Add LOGOS (Local geometric support for high-outlier spatial verification)…

Add LOGOS (Local geometric support for high-outlier spatial verification) features matching strategy.

modules/xfeatures2d/doc/xfeatures2d.bib

@@ -71,6 +71,15 @@
   publisher = {Kluwer Academic Publishers}
 }
 
+@article{Lowry2018LOGOSLG,
+  title = {LOGOS: Local Geometric Support for High-Outlier Spatial Verification},
+  author = {Stephanie Lowry and Henrik Andreasson},
+  journal = {2018 IEEE International Conference on Robotics and Automation (ICRA)},
+  year = {2018},
+  pages = {7262-7269},
+  doi = {10.1109/ICRA.2018.8460988},
+}
+
 @article{Mikolajczyk2004,
   title = {Scale \& affine invariant interest point detectors},
   author = {Mikolajczyk, Krystian and Schmid, Cordelia},

modules/xfeatures2d/include/opencv2/xfeatures2d.hpp

@@ -55,7 +55,9 @@ known to be patented. You need to set the OPENCV_ENABLE_NONFREE option in cmake
 
     @defgroup xfeatures2d_match Experimental 2D Features Matching Algorithm
 
-This section describes the GMS (Grid-based Motion Statistics) matching strategy.
+This section describes the following matching strategies:
+    - GMS: Grid-based Motion Statistics, @cite Bian2017gms
+    - LOGOS: Local geometric support for high-outlier spatial verification, @cite Lowry2018LOGOSLG
 
 @}
 */
@@ -969,7 +971,7 @@ CV_EXPORTS void FASTForPointSet( InputArray image, CV_IN_OUT std::vector<KeyPoin
 //! @addtogroup xfeatures2d_match
 //! @{
 
-/** @brief GMS  (Grid-based Motion Statistics) feature matching strategy by @cite Bian2017gms .
+/** @brief GMS (Grid-based Motion Statistics) feature matching strategy described in @cite Bian2017gms .
     @param size1 Input size of image1.
     @param size2 Input size of image2.
     @param keypoints1 Input keypoints of image1.
@@ -984,10 +986,24 @@ CV_EXPORTS void FASTForPointSet( InputArray image, CV_IN_OUT std::vector<KeyPoin
         If matching results are not satisfying, please add more features. (We use 10000 for images with 640 X 480).
         If your images have big rotation and scale changes, please set withRotation or withScale to true.
  */
+CV_EXPORTS_W void matchGMS(const Size& size1, const Size& size2, const std::vector<KeyPoint>& keypoints1, const std::vector<KeyPoint>& keypoints2,
+                           const std::vector<DMatch>& matches1to2, CV_OUT std::vector<DMatch>& matchesGMS, const bool withRotation = false,
+                           const bool withScale = false, const double thresholdFactor = 6.0);
 
-CV_EXPORTS_W void matchGMS( const Size& size1, const Size& size2, const std::vector<KeyPoint>& keypoints1, const std::vector<KeyPoint>& keypoints2,
-                          const std::vector<DMatch>& matches1to2, CV_OUT std::vector<DMatch>& matchesGMS, const bool withRotation = false,
-                          const bool withScale = false, const double thresholdFactor = 6.0 );
+/** @brief LOGOS (Local geometric support for high-outlier spatial verification) feature matching strategy described in @cite Lowry2018LOGOSLG .
+    @param keypoints1 Input keypoints of image1.
+    @param keypoints2 Input keypoints of image2.
+    @param nn1 Index to the closest BoW centroid for each descriptors of image1.
+    @param nn2 Index to the closest BoW centroid for each descriptors of image2.
+    @param matches1to2 Matches returned by the LOGOS matching strategy.
+    @note
+        This matching strategy is suitable for features matching against large scale database.
+        First step consists in constructing the bag-of-words (BoW) from a representative image database.
+        Image descriptors are then represented by their closest codevector (nearest BoW centroid).
+ */
+CV_EXPORTS_W void matchLOGOS(const std::vector<KeyPoint>& keypoints1, const std::vector<KeyPoint>& keypoints2,
+                             const std::vector<int>& nn1, const std::vector<int>& nn2,
+                             std::vector<DMatch>& matches1to2);
 
