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voronoi.cxx |

Generate a Voronoi diagram, using distanceTransform() and seededRegionGrowing()
Usage: `voronoi`, generates: `distances.gif` (Euclidean distance transform) and `voronoi.gif` (Voronoi diagram)

    /************************************************************************/
    /*                                                                      */
    /*               Copyright 1998-2002 by Ullrich Koethe                  */
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    /*    This file is part of the VIGRA computer vision library.           */
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    #include <iostream>
    #include "vigra/stdimage.hxx"
    #include "vigra/stdimagefunctions.hxx"
    #include "vigra/distancetransform.hxx"
    #include "vigra/labelimage.hxx"
    #include "vigra/seededregiongrowing.hxx"
    #include "vigra/impex.hxx"

    using namespace vigra;

    int main(int argc, char ** argv)
    {
        try
        {
            int number_of_points = 25;
            int size = 512;

            // create input image
            vigra::FImage in(size, size);

            // paint it black
            in = 0;

            for(int i=1; i<=number_of_points; ++i)
            {
                // mark a number of points
                int x = (int)((float)rand() / RAND_MAX * size);
                int y = (int)((float)rand() / RAND_MAX * size);

                // label each point with a unique number
                in(x,y) = i;
            }

            // create output image and paint it white
            vigra::IImage out(size, size);
            out = 255;

            // in the output image, paint the points black which were
            // marked in the input image
            initImageIf(destImageRange(out), maskImage(in), 0);

            // create image to hold the distance transform
            vigra::FImage distances(size, size);

            // calculate Euclidean distance transform
            distanceTransform(srcImageRange(in), destImage(distances), 0, 2);

            exportImage(srcImageRange(distances), vigra::ImageExportInfo("distances.gif"));
            std::cout << "Wrote distance transform (distances.gif)" << std::endl;

            // initialize statistics functor for region growing
            vigra::ArrayOfRegionStatistics<vigra::SeedRgDirectValueFunctor<float> >
                statistics(number_of_points);

            // perform region growing, starting at the points marked in the input
            // image; as the feature (first source) image contains the distances,
            // the will calculate the voronoi regions of these points
            seededRegionGrowing(srcImageRange(distances), srcImage(in),
                                destImage(in), statistics);

            // in the output image, mark the borders of the voronoi regions black
            regionImageToEdgeImage(srcImageRange(in), destImage(out), 0);

            exportImage(srcImageRange(out), vigra::ImageExportInfo("voronoi.gif"));
            std::cout << "Wrote voronoi diagram (voronoi.gif)" << std::endl;
        }
        catch (vigra::StdException & e)
        {
            std::cout << e.what() << std::endl;
            return 1;
        }

        return 0;
    }

© Ullrich Köthe (ullrich.koethe@iwr.uni-heidelberg.de) Heidelberg Collaboratory for Image Processing, University of Heidelberg, Germany | html generated using doxygen and Python vigra 1.9.0 (Tue Nov 6 2012)