pointtransformaffine.h

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/* ============================================================
 *
 * This file is a part of digiKam project
 * https://www.digikam.org
 *
 * Date        : 16/08/2016
 * Description : point transform class and its utilities that models
 *               affine transformations between two sets of 2d-points.
 *
 * Copyright (C) 2016      by Omar Amin <Omar dot moh dot amin at gmail dot com>
 * Copyright (C) 2016-2022 by Gilles Caulier <caulier dot gilles at gmail dot com>
 *
 * This program 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 2, or (at your option)
 * any later version.
 *
 * This program 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.
 *
 * ============================================================ */
 
#ifndef DIGIKAM_POINT_TRANSFORM_AFFINE_H
#define DIGIKAM_POINT_TRANSFORM_AFFINE_H
 
// C++ includes
 
#include <vector>
#include <iostream>
 
// Local includes
 
#include "matrixoperations.h"
#include "vectoroperations.h"
 
namespace Digikam
{
 
class PointTransformAffine
{
public:
 
    PointTransformAffine();
    PointTransformAffine(const std::vector<std::vector<float> >& m_,
                         const std::vector<float>& b_);
    explicit PointTransformAffine(const std::vector<std::vector<float> >& m_);
 
    const std::vector<float> operator() (const std::vector<float>& p) const;
 
    const std::vector<std::vector<float> >& get_m() const;
    const std::vector<float>& get_b() const;
 
private:
 
    std::vector<std::vector<float> > m;
    std::vector<float>               b;
};
 
// ----------------------------------------------------------------------------------------
 
PointTransformAffine operator* (const PointTransformAffine& lhs,
                                const PointTransformAffine& rhs);
 
// ----------------------------------------------------------------------------------------
 
PointTransformAffine inv(const PointTransformAffine& trans);
 
// ----------------------------------------------------------------------------------------
 
template <typename T>
PointTransformAffine findAffineTransform(const std::vector<std::vector<T> >& fromPoints,
                                         const std::vector<std::vector<T> >& toPoints)
{
    std::vector<std::vector<float> > P(3, std::vector<float>(fromPoints.size()));
    std::vector<std::vector<float> > Q(2, std::vector<float>(fromPoints.size()));
 
    for (unsigned long i = 0 ; i < fromPoints.size() ; ++i)
    {
        P[0][i] = fromPoints[i][0];
        P[1][i] = fromPoints[i][1];
        P[2][i] = 1;
 
        Q[0][i] = toPoints[i][0];
        Q[1][i] = toPoints[i][1];
    }
 
    const std::vector<std::vector<float> > m = Q * MatrixOperations::pinv(P);
 
    return PointTransformAffine(m);
}
 
// ----------------------------------------------------------------------------------------
 
PointTransformAffine findSimilarityTransform(const std::vector<std::vector<float> >& fromPoints,
                                             const std::vector<std::vector<float> >& toPoints);
 
} // namespace Digikam
 
#endif // DIGIKAM_POINT_TRANSFORM_AFFINE_H