 //! @}
 

modules/xfeatures2d/src/logos.cpp

+// This file is part of OpenCV project.
+// It is subject to the license terms in the LICENSE file found in the top-level directory
+// of this distribution and at http://opencv.org/license.html
+#include "precomp.hpp"
+#include "logos/Logos.hpp"
+
+namespace cv
+{
+namespace xfeatures2d
+{
+void matchLOGOS(const std::vector<KeyPoint>& keypoints1, const std::vector<KeyPoint>& keypoints2,
+                const std::vector<int>& nn1, const std::vector<int>& nn2, std::vector<DMatch>& matches1to2)
+{
+    CV_CheckEQ(keypoints1.size(), nn1.size(), "Number of keypoints1 must be equal to the number of nn1.");
+    CV_CheckEQ(keypoints2.size(), nn2.size(), "Number of keypoints2 must be equal to the number of nn2.");
+    if (keypoints1.empty() || keypoints2.empty())
+    {
+        return;
+    }
+
+    std::vector<logos::Point*> vP1, vP2;
+    vP1.reserve(keypoints1.size());
+    vP2.reserve(keypoints2.size());
+
+    for (size_t i = 0; i < keypoints1.size(); i++)
+    {
+        logos::Point* pt1 = new logos::Point(keypoints1[i].pt.x, keypoints1[i].pt.y,
+                                             static_cast<float>(keypoints1[i].angle*CV_PI/180),
+                                             keypoints1[i].size, nn1[i]);
+        vP1.push_back(pt1);
+    }
+
+    for (size_t i = 0; i < keypoints2.size(); i++)
+    {
+        logos::Point* pt2 = new logos::Point(keypoints2[i].pt.x, keypoints2[i].pt.y,
+                                             static_cast<float>(keypoints2[i].angle*CV_PI/180),
+                                             keypoints2[i].size, nn2[i]);
+        vP2.push_back(pt2);
+    }
+
+    logos::Logos logos;
+    std::vector<logos::PointPair*> globalMatches;
+    logos.estimateMatches(vP1, vP2, globalMatches);
+
+    matches1to2.clear();
+    matches1to2.reserve(globalMatches.size());
+    for (size_t i = 0; i < globalMatches.size(); i++)
+    {
+        logos::PointPair* pp = globalMatches[i];
+        matches1to2.push_back(DMatch(pp->getPos1(), pp->getPos2(), 0));
+    }
+
+    for (size_t i = 0; i < globalMatches.size(); i++)
+    {
+        delete globalMatches[i];
+    }
+
+    for (size_t i = 0; i < vP1.size(); i++)
+    {
+        delete vP1[i];
+    }
+
+    for (size_t i = 0; i < vP2.size(); i++)
+    {
+        delete vP2[i];
+    }
+}
+} //namespace xfeatures2d
+} //namespace cv

