DGtal  1.2.0

Examples of 2D and 3D basic image subsampling.

Illustration of the resulting subsampling produced by this example.
#include <iostream>
#include "ConfigExamples.h"
#include "DGtal/helpers/StdDefs.h"
#include "DGtal/base/Common.h"
#include "DGtal/kernel/BasicPointFunctors.h"
#include "DGtal/images/ConstImageAdapter.h"
#include "DGtal/images/ImageContainerBySTLVector.h"
#include "DGtal/io/readers/GenericReader.h"
#include "DGtal/io/writers/GenericWriter.h"
using namespace std;
using namespace DGtal;
int main( int /*argc*/, char** /*argv*/ )
typedef ImageContainerBySTLVector < Z2i::Domain, unsigned char> Image2D;
typedef ConstImageAdapter<Image2D, Image2D::Domain,
functors::Identity > ConstImageAdapterForSubSampling;
typedef ImageContainerBySTLVector < Z3i::Domain, unsigned char> Image3D;
typedef ConstImageAdapter<Image3D, Image3D::Domain,
functors::Identity > ConstImageAdapterForSubSampling3D;
trace.beginBlock ( "Example imageBasicSubsampling" );
std::string imageFilename3D = examplesPath + "samples/Al.100.vol";
std::string imageFilename2D = examplesPath + "samples/church.pgm";
Image3D image3D = GenericReader<Image3D>::import( imageFilename3D );
Image2D image2D = GenericReader<Image2D>::import( imageFilename2D );
for (unsigned int i=1; i<=20; i*=2){
std::vector<Z2i::Domain::Size> aGridSize2D;
// Construction of the functor for the 2D domain subsampling from a given grid size and shift.
DGtal::functors::BasicDomainSubSampler<Image2D::Domain> subSampler2D(image2D.domain(), aGridSize2D, Z2i::Point(0 ,0));
functors::Identity df;
// Get the new domain produces from the subsampler and define the ConstImageAdapter:
Image2D::Domain subSampledDomain2D = subSampler2D.getSubSampledDomain();
ConstImageAdapterForSubSampling subsampledImage2D (image2D, subSampledDomain2D, subSampler2D, df);
stringstream outputname;
outputname << "subSampledImage"<< i<< "x"<< i << ".pgm" ;
GenericWriter<ConstImageAdapterForSubSampling>::exportFile(outputname.str(), subsampledImage2D );
trace.info() << "Exporting 2D subsampled image by grid size :" << i << "x"<< i<< " in "<< outputname.str() << std::endl;
for (unsigned int i=1; i<=20; i*=2){
std::vector<Z3i::Domain::Size> aGridSize3D;
// Construction of the functor for the 3D domain subsampling from a given grid size and shift.
DGtal::functors::BasicDomainSubSampler<Image3D::Domain> subSampler3D(image3D.domain(), aGridSize3D, Z3i::Point(0 ,0, 0));
// Get the new domain produces from the subsampler and define the ConstImageAdapter:
Image3D::Domain subSampledDomain3D = subSampler3D.getSubSampledDomain();
ConstImageAdapterForSubSampling3D subsampledImage3D (image3D, subSampledDomain3D, subSampler3D, df);
stringstream outputname3D;
outputname3D << "subSampledImage3D"<< i<< "x"<< i << ".vol" ;
GenericWriter<ConstImageAdapterForSubSampling3D>::exportFile(outputname3D.str(), subsampledImage3D );
trace.info() << "Exporting 3D subsampled image by grid size :" << i << "x"<< i<< "x"<< i<< " in "<< outputname3D.str() << std::endl;
return 0;
// //
void beginBlock(const std::string &keyword="")
std::ostream & info()
double endBlock()
Aim: Functor that subsamples an initial domain by given a grid size and a shift vector....
DGtal is the top-level namespace which contains all DGtal functions and types.
Trace trace
Definition: Common.h:154
Aim: Define a simple default functor that just returns its argument.
int main(int argc, char **argv)
MyPointD Point
Definition: testClone2.cpp:383
HyperRectDomain< Space > Domain