DGtal 1.3.0
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curvature-measures-nc-XY-3d.cpp File Reference
DGtal Examples
#include <iostream>
#include <algorithm>
#include "DGtal/base/Common.h"
#include "DGtal/math/linalg/EigenDecomposition.h"
#include "DGtal/shapes/SurfaceMesh.h"
#include "DGtal/shapes/SurfaceMeshHelper.h"
#include "DGtal/geometry/meshes/NormalCycleComputer.h"
#include "DGtal/io/writers/SurfaceMeshWriter.h"
#include "DGtal/io/colormaps/GradientColorMap.h"
#include "DGtal/io/colormaps/QuantifiedColorMap.h"
#include "DGtal/helpers/Shortcuts.h"

Go to the source code of this file.

Functions

DGtal::GradientColorMap< double > makeColorMap (double min_value, double max_value)
 [curvature-measures-Includes] More...
 
void usage (int argc, char *argv[])
 
int main (int argc, char *argv[])
 

Detailed Description

This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.

Author
Jacques-Olivier Lachaud (jacqu.nosp@m.es-o.nosp@m.livie.nosp@m.r.la.nosp@m.chaud.nosp@m.@uni.nosp@m.v-sav.nosp@m.oie..nosp@m.fr ) Laboratory of Mathematics (CNRS, UMR 5127), University of Savoie, France
Date
2021/10/25

An example file named curvature-measures-nc-XY-3d.

This file is part of the DGtal library.

Definition in file curvature-measures-nc-XY-3d.cpp.

Function Documentation

◆ main()

int main ( int  argc,
char *  argv[] 
)

[curvature-measures-Typedefs]

[curvature-measures-Typedefs]

[curvature-measures-SurfaceMesh]

[curvature-measures-SurfaceMesh]

[curvature-measures-NC]

[curvature-measures-NC]

[curvature-measures-estimations]

[curvature-measures-estimations]

[curvature-measures-check]

[curvature-measures-check]

[curvature-measures-output]

[curvature-measures-output]

Definition at line 124 of file curvature-measures-nc-XY-3d.cpp.