modules/xfeatures2d/src/logos/Logos.cpp

+// This file is part of OpenCV project.
+// It is subject to the license terms in the LICENSE file found in the top-level directory
+// of this distribution and at http://opencv.org/license.html
+/*
+ * MIT License
+ *
+ * Copyright (c) 2018 Stephanie Lowry
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#include <cmath>
+#include "Logos.hpp"
+#include <opencv2/core.hpp>
+
+namespace logos
+{
+Logos::Logos()
+{
+    LogosParameters defaultParams;
+    init(defaultParams);
+}
+
+Logos::Logos(const LogosParameters& p)
+{
+    init(p);
+}
+
+void Logos::init(const LogosParameters& p)
+{
+    setParams(p);
+    LB = static_cast<float>(-CV_PI);
+    BINSIZE = logosParams.GLOBALORILIMIT/3;
+    BINNUMBER = static_cast<unsigned int>(ceil(2*CV_PI/BINSIZE));
+    bins.resize(BINNUMBER);
+    std::fill(bins.begin(), bins.end(), 0);
+}
+
+int Logos::estimateMatches(std::vector<Point*> vP1, std::vector<Point*> vP2, std::vector<PointPair*>& globalmatches)
+{
+    matches.clear();
+
+    // for each point
+    int count1 = 0;
+
+    for (std::vector<Point*>::iterator pit1 = vP1.begin(); pit1 != vP1.end(); ++pit1, count1++)
+    {
+        (*pit1)->nearestNeighbours(vP1, count1, getNum1());
+        int count2 = 0;
+
+        // find possible matches
+        for (std::vector<Point*>::iterator pit2 = vP2.begin(); pit2 != vP2.end(); ++pit2, count2++)
+        {
+            if ((*pit1)->getLabel() != (*pit2)->getLabel())
+            {
+                continue;
+            }
+            // this is a possible match in Image 2
+            // get nearest neighbours
+            (*pit2)->nearestNeighbours(vP2, count2, getNum2());
+
+            PointPair* ptpr = new PointPair(*pit1, *pit2);
+            ptpr->addPositions(count1, count2);
+            ptpr->computeLocalSupport(pp, getNum2());
+
+            // calc matches
+            int support = 0;
+            for (std::vector<PointPair*>::const_iterator it = pp.begin(); it < pp.end(); ++it)
+            {
+                Match m(ptpr, *it);
+                if (evaluateMatch(m))
+                {
+                    support++;
+                }
+            }
+            for (size_t i = 0; i < pp.size(); i++)
+            {
+                delete pp[i];
+            }
+            pp.clear();
+            if (support > 0)
+            {
+                ptpr->setSupport(support);
+                matches.push_back(ptpr);
+                updateBin(ptpr->getRelOri());
+            }
+            else
+            {
+                delete ptpr;
+                ptpr = NULL;
+            }
+        }
+    }
+
+    // do global orientation
+    double maxang = calcGlobalOrientation();
+
+    // find which matches are within global orientation limit
+    int numinliers = 0;
+    globalmatches.clear();
+    for (std::vector<PointPair*>::iterator it = matches.begin(); it != matches.end(); ++it)
+    {
+        if (std::fabs((*it)->getRelOri() - maxang) < logosParams.GLOBALORILIMIT)
+        {
+            numinliers++;
+            globalmatches.push_back(*it);
+        }
+        else
+        {
+            delete *it;
+            *it = NULL;
+        }
+    }
+
+    return numinliers;
+}
+
+bool Logos::evaluateMatch(const Match& m) const
+{
+    return ((m.getRelOrientation() < getIntraOriLimit()) &&
+            (m.getRelScale() < getIntraScaleLimit()) &&
+            (m.getInterOrientation() < getInterOriLimit()) &&
+            (m.getInterScale() < getInterScaleLimit()));
+}
+
+void Logos::updateBin(float input)
+{
+    unsigned int binnumber = static_cast<unsigned int>(cvFloor((input-LB) / BINSIZE));
+    // compare binnumber to BINNUMBER
+    if (binnumber < BINNUMBER)
+    {
+        bins[binnumber]++;
+    }
+    else
+    {
+        bins[BINNUMBER-1]++;
+    }
+}
+
+float Logos::calcGlobalOrientation()
+{
+    // find max bin
+    // check BINNUMBER is big enough
+    if (BINNUMBER < 3)
+    {
+        return 0;
+    }
+
+    std::vector<int> bins2(BINNUMBER);
+    int maxval = 0;
+    unsigned int maxix = 0;
+    bins2[0] = bins[0] + bins[1] + bins[BINNUMBER-1];
+    maxval = bins2[0];
+    for (unsigned int i = 1; i < BINNUMBER; i++)
+    {
+        if (i == BINNUMBER-1)
+        {
+            bins2[i] = bins[i]+bins[i-1]+bins[0];
+        }
+        else
+        {
+            bins2[i] = bins[i]+bins[i-1]+bins[i+1];
+        }
+        if (bins2[i] > maxval)
+        {
+            maxval = bins2[i];
+            maxix = i;
+        }
+    }
+
+    // convert to an angle
+    return LB + maxix*BINSIZE + BINSIZE/2;
+}
+}

