NAME

       fdk - cone-beam reconstruction from projections using the FDK algorithm

       The  term  FDK  refers  to  the authors Feldkamp, Davis, and Kress who wrote the seminal paper "Practical
       cone-beam algorithm" in 1984.  Their paper describes a filtered back-projection reconstruction  algorithm
       for cone-beam geometries.  The fdk program in plastimatch is an implmenetation of the FDK algorithm.

FDK USAGE

       The  fdk  program takes a directory of 2D projection images as input, and generates a single 3D volume as
       output.

       The command line usage is:

          Usage: fdk [options]
          Options:
           -A hardware            Either "cpu" or "cuda" (default=cpu)
           -a "num ((num) num)"   Use this range of images
           -r "r1 r2 r3"          Set output resolution (in voxels)
           -f filter              Either "none" or "ramp" (default=ramp)
           -s scale               Scale the intensity of the output file
           -z "s1 s2 s3"          Physical size of the reconstruction (in mm)
           -I indir               The input directory
           -O outfile             The output file

       The usage of the fdk program is best understood by following along with the tutorials: fdk_tutorial_i and
       fdk_tutorial_ii.

INPUT FILES

       Three different formats of input files are supported.  These are:

       • Pfm format image files with geometry txt files

       • Raw format image files with geometry txt files

       • Varian hnd files

       The pfm and raw files are similar, in that they store the image  as  an  array  of  4-byte  little-endian
       floats.   The  only difference is that the pfm file has a header which stores the image size, and the raw
       file does not.

       Each pfm or raw image file must have a geometry file in the same directory with the .txt extension.   For
       example,  if  you  want  to  use  image_0000.pfm  in  a  reconstruction,  you  should supply another file
       image_0000.txt which contains the geometry.  A brief description of the geometry file format is given  in
       proj_mat_file_format.

       The sequence of files should be stored with the pattern:
          XXXXYYYY.ZZZ

       where  XXXX  is a prefix, YYYY is a number, and .ZZZ is the extension of a known type (either .hnd, .pfm,
       or .raw).

       For example the following would be a good directory layout for pfm files:

          Files/image_00.pfm
          Files/image_00.txt
          Files/image_01.pfm
          Files/image_01.txt
          etc...

       The Varian hnd files should be stored in the original layout.  For example:

          Files/ProjectionInfo.xml
          Files/Scan0/Proj_0000.hnd
          Files/Scan0/Proj_0001.hnd
          etc...

       No geometry txt files are needed to reconstruct from Varian hnd format.

IMAGE GEOMETRY

       By default, when you generate a DRR, the image is oriented as if the virtual x-ray source were a  camera.
       That  means  that  for a right lateral film, the columns of the image go from inf to sup, and the rows go
       from ant to post.  The Varian OBI system produces HND files, which are oriented differently. For a  right
       lateral  film,  the  columns  of the HND images go from ant to post, and the rows go from sup to inf.  An
       illustration of this idea is shown in the figure below.
         [image] Geometry of Varian HND files.UNINDENT

AUTHOR

       Plastimatch   is   a   collaborative   project.    For    additional    documentation,    please    visit
       http://plastimatch.org.      For     questions,    comments,    and    bug    reports,    please    visit
       http://groups.google.com/group/plastimatch.

COPYRIGHT

       Plastimatch development team (C) 2010-2015.  You are free to  use,  modify,  and  distribute  plastimatch
       according to a BSD-style license.  Please see LICENSE.TXT for details.

Plastimatch 1.7.0                                 Dec 18, 2017                                            FDK(1)