Added detection of cirlces' grid pattern

pull/13383/head
Ilya Lysenkov 14 years ago
parent 24206bd19f
commit 964df356bf
  1. 7
      modules/calib3d/include/opencv2/calib3d/calib3d.hpp
  2. 288
      modules/calib3d/src/blobdetector.cpp
  3. 92
      modules/calib3d/src/blobdetector.hpp
  4. 58
      modules/calib3d/src/calibinit.cpp
  5. 850
      modules/calib3d/src/circlesgrid.cpp
  6. 156
      modules/calib3d/src/circlesgrid.hpp

@ -542,7 +542,12 @@ CV_EXPORTS_W void drawChessboardCorners( Mat& image, Size patternSize,
CV_EXPORTS void drawChessboardCorners( Mat& image, Size patternSize,
const vector<Point2f>& corners,
bool patternWasFound );
//! finds circles' grid pattern of the specified size in the image
CV_EXPORTS_W bool findCirclesGrid( const Mat& image, Size patternSize,
CV_OUT vector<Point2f>& centers,
int flags=0 );
enum
{
CALIB_USE_INTRINSIC_GUESS = CV_CALIB_USE_INTRINSIC_GUESS,

@ -0,0 +1,288 @@
/*M///////////////////////////////////////////////////////////////////////////////////////
//
// IMPORTANT: READ BEFORE DOWNLOADING, COPYING, INSTALLING OR USING.
//
// By downloading, copying, installing or using the software you agree to this license.
// If you do not agree to this license, do not download, install,
// copy or use the software.
//
//
// License Agreement
// For Open Source Computer Vision Library
//
// Copyright (C) 2000-2008, Intel Corporation, all rights reserved.
// Copyright (C) 2009, Willow Garage Inc., all rights reserved.
// Third party copyrights are property of their respective owners.
//
// Redistribution and use in source and binary forms, with or without modification,
// are permitted provided that the following conditions are met:
//
// * Redistribution's of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
//
// * Redistribution's in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
//
// * The name of the copyright holders may not be used to endorse or promote products
// derived from this software without specific prior written permission.
//
// This software is provided by the copyright holders and contributors "as is" and
// any express or implied warranties, including, but not limited to, the implied
// warranties of merchantability and fitness for a particular purpose are disclaimed.
// In no event shall the Intel Corporation or contributors be liable for any direct,
// indirect, incidental, special, exemplary, or consequential damages
// (including, but not limited to, procurement of substitute goods or services;
// loss of use, data, or profits; or business interruption) however caused
// and on any theory of liability, whether in contract, strict liability,
// or tort (including negligence or otherwise) arising in any way out of
// the use of this software, even if advised of the possibility of such damage.
//
//M*/
#include "blobdetector.hpp"
using namespace cv;
BlobDetectorParameters::BlobDetectorParameters()
{
thresholdStep = 10;
minThreshold = 50;
maxThreshold = 220;
maxCentersDist = 10;
defaultKeypointSize = 1;
minRepeatability = 2;
filterByColor = true;
computeRadius = true;
isGrayscaleCentroid = false;
centroidROIMargin = 2;
filterByArea = true;
minArea = 25;
maxArea = 5000;
filterByInertia = true;
//minInertiaRatio = 0.6;
minInertiaRatio = 0.1;
filterByConvexity = true;
//minConvexity = 0.8;
minConvexity = 0.95;
filterByCircularity = false;
minCircularity = 0.8;
}
BlobDetector::BlobDetector(const BlobDetectorParameters &parameters) :
params(parameters)
{
}
void BlobDetector::detect(const cv::Mat& image, vector<cv::KeyPoint>& keypoints, const cv::Mat& mask) const
{
detectImpl(image, keypoints, mask);
}
Point2d BlobDetector::computeGrayscaleCentroid(const Mat &image, const vector<Point> &contour) const
{
Rect rect = boundingRect(Mat(contour));
rect.x -= params.centroidROIMargin;
rect.y -= params.centroidROIMargin;