modules/xfeatures2d/src/logos/Logos.hpp

+// This file is part of OpenCV project.
+// It is subject to the license terms in the LICENSE file found in the top-level directory
+// of this distribution and at http://opencv.org/license.html
+/*
+ * MIT License
+ *
+ * Copyright (c) 2018 Stephanie Lowry
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#ifndef LOGOS_HPP
+#define LOGOS_HPP
+
+#include "Point.hpp"
+#include "Match.hpp"
+#include "PointPair.hpp"
+
+namespace logos
+{
+struct LogosParameters
+{
+    LogosParameters() :
+        INTRAORILIMIT(0.1f), INTRASCALELIMIT(0.1f), INTERORILIMIT(0.1f), INTERSCALELIMIT(0.1f), GLOBALORILIMIT(0.1f),
+        NUM1(5), NUM2(5) {}
+
+    float INTRAORILIMIT;
+    float INTRASCALELIMIT;
+    float INTERORILIMIT;
+    float INTERSCALELIMIT;
+    float GLOBALORILIMIT;
+    int NUM1;
+    int NUM2;
+};
+
+class Logos
+{
+private:
+    std::vector<PointPair*> pp;
+    std::vector<PointPair*> matches;
+
+    LogosParameters logosParams;
+    float LB;
+    float BINSIZE;
+    unsigned int BINNUMBER;
+    std::vector<int> bins;
+
+public:
+    Logos();
+    Logos(const LogosParameters& p);
+
+    void init(const LogosParameters& p);
+
+    int estimateMatches(std::vector<Point*> vP1, std::vector<Point*> vP2, std::vector<PointPair*>& globalmatches);
+    bool evaluateMatch(const Match& m) const;
+
+    inline float getIntraOriLimit() const { return logosParams.INTRAORILIMIT; }
+    inline float getIntraScaleLimit() const { return logosParams.INTRASCALELIMIT; }
+    inline float getInterOriLimit() const { return logosParams.INTERORILIMIT; }
+    inline float getInterScaleLimit() const { return logosParams.INTERSCALELIMIT; }
+    inline float getGlobalOriLimit() const { return logosParams.GLOBALORILIMIT; }
+    inline int getNum1() const { return logosParams.NUM1; }
+    inline int getNum2() const { return logosParams.NUM2; }
+
+    void updateBin(float input);
+    float calcGlobalOrientation();
+
+    inline void setParams(const LogosParameters& p) { logosParams = p; }
+};
+}
+
+#endif

modules/xfeatures2d/src/logos/Match.cpp

+// This file is part of OpenCV project.
+// It is subject to the license terms in the LICENSE file found in the top-level directory
+// of this distribution and at http://opencv.org/license.html
+/*
+ * MIT License
+ *
+ * Copyright (c) 2018 Stephanie Lowry
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#include <algorithm>    // std::min
+#include <cmath>        // log, acos
+#include <iostream>
+#include <opencv2/core.hpp>
+#include "Match.hpp"
+
+namespace logos
+{
+Match::Match(PointPair* r_, PointPair* s_) :
+    r(r_), s(s_)
+{
+    calculateInternalVariables();
+    setRelOrientation();
+    setRelScale();
+    interOrientationAndScale();
+}
+
+void Match::calculateInternalVariables()
+{
+    vijx = r->getx1() - s->getx1();
+    vijy = r->gety1() - s->gety1();
+    vmnx = r->getx2() - s->getx2();
+    vmny = r->gety2() - s->gety2();
+}
+
+void Match::setRelOrientation()
+{
+    relOrientation = angleAbsDiff(r->getRelOri(), s->getRelOri());
+}
+
+void Match::setRelScale()
+{
+    relScale = std::fabs(r->getRelScale() - s->getRelScale());
+}
+
+float Match::angleAbsDiff(float a1, float a2)
+{
+    float ad = std::fabs(a1-a2);
+    while (ad > 2*CV_PI)
+    {
+        ad = static_cast<float>(ad-2*CV_PI);
+    }
+    ad = std::min(std::fabs(ad), std::fabs(static_cast<float>(2*CV_PI-std::fabs(ad))));
+
+    return ad;
+}
+
+void Match::interOrientationAndScale()
+{
+    float cp =  vijx*vmny - vijy*vmnx; // analogous to 2D cross product
+    float nmij = std::sqrt(vijx*vijx + vijy*vijy);
+    float nmnm = std::sqrt(vmnx*vmnx + vmny*vmny);
+
+    float fr = (vijx*vmnx+vijy*vmny) / (nmij*nmnm);  // numerator equivalent to dot product
+    fr = std::min(std::max(fr, -1.0f), 1.0f);
+    ro3 = std::acos(fr)*sign(cp);
+
+    rs3 = std::log(nmij) - std::log(nmnm);
+
+    interOrientation = angleAbsDiff(r->getRelOri(), ro3);
+    interScale = std::fabs(r->getRelScale() - rs3);
+}
+
+void Match::printMatch() const
+{
+    std::cout << "Relative Orientation: " << relOrientation << std::endl;
+    std::cout << "Relative Scale: " << relScale << std::endl;
+    std::cout << "Inter Orientation: " << interOrientation << std::endl;
+    std::cout << "Inter Scale: " << interScale << std::endl;
+    std::cout << "Global Relative Orientation: " << r->getRelOri() << std::endl;
+}
+
+int Match::sign(float x)
+{
+    return (x > 0) - (x < 0);
+}
+}

