Signal.h

#ifndef _Signal_h_
#define _Signal_h_
/* -------------------------------------------------------------------------- *
 *                             OpenSim:  Signal.h                             *
 * -------------------------------------------------------------------------- *
 * The OpenSim API is a toolkit for musculoskeletal modeling and simulation.  *
 * See http://opensim.stanford.edu and the NOTICE file for more information.  *
 * OpenSim is developed at Stanford University and supported by the US        *
 * National Institutes of Health (U54 GM072970, R24 HD065690) and by DARPA    *
 * through the Warrior Web program.                                           *
 *                                                                            *
 * Copyright (c) 2005-2017 Stanford University and the Authors                *
 * Author(s): Frank C. Anderson                                               *
 *                                                                            *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may    *
 * not use this file except in compliance with the License. You may obtain a  *
 * copy of the License at http://www.apache.org/licenses/LICENSE-2.0.         *
 *                                                                            *
 * Unless required by applicable law or agreed to in writing, software        *
 * distributed under the License is distributed on an "AS IS" BASIS,          *
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.   *
 * See the License for the specific language governing permissions and        *
 * limitations under the License.                                             *
 * -------------------------------------------------------------------------- */

/* Note: This code was originally developed by Realistic Dynamics Inc. 
 * Author: Frank C. Anderson 
 */

#include "osimCommonDLL.h"
#include <vector>

namespace OpenSim {

template <class T> class Array;

//=============================================================================
//=============================================================================
/**
 * A class for signal processing.
 */
class OSIMCOMMON_API Signal
{
//=============================================================================
// DATA
//=============================================================================

//=============================================================================
// METHODS
//=============================================================================
public:
    //--------------------------------------------------------------------------
    // CONSTRUCTION
    //--------------------------------------------------------------------------
    //Signal();
    //virtual ~Signal();

    //--------------------------------------------------------------------------
    // FILTERS
    //--------------------------------------------------------------------------
    static int
        SmoothSpline(int aDegree,double aDeltaT,double aCutOffFrequency,
        int aN,double *aTimes,double *aSignal,double *rFilteredSignal);
    static int
        LowpassIIR(double aDeltaT,double aCutOffFrequency,
        int aN,const double *aSignal,double *rFilteredSignal);
    static int
        LowpassFIR(int aOrder,double aDeltaT,double aCutoffFrequency,
        int aN,double *aSignal,double *rFilteredSignal);
    static int
        BandpassFIR(int aOrder,double aDeltaT,
        double aLowFrequency,double aHighFrequency,
        int aN,double *aSignal,double *aFilteredSignal);

    //--------------------------------------------------------------------------
    // PADDING
    //--------------------------------------------------------------------------
    /// Pad a signal with a specified number of data points.
    ///
    /// The signal is prepended and appended with a reflected and negated
    /// portion of the signal of the appropriate size so as to preserve the
    /// value and slope of the signal.
    ///
    /// @param aPad Size of the pad-- number of points to prepend and append.
    /// @param aN Number of data points in the signal.
    /// @param aSignal Signal to be padded.
    /// @return Padded signal. The size is aN + 2*aPad.
    static std::vector<double> Pad(int aPad, int aN, const double aSignal[]);
    static void Pad(int aPad, OpenSim::Array<double>& aSignal);

    //--------------------------------------------------------------------------
    // POINT REDUCTION
    //--------------------------------------------------------------------------
    static int
        ReduceNumberOfPoints(double aDistance,
        Array<double> &rTime,Array<double> &rSignal);


    //--------------------------------------------------------------------------
    // CORE MATH
    //--------------------------------------------------------------------------
    static double sinc(double x);
    static double hamming(int k,int M);

//=============================================================================
};  // END class Signal

}; //namespace
//=============================================================================
//=============================================================================

#endif  // __Signal_h__