This example shows the computation of the VCM of a digital surface read from a .vol file. The normal is estimated from the diagonalization of the VCM tensor, while the orientation is deduced from the orientation of the trivial surfel normals. Feature detection is achieved with the eigenvalues of the VCM. A red color indicates a feature. Normals are displayed as black lines.
#include <iostream>
#include "DGtal/base/Common.h"
#include "DGtal/helpers/StdDefs.h"
#include "DGtal/kernel/BasicPointPredicates.h"
#include "DGtal/math/linalg/EigenDecomposition.h"
#include "DGtal/topology/helpers/Surfaces.h"
#include "DGtal/topology/DigitalSurface.h"
#include "DGtal/topology/ImplicitDigitalSurface.h"
#include "DGtal/images/ImageSelector.h"
#include "DGtal/images/IntervalForegroundPredicate.h"
#include "DGtal/geometry/volumes/distance/ExactPredicateLpSeparableMetric.h"
#include "DGtal/geometry/surfaces/estimation/VoronoiCovarianceMeasureOnDigitalSurface.h"
#include "DGtal/io/colormaps/GradientColorMap.h"
#include "DGtal/io/viewers/PolyscopeViewer.h"
#include "DGtal/io/readers/GenericReader.h"
#include "ConfigExamples.h"
int main(
int argc,
char** argv )
{
typedef KSpace::Surfel
Surfel;
typedef KSpace::Cell Cell;
KernelFunction > VCMOnSurface;
typedef VCMOnSurface::Surfel2Normals::const_iterator S2NConstIterator;
string inputFilename = examplesPath + "samples/Al.100.vol";
trace.info() <<
"File = " << inputFilename << std::endl;
int thresholdMin = 0;
trace.info() <<
"Min image thres. = " << thresholdMin << std::endl;
int thresholdMax = 1;
trace.info() <<
"Max image thres. = " << thresholdMax << std::endl;
const double R = 20;
trace.info() <<
"Big radius R = " << R << std::endl;
const double r = 3;
trace.info() <<
"Small radius r = " << r << std::endl;
const double trivial_r = 3;
trace.info() <<
"Trivial radius t = " << trivial_r << std::endl;
const double T = 0.1;
trace.info() <<
"Feature thres. T = " << T << std::endl;
const double size = 1.0;
trace.beginBlock(
"Loading image into memory and build digital surface." );
ThresholdedImage thresholdedImage(
image, thresholdMin, thresholdMax );
trace.beginBlock(
"Extracting boundary by scanning the space. " );
ks.init(
image.domain().lowerBound(),
image.domain().upperBound(),
true );
DigitalSurfaceContainer* container =
new DigitalSurfaceContainer( ks, thresholdedImage, surfAdj, bel, false );
trace.info() <<
"Digital surface has " <<
surface.size() <<
" surfels." << std::endl;
Metric l2;
KernelFunction chi( 1.0, r );
VCMOnSurface vcm_surface(
surface, embType, R, r,
chi, trivial_r, l2, true );
trace.beginBlock(
"Displaying VCM" );
PolyscopeViewer<> viewer( ks );
Cell dummy;
RealVector lambda;
for ( S2NConstIterator it = vcm_surface.mapSurfel2Normals().begin(),
itE = vcm_surface.mapSurfel2Normals().end(); it != itE; ++it )
{
Point kp = ks.sKCoords( s );
RealPoint rp( 0.5 * (
double) kp[ 0 ], 0.5 * (
double) kp[ 1 ], 0.5 * (
double) kp[ 2 ] );
RealVector n = it->second.vcmNormal;
vcm_surface.getChiVCMEigenvalues( lambda, s );
double ratio = lambda[ 1 ] / ( lambda[ 0 ] + lambda[ 1 ] + lambda[ 2 ] );
viewer.
drawColor( grad( ratio > T ? T : ratio ) );
viewer << ks.unsigns( s );
n *= size;
}
return 0;
}
Structure representing an RGB triple with alpha component.
void drawColor(const DGtal::Color &color)
std::string drawLine(const RealPoint &a, const RealPoint &b, const std::string &uname="Line_{i}")
Aim: implements separable l_p metrics with exact predicates.
Aim: This class template may be used to (linearly) convert scalar values in a given range into a colo...
void addColor(const Color &color)
Aim: Parallelepidec region of a digital space, model of a 'CDomain'.
Aim: A model of CDigitalSurfaceContainer which defines the digital surface as the boundary of an impl...
void show() override
Starts the event loop and display of elements.
static SCell findABel(const KSpace &K, const PointPredicate &pp, unsigned int nbtries=1000)
Aim: Represent adjacencies between surfel elements, telling if it follows an interior to exterior ord...
Aim: This class specializes the Voronoi covariance measure for digital surfaces. It adds notably the ...
Aim: Define a simple Foreground predicate thresholding image values between two constant values (the ...
CountedPtr< SH3::DigitalSurface > surface
SpaceND< 3, Integer > Space
KhalimskySpaceND< 3, Integer > KSpace
Space::RealVector RealVector
Space::RealPoint RealPoint
DGtal is the top-level namespace which contains all DGtal functions and types.
Surfel2PointEmbedding
Possible embeddings for surfel as point(s)
static TContainer import(const std::string &filename, std::vector< unsigned int > dimSpace=std::vector< unsigned int >())
ImageContainerBySTLVector< Domain, Value > Type
ImageContainerBySTLVector< Domain, Value > Image
HyperRectDomain< Space > Domain
PointVector< 3, double > RealPoint