topology/volToOFF.cpp

Marching-cube like surface extracted using the combinatorial manifold structure of digital surfaces.

See also:

Application to export surface in OFF format

On the lobser.vol volume, volToOFF.cpp builds an OFF surface of 155068 vertices, 154910 faces, 310136 edges in 3879ms+1646ms.

# Commands
$ ./examples/topology/volToOff ../examples/samples/cat10.vol 1 255 0
$ ./examples/topology/volToOff ../examples/samples/lobster.vol 50 255 0

Marching-cube surface of cat10.vol file.

Marching-cube surface of lobster.vol file.

#include <iostream>
#include "DGtal/base/Common.h"
#include "DGtal/io/readers/VolReader.h"
#include "DGtal/helpers/StdDefs.h"
#include "DGtal/topology/helpers/Surfaces.h"
#include "DGtal/topology/DigitalSurface.h"
#include "DGtal/topology/SetOfSurfels.h"
#include "DGtal/images/ImageSelector.h"
#include "DGtal/images/imagesSetsUtils/SetFromImage.h"


using namespace std;
using namespace DGtal;
using namespace Z3i;



void usage( int, char** argv )
{
  std::cerr << "Usage: " << argv[ 0 ] << " <fileName.vol> <minT> <maxT> <int=0|ext=1>" << std::endl;
  std::cerr << "\t - displays the boundary of the shape stored in vol file <fileName.vol> as an OFF geomview surface file. It is a kind of marching-cube surface, defined by duality with respect to the digital surface." << std::endl;
  std::cerr << "\t - voxel v belongs to the shape iff its value I(v) follows minT <= I(v) <= maxT." << std::endl;
  std::cerr << "\t - 0: interior adjacency, 1: exterior adjacency." << std::endl;
}

int main( int argc, char** argv )
{
  if ( argc < 5 )
    {
      usage( argc, argv );
      return 1;
    }
  std::string inputFilename = argv[ 1 ];
  unsigned int minThreshold = atoi( argv[ 2 ] );
  unsigned int maxThreshold = atoi( argv[ 3 ] );
  bool intAdjacency = atoi( argv[ 4 ] ) == 0;

  trace.beginBlock( "Reading vol file into an image." );
  typedef ImageSelector < Domain, int>::Type Image;
  Image image = VolReader<Image>::importVol(inputFilename);
  DigitalSet set3d (image.domain());
  SetPredicate<DigitalSet> set3dPredicate( set3d );
  SetFromImage<DigitalSet>::append<Image>(set3d, image,
                                          minThreshold, maxThreshold);
  trace.endBlock();

  // Construct the Khalimsky space from the image domain
  KSpace K;
  bool space_ok = K.init( image.domain().lowerBound(),
                          image.domain().upperBound(), true );
  if (!space_ok)
    {
      trace.error() << "Error in the Khamisky space construction."<<std::endl;
      return 2;
    }

  typedef SurfelAdjacency<KSpace::dimension> MySurfelAdjacency;
  MySurfelAdjacency surfAdj( intAdjacency ); // interior in all directions.

  trace.beginBlock( "Extracting boundary by scanning the space. " );
  typedef KSpace::Surfel Surfel;
  typedef KSpace::SurfelSet SurfelSet;
  typedef SetOfSurfels< KSpace, SurfelSet > MySetOfSurfels;
  typedef DigitalSurface< MySetOfSurfels > MyDigitalSurface;

  MySetOfSurfels theSetOfSurfels( K, surfAdj );
  Surfaces<KSpace>::sMakeBoundary( theSetOfSurfels.surfelSet(),
                                   K, set3dPredicate,
                                   image.domain().lowerBound(),
                                   image.domain().upperBound() );
  MyDigitalSurface digSurf( theSetOfSurfels );
  trace.info() << "Digital surface has " << digSurf.size() << " surfels."
               << std::endl;
  trace.endBlock();

  trace.beginBlock( "Making OFF surface <marching-cube.off>. " );
  ofstream out( "marching-cube.off" );
  if ( out.good() )
    digSurf.exportSurfaceAs3DOFF( out );
  out.close();
  trace.endBlock();

  return 0;
}