DGtal  1.5.beta
digpoly-curvature-measures-cnc-3d.cpp
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1 
113 #include <iostream>
114 #include <fstream>
115 #include <algorithm>
116 #include "DGtal/base/Common.h"
117 #include "DGtal/shapes/SurfaceMesh.h"
119 #include "DGtal/geometry/meshes/CorrectedNormalCurrentComputer.h"
121 #include "DGtal/helpers/Shortcuts.h"
122 #include "DGtal/helpers/ShortcutsGeometry.h"
123 #include "DGtal/io/writers/SurfaceMeshWriter.h"
124 #include "DGtal/io/colormaps/GradientColorMap.h"
125 #include "DGtal/io/colormaps/QuantifiedColorMap.h"
126 
128 makeColorMap( double min_value, double max_value )
129 {
130  DGtal::GradientColorMap< double > gradcmap( min_value, max_value );
131  gradcmap.addColor( DGtal::Color( 0, 0, 255 ) );
132  gradcmap.addColor( DGtal::Color( 0, 255, 255 ) );
133  gradcmap.addColor( DGtal::Color( 255, 255, 255 ) );
134  gradcmap.addColor( DGtal::Color( 255, 255, 0 ) );
135  gradcmap.addColor( DGtal::Color( 255, 0, 0 ) );
136  return gradcmap;
137 }
138 
139 void usage( int argc, char* argv[] )
140 {
141  using namespace DGtal;
142  using namespace DGtal::Z3i;
143  typedef Shortcuts< KSpace > SH;
144  std::cout << "Usage: " << std::endl
145  << "\t" << argv[ 0 ] << " <P> <B> <h> <R> <mode>" << std::endl
146  << std::endl
147  << "Computation of mean and Gaussian curvatures on an " << std::endl
148  << "digitized implicit shape using constant or " << std::endl
149  << "interpolated corrected curvature measures (based " << std::endl
150  << "on the theory of corrected normal currents)." << std::endl
151  << "- builds the surface mesh from polynomial <P>" << std::endl
152  << "- <B> defines the digitization space size [-B,B]^3" << std::endl
153  << "- <h> is the gridstep digitization" << std::endl
154  << "- <R> is the radius of the measuring balls" << std::endl
155  << "- <mode> is either Const for constant corrected normal" << std::endl
156  << " vector field or Interp for interpolated corrected" << std::endl
157  << " normal vector field." << std::endl
158  << "It produces several OBJ files to display mean and" << std::endl
159  << "Gaussian curvature estimation results: `example-cnc-H.obj`" << std::endl
160  << "and `example-cnc-G.obj` as well as the associated MTL file." << std::endl;
161  std::cout << "You may either write your own polynomial as 3*x^2*y-z^2*x*y+1" << std::endl
162  <<"or use a predefined polynomial in the following list:" << std::endl;
163  auto L = SH::getPolynomialList();
164  for ( const auto& p : L )
165  std::cout << p.first << " : " << p.second << std::endl;
166 }
167 
168 int main( int argc, char* argv[] )
169 {
170  if ( argc <= 1 )
171  {
172  usage( argc, argv );
173  return 0;
174  }
176  using namespace DGtal;
177  using namespace DGtal::Z3i;
180  typedef Shortcuts< KSpace > SH;
181  typedef ShortcutsGeometry< KSpace > SHG;
183  std::string poly = argv[ 1 ]; // polynomial
184  const double B = argc > 2 ? atof( argv[ 2 ] ) : 1.0; // max ||_oo bbox
185  const double h = argc > 3 ? atof( argv[ 3 ] ) : 1.0; // gridstep
186  const double R = argc > 4 ? atof( argv[ 4 ] ) : 2.0; // radius of measuring ball
