function fwhm

Returns the second order moment of X centered at [XCENTER, YCENTER] within RADIUS, which corresponds to the FWHM at that location. The parameter RADIUS is optional. If skipped, a default of 5 pixels will be used.

Syntax
result = fwhm(X, XCENTER, YCENTER [, RADIUS])

Arguments
X:   A matrix.
XCENTER:   An integer number.
YCENTER:   An integer number.
RADIUS:   An integer number.