, subtasks, sub-subtasks, and relationship ........................................ 9

4.4.1 Experimental condition ............................................................................................................................................. 9

4.4.2 Task.............................................................................................................................................................................................. 9

4.4.3 Subtask ..................................................................................................................................................................................10

4.4.4 Sub-subtask .......................................................................................................................................................................10

4.4.5 Relationship ......................................................................................................................................................................10

5 Recording equipment ...................................................................................................................................................................................11

5.1 General ........................................................................................................................................................................................................11

5.2 Eye tracking equipment ...............................................................................................................................................................12

5.2.1 General...................................................................................................................................................................................12

5.2.2 Head-mounted eye tracking systems ..........................................................................................................12

5.2.3 Remote eye tracking systems .............................................................................................................................13

5.3 Setup and verification of calibration of eye tracking systems .....................................................................13

5.3.1 General...................................................................................................................................................................................13

5.3.2 Recording with eye tracking systems .........................................................................................................13

5.3.3 Recording with remote eye tracking systems ......................................................................................14

5.3.4 Camera only systems for manual eye-glance analysis ..................................................................14

5.4 Setup and check of recording ..................................................................................................................................................14

5.5 Additional equipments ......... .........................................................................................................................................................14

5.6 Installation ...............................................................................................................................................................................................14

6 Data reduction .....................................................................................................................................................................................................15

6.1 General ........................................................................................................................................................................................................15

6.2 Sample interval ....................................................................................................................................................................................15

6.3 Manual reduction by raters/data analysts ...................................................................................................................15

6.4 Manual reduction by raters/data analysts of data from a camera only setup ..............................15

6.5 Manual reduction by raters/data analysts of data from an eye tracking system .......................15

6.6 Data Protocol for manual reduction ..................................................................................................................................16

6.7 Summary data .......................................................................................................................................................................................16

7 Data reduction using automated gaze analysis of eye tracking system....................................................17

7.1 General ........................................................................................................................................................................................................17

7.2 Data quality verification using 5 % of entire collected data .........................................................................17

7.2.1 Positional/orientation errors ............................................................................................................................17

© ISO 2020 – All rights reserved iii
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ISO 15007:2020(E)

7.2.2 Detection time errors ........................................................................................................................................... .....17

7.2.3 Verification of Cohen’s kappa to secure accuracy of automated analysis ....................18

7.3 Availability of the eye tracker data .....................................................................................................................................18

8 Data analysis and presentation ..........................................................................................................................................................19

8.1 General ........................................................................................................................................................................................................19

8.2 Interpretation of findings from analyses of glance metrics ..........................................................................19

8.3 Interpretation of multiple glance metrics ....................................................................................................................20

Annex A (normative) Manual reduction procedures ........................................................................................................................22

Annex B (normative) Verification of calibration — Check of availability and calibration

accuracy of tracking equipment before recording data using a verification of

calibration procedure ..................................................................................................................................................................................27

Annex C (normative) Eye tracker validation task (EVT) ...............................................................................................................32

Annex D (normative) 5 % data verification — Check of reliability after data recording and

before statistical data analysis ...........................................................................................................................................................38

Annex E (normative) Calculating a Cohen’s kappa for one participant ........................................................................39

Annex F (informative) Supporting figures to explain terms and definitions...........................................................41

Annex G (informative) Supporting information for performing and analysing experiments

to determine driver visual behaviour .........................................................................................................................................46

Annex H (informative) Collection and analysis of (long-term) on-road visual data ........................................48

Annex I (informative) Additional recording equipment ...............................................................................................................49

Bibliography .............................................................................................................................................................................................................................50

iv © ISO 2020 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 15007:2020(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/

iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 39,

Ergonomics.