125{
126 if ( argc <= 1 )
127 {
128 usage( argc, argv );
129 return 0;
130 }
132 using namespace DGtal;
133 using namespace DGtal::Z3i;
134 typedef SurfaceMesh< RealPoint, RealVector > SM;
135 typedef NormalCycleComputer< RealPoint, RealVector > NC;
136 typedef SurfaceMeshHelper< RealPoint, RealVector > SMH;
138 // a shape in "torus|lantern|sphere"
139 std::string input = argv[ 1 ];
140 int m = argc > 2 ? atoi( argv[ 2 ] ) : 20; // nb latitude points
141 int n = argc > 3 ? atoi( argv[ 3 ] ) : 20; // nb longitude points
142 double R = argc > 4 ? atof( argv[ 4 ] ) : 0.5; // radius of measuring ball
143
145 SM smesh;
146 double exp_K1_min = 0.0;
147 double exp_K1_max = 0.0;
148 double exp_K2_min = 0.0;
149 double exp_K2_max = 0.0;
150 if ( input == "torus" )
151 {
152 const double big_radius = 3.0;
153 const double small_radius = 1.00001; // avoid codacy warnings
154 smesh = SMH::makeTorus( big_radius, small_radius,
155 RealPoint { 0.0, 0.0, 0.0 }, m, n, 0,
156 SMH::NormalsType::VERTEX_NORMALS );
157 exp_K1_min = ( 1.0 / ( small_radius - big_radius ) );
158 exp_K1_max = ( 1.0 / ( big_radius + small_radius ) );
159 exp_K2_min = 1.0 / small_radius;
160 exp_K2_max = 1.0 / small_radius;
161 }
162 else if ( input == "sphere" )
163 {
164 const double radius = 2.0;
165 smesh = SMH::makeSphere( radius, RealPoint { 0.0, 0.0, 0.0 }, m, n,
166 SMH::NormalsType::VERTEX_NORMALS );
167 exp_K1_min = 1.0 / radius;
168 exp_K1_max = 1.0 / radius;
169 exp_K2_min = 1.0 / radius;
170 exp_K2_max = 1.0 / radius;
171 }
172 else if ( input == "lantern" )
173 {
174 const double radius = 2.0;
175 smesh = SMH::makeLantern( radius, 1.0, RealPoint { 0.0, 0.0, 0.0 }, m, n,
176 SMH::NormalsType::VERTEX_NORMALS );
177 exp_K1_min = 0.0;
178 exp_K1_max = 0.0;
179 exp_K2_min = 1.0 / radius;
180 exp_K2_max = 1.0 / radius;
181 }
183
185 // builds a NormalCycleComputer object onto the torus mesh
186 NC nc( smesh );
187 // computes area, anisotropic XY curvature measures
188 auto mu0 = nc.computeMu0();
189 auto muXY = nc.computeMuXY();
191
193 // Estimates principal curvatures (K1,K2) and directions (D1,D2) by
194 // measure normalization and eigen decomposition.
195 std::vector< double > K1( smesh.nbFaces() );
196 std::vector< double > K2( smesh.nbFaces() );
197 std::vector< RealVector > D1( smesh.nbFaces() );
198 std::vector< RealVector > D2( smesh.nbFaces() );
199 // Principal directions computation requires a local face normal
200 smesh.computeFaceNormalsFromPositions();
201 for ( auto f = 0; f < smesh.nbFaces(); ++f )
202 {
203 const auto b = smesh.faceCentroid( f );
204 const auto N = smesh.faceNormals()[ f ];
205 const auto area = mu0 .measure( b, R, f );
206 const auto M = muXY.measure( b, R, f );
207 std::tie( K1[ f ], K2[ f ], D1[ f ], D2[ f ] )
208 = nc.principalCurvatures( area, M, N );
209 }
211
213 auto K1_min_max = std::minmax_element( K1.cbegin(), K1.cend() );
214 auto K2_min_max = std::minmax_element( K2.cbegin(), K2.cend() );
215 std::cout << "Expected k1 curvatures:"
216 << " min=" << exp_K1_min << " max=" << exp_K1_max
217 << std::endl;
218 std::cout << "Computed k1 curvatures:"
219 << " min=" << *K1_min_max.first << " max=" << *K1_min_max.second
220 << std::endl;
221 std::cout << "Expected k2 curvatures:"
222 << " min=" << exp_K2_min << " max=" << exp_K2_max
223 << std::endl;
224 std::cout << "Computed k2 curvatures:"
225 << " min=" << *K2_min_max.first << " max=" << *K2_min_max.second
226 << std::endl;
228
230 typedef SurfaceMeshWriter< RealPoint, RealVector > SMW;
231 typedef Shortcuts< KSpace > SH;
232 const auto colormapK1 = makeQuantifiedColorMap( makeColorMap( -0.625, 0.625 ) );
233 const auto colormapK2 = makeQuantifiedColorMap( makeColorMap( -0.625, 0.625 ) );
234 auto colorsK1 = SMW::Colors( smesh.nbFaces() );
235 auto colorsK2 = SMW::Colors( smesh.nbFaces() );
236 for ( auto i = 0; i < smesh.nbFaces(); i++ )
237 {
238 colorsK1[ i ] = colormapK1( K1[ i ] );
239 colorsK2[ i ] = colormapK2( K2[ i ] );
240 }
241 SMW::writeOBJ( "example-nc-K1", smesh, colorsK1 );
242 SMW::writeOBJ( "example-nc-K2", smesh, colorsK2 );
243 const auto avg_e = smesh.averageEdgeLength();
244 SH::RealPoints positions( smesh.nbFaces() );
245 for ( auto f = 0; f < positions.size(); ++f )
246 {
247 D1[ f ] *= smesh.localWindow( f );
248 positions[ f ] = smesh.faceCentroid( f ) - 0.5 * D1[ f ];
249 }
250 SH::saveVectorFieldOBJ( positions, D1, 0.05 * avg_e, SH::Colors(),
251 "example-nc-D1",
252 SH::Color::Black, SH::Color( 0, 128, 0 ) );
253 for ( auto f = 0; f < positions.size(); ++f )
254 {
255 D2[ f ] *= smesh.localWindow( f );
256 positions[ f ] = smesh.faceCentroid( f ) - 0.5 * D2[ f ];
257 }
258 SH::saveVectorFieldOBJ( positions, D2, 0.05 * avg_e, SH::Colors(),
259 "example-nc-D2",
260 SH::Color::Black, SH::Color(128, 0,128 ) );
261
263 return 0;
264}
DGtal::Shortcuts
Aim: This class is used to simplify shape and surface creation. With it, you can create new shapes an...
Definition: Shortcuts.h:105
makeColorMap
DGtal::GradientColorMap< double > makeColorMap(double min_value, double max_value)
[curvature-measures-Includes]
Definition: curvature-measures-nc-XY-3d.cpp:97
DGtal::Z2i::K2
KSpace K2
Definition: StdDefs.h:78
DGtal::Z3i
Z3i this namespace gathers the standard of types for 3D imagery.
DGtal
DGtal is the top-level namespace which contains all DGtal functions and types.
Definition: ClosedIntegerHalfPlane.h:49
DGtal::makeQuantifiedColorMap
QuantifiedColorMap< TColorMap > makeQuantifiedColorMap(TColorMap colormap, int nb=50)
Definition: QuantifiedColorMap.h:113
DGtal::NormalCycleComputer
Aim: Utility class to compute curvatures measures induced by (1) the normal cycle induced by a Surfac...
Definition: NormalCycleComputer.h:68
DGtal::SurfaceMeshHelper
Aim: An helper class for building classical meshes.
Definition: SurfaceMeshHelper.h:64
DGtal::SurfaceMeshWriter
Aim: An helper class for writing mesh file formats (Waverfront OBJ at this point) and creating a Surf...
Definition: SurfaceMeshWriter.h:65
DGtal::SurfaceMesh
Aim: Represents an embedded mesh as faces and a list of vertices. Vertices may be shared among faces ...
Definition: SurfaceMesh.h:92
RealPoint
Z2i::RealPoint RealPoint
Definition: testAstroid2D.cpp:46

