This transforms data into frequency domain utilising libfftw3f-3.dll ( or, FFTW3 dll, or fftw.dll) of fftw.org being available in path. It should be kept in mind that most of the image frequency values are near around 0. Caution must be excercised in specifying fromf. This function checks for anamolous values within a width of span and corrects by replacing with a median value. Small values of 3 to 15 may be prefered for span. Regular noise of vertical or sub vertical orientation are removed by this function. If noise is near Horizontal, Transpose function may be used before and after. Check for values to be used by running F1Quiver with test = 1 prior ( and after to confirm).