This edition cancels and replaces ISO 15007-1:2014 and ISO/TS 15007-2:2014, which have been

technically revised.
The main changes compared to the previous editions are as follows:

— integration of ISO 15007-1 (Part 1: Definitions and parameters) and ISO/TS 15007-2 (Part 2: Equipment

and procedures) into one document;
— detailed description of different data reduction procedures;
— detailed description of procedures and criteria for quality assurance.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
© ISO 2020 – All rights reserved v
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ISO 15007:2020(E)
Introduction

This document supports the quantification and description of visual behaviour while using TICS

(transport information and control systems) and driving vehicles in different driving levels of

automation. It supports the quantification of information acquisition related to internal and vehicle

external environment/objects (e.g. vehicles, billboards, information displays, variable message signs).

It provides assistance in the assessment of driver state considering visual attention. This document

does not address fatigue and drowsiness.

This document describes the phases of visual behaviour assessment including the following steps:

— calibration setup and calibration verification (piloting phase);
— data collection;
— data reduction;
— quality assessment;
— data presentation.

Each of these steps should be handled with care, documented and checked for quality before moving to

the next step.
vi © ISO 2020 – All rights reserved
---------------------- Page: 6 ----------------------
INTERNATIONAL STANDARD ISO 15007:2020(E)
Road vehicles — Measurement and analysis of driver
visual behaviour with respect to transport information and
control systems
1 Scope

This document defines key terms and parameters applied in the analysis of driver visual behaviour

focused on glance and glance-related measures. It provides guidelines and minimum requirements on

equipment and procedures for analysing driver visual behaviour including assessment of TICS to:

— plan evaluation trials;
— specify (and install) data capture equipment; and

— validate, analyse, interpret and report visual-behaviour metrics (standards of measurement).

The parameters and definitions described below provide a common source of reference for driver

visual behaviour data.

It is applicable to on-road trials (e.g. field operational tests or naturalistic studies), and laboratory-

based driving studies. The procedures described in this document can also apply to more general

assessments of driver visual behaviour. Data collected and analysed according to this document will

allow comparisons to be performed across different TICS applications and experimental scenarios.

2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at https:// www .iso .org/ obp
3.1 Basic terms
3.1.1
area of interest
AOI
pre-determined area within the visual scene
Note 1 to entry: Region of interest (ROI) is used as a synonym.

Note 2 to entry: An AOI will be no smaller than the normal resolution of the eye-measurement system being used

(e.g. no smaller than 0,5 ° for typical eye tracking systems). See F.1.
EXAMPLE A rear-view mirror.
© ISO 2020 – All rights reserved 1
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ISO 15007:2020(E)
3.1.2
blink
short period of time in which the eye is closed by the eyelid

Note 1 to entry: The blink starts when the eyelid starts moving downwards and ends when the eye is fully

opened again.

Note 2 to entry: According to the duration for which the eye is closed the following classification applies (see

Reference [13]):
— normal blinks: ≤300 ms (mean duration 257 ms; standard deviation 11 ms);
— long closed durations: 300 ms to 500 ms;
— eye-lid closures: ≥500 ms (indicating microsleeps).

Note 3 to entry: Depending on participant state and/or glance (3.1.6) direction of a participant the eyelid may not

fully open, although the blink might end. Especially in these cases the visibility of the pupil or major part of the

pupil is important for correct gaze recognition.
Key
1 closing phase
2 opening phase
x vertical positioning of upper eyelid
Open.
Partially closed.
Closed.
Figure 1 — Phases of a blink (see Reference [17])

Note 4 to entry: A blink is performed by the down movements the upper eye lid while lower eyelid remains static.