References makeColorMap().

◆ makeColorMap()

DGtal::GradientColorMap< double > makeColorMap ( double  min_value,
double  max_value 
)

[curvature-measures-Includes]

[curvature-measures-Includes]

Definition at line 97 of file curvature-measures-nc-XY-3d.cpp.

98{
99 DGtal::GradientColorMap< double > gradcmap( min_value, max_value );
100 gradcmap.addColor( DGtal::Color( 0, 0, 255 ) );
101 gradcmap.addColor( DGtal::Color( 0, 255, 255 ) );
102 gradcmap.addColor( DGtal::Color( 255, 255, 255 ) );
103 gradcmap.addColor( DGtal::Color( 255, 255, 0 ) );
104 gradcmap.addColor( DGtal::Color( 255, 0, 0 ) );
105 return gradcmap;
106}
DGtal::Color
Structure representing an RGB triple with alpha component.
Definition: Color.h:68
DGtal::GradientColorMap
Aim: This class template may be used to (linearly) convert scalar values in a given range into a colo...
Definition: GradientColorMap.h:120

References DGtal::GradientColorMap< PValue, PDefaultPreset, PDefaultFirstColor, PDefaultLastColor >::addColor().

Referenced by main().

◆ usage()

void usage ( int  argc,
char *  argv[] 
)

Definition at line 108 of file curvature-measures-nc-XY-3d.cpp.

109{
110 std::cout << "Usage: " << std::endl
111 << "\t" << argv[ 0 ] << " <shape> <m> <n> <R>" << std::endl
112 << std::endl
113 << "Computation of principal curvatures and directions on a shape, " << std::endl
114 << "using Normal Cycle anisotropic curvature measure." << std::endl
115 << "- builds a <shape> in {torus,lantern,sphere}, with " << std::endl
116 << " <m> latitude points and <n> longitude points." << std::endl
117 << "- <R> is the radius of the measuring balls." << std::endl
118 << "It produces several OBJ files to display principal " << std::endl
119 << "curvatures and directions estimations: `example-cnc-K1.obj`" << std::endl
120 << "`example-cnc-K2.obj`, `example-cnc-D1.obj`, and" << std::endl
121 << "`example-cnc-D2.obj` as well as associated MTL files." << std::endl;
122}
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