Boulder Laboratory for 3-Dimensional Electron Microscopy of Cells

FFTRANS(1)							     FFTRANS(1)

NAME
  fftrans - to compute forward or reverse fourier transform of images

SYNOPSIS
  fftrans [options] [input filename] [output filename]

DESCRIPTION
  This program will do 2- or 3-dimensional FFT's in either direction. The
  real-space origin is at (1,1) and the origin of reciprocal space is at
  (1,NY/2+1) for 2-D FFT's.  The FT of an image NX,NY is NX/2+1,NY complex
  values.  For 3-D FFT's, the origin is at (1,NY/2+1,NZ/2+1)

  All transforms are done using Lynn ten Eyck's subroutines. These allow
  arbitrary-sized images with dimensions that are even and have a 
  LARGEST PRIME factor of 19.

  3-D images are treated as stacks of images that are transformed
  independently in 2-D, unless the -3dfft option is given.  Large images (up
  to 5K x 5K) are transformed in memory.  Very large images (up to 8192 x
  8192) are transformed using the disk-based routine BIGFFT.  In this case,
  only a single section can be transformed.

  If no command line arguments are given the program will request the input
  and output file names interactively.  Otherwise, the program uses the PIP
  package for input (see pip).  The following options can be specified
  either as command line arguments (with the -) or one per line in a command
  file (without the -):

 -input OR -InputFile   File name
    Input file with image or Fourier transform

 -output OR -OutputFile   File name
    Output file for Fourier transform or inverse transform

 -3dfft
    Take 3D instead of 2D FFT

 -mode OR -Mode   Integer
    Mode of output file for inverse transform: 0 for bytes, 1 for integers
    (default is 2 for reals)

 -quiet OR -Quiet
    Suppress header and min/max/mean outputs

 -help OR -usage
    Print help output.

  -StandardInput
     Read parameter entries from standard input.


HISTORY
  Originally written by David Agard for VAX.  David Mastronarde modified to do
  in "memory" rather than use giantfft as long as the image will actually fit
  into the dimensioned array.  Also, changed to properly package arrays in
  memory and use iwrsec to write sections.
  10/24/04: Converted to PIP input and added 3D FFT, mode, quiet options.