Algorithms.h

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/*******************************************************************************************************
 ReadFramework is the basis for modules developed at CVL/TU Wien for the EU project READ. 
  
 Copyright (C) 2016 Markus Diem <diem@caa.tuwien.ac.at>
 Copyright (C) 2016 Stefan Fiel <fiel@caa.tuwien.ac.at>
 Copyright (C) 2016 Florian Kleber <kleber@caa.tuwien.ac.at>

 This file is part of ReadFramework.

 ReadFramework is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.

 ReadFramework 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/>.

 The READ project  has  received  funding  from  the European  Union’s  Horizon  2020  
 research  and innovation programme under grant agreement No 674943
 
 related links:
 [1] http://www.caa.tuwien.ac.at/cvl/
 [2] https://transkribus.eu/Transkribus/
 [3] https://github.com/TUWien/
 [4] http://nomacs.org
 *******************************************************************************************************/

#pragma once

#include "Shapes.h"

#pragma warning(push, 0)    // no warnings from includes
#include <QSharedPointer>
#include <opencv2/core.hpp>
#pragma warning(pop)

#pragma warning (disable: 4251) // inlined Qt functions in dll interface

#ifndef DllCoreExport
#ifdef DLL_CORE_EXPORT
#define DllCoreExport Q_DECL_EXPORT
#else
#define DllCoreExport Q_DECL_IMPORT
#endif
#endif

// Qt defines
class QSettings;

namespace rdf {

// read defines
class Pixel;
class PixelEdge;

class DllCoreExport Algorithms {

public:

    static int doubleEqual(double a, double b);
    static double absAngleDiff(double a, double b);
    static double signedAngleDiff(double a, double b);

    // convenience functions
    static double min(const QVector<double>& vec);
    static double max(const QVector<double>& vec);

    static double normAngleRad(double angle, double startIvl = 0.0, double endIvl = 2.0*CV_PI);
    static double angleDist(double angle1, double angle2, double maxAngle = 2.0*CV_PI);

    // template functions --------------------------------------------------------------------
    
    template <typename numFmt>
    static double statMoment(const QList<numFmt>& valuesIn, double momentValue, bool interpolated = true) {

        // no stat moment if we have 1 value
        if (valuesIn.size() == 1)
            return valuesIn[0];
        
        // return mean if we have two & interpolation is turned on
        if (valuesIn.size() == 2 && interpolated) {
            return (valuesIn[0] + valuesIn[1]) / 2.0;
        }
        else if (valuesIn.size() == 2)
            return valuesIn[0];

        QList<numFmt> values = valuesIn;
        qSort(values);

        size_t lSize = values.size();
        double moment = -1;
        unsigned int momIdx = cvCeil(lSize*momentValue);
        unsigned int idx = 1;

        // find the statistical moment
        for (auto val : values) {

            // skip
            if (idx < momIdx) {
                idx++;
                continue;
            }

            // compute mean between this and the next element
            if (lSize % 2 == 0 && momIdx < lSize && interpolated)
                moment = ((double)val + values[idx+1])*0.5;
            else
                moment = (double)val;
            break;
        }

        return moment;
    }

};

class DllCoreExport LineFitting {

public:
    LineFitting(const QVector<Vector2D>& pts);

    Line fitLineLMS() const;
    Line fitLine() const;

protected:
    // parameters:
    int mNumSets = 1000;    // # random sets generated
    int mSetSize = 2;       // if 2, lines are directly returned
    double mEps = 0.1;      // if LMS is smaller than that, we break
    double mMinLength = 2;  // minimum line length

    QVector<Vector2D> mPts;

    void sample(const QVector<Vector2D>& pts, QVector<Vector2D>& set, int setSize = 2) const;
    double medianResiduals(const QVector<Vector2D>& pts, const Line& line) const;
};

// pixel distance functions
namespace PixelDistance {
    DllCoreExport double euclidean(const Pixel* px1, const Pixel* px2);
    DllCoreExport double mahalanobis(const Pixel* px1, const Pixel* px2);
    DllCoreExport double bhattacharyya(const Pixel* px1, const Pixel* px2);
    DllCoreExport double angleWeighted(const Pixel* px1, const Pixel* px2);

    DllCoreExport typedef double (*PixelDistanceFunction)(const Pixel* px1, const Pixel* px2);

    DllCoreExport double spacingWeighted(const PixelEdge* edge);
    DllCoreExport double orientationWeighted(const PixelEdge* edge);
    DllCoreExport double euclidean(const PixelEdge* edge);
    DllCoreExport typedef double (*EdgeWeightFunction)(const PixelEdge* edge);
}

}