Upper eyelid movement is considered in defining a blink.
3.1.3
direction of gaze

orientation of the eye to the area of interest (3.1.1) to which the eyes are directed to

2 © ISO 2020 – All rights reserved
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ISO 15007:2020(E)
3.1.4
fixation

short temporal holds of movements that keep alignment of the eyes to a particular point within an AOI

(3.1.1) which falls on the fovea (the middle of the retina responsible for our central, sharpest vision) for

a given time period

Note 1 to entry: Typically, individual fixations last from 100 ms to 2 000 ms (see Reference [5]). Fixations are the

briefest of pauses during which visual information extraction is done by the eyes-and-brain from spatial areas

that fall on the fovea of the eye (and hence are quite small). During fixation, there are believed to be at least

three processes taking place (see Reference [16]) 1) analysis of the image falling on the fovea, 2) selection of a

new saccade (3.1.7) target and 3) programming of the saccade to-be-made-next. It is not yet known how these

processes are synchronized by the brain, nor how precisely they are synchronized – since fixation durations

are not always long enough to comprehend completion of all the processes. (Sometimes the eyes move before

information extraction from the site of fixation has been completed, as evidenced by frequent corrective return

fixations to a site under some conditions that was fixated too briefly.) There is evidence that the brain both pre-

programs fixation duration, and also does “process-monitoring” during a fixation to determine if analysis of the

foveal image is complete within the fixation’s duration before moving on. Thus, fixation time is dependent on

both the immediate stimulus and the history of prior fixations. The contribution of both components suggests

that fixation time may depend on the task and the amount of useful information in the fixated display (or viewed

information) (see Reference [7]).
Note 2 to entry: See F.1 to F.4.
3.1.5
fly through

small ‘snapshot’ of a saccade (3.1.7) (<120 ms) that may be an artefact captured when the eye is

moving from one area of interest (3.1.1) to another area of interest, and passing through one or more

intermediate Areas of Interest in between

EXAMPLE The eye moves from the road scene ahead to the instrument cluster and passes the head-up

display.

Note 1 to entry: Sometimes a small ‘snapshot’ of such a saccade may appear to be a short fixation (3.1.4), when it

is really still part of the saccade. Such fly throughs (<120 ms) are not treated as fixations. Fly throughs may be

grouped with the saccade they are part of, if saccades are being measured.

Note 2 to entry: Research shows that fixations cannot be shorter than 100 ms (see Reference [10]).

3.1.6
glance

temporal maintaining of visual gaze within an AOI (3.1.1), bounded by the perimeter of the AOI which

can be comprised of more than one fixation (3.1.4) and saccades (3.1.7) within the AOI and its duration

is measured as glance duration (3.2.1.3)

Note 1 to entry: A glance is a scientific construct that sums over one or more fixations that are made contiguously

within a given area of interest (but one that is larger than the area corresponding to the eye’s foveal region –

an area that usually requires more than one fixation to view). The construct of a glance, therefore, typically

comprehends more than a single fixation and is a coarser unit of analysis than a single fixation (since it is summing

over fixations that are contiguous in time and spatially proximal within an area of interest. The construct of

a “glance” is needed because often the salient questions in a study relate to the amount of contiguous time

spent gazing at a particular area of interest (before the eyes move away from it). Of course, in some instances,

the “glance” construct is also necessary because some measurement approaches are not capable of the fine

discriminations needed to identify individual fixations (spatially and temporally) – and can only discriminate

at the spatial/temporal granularity of glances. Thus, “glances” are a coarser measure of visual information

extraction by the eyes/brain from a continuously viewed but somewhat larger spatial region. Typical glance

lengths vary by stimulus and task but might (for example) range from 500 ms to 3 s for a task like “tuning the

radio” (see Reference [11]).
Note 2 to entry: See F.1 to F.4.
© ISO 2020 – All rights reserved 3
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ISO 15007:2020(E)
3.1.7
saccade

brief, fast movement of the eyes that changes the point of fixation (3.1.4), within an AOI (3.1.1) or

between different AOIs

Note 1 to entry: Saccades reach velocities as high as 500°/s (see Reference [10]), whereby the mean saccade

ranges between 1° (text reading) to 5° (scene perception) (see Reference [14]).
Note 2 to entry: See F.1 to F.4.
3.1.8
smooth pursuit movement

smooth continuous movement of the eyes made to closely follow/pursue a moving object or signal

Note 1 to entry: Humans generally perform smooth pursuit movements better in the horizontal than vertical

dimension, and better in the downward than upward direction. Smooth pursuit movements can have a velocity

as high as 90°/s (see Reference [9]).
3.1.9
sample interval
the epoch of time over which measurements are taken

EXAMPLE The duration of an in-vehicle task on entering a destination into a route guidance system, where

the evaluation in interest is to evaluate the driver behaviour when the driver performs a task of entering the

destination.