187  std::string mode = argc > 5 ? argv[ 5 ] : "Const"; // either Const or Interp
188  bool interpolated = mode == "Interp";
189  if ( interpolated )
190  std::cout << "Using vertex-*Interpolated* Corrected Normal Current" << std::endl;
191  else
192  std::cout << "Using face-*Constant* Corrected Normal Current" << std::endl;
194  // Read polynomial and build digital surface
195  auto params = SH::defaultParameters() | SHG::defaultParameters();
196  params( "t-ring", 3 )( "surfaceTraversal", "Default" );
197  params( "polynomial", poly )( "gridstep", h );
198  params( "minAABB", -B )( "maxAABB", B );
199  params( "offset", 3.0 );
200  auto shape = SH::makeImplicitShape3D( params );
201  auto K = SH::getKSpace( params );
202  auto dshape = SH::makeDigitizedImplicitShape3D( shape, params );
203  auto bimage = SH::makeBinaryImage( dshape, params );
204  if ( bimage == nullptr )
205  {
206  trace.error() << "Unable to read polynomial <"
207  << poly.c_str() << ">" << std::endl;
208  return 1;
209  }
210  auto sembedder = SH::getSCellEmbedder( K );
211  auto embedder = SH::getCellEmbedder( K );
212  auto surface = SH::makeDigitalSurface( bimage, K, params );
213  auto surfels = SH::getSurfelRange( surface, params );
214  trace.info() << "- surface has " << surfels.size()<< " surfels." << std::endl;
216 
218  SM smesh;
219  std::vector< SM::Vertices > faces;
220  SH::Cell2Index c2i;
221  auto pointels = SH::getPointelRange( c2i, surface );
222  auto vertices = SH::RealPoints( pointels.size() );
223  std::transform( pointels.cbegin(), pointels.cend(), vertices.begin(),
224  [&] (const SH::Cell& c) { return h * embedder( c ); } );
225  for ( auto&& surfel : *surface )
226  {
227  const auto primal_surfel_vtcs = SH::getPointelRange( K, surfel );
228  SM::Vertices face;
229  for ( auto&& primal_vtx : primal_surfel_vtcs )
230  face.push_back( c2i[ primal_vtx ] );
231  faces.push_back( face );
232  }
233  smesh.init( vertices.cbegin(), vertices.cend(),
234  faces.cbegin(), faces.cend() );
235  trace.info() << smesh << std::endl;
237 
239  auto exp_H = SHG::getMeanCurvatures( shape, K, surfels, params );
240  auto exp_G = SHG::getGaussianCurvatures( shape, K, surfels, params );
242 
244  // Builds a CorrectedNormalCurrentComputer object onto the SurfaceMesh object
245  CNC cnc( smesh );
246  // Estimates normal vectors using Convolved Trivial Normal estimator
247  auto face_normals = SHG::getCTrivialNormalVectors( surface, surfels, params );
248  // Set corrected face normals => Corrected Normal Current with
249  // constant per face corrected vector field.
250  smesh.setFaceNormals( face_normals.cbegin(), face_normals.cend() ); // CCNC
251  // Set corrected vertex normals => Corrected Normal Current with
252  // smooth linearly interpolated per face corrected vector field.
253  if ( interpolated ) smesh.computeVertexNormalsFromFaceNormals(); // ICNC
254  // computes area, mean and Gaussian curvature measures
255  auto mu0 = cnc.computeMu0();
256  auto mu1 = cnc.computeMu1();
257  auto mu2 = cnc.computeMu2();
259 
261  // estimates mean (H) and Gaussian (G) curvatures by measure normalization.