modules/xfeatures2d/src/logos/Match.hpp

+// This file is part of OpenCV project.
+// It is subject to the license terms in the LICENSE file found in the top-level directory
+// of this distribution and at http://opencv.org/license.html
+/*
+ * MIT License
+ *
+ * Copyright (c) 2018 Stephanie Lowry
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#ifndef MATCH_HPP
+#define MATCH_HPP
+
+#include "PointPair.hpp"
+
+namespace logos
+{
+class Match
+{
+private:
+    PointPair* r;
+    PointPair* s;
+    float relOrientation;
+    float relScale;
+    float interOrientation;
+    float interScale;
+
+    // Internal variables
+    float ro3;
+    float rs3;
+    float vijx;
+    float vijy;
+    float vmnx;
+    float vmny;
+
+    // Internal functions
+    void calculateInternalVariables();
+    void setRelOrientation();
+    void setRelScale();
+    float angleDiff(float a1,float a2);
+    float angleAbsDiff(float a1, float a2);
+    void interOrientationAndScale();
+    int sign(float x);
+
+public:
+    Match(PointPair* r, PointPair* s);
+
+    inline float getRelOrientation() const { return relOrientation; }
+    inline float getRelScale() const { return relScale; }
+    inline float getInterOrientation() const { return interOrientation; }
+    inline float getInterScale() const { return interScale; }
+
+    void printMatch() const;
+};
+}
+
+#endif

modules/xfeatures2d/src/logos/Point.cpp

+// This file is part of OpenCV project.
+// It is subject to the license terms in the LICENSE file found in the top-level directory
+// of this distribution and at http://opencv.org/license.html
+/*
+ * MIT License
+ *
+ * Copyright (c) 2018 Stephanie Lowry
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#include <iostream>
+#include <algorithm> // std::sort
+#include "Point.hpp"
+
+namespace logos
+{
+static bool cMP(const MatchPoint& m, const MatchPoint& n)
+{
+    return (m.sd < n.sd);
+}
+
+Point::Point() :
+    x(0), y(0), orientation(0), scale(1), nnVector(), nnFound(false), label(0)
+{
+}
+
+Point::Point(float x_, float y_, float orientation_, float scale_, int label_) :
+    x(x_), y(y_), orientation(orientation_), scale(scale_), nnVector(), nnFound(false), label(label_)
+{
+}
+
+void Point::nearestNeighbours(const std::vector<Point*>& vP, int index, int N)
+{
+    nearestNeighboursNaive(vP, index, N);
+}
+
+void Point::nearestNeighboursNaive(const std::vector<Point*>& vP, int index, int N)
+{
+    // only want to calculate once.
+    if (nnFound)
+    {
+        return;
+    }
+
+    std::vector<MatchPoint> minMatch;
+    minMatch.reserve(vP.size());
+
+    int i = 0;
+    for (std::vector<Point*>::const_iterator it = vP.begin(); it != vP.end(); ++it, i++)
+    {
+        // A point is not it's own neighbour
+        if (i == index)
+        {
+            continue;
+        }
+        float sd = squareDist(getx(), gety(), (*it)->getx(), (*it)->gety());
+        MatchPoint mP(sd, i);
+        minMatch.push_back(mP);
+    }
+
+    std::sort(minMatch.begin(), minMatch.end(), cMP);
+    nnVector.resize(static_cast<size_t>(N));
+    int count = 0;
+    for (std::vector<MatchPoint>::const_iterator mmit = minMatch.begin(); count < N; ++mmit, count++)
+    {
+        nnVector[static_cast<size_t>(count)] = vP[static_cast<size_t>(mmit->index)];
+    }
+
+    nnFound = true;
+}
+
+void Point::matchLabel(int label_, std::vector<Point*>& matchNN)
+{
+    for (std::vector<Point*>::const_iterator nnIterator = nnVector.begin();
+         nnIterator != nnVector.end(); ++nnIterator)
+    {
+        if ((*nnIterator)->label == label_)
+        {
+            matchNN.push_back(*nnIterator);
+        }
+    }
+}
+
+void Point::printPoint() const
+{
+    std::cout << getx() << " "
+              << gety() << " " << getOrientation() << " "
+              << getScale() << " " << getLabel() << std::endl;
+}
+
+void Point::printNN() const
+{
+    for(std::vector<Point*>::const_iterator nnIterator = nnVector.begin();
+        nnIterator != nnVector.end(); ++nnIterator)
+    {
+        (*nnIterator)->printPoint();
+    }
+}
+
+float Point::squareDist(float x1, float y1, float x2, float y2)
+{
+    return (x1-x2)*(x1-x2) + (y1-y2)*(y1-y2);
+}
+}