Note 1 to entry: Usually, this will be the contiguous epoch of time that is associated with an event or task that

is of interest in the study. The sample interval is the period of time (from start to end) during which data are

extracted.
3.1.10
transition

change in eye fixation (3.1.4) location from one defined area of interest (3.1.1) location to a different

defined area of interest

Note 1 to entry: A transition could be composed of a large saccade (3.1.7) with further head movements to

compensate the required total amount of viewing deviation when changing from one AOI to another. E.g. visual

task to observe mirror, diverted from the main task while observing the road ahead.

Note 2 to entry: See F.1 and F.2.
3.1.11
visual angle

angle subtended at the eye by a viewed object or separation between viewed objects

Note 1 to entry: The figure below shows the visual angle α.
Figure 2 — Visual angle α
3.1.12
visual demand

degree or quantity of visual activity required to extract information from an object to perform a

specific task

Note 1 to entry: This can be determined by, e.g. number of glances (3.2.2.6), total glance time (3.2.2.11). See F.1.

4 © ISO 2020 – All rights reserved
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ISO 15007:2020(E)
3.1.13
visual display
device used to present visual information
Note 1 to entry: See F.1.
3.2 Terms for metrics
3.2.1 Basic direct metrics
3.2.1.1
duration of diversion

period of glance duration(s) (3.2.1.3) associated with directions of gaze away from one area of interest

(3.1.1) to another area of interest during a defined period of interest
Note 1 to entry: See F.3.
3.2.1.2
dwell time

sum of consecutive individual fixation (3.1.4) and saccade (3.1.7) times to an AOI (3.1.1) in a single

glance (3.1.6)
Note 1 to entry: See F.4.
3.2.1.3
glance duration

time from the moment at which the direction of gaze (3.1.3) moves towards an AOI (3.1.1) to the moment

it moves away from it
EXAMPLE A look at the inside rear-view mirror.

Note 1 to entry: Under certain specific conditions, this may be operationalized differently. See F.2.

3.2.1.4
minimum glance duration
shortest possible duration for a fixation (3.1.4) to an AOI (3.1.1)

Note 1 to entry: The “small fixations” observed to an area of interest of ≤120 ms are classified as fly through

(3.1.5).

Note 2 to entry: Fixations to an area of interest ≤120 ms are physically not possible. If an eye tracker is in use and

records such duration it can be classified as part of a transition (3.1.10) between areas of interest and it is not

taken into a glance (3.1.6) period.
3.2.1.5
transition time

duration between the end of the last fixation (3.1.4) on an AOI (3.1.1) and the start of the first fixation

on another AOI

EXAMPLE Visual task to observe mirror, diverted from the main task while observing the road ahead.

Note 1 to entry: A transition (3.1.10) could be composed of a large saccade (3.1.7) with further head movement to

compensate the required total amount of viewing deviation when changing from one AOI to another.

3.2.2 Glance derived metrics
3.2.2.1
glance location probability

probability that the eyes are fixated at an AOI (3.1.1) (or set of related AOIs) during a condition, task,

subtask or
...

