FDK(1)								    Plastimatch 							    FDK(1)

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 "brook" 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
	-F {F,H}	       Full or half fan bow-tie filter correction

       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:

       o Pfm format image files with geomtry txt files

       o Raw format image files with geomtry txt files

       o 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  lat-
       eral  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 more 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) 2010-2011.  You are free to use, modify, and distribute plastimatch  according	to  a  BSD-style  license.
       Please see LICENSE.TXT for details.

Plastimatch 1.5 						   June 11, 2011							    FDK(1)