cvd/integral_image.h

/*
        This file is part of the CVD Library.

        Copyright (C) 2005 The Authors

        This library 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 2.1 of the License, or (at your option) any later version.

        This library 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
        Lesser General Public License for more details.

        You should have received a copy of the GNU Lesser General Public
        License along with this library; if not, write to the Free Software
        Foundation, Inc.,
    51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
*/

#ifndef CVD_INC_INTEGRAL_IMAGE_H
#define CVD_INC_INTEGRAL_IMAGE_H

#include <cvd/image.h>
#include <cvd/vision.h>

namespace CVD
{
    template<class S, class D> void integral_image(const SubImage<S>& in, SubImage<D>& out)
    {
        if( in.size() != out.size())
            throw Exceptions::Vision::IncompatibleImageSizes("integral_image");
        
        //Do the first row. 
        D sum = 0;
        for(int x=0; x < in.size().x; x++)
        {
            sum += in[0][x];
            out[0][x] = sum;
        }

        //Do the remainder of the image
        for(int y=1; y < in.size().y; y++)
        {
            D sum = 0;

            for(int x=0; x < in.size().x; x++)
            {
                sum += in[y][x];
                out[y][x] = sum + out[y-1][x];
            }
        }
    }
    #ifndef DOXYGEN_IGNORE_INTERNAL
        namespace Internal
        {
            template<class C> class IntegralImage{};

            template<class C>  struct ImagePromise<IntegralImage<C> >
            {
                ImagePromise(const SubImage<C>& im)
                :i(im)
                {}

                const SubImage<C>& i;
                template<class D> void execute(Image<D>& j)
                {
                    j.resize(i.size());
                    integral_image<C,D>(i, j);
                }
            };
        };

        template<class C> Internal::ImagePromise<Internal::IntegralImage<C> > integral_image(const SubImage<C>& c)
        {
            return Internal::ImagePromise<Internal::IntegralImage<C> >(c);
        }
    #else
        template<class S, class D> Image<D> integral_image(const BasicImage<S>& from);

    #endif

}


#endif

---