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 15007
ISO/TC 22/SC 39
Road vehicles — Measurement and
Secretariat: ANSI
analysis of driver visual behaviour
Voting begins on:
2020­06­01 with respect to transport information
and control systems
Voting terminates on:
2020­07­27
Véhicules routiers — Mesurage et analyse du comportement visuel
du conducteur en relation avec les systèmes de commande et
d'information du transport
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
ISO/FDIS 15007:2020(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN­
DARDS TO WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS. ISO 2020
---------------------- Page: 1 ----------------------
ISO/FDIS 15007:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH­1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/FDIS 15007:2020(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

3.1 Basic terms ................................................................................................................................................................................................. 1

3.2 Terms for metrics .................................................................................................................................................................................. 5

3.2.1 Basic direct metrics ....................................................................................................................................................... 5

3.2.2 Glance derived metrics ............................................................................................................................................... 5

4 Trial planning and evaluation ................................................................................................................................................................ 7

4.1 General ........................................................................................................................................................................................................... 7

4.2 Trial planning ........................................................................................................................................................................................... 8

4.2.1 General...................................................................................................................................................................................... 8

4.2.2 Roadway/traffic specification .............................................................................................................................. 8

4.2.3 Vehicle specification ..................................................................................................................................................... 8

4.2.4 TICS specification ............................................................................................................................................................ 8

4.2.5 Participant selection ..................................................................................................................................................... 8

4.2.6 Participant training........................................................................................................................................................ 8

4.2.7 Data exclusion .................................................................................................................................................................... 8

4.3 Steps for data acquisition and data processing .......................................................................................................... 9

4.4 Experimental conditions, tasks, subtasks, sub-subtasks, and relationship ........................................ 9

4.4.1 Experimental condition ............................................................................................................................................. 9

4.4.2 Task.............................................................................................................................................................................................. 9

4.4.3 Subtask ..................................................................................................................................................................................10

4.4.4 Sub-subtask .......................................................................................................................................................................10

4.4.5 Relationship ......................................................................................................................................................................10

5 Recording equipment ...................................................................................................................................................................................11

5.1 General ........................................................................................................................................................................................................11

5.2 Eye tracking equipment ...............................................................................................................................................................12

5.2.1 General...................................................................................................................................................................................12

5.2.2 Head-mounted eye tracking systems ..........................................................................................................12

5.2.3 Remote eye tracking systems .............................................................................................................................13

5.3 Setup and verification of calibration of eye tracking systems .....................................................................13

5.3.1 General...................................................................................................................................................................................13

5.3.2 Recording with eye tracking systems .........................................................................................................13

5.3.3 Recording with remote eye tracking systems ......................................................................................14

5.3.4 Camera only systems for manual eye-glance analysis ..................................................................14

5.4 Setup and check of recording ..................................................................................................................................................14

5.5 Additional equipments ......... .........................................................................................................................................................14

5.6 Installation ...............................................................................................................................................................................................14

6 Data reduction .....................................................................................................................................................................................................15

6.1 General ........................................................................................................................................................................................................15

6.2 Sample interval ....................................................................................................................................................................................15

6.3 Manual reduction by raters/data analysts ...................................................................................................................15

6.4 Manual reduction by raters/data analysts of data from a camera only setup ..............................15

6.5 Manual reduction by raters/data analysts of data from an eye tracking system .......................15

6.6 Data Protocol for manual reduction ..................................................................................................................................16

6.7 Summary data .......................................................................................................................................................................................17

7 Data reduction using automated gaze analysis of eye tracking system....................................................18

7.1 General ........................................................................................................................................................................................................18

7.2 Data quality verification using 5 % of entire collected data .........................................................................18

7.2.1 Positional/orientation errors ............................................................................................................................18

© ISO 2020 – All rights reserved iii
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ISO/FDIS 15007:2020(E)

7.2.2 Detection time errors ........................................................................................................................................... .....18

7.2.3 Verification of Cohen’s kappa to secure accuracy of automated analysis ....................19

7.3 Availability of the eye tracker data .....................................................................................................................................19

8 Data analysis and presentation ..........................................................................................................................................................20

8.1 General ........................................................................................................................................................................................................20

8.2 Interpretation of findings from analyses of glance metrics ..........................................................................20

8.3 Interpretation of multiple glance metrics ....................................................................................................................21