262  std::vector< double > H( smesh.nbFaces() );
263  std::vector< double > G( smesh.nbFaces() );
264  for ( auto f = 0; f < smesh.nbFaces(); ++f )
265  {
266  const auto b = smesh.faceCentroid( f );
267  const auto area = mu0.measure( b, R, f );
268  H[ f ] = cnc.meanCurvature ( area, mu1.measure( b, R, f ) );
269  G[ f ] = cnc.GaussianCurvature( area, mu2.measure( b, R, f ) );
270  }
272 
274  auto H_min_max = std::minmax_element( H.cbegin(), H.cend() );
275  auto G_min_max = std::minmax_element( G.cbegin(), G.cend() );
276  auto exp_H_min_max = std::minmax_element( exp_H.cbegin(), exp_H.cend() );
277  auto exp_G_min_max = std::minmax_element( exp_G.cbegin(), exp_G.cend() );
278  std::cout << "Expected mean curvatures:"
279  << " min=" << *exp_H_min_max.first << " max=" << *exp_H_min_max.second
280  << std::endl;
281  std::cout << "Computed mean curvatures:"
282  << " min=" << *H_min_max.first << " max=" << *H_min_max.second
283  << std::endl;
284  std::cout << "Expected Gaussian curvatures:"
285  << " min=" << *exp_G_min_max.first << " max=" << *exp_G_min_max.second
286  << std::endl;
287  std::cout << "Computed Gaussian curvatures:"
288  << " min=" << *G_min_max.first << " max=" << *G_min_max.second
289  << std::endl;
290  const auto error_H = SHG::getScalarsAbsoluteDifference( H, exp_H );
291  const auto stat_error_H = SHG::getStatistic( error_H );
292  const auto error_H_l2 = SHG::getScalarsNormL2( H, exp_H );
293  trace.info() << "|H-H_CNC|_oo = " << stat_error_H.max() << std::endl;
294  trace.info() << "|H-H_CNC|_2 = " << error_H_l2 << std::endl;
295  const auto error_G = SHG::getScalarsAbsoluteDifference( G, exp_G );
296  const auto stat_error_G = SHG::getStatistic( error_G );
297  const auto error_G_l2 = SHG::getScalarsNormL2( G, exp_G );
298  trace.info() << "|G-G_CNC|_oo = " << stat_error_G.max() << std::endl;
299  trace.info() << "|G-G_CNC|_2 = " << error_G_l2 << std::endl;
301 
303  // Remove normals for better blocky display.
304  smesh.vertexNormals() = SH::RealVectors();
305  smesh.faceNormals() = SH::RealVectors();
307  const double Hmax = std::max( fabs( *exp_H_min_max.first ),
308  fabs( *exp_H_min_max.second ) );
309  const double Gmax = std::max( fabs( *exp_G_min_max.first ),
310  fabs( *exp_G_min_max.second ) );
311  const auto colormapH = makeQuantifiedColorMap( makeColorMap( -Hmax, Hmax ) );
312  const auto colormapG = makeQuantifiedColorMap( makeColorMap( -Gmax, Gmax ) );
313  auto colorsH = SMW::Colors( smesh.nbFaces() );
314  auto colorsG = SMW::Colors( smesh.nbFaces() );
315  for ( auto i = 0; i < smesh.nbFaces(); i++ )
316  {
317  colorsH[ i ] = colormapH( H[ i ] );
318  colorsG[ i ] = colormapG( G[ i ] );
319  }
320  SMW::writeOBJ( "example-cnc-H", smesh, colorsH );
321  SMW::writeOBJ( "example-cnc-G", smesh, colorsG );
323  return 0;
324 }
Structure representing an RGB triple with alpha component.
Definition: Color.h:68
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: This class is used to simplify shape and surface creation. With it, you can create new shapes an...
Aim: This class is used to simplify shape and surface creation. With it, you can create new shapes an...
Definition: Shortcuts.h:105
std::ostream & error()
std::ostream & info()
CountedPtr< SH3::DigitalSurface > surface
int main(int argc, char *argv[])
DGtal::GradientColorMap< double > makeColorMap(double min_value, double max_value)
[curvature-measures-Includes]
void usage(int argc, char *argv[])
SMesh::Vertices Vertices
Z3i this namespace gathers the standard of types for 3D imagery.
DGtal is the top-level namespace which contains all DGtal functions and types.
QuantifiedColorMap< TColorMap > makeQuantifiedColorMap(TColorMap colormap, int nb=50)
Trace trace
Definition: Common.h:153
Aim: Utility class to compute curvature measures induced by (1) a corrected normal current defined by...
Aim: An helper class for writing mesh file formats (Waverfront OBJ at this point) and creating a Surf...
Aim: Represents an embedded mesh as faces and a list of vertices. Vertices may be shared among faces ...
Definition: SurfaceMesh.h:92
int max(int a, int b)
KSpace K
KSpace::Cell Cell