iMap: a novel method for statistical fixation mapping of eye movement data.

Caldara, R. and Miellet, S., 2011. iMap: a novel method for statistical fixation mapping of eye movement data. Behavior Research Methods , 43 (3), 864 - 878 .

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DOI: 10.3758/s13428-011-0092-x

Abstract

Eye movement data analyses are commonly based on the probability of occurrence of saccades and fixations (and their characteristics) in given regions of interest (ROIs). In this article, we introduce an alternative method for computing statistical fixation maps of eye movements--iMap--based on an approach inspired by methods used in functional magnetic resonance imaging. Importantly, iMap does not require the a priori segmentation of the experimental images into ROIs. With iMap, fixation data are first smoothed by convolving Gaussian kernels to generate three-dimensional fixation maps. This procedure embodies eyetracker accuracy, but the Gaussian kernel can also be flexibly set to represent acuity or attentional constraints. In addition, the smoothed fixation data generated by iMap conform to the assumptions of the robust statistical random field theory (RFT) approach, which is applied thereafter to assess significant fixation spots and differences across the three-dimensional fixation maps. The RFT corrects for the multiple statistical comparisons generated by the numerous pixels constituting the digital images. To illustrate the processing steps of iMap, we provide sample analyses of real eye movement data from face, visual scene, and memory processing. The iMap MATLAB toolbox is editable and freely available for download online (www.unifr.ch/psycho/ibmlab/).

Item Type:Article
ISSN:1554-351X
Uncontrolled Keywords:Algorithms ; Biometry ; Data Interpretation, Statistical ; Eye Movement Measurements ; Eye Movements ; Humans ; Software
Subjects:UNSPECIFIED
Group:Faculty of Science and Technology
ID Code:22091
Deposited By: Unnamed user with email symplectic@symplectic
Deposited On:12 Jun 2015 10:29
Last Modified:12 Jun 2015 10:29

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