Annex A (normative) Manual reduction procedures ........................................................................................................................23

Annex B (normative) Verification of calibration — Check of availability and calibration

accuracy of tracking equipment before recording data using a verification of

calibration procedure ..................................................................................................................................................................................28

Annex C (normative) Eye tracker validation task (EVT) ...............................................................................................................33

Annex D (normative) 5 % data verification — Check of reliability after data recording and

before statistical data analysis ...........................................................................................................................................................39

Annex E (normative) Calculating a Cohen’s kappa for one participant ........................................................................40

Annex F (informative) Supporting figures to explain terms and definitions...........................................................42

Annex G (informative) Supporting information for performing and analysing experiments

to determine driver visual behaviour .........................................................................................................................................47

Annex H (informative) Collection and analysis of (long-term) on-road visual data ........................................49

Annex I (informative) Additional recording equipment ...............................................................................................................50

Bibliography .............................................................................................................................................................................................................................51

iv © ISO 2020 – All rights reserved
---------------------- Page: 4 ----------------------
ISO/FDIS 15007:2020(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

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electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

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expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/

iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 39,

Ergonomics.

This edition cancels and replaces ISO 15007­1:2014 and ISO/TS 15007­2:2014, which have been

technically revised.
The main changes compared to the previous editions are as follows:

— integration of ISO 15007­1 (Part 1: Definitions and parameters) and ISO/TS 15007­2 (Part 2: Equipment

and procedures) into one document;
— detailed description of different data reduction procedures;
— detailed description of procedures and criteria for quality assurance.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
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ISO/FDIS 15007:2020(E)
Introduction

This document supports the quantification and description of visual behaviour while using TICS

(transport information and control systems) and driving vehicles in different driving levels of

automation. It supports the quantification of information acquisition related to internal and vehicle

external environment/objects (e.g. vehicles, billboards, information displays, variable message signs).

It provides assistance in the assessment of driver state considering visual attention. This document

does not address fatigue and drowsiness.

This document describes the phases of visual behaviour assessment including the following steps:

— calibration setup and calibration verification (piloting phase);
— data collection;
— data reduction;
— quality assessment;
— data presentation.

Each of these steps should be handled with care, documented and checked for quality before moving to

the next step.
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FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 15007:2020(E)
Road vehicles — Measurement and analysis of driver
visual behaviour with respect to transport information and
control systems
1 Scope

This document defines key terms and parameters applied in the analysis of driver visual behaviour

focused on glance and glance-related measures. It provides guidelines and minimum requirements on

equipment and procedures for analysing driver visual behaviour including assessment of TICS to:

— plan evaluation trials,
— specify (and install) data capture equipment, and

— validate, analyse, interpret and report visual-behaviour metrics (standards of measurement).

The parameters and definitions described below provide a common source of reference for driver

visual behaviour data.

It is applicable to on-road trials (e.g. field operational tests or naturalistic studies), and laboratory-

based driving studies. The procedures described in this document can also apply to more general

assessments of driver visual behaviour. Data collected and analysed according to this document will

allow comparisons to be performed across different TICS applications and experimental scenarios.

2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at https:// www .iso .org/ obp
3.1 Basic terms
3.1.1
area of interest
AOI
pre­determined area within the visual scene
Note 1 to entry: Region of interest (ROI) is used as a synonym.

Note 2 to entry: An AOI will be no smaller than the normal resolution of the eye-measurement system being used

(e.g. no smaller than 0,5 ° for typical eye tracking systems). See F.1.
EXAMPLE A rear­view mirror.
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ISO/FDIS 15007:2020(E)
3.1.2
blink
short period of time in which the eye is closed by the eyelid

Note 1 to entry: The blink starts when the eyelid starts moving downwards and ends when the eye is fully

opened again.