modules/xfeatures2d/src/logos/Point.hpp

+// This file is part of OpenCV project.
+// It is subject to the license terms in the LICENSE file found in the top-level directory
+// of this distribution and at http://opencv.org/license.html
+/*
+ * MIT License
+ *
+ * Copyright (c) 2018 Stephanie Lowry
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#ifndef POINT_HPP
+#define POINT_HPP
+
+#include <vector>
+
+namespace logos
+{
+struct MatchPoint
+{
+    float sd;
+    int index;
+
+    MatchPoint(float sd_, int idx) :
+        sd(sd_), index(idx) {}
+};
+
+class Point
+{
+private:
+    float x;
+    float y;
+    float orientation;
+    float scale;
+    std::vector<Point*> nnVector;
+    bool nnFound;
+    int label;
+
+public:
+    Point();
+    Point(float x_, float y_, float orientation_, float scale_, int label_ = 0);
+
+    inline float getx() const { return x; }
+    inline float gety() const { return y; }
+    inline float getOrientation() const { return orientation; }
+    inline float getScale() const { return scale; }
+
+    inline int getLabel() const { return label; }
+    inline void setLabel(int label_) { label = label_; }
+
+    inline void getNNVector(std::vector<Point*>& nnv) const { nnv = nnVector; }
+    void matchLabel(int label, std::vector<Point*>& mNN);
+
+    void nearestNeighbours(const std::vector<Point*>& vP, int index, int N);
+    void nearestNeighboursNaive(const std::vector<Point*>& vP, int index, int N);
+
+    void printPoint() const;
+    void printNN() const;
+
+    float squareDist(float x1, float y1, float x2, float y2);
+};
+}
+
+#endif

