Using the GUI (4): Optional for preprocessing
Optional features include the aforementioned Rescale, Mask generation and spatial Normalization on the fixation map.
Rescale: Linear downsampling using imresize in Matlab with "nearest" method.
Mask: In iMap4, model fitting is only performed within a given mask, as the sparse outliners in 2D fixation map are very likely to generate erroneous estimation. The default threshold is the full width at half maximum (FWHM) for the minimal fixation duration after smoothing.
Normalization (not shown here) could be done either by performing pixel-wise Z-score or divide by total trial/condition duration.