GaussianFilter.cpp

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/*
 * This file is part of ArmarX.
 *
 * Copyright (C) 2011-2017, High Performance Humanoid Technologies (H2T), Karlsruhe Institute of Technology (KIT), all rights reserved.
 *
 * ArmarX is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * ArmarX 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/>.
 *
 * @package    ArmarX
 * @author     Mirko Waechter( mirko.waechter at kit dot edu)
 * @date       2017
 * @copyright  http://www.gnu.org/licenses/gpl-2.0.txt
 *             GNU General Public License
 */
#include "GaussianFilter.h"
 
#include <cmath>
 
namespace armarx::rtfilters
{
 
    GaussianFilter::GaussianFilter(size_t windowSize, double filterWidthInMs) :
        RTFilterBase(windowSize), filterWidthInSec(0.001f * filterWidthInMs)
    {
    }
 
    GaussianFilter::GaussianFilter(size_t windowSize, IceUtil::Time filterWidth) :
        RTFilterBase(windowSize), filterWidthInSec(filterWidth.toSecondsDouble())
    {
    }
 
    RTFilterBasePtr
    GaussianFilter::clone() const
    {
        RTFilterBase* v = new GaussianFilter(*this);
        return RTFilterBasePtr(v);
    }
 
    double
    GaussianFilter::calculate()
    {
        if (dataHistory.empty())
        {
            return 0.0;
        }
 
        const double sigma = filterWidthInSec / 3.0;
        //-log(0.05) / pow(itemsToCheck+1+centerIndex,2) * ( sqrt(1.0/h) * sqrt(2*3.14159265));
 
        double weightedSum = 0;
        double sumOfWeight = 0;
 
 
        auto newestTimestamp = dataHistory.rbegin()->first.toMilliSecondsDouble();
 
        const double sqrt2PI = std::sqrt(2 * M_PI);
        double quotient = (2 * sigma * sigma);
        double quotient2 = sigma * sqrt2PI;
 
        for (auto it = dataHistory.begin(); it != dataHistory.end(); it++)
        {
            double value = it->second;
            double diff = 0.001 * (it->first.toMilliSecondsDouble() - newestTimestamp);
 
            double squared = diff * diff;
            const double gaussValue = std::exp(-squared / quotient) / (quotient2);
            sumOfWeight += gaussValue;
            weightedSum += gaussValue * value;
        }
 
        double result;
        result = weightedSum / sumOfWeight;
        return result;
    }
 
} // namespace armarx::rtfilters