Applies Fourier filter to 2D or 3D real picture.
Coefficients of the filter are read from a document file.
USAGE
.OPERATION: FD
.INPUT FILE: PIC001
[Enter name of input file containing real picture.]
.OUTPUT FILE: FIC001
[Enter name of output file containing filtered real picture.]
.FILTER DOC FILE: my_filter
[Enter name of document file. First column should contain
coefficients of a Fourier filter.]
NOTES
The Fourier transform of the input file is multiplied
by the filter coefficients read from a document file.
Filter coefficients should be stored in in the first
column. The first key is assumed to correspond to zero
frequency, the second key to the first bin in Fourier
space, and so on. If the document file has fewer keys
than the number of bins in Fourier space (SQRT(2)*[N/2+1],
where N is the maximum dimension of the image in real space),
the remaining filter coefficients are assumed to be equal
to zero.