Note 2 to entry: According to the duration for which the eye is closed the following classification applies (see

Reference [13]):
— Normal blinks: ≤300 ms (mean duration 257 ms; standard deviation 11 ms)
— Long closed durations: 300 ms to 500 ms
— Eye-lid closures: ≥500 ms (indicating microsleeps)

Note 3 to entry: Depending on participant state and/or glance (3.1.6) direction of a participant the eyelid may not

fully open, although the blink might end. Especially in these cases the visibility of the pupil or major part of the

pupil is important for correct gaze recognition.
Key
1 closing phase
2 opening phase
x vertical positioning of upper eyelid
Open.
Partially closed.
Closed.
Figure 1 — Phases of a blink (see Reference [17])

Note 4 to entry: A blink is performed by the down movements the upper eye lid while lower eyelid remains static.

Upper eyelid movement is considered in defining a blink.
3.1.3
direction of gaze

orientation of the eye to the area of interest (3.1.1) to which the eyes are directed to

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ISO/FDIS 15007:2020(E)
3.1.4
fixation

short temporal holds of movements that keep alignment of the eyes to a particular point within an AOI

(3.1.1) which falls on the fovea (the middle of the retina responsible for our central, sharpest vision) for

a given time period

Note 1 to entry: Typically, individual fixations last from 100 ms to 2 000 ms (see Reference [5]). Fixations are the

briefest of pauses during which visual information extraction is done by the eyes-and-brain from spatial areas

that fall on the fovea of the eye (and hence are quite small). During fixation, there are believed to be at least

three processes taking place (see Reference [16]) 1) analysis of the image falling on the fovea, 2) selection of a

new saccade (3.1.7) target and 3) programming of the saccade to-be-made-next. It is not yet known how these

processes are synchronized by the brain, nor how precisely they are synchronized – since fixation durations

are not always long enough to comprehend completion of all the processes. (Sometimes the eyes move before

information extraction from the site of fixation has been completed, as evidenced by frequent corrective return

fixations to a site under some conditions that was fixated too briefly). There is evidence that the brain both pre-

programs fixation duration, and also does “process-monitoring” during a fixation to determine if analysis of the

foveal image is complete within the fixation’s duration before moving on. Thus, fixation time is dependent on

both the immediate stimulus and the history of prior fixations. The contribution of both components suggests

that fixation time may depend on the task and the amount of useful information in the fixated display (or viewed

information) (see Reference [7]).
Note 2 to entry: See F.1 to F.4.
3.1.5
fly through

small ‘snapshot’ of a saccade (3.1.7) (<120 ms) that may be an artefact captured when the eye is

moving from one area of interest (3.1.1) to another area of interest, and passing through one or more

intermediate Areas of Interest in between

EXAMPLE The eye moves from the road scene ahead to the instrument cluster and passes the head-up

display.

Note 1 to entry: Sometimes a small ‘snapshot’ of such a saccade may appear to be a short fixation (3.1.4), when it

is really still part of the saccade. Such fly throughs (<120 ms) are not treated as fixations. Fly throughs may be

grouped with the saccade they are part of, if saccades are being measured.

Note 2 to entry: Research shows that fixations cannot be shorter than 100 ms (see Reference [10]).

3.1.6
glance

temporal maintaining of visual gaze within an AOI (3.1.1), bounded by the perimeter of the AOI which

can be comprised of more than one fixation (3.1.4) and saccades (3.1.7) within the AOI and its duration

is measured as glance duration (3.2.1.3)

Note 1 to entry: A glance is a scientific construct that sums over one or more fixations that are made contiguously

within a given area of interest (but one that is larger than the area corresponding to the eye’s foveal region –

an area that usually requires more than one fixation to view). The construct of a glance, therefore, typically

comprehends more than a single fixation and is a coarser unit of analysis than a single fixation (since it is summing

over fixations that are contiguous in time and spatially proximal within an area of interest. The construct of

a “glance” is needed because often the salient questions in a study relate to the amount of contiguous time

spent gazing at a particular area of interest (before the eyes move away from it). Of course, in some instances,

the “glance” construct is also necessary because some measurement approaches are not capable of the fine

