MaxDensity.cpp

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// kate: replace-tabs off; indent-width 4; indent-mode normal
// vim: ts=4:sw=4:noexpandtab
/*
 
Copyright (c) 2010--2018,
François Pomerleau and Stephane Magnenat, ASL, ETHZ, Switzerland
You can contact the authors at <f dot pomerleau at gmail dot com> and
<stephane at magnenat dot net>
 
All rights reserved.
 
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
    * Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.
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      notice, this list of conditions and the following disclaimer in the
      documentation and/or other materials provided with the distribution.
    * Neither the name of the <organization> nor the
      names of its contributors may be used to endorse or promote products
      derived from this software without specific prior written permission.
 
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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*/
#include "MaxDensity.h"
 
// MaxDensityDataPointsFilter
// Constructor
template<typename T>
MaxDensityDataPointsFilter<T>::MaxDensityDataPointsFilter(const Parameters& params):
        PointMatcher<T>::DataPointsFilter("MaxDensityDataPointsFilter", 
                MaxDensityDataPointsFilter::availableParameters(), params),
        maxDensity(Parametrizable::get<T>("maxDensity"))
{
}
 
// Compute
template<typename T>
typename PointMatcher<T>::DataPoints MaxDensityDataPointsFilter<T>::filter(
        const DataPoints& input)
{
        DataPoints output(input);
        inPlaceFilter(output);
        return output;
}
 
// In-place filter
template<typename T>
void MaxDensityDataPointsFilter<T>::inPlaceFilter(
        DataPoints& cloud)
{
        typedef typename DataPoints::View View;
 
        // Force densities to be computed
        if (!cloud.descriptorExists("densities"))
        {
                throw InvalidField("MaxDensityDataPointsFilter: Error, no densities found in descriptors.");
        }
 
        const int nbPointsIn = cloud.features.cols();
        View densities = cloud.getDescriptorViewByName("densities");
        const T lastDensity = densities.maxCoeff();
        const int nbSaturatedPts = (densities.array() == lastDensity).count();
 
        // fill cloud values
        int j = 0;
        for (int i = 0; i < nbPointsIn; ++i)
        {
                const T density(densities(0,i));
                if (density > maxDensity)
                {
                        const float r = (float)std::rand()/(float)RAND_MAX;
                        float acceptRatio = maxDensity/density;
 
                        // Handle saturation value of density
                        if (density == lastDensity)
                        {
                                acceptRatio = acceptRatio * (1-nbSaturatedPts/nbPointsIn);
                        }
 
                        if (r < acceptRatio)
                        {
                                cloud.setColFrom(j, cloud, i);
                                ++j;
                        }
                }
                else
                {
                        cloud.setColFrom(j, cloud, i);
                        ++j;
                }
        }
 
        cloud.conservativeResize(j);
}
 
template struct MaxDensityDataPointsFilter<float>;
template struct MaxDensityDataPointsFilter<double>;