DGtal 1.3.0
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Examples of breadth-first traversal on a digital surface You can use these commands:

* # Commands
* $ ./examples/topology/volBreadthFirstTraversal ../examples/samples/lobster.vol 50 255
* $ ./examples/topology/volBreadthFirstTraversal ../examples/samples/cat10.vol 1 255

to get these pictures:

Examples of breadth-first traversal on a digital surface.
#include <iostream>
#include <queue>
#include <QImageReader>
#include "DGtal/io/readers/VolReader.h"
#include "DGtal/io/DrawWithDisplay3DModifier.h"
#include "DGtal/io/Color.h"
#include "DGtal/io/colormaps/HueShadeColorMap.h"
#include "DGtal/images/ImageSelector.h"
#include "DGtal/images/imagesSetsUtils/SetFromImage.h"
#include "DGtal/shapes/Shapes.h"
#include "DGtal/helpers/StdDefs.h"
#include "DGtal/topology/DigitalSurface.h"
#include "DGtal/topology/LightImplicitDigitalSurface.h"
#include "DGtal/io/viewers/Viewer3D.h"
using namespace std;
using namespace DGtal;
using namespace Z3i;
void usage( int, char** argv )
std::cerr << "Usage: " << argv[ 0 ] << " <fileName.vol> <minT> <maxT>" << std::endl;
std::cerr << "\t - displays the boundary of the shape stored in vol file <fileName.vol>." << std::endl;
std::cerr << "\t - voxel v belongs to the shape iff its value I(v) follows minT <= I(v) <= maxT." << std::endl;
int main( int argc, char** argv )
if ( argc < 4 )
usage( argc, argv );
return 1;
std::string inputFilename = argv[ 1 ];
unsigned int minThreshold = atoi( argv[ 2 ] );
unsigned int maxThreshold = atoi( argv[ 3 ] );
trace.beginBlock( "Reading vol file into an image." );
typedef ImageSelector < Domain, int>::Type Image;
Image image = VolReader<Image>::importVol(inputFilename);
DigitalSet set3d (image.domain());
minThreshold, maxThreshold);
trace.beginBlock( "Construct the Khalimsky space from the image domain." );
KSpace ks;
bool space_ok = ks.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( true ); // interior in all directions.
trace.beginBlock( "Set up digital surface." );
SCell bel = Surfaces<KSpace>::findABel( ks, set3d, 100000 );
MyDigitalSurfaceContainer* ptrSurfContainer =
new MyDigitalSurfaceContainer( ks, set3d, surfAdj, bel );
MyDigitalSurface digSurf( ptrSurfContainer ); // acquired
trace.beginBlock( "Extracting boundary by tracking from an initial bel." );
typedef BreadthFirstVisitor<MyDigitalSurface> MyBreadthFirstVisitor;
typedef MyBreadthFirstVisitor::Node MyNode;
typedef MyBreadthFirstVisitor::Size MySize;
MyBreadthFirstVisitor visitor( digSurf, bel );
unsigned long nbSurfels = 0;
MyNode node;
while ( ! visitor.finished() )
node = visitor.current();
MySize maxDist = node.second;
trace.beginBlock( "Displaying surface in Viewer3D." );
QApplication application(argc,argv);
Viewer3D<> viewer;
HueShadeColorMap<MySize,1> hueShade( 0, maxDist );
MyBreadthFirstVisitor visitor2( digSurf, bel );
viewer << CustomColors3D( Color::Black, Color::White )
<< ks.unsigns( bel );
while ( ! visitor2.finished() )
node = visitor2.current();
Color c = hueShade( node.second );
viewer << CustomColors3D( Color::Red, c )
<< ks.unsigns( node.first );
viewer << Viewer3D<>::updateDisplay;
trace.info() << "nb surfels = " << nbSurfels << std::endl;
return application.exec();
Aim: This class is useful to perform a breadth-first exploration of a graph given a starting point or...
Structure representing an RGB triple with alpha component.
Definition: Color.h:68
Aim: Represents a set of n-1-cells in a nD space, together with adjacency relation between these cell...
Aim: This class template may be used to (linearly) convert scalar values in a given range into a colo...
Aim: A model of CDigitalSurfaceContainer which defines the digital surface as the boundary of an impl...
Aim: A utility class for constructing surfaces (i.e. set of (n-1)-cells).
Definition: Surfaces.h:79
Aim: Represent adjacencies between surfel elements, telling if it follows an interior to exterior ord...
void beginBlock(const std::string &keyword="")
std::ostream & error()
std::ostream & info()
double endBlock()
virtual void show()
Overload QWidget method in order to add a call to updateList() method (to ensure that the lists are w...
Z3i::SCell SCell
DigitalSurface< MyDigitalSurfaceContainer > MyDigitalSurface
DigitalSetBoundary< KSpace, DigitalSet > MyDigitalSurfaceContainer
DGtal is the top-level namespace which contains all DGtal functions and types.
Trace trace
Definition: Common.h:154
STL namespace.
Aim: Define utilities to convert a digital set into an image.
Definition: SetFromImage.h:64
Aim: implements methods to read a "Vol" file format.
Definition: VolReader.h:90
int main()
Definition: testBits.cpp:56
ImageContainerBySTLVector< Domain, Value > Image
Z2i::DigitalSet DigitalSet