discriminations needed to identify individual fixations (spatially and temporally) – and can only discriminate

at the spatial/temporal granularity of glances. Thus, “glances” are a coarser measure of visual information

extraction by the eyes/brain from a continuously viewed but somewhat larger spatial region. Typical glance

lengths vary by stimulus and task but might (for example) range from 500 ms to 3 s for a task like “tuning the

radio” (see Reference [11]).
Note 2 to entry: See F.1 to F.4.
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ISO/FDIS 15007:2020(E)
3.1.7
saccade

brief, fast movement of the eyes that changes the point of fixation (3.1.4), within an AOI (3.1.1) or

between different AOIs

Note 1 to entry: Saccades reach velocities as high as 500°/s (see Reference [10]), whereby the mean saccade

ranges between 1° (text reading) to 5° (scene perception) (see Reference [14]).
Note 2 to entry: See F.1 to F.4.
3.1.8
smooth pursuit movement

smooth continuous movement of the eyes made to closely follow/pursue a moving object or signal

Note 1 to entry: Humans generally perform smooth pursuit movements better in the horizontal than vertical

dimension, and better in the downward than upward direction. Smooth pursuit movements can have a velocity

as high as 90°/s (see Reference [9]).
3.1.9
sample interval
the epoch of time over which measurements are taken

EXAMPLE The duration of an in-vehicle task on entering a destination into a route guidance system, where

the evaluation in interest is to evaluate the driver behaviour when the driver performs a task of entering the

destination.

Note 1 to entry: Usually, this will be the contiguous epoch of time that is associated with an event or task that

is of interest in the study. The sample interval is the period of time (from start to end) during which data are

extracted.
3.1.10
transition

change in eye fixation (3.1.4) location from one defined area of interest (3.1.1) location to a different

defined area of interest

Note 1 to entry: A transition could be composed of a large saccade (3.1.7) with further head movements to

compensate the required total amount of viewing deviation when changing from one AOI to another. E.g. visual

task to observe mirror, diverted from the main task while observing the road ahead.

Note 2 to entry: See F.1 and F.2.
3.1.11
visual angle

angle subtended at the eye by a viewed object or separation between viewed objects

Note 1 to entry: The figure below shows the visual angle α.
Figure 2 — Visual angle α
3.1.12
visual demand

degree or quantity of visual activity required to extract information from an object to perform a

specific task

Note 1 to entry: This can be determined by, e.g. number of glances (3.2.2.6), total glance time (3.2.2.11). See F.1.

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ISO/FDIS 15007:2020(E)
3.1.13
visual display
device used to present visual information
Note 1 to entry: See F.1.
3.2 Terms for metrics
3.2.1 Basic direct metrics
3.2.1.1
duration of diversion

period of glance duration(s) (3.2.1.3) associated with directions of gaze away from one area of interest

(3.1.1) to another area of interest during a defined period of interest
Note 1 to entry: See F.3.
3.2.1.2
dwell time

sum of consecutive individual fixation (3.1.4) and saccade (3.1.7) times to an AOI (3.1.1) in a single

glance (3.1.6)
Note 1 to entry: See F.4.
3.2.1.3
glance duration

time from the moment at which the direction of gaze (3.1.3) moves towards an AOI (3.1.1) to the moment

it moves away from it
EXAMPLE The inside rear­view mirror.

Note 1 to entry: Under certain specific conditions, this may be operationalized differently. See F.2.

3.2.1.4
minimum glance duration
shortest possible duration for a fixation (3.1.4) to an AOI (3.1.1)

Note 1 to entry: The “small fixations” observed to an area of interest of ≤120 ms are classified as fly through

(3.1.5).

Note 2 to entry: Fixations to an area of interest ≤120 ms are physically not possible. If an eye tracker is in use and

records such duration it can be classified as part of a transition (3.1.10) between areas of interest and it is not

taken into a glance (3.1.6) pe
...

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