fScan Reference Manual, Chapter 2 (CmdLineOptions): convolve
Convolve -- Convolve images using image matrix kernal
usage: -convolve flag scale kernal offset
This smooths images or activation maps by performing a spatial convolution of each voxel. The arguments are:
0 - initialize activation map with filter flag ON (default is OFF.) This is equivalent to entering the 'f' (Toggle FILTER) command interactively as soon as the map window appears. This setting does not affect the input images themselves.
1 - Convlolve each input image with a Gaussian kernal. This is the default if no FLG value is specified. The alternative to Gaussian is a simple smoothing kernal (i.e., 3×3 with all elements equal 1/9).
2 - Subtract the filtered value from the original (default is to replace the filtered value for the original). This option acts as an enhancing filter. SCALE Specify the width of the Gaussian kernal (default is 1.5 voxels).
SCALE - scaling factor
KERNAL - The kernal is the small image matrix that will be convolved with your image. It can be entered explicitly from a disk file (if KERNAL is a file name) or from an array in PDIGMFILE (if KERNAL is a number; see “fscan help”). The dimensions of the kernal will be taken from the input array.
OFFSET - Specify an offset value to add to each element after the convolution.