Converts EyeLink 1000 Edf files into Matlab

Version 1.20

Adrian Etter Marc Biedermann

University of Zurich Department of Economics Schönberggasse 1 CH-8001 Zurich

E-Mail: [email protected]

URL:

• https://www.econ.uzh.ch/en/people/staff/etter.html
• https://www.econ.uzh.ch/en/people/staff/biedermann.html

2018 May 22.

Edf2Mat is a Matlab Toolbox for easy conversion of EyeLink Edf result files. For fast verification of valid data, there is an included plot function, which displays eye movement, pupil size and a heatmap of the eye movement. There are a few examples in the example file which help analyze eye data.

Copyright © 2007-2016 Adrian Etter, Marc Biedermann, University of Zurich. All rights reserved.

This document may be copied, modified, reproduced and redistributed for educational and personal use as long as the original author is mentioned and cited.

MATLAB® is a registered Trademark of MathWorks, Inc.™ (http:https://www.mathworks.com). EyeLink® is a registered trademark of SR Research Ltd., Mississauga, Ontario, Canada (http:https://www.sr-research.com)

You are allowed to use this software for free, but please acknowledge if you are using this software to process Edf-files:

The conversion of the EyeLink® 1000 Edf files was done with the Edf2Mat Matlab Toolbox designed and developed by Adrian Etter and Marc Biedermann at the University of Zurich.

Edf2Mat Toolbox is Licensed under the MIT License. The Edf2Mat Toolbox uses slightly modified code (Kovach, 2011) from C. Kovach 2007.

• Ensure the Visual C++ Redistributable for Visual Studio 2015 is installed
• Ensure the Visual C++ Redistributable for Visual Studio 2008 is installed

the edfapi.framework must be in /Library/Frameworks. The Library can be found in the Package. Attention: If the Zip file was unpacked on windows first, and then copied, the folder structure will be broken. The zip-file must be extracted on a Mac in order to work. Otherwise the symlinks will be broken.

on os x in /Library/Frameworks it should look like the following

edfapi.framework/
├── Headers -> Versions/Current/Headers
├── Resources -> Versions/Current/Resources
├── Versions
│   ├── A
│   │   ├── Headers
│   │   │   ├── edf.h
│   │   │   ├── edf_data.h
│   │   │   └── edftypes.h
│   │   ├── Resources
│   │   │   └── Info.plist
│   │   └── edfapi
│   └── Current -> A
└── edfapi -> Versions/Current/edfapi

• The Edf2Mat Class
• All files in the private folder
• All Dlls in the private folder

There is an Example.m script. Have a look at it. Type help for help

help Edf2Mat

Edf2Mat is a converter to convert Eyetracker data files to
Matlab file and perform some tasks on the data

The new procedure uses code from SR-Research that returns all info of
the edf and not just part of it. The new routine is based on the work
of C. Kovach 2007 and is only for non-commercial use!



Syntax: Edf2Mat(filename);
      Edf2Mat(filename, verbose);

Inputs: filename: must be of type *.edf useOldProcedure: If you want to use the old procedure with edf2asc.exe, you can set this argument to true, default is false verbose: logical, can be true or false, default is true. If you want to suppress output to console, verbose has to be false

The Basic functionality is as follows: Convert Edf File

edf1 = Edf2Mat('fMRI_Results_sub_025_270712EYE25r1.edf');

Calling the Edf2Mat with a filename converts the given edf file to a Matlab structure, which will be available in the Matlab workspace. In order to save the produced structure to a matfile, just call “save(edf1)”, whereas edf1 is the variable assign when calling the Edf2Mat Class.

The Edf2Mat class has its own plot functionality to plot the content. It’s more for a fast forward validation of data than actually the way you should plot your data.

plot(edf1);

In order to plot eye movement only in a specified time range, the Matlab builitin plot command could be used as following:

figure();
plot(edf1.Samples.posX(end - 2000:end), edf1.Samples.posY(end - 2000:end), 'o');

To simply plot the pupil size for a given time window, the pupil size array can be accessed as stated in the next line.

figure();
plot(edf1.Samples.pa(2, end - 500:end));

plotHeatmap(edf1)

Many thanks to Stefan Schmid and Adrian Etter to point out typos.

Kovach, C. (2011, 01 12). SR Research. Retrieved from SR Research Support: https://www.sr-support.com/showthread.php?255-Import-of-EDF-file-into-Matlab&p=6781#post6781