modules/xfeatures2d/src/logos/PointPair.cpp

+// This file is part of OpenCV project.
+// It is subject to the license terms in the LICENSE file found in the top-level directory
+// of this distribution and at http://opencv.org/license.html
+/*
+ * MIT License
+ *
+ * Copyright (c) 2018 Stephanie Lowry
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#include <opencv2/core.hpp>
+#include "PointPair.hpp"
+
+namespace logos
+{
+PointPair::PointPair(Point* p_, Point* q_) :
+    p(p_), q(q_), support(0), pos1(0), pos2(0)
+{
+    calculateInternalVariables();
+}
+
+void PointPair::computeLocalSupport(std::vector<PointPair*>& pp, int N)
+{
+    std::vector<Point*> nnVector;
+    p->getNNVector(nnVector); // Exposes the nearest neighbours
+
+    // for each nearest neighbour
+    for (std::vector<Point*>::iterator nnIterator = nnVector.begin(); nnIterator != nnVector.end(); ++nnIterator)
+    {
+        // is there a matching nearestNeighbour?
+        std::vector<Point*> matchNN;
+        matchNN.reserve(static_cast<size_t>(N));
+        q->matchLabel((*nnIterator)->getLabel(), matchNN);
+        for (std::vector<Point*>::const_iterator mit = matchNN.begin(); mit != matchNN.end(); ++mit)
+        {
+            PointPair* m = new PointPair(*nnIterator, *mit);
+            pp.push_back(m);
+        }
+    }
+}
+
+void PointPair::calculateInternalVariables()
+{
+    relOri = angleDiff(p->getOrientation(), q->getOrientation());
+    relScale = std::log(p->getScale()) - std::log(q->getScale());
+}
+
+float PointPair::angleDiff(float a1, float a2)
+{
+    float ad = a1 - a2;
+    while (ad > CV_PI)
+    {
+        ad = static_cast<float>(ad-2*CV_PI);
+    }
+    while (ad < -CV_PI)
+    {
+        ad = static_cast<float>(ad + 2*CV_PI);
+    }
+    return ad;
+}
+}

modules/xfeatures2d/src/logos/PointPair.hpp

+// This file is part of OpenCV project.
+// It is subject to the license terms in the LICENSE file found in the top-level directory
+// of this distribution and at http://opencv.org/license.html
+/*
+ * MIT License
+ *
+ * Copyright (c) 2018 Stephanie Lowry
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#ifndef POINTPAIR_HPP
+#define POINTPAIR_HPP
+
+#include "Point.hpp"
+
+namespace logos
+{
+class PointPair
+{
+private:
+    Point* p;
+    Point* q;
+    int support;
+    float relOri;
+    float relScale;
+    int pos1;
+    int pos2;
+
+    float angleDiff(float a1, float a2);
+
+public:
+    PointPair(Point* p_, Point* q_);
+
+    void computeLocalSupport(std::vector<PointPair*>& pp, int N);
+
+    void calculateInternalVariables();
+
+    float getRelOri() const { return relOri; }
+    float getRelScale() const { return relScale; }
+
+    float getx1() const { return p->getx(); }
+    float getx2() const { return q->getx(); }
+    float gety1() const { return p->gety(); }
+    float gety2() const { return q->gety(); }
+
+    void addPositions(int pos1_, int pos2_) { pos1 = pos1_; pos2 = pos2_; }
+    int getPos1() const { return pos1; }
+    int getPos2() const { return pos2; }
+
+    int getSupport() const { return support; }
+    void setSupport(int support_) { support = support_; }
+};
+}
+
+#endif

