ButterworthFilter.cpp

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/*
 * This file is part of ArmarX.
 *
 * Copyright (C) 2011-2016, 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       2016
 * @copyright  http://www.gnu.org/licenses/gpl-2.0.txt
 *             GNU General Public License
 */
 
#include "ButterworthFilter.h"
 
#include <cmath>
 
#include <ArmarXCore/core/exceptions/local/ExpressionException.h>
#include <ArmarXCore/core/logging/Logging.h>
 
namespace armarx
{
    armarx::filters::ButterworthFilter::ButterworthFilter()
    {
    }
 
    void
    armarx::filters::ButterworthFilter::reset(double frequency,
                                              int sampleRate,
                                              PassType filterPassType,
                                              double resonance)
    {
        this->resonance = resonance;
        this->frequency = frequency;
        this->sampleRate = sampleRate;
        this->filterPassType = filterPassType;
        switch (filterPassType)
        {
            case Lowpass:
                c = 1.0 / tan(M_PI * frequency / sampleRate);
                a1 = 1.0 / (1.0 + resonance * c + c * c);
                a2 = 2.0 * a1;
                a3 = a1;
                b1 = 2.0 * (1.0 - c * c) * a1;
                b2 = (1.0 - resonance * c + c * c) * a1;
                break;
            case Highpass:
                c = tan(M_PI * frequency / sampleRate);
                a1 = 1.0 / (1.0 + resonance * c + c * c);
                a2 = -2.0 * a1;
                a3 = a1;
                b1 = 2.0 * (c * c - 1.0) * a1;
                b2 = (1.0 - resonance * c + c * c) * a1;
                break;
            default:
                ARMARX_INFO << "Unknown pass type";
        }
    }
 
    armarx::filters::ButterworthFilter::ButterworthFilter(double frequency,
                                                          int sampleRate,
                                                          armarx::PassType filterPassType,
                                                          double resonance)
    {
        reset(frequency, sampleRate, filterPassType, resonance);
    }
 
    void
    filters::ButterworthFilter::setInitialValue(double value)
    {
        for (auto& v : inputHistory)
        {
            v = value;
        }
        for (auto& v : outputHistory)
        {
            v = value;
        }
    }
 
    armarx::ParameterTypeList
    armarx::filters::ButterworthFilter::getSupportedTypes(const Ice::Current&) const
    {
        ParameterTypeList result;
        result.push_back(VariantType::Int);
        result.push_back(VariantType::Long);
        result.push_back(VariantType::Float);
        result.push_back(VariantType::Double);
        return result;
    }
 
    void
    armarx::filters::ButterworthFilter::update(Ice::Long,
                                               const armarx::VariantBasePtr& value,
                                               const Ice::Current&)
    {
        //no lock required since no member data is changed
        VariantPtr var = VariantPtr::dynamicCast(value);
        if (!var->getInitialized())
        {
            return;
        }
 
        double newInput = 0.0;
        auto type = var->getType();
        if (type == VariantType::Float)
        {
            newInput = static_cast<double>(var->getFloat());
        }
        else if (type == VariantType::Double)
        {
            newInput = var->getDouble();
        }
        else if (type == VariantType::Int)
        {
            newInput = static_cast<double>(var->getInt());
        }
        else if (type == VariantType::Long)
        {
            newInput = static_cast<double>(var->getLong());
        }
        update(newInput);
    }
 
    void
    armarx::filters::ButterworthFilter::update(double newInput)
    {
        std::unique_lock lock(historyMutex);
        ARMARX_CHECK_EXPRESSION(!std::isnan(newInput));
        double newOutput = a1 * newInput + a2 * this->inputHistory[0] + a3 * this->inputHistory[1] -
                           b1 * this->outputHistory[0] - b2 * this->outputHistory[1];
        ARMARX_CHECK_EXPRESSION(!std::isnan(newOutput));
        this->inputHistory[1] = this->inputHistory[0];
        this->inputHistory[0] = newInput;
 
        this->outputHistory[2] = this->outputHistory[1];
        this->outputHistory[1] = this->outputHistory[0];
        this->outputHistory[0] = newOutput;
    }
 
    armarx::VariantBasePtr
    armarx::filters::ButterworthFilter::getValue(const Ice::Current&) const
    {
        std::unique_lock lock(historyMutex);
 
        return new Variant(outputHistory[0]);
    }
 
    double
    armarx::filters::ButterworthFilter::getRawValue() const
    {
        std::unique_lock lock(historyMutex);
        return outputHistory[0];
    }
 
    armarx::VariantBasePtr
    armarx::filters::ButterworthFilter::calculate(const Ice::Current&) const
    {
        std::unique_lock lock(historyMutex);
 
        return new Variant(outputHistory[0]);
    }
 
    StringFloatDictionary
    armarx::filters::ButterworthFilter::getProperties(const Ice::Current&) const
    {
        StringFloatDictionary props;
        props["resonance"] = resonance;
        props["frequency"] = frequency;
        props["sampleRate"] = sampleRate;
        props["filterPassType"] = (int)(filterPassType);
        return props;
    }
 
    void
    armarx::filters::ButterworthFilter::setProperties(const StringFloatDictionary& newValues,
                                                      const Ice::Current&)
    {
        auto it = newValues.find("resonance");
        if (it != newValues.end())
        {
            resonance = it->second;
        }
 
        it = newValues.find("frequency");
        if (it != newValues.end())
        {
            frequency = it->second;
        }
 
        it = newValues.find("sampleRate");
        if (it != newValues.end())
        {
            sampleRate = it->second;
        }
 
        it = newValues.find("filterPassType");
        if (it != newValues.end())
        {
            filterPassType = static_cast<PassType>(it->second);
        }
        reset(frequency, sampleRate, filterPassType, resonance);
    }
} // namespace armarx