Level 2 Help for FFTMAGIC

INP specifies the initial estimate picture (EST) and the reference picture 
(REF).  The initial estimate picture will be used to obtain the unknown part
of the Fourier transform.  EST is usually a random noise scene.  The reference
picture's Fourier transform will be used (either the amplitude or the phase)
as a "known" quantity.

OUT specifies the picture whose Fourier transform corresponds either in phase
or amplitude to REF after ITER iterations.

OUTFMT specifies the format for output data.  The valid values are OUTBYTE,
OUTHALF, OUTINTEG, and OUTREAL.  The default is to use the format of the
input pictures.

MODE=PHASE (or 'PHASE) specifies that the phase of the reference picture (REF)
will be used as a boundary condition, leaving the amplitude to be determined. 
The default is for the amplitude to be used as the boundary condition. 

ITER specifies the maximum number of iterations allowed.  If no pixels are 
reset on any pass, the iteration process is terminated.  Default is ITER=100.

'PRINT causes the number of pixels changed and the sum of the
negative pixels to be printed at each iteration.  

BETA specifies the real value to be multiplied by each negative pixel in order
to render it positive or zero.  The negative of BETA is used in the program,
and only every other iteration is used.  The default is BETA = 0.5 .

The PSF keyword is used in the form PSF=(N,L1,S1,R1,...,Ln,Sn,Rn), where 
each L, S, and R triplet specifies the line, sample, and radius of a 
point-spread function in the reference (REF) image.  If PSF is specified,
each center position is re-centered at the max DN value in each circular area
and the sum of the pixels less background (determined from the border points)
is computed for the values within the circle.  Then, for each iteration, all
of the points inside each circle are set to the mean DN of the border points
and the central pixel is set to the mean DN plus the sum of the DN's as
previously computed.  PSF acts as an additional boundary condition for stellar-
type point-spread functions.