modules/xfeatures2d/test/test_logos_matcher.cpp

+// This file is part of OpenCV project.
+// It is subject to the license terms in the LICENSE file found in the top-level directory
+// of this distribution and at http://opencv.org/license.html.
+
+#include "test_precomp.hpp"
+
+namespace opencv_test { namespace {
+
+static void loadKeypoints(const std::string& vP_path,
+                          const std::string& oP_path,
+                          const std::string& sP_path,
+                          const std::string& w_path,
+                          std::vector<cv::KeyPoint>& keypoints,
+                          std::vector<int>& nn)
+{
+    {
+        std::ifstream file(vP_path.c_str());
+        if (file.is_open())
+        {
+            float x = 0, y = 0;
+            while (file >> x >> y)
+            {
+                keypoints.push_back(cv::KeyPoint(x, y, 0));
+            }
+        }
+    }
+    {
+        std::ifstream file(oP_path.c_str());
+        if (file.is_open())
+        {
+            float orientation = 0;
+            size_t idx = 0;
+            while (file >> orientation)
+            {
+                keypoints[idx].angle = static_cast<float>(orientation * 180.0 / CV_PI);
+                idx++;
+            }
+        }
+    }
+    {
+        std::ifstream file(sP_path.c_str());
+        if (file.is_open())
+        {
+            float scale = 0;
+            size_t idx = 0;
+            while (file >> scale)
+            {
+                keypoints[idx].size = scale;
+                idx++;
+            }
+        }
+    }
+    {
+        std::ifstream file(w_path.c_str());
+        if (file.is_open())
+        {
+            int neighborIdx = 0;
+            while (file >> neighborIdx)
+            {
+                nn.push_back(neighborIdx);
+            }
+        }
+    }
+
+    ASSERT_TRUE(!keypoints.empty());
+}
+
+static void loadGroundTruth(const std::string& d1_path,
+                            const std::string& b1_path,
+                            std::vector<cv::DMatch>& groundTruth)
+{
+    std::vector<int> d1_vec;
+    {
+        std::ifstream file(d1_path.c_str());
+        if (file.is_open())
+        {
+            int idx = 0;
+            while (file >> idx)
+            {
+                d1_vec.push_back(idx-1);
+            }
+        }
+    }
+
+    std::vector<int> b1_vec;
+    {
+        std::ifstream file(b1_path.c_str());
+        if (file.is_open())
+        {
+            int idx = 0;
+            while (file >> idx)
+            {
+                b1_vec.push_back(idx-1);
+            }
+        }
+    }
+
+    ASSERT_TRUE(!d1_vec.empty());
+    ASSERT_EQ(d1_vec.size(), b1_vec.size());
+
+    for (size_t i = 0; i < d1_vec.size(); i++)
+    {
+        groundTruth.push_back(cv::DMatch(d1_vec[i], b1_vec[i], 0));
+    }
+}
+
+TEST(XFeatures2d_LogosMatcher, logos_matcher_regression)
+{
+    const std::string vP1_path = cvtest::findDataFile("detectors_descriptors_evaluation/matching/LOGOS/vP1.txt");
+    const std::string oP1_path = cvtest::findDataFile("detectors_descriptors_evaluation/matching/LOGOS/oP1.txt");
+    const std::string sP1_path = cvtest::findDataFile("detectors_descriptors_evaluation/matching/LOGOS/sP1.txt");
+    const std::string w1_path = cvtest::findDataFile("detectors_descriptors_evaluation/matching/LOGOS/w1.txt");
+
+    const std::string vP2_path = cvtest::findDataFile("detectors_descriptors_evaluation/matching/LOGOS/vP2.txt");
+    const std::string oP2_path = cvtest::findDataFile("detectors_descriptors_evaluation/matching/LOGOS/oP2.txt");
+    const std::string sP2_path = cvtest::findDataFile("detectors_descriptors_evaluation/matching/LOGOS/sP2.txt");
+    const std::string w2_path = cvtest::findDataFile("detectors_descriptors_evaluation/matching/LOGOS/w2.txt");
+
+    std::vector<cv::KeyPoint> keypoints1, keypoints2;
+    std::vector<int> nn1, nn2;
+    loadKeypoints(vP1_path, oP1_path, sP1_path, w1_path, keypoints1, nn1);
+    loadKeypoints(vP2_path, oP2_path, sP2_path, w2_path, keypoints2, nn2);
+
+    std::vector<cv::DMatch> matchesLogos;
+    matchLOGOS(keypoints1, keypoints2, nn1, nn2, matchesLogos);
+
+    std::vector<cv::DMatch> groundTruth;
+    const std::string d1_path = cvtest::findDataFile("detectors_descriptors_evaluation/matching/LOGOS/d1.txt");
+    const std::string b1_path = cvtest::findDataFile("detectors_descriptors_evaluation/matching/LOGOS/b1.txt");
+    loadGroundTruth(d1_path, b1_path, groundTruth);
+
+    int correctMatches = 0;
+    for (size_t i = 0; i < matchesLogos.size(); i++)
+    {
+        for (size_t j = 0; j < groundTruth.size(); j++)
+        {
+            if (groundTruth[j].queryIdx == matchesLogos[i].queryIdx &&
+                groundTruth[j].trainIdx == matchesLogos[j].trainIdx)
+            {
+                correctMatches++;
+                break;
+            }
+        }
+    }
+
+    ASSERT_EQ(static_cast<int>(groundTruth.size()), correctMatches)
+            << "groundTruth: " << groundTruth.size()
+            << " ; matchesLogos: " << matchesLogos.size()
+            << " ; correctMatches: " << correctMatches;
+}
+
+}} // namespace