EHCA is a MATLAB tool to analyze eye and head coordination. Parameters that are detected are such as eye delay, head offset, eye/head amplitudes and durations.
The tool and a use case was published in a peer-reviewed scientific journal, please cite my work if you use my software:
Schwab, S., Würmle, O., & Altorfer, A. (2012). Analysis of eye and head coordination in a visual peripheral recognition task. Journal of Eye Movement Research 5(2):3, 1-9.
To access the tool from within MATLAB, you have to add the ehca folder to the MATLAB path (File... Set Path...). The tool is started by typing 'ehca' in the MATLAB command window.
>> ehca
From the GUI, a *.mat file can be loaded, which contains your data. Example data is contained in ehca_demo.mat. The data file requires the following specification:
There has to be a struct variable named 'segments', which contains the cells 'time', 'head', 'eye' and 'gaze', which contain the data for each trial. Here, the data contains 11 trials (data segments).
time: {1x11 cell}
head: {1x11 cell}
eye: {1x11 cell}
gaze: {1x11 cell}
To see such a data structure, load the ehca_demo.mat from the command window:
>> load ehca_demo.mat
Parameter detection can be conducted for each of the 11 trials, and the trials can be visually inspected for proper parameter detection. Therefore, press 'Parameter Detection' and browse through the trials by pressing the next button (>).
To access the data, type
>> global ehdata
The ehdata is a global variable that contains the parameters detected (ehdata.param). However, with some of the trials, parameter detection may fail. Therefore, parameters can be accessed to replace wrong parameters with NaN values before subject statistics are performed.
It is recommended to save the cleaned up values in a different variable, since a new parameter detection will just overwrite ehdata.param.
>> myparam = ehdata.param
At the end, don't forget to save your analyzed data ;)
>> save subjectA.mat
Project home page: https://github.com/schw4b/ehca
Simon Schwab - May 2012