rect.width += 2 * params.centroidROIMargin;
rect.height += 2 * params.centroidROIMargin;
rect.x = rect.x < 0 ? 0 : rect.x;
rect.y = rect.y < 0 ? 0 : rect.y;
rect.width = rect.x + rect.width < image.cols ? rect.width : image.cols - rect.x;
rect.height = rect.y + rect.height < image.rows ? rect.height : image.rows - rect.y;
Mat roi = image(rect);
assert( roi.type() == CV_8UC1 );
Mat invRoi = 255 - roi;
invRoi.convertTo(invRoi, CV_32FC1);
invRoi = invRoi.mul(invRoi);
Moments moms = moments(invRoi);
Point2d tl = rect.tl();
Point2d roiCentroid(moms.m10 / moms.m00, moms.m01 / moms.m00);
Point2d centroid = tl + roiCentroid;
return centroid;
}
void BlobDetector::findBlobs(const cv::Mat &image, const cv::Mat &binaryImage, vector<Center> &centers) const
{
centers.clear();
vector<vector<Point> > contours;
Mat tmpBinaryImage = binaryImage.clone();
findContours(tmpBinaryImage, contours, CV_RETR_LIST, CV_CHAIN_APPROX_NONE);
//Mat keypointsImage;
//cvtColor( binaryImage, keypointsImage, CV_GRAY2RGB );
//Mat contoursImage;
//cvtColor( binaryImage, contoursImage, CV_GRAY2RGB );
//drawContours( contoursImage, contours, -1, Scalar(0,255,0) );
//imshow("contours", contoursImage );
for (size_t contourIdx = 0; contourIdx < contours.size(); contourIdx++)
{
Center center;
center.confidence = 1;
Moments moms = moments(Mat(contours[contourIdx]));
if (params.filterByArea)
{
double area = moms.m00;
if (area < params.minArea || area > params.maxArea)
continue;
}
if (params.filterByCircularity)
{
double area = moms.m00;
double perimeter = arcLength(Mat(contours[contourIdx]), true);
double ratio = 4 * M_PI * area / (perimeter * perimeter);
if (ratio < params.minCircularity)
continue;
}
if (params.filterByInertia)
{
double denominator = sqrt(pow(2 * moms.mu11, 2) + pow(moms.mu20 - moms.mu02, 2));
const double eps = 1e-2;
double ratio;
if (denominator > eps)
{
double cosmin = (moms.mu20 - moms.mu02) / denominator;
double sinmin = 2 * moms.mu11 / denominator;
double cosmax = -cosmin;
double sinmax = -sinmin;
double imin = 0.5 * (moms.mu20 + moms.mu02) - 0.5 * (moms.mu20 - moms.mu02) * cosmin - moms.mu11 * sinmin;
double imax = 0.5 * (moms.mu20 + moms.mu02) - 0.5 * (moms.mu20 - moms.mu02) * cosmax - moms.mu11 * sinmax;
ratio = imin / imax;
}
else
{
ratio = 1;
}
if (ratio < params.minInertiaRatio)
continue;
center.confidence = ratio * ratio;
}
if (params.filterByConvexity)
{
vector<Point> hull;
convexHull(Mat(contours[contourIdx]), hull);
double area = contourArea(Mat(contours[contourIdx]));
double hullArea = contourArea(Mat(hull));
double ratio = area / hullArea;
if (ratio < params.minConvexity)
continue;
}
if (params.isGrayscaleCentroid)
center.location = computeGrayscaleCentroid(image, contours[contourIdx]);
else
center.location = Point2d(moms.m10 / moms.m00, moms.m01 / moms.m00);
if (params.filterByColor)
{
if (binaryImage.at<uchar> (center.location.y, center.location.x) == 255)
continue;
}
if (params.computeRadius)
{
vector<double> dists;
for (size_t pointIdx = 0; pointIdx < contours[contourIdx].size(); pointIdx++)
{
Point2d pt = contours[contourIdx][pointIdx];
dists.push_back(norm(center.location - pt));
}
std::sort(dists.begin(), dists.end());
center.radius = (dists[(dists.size() - 1) / 2] + dists[dists.size() / 2]) / 2.;
}
centers.push_back(center);
//circle( keypointsImage, center.location, 1, Scalar(0,0,255), 1 );
}
//imshow("bk", keypointsImage );
//waitKey();
}
void BlobDetector::detectImpl(const cv::Mat& image, std::vector<cv::KeyPoint>& keypoints, const cv::Mat& mask) const
{
keypoints.clear();
Mat grayscaleImage;
if (image.channels() == 3)
cvtColor(image, grayscaleImage, CV_BGR2GRAY);
else
grayscaleImage = image;
vector<vector<Center> > centers;
for (double thresh = params.minThreshold; thresh < params.maxThreshold; thresh += params.thresholdStep)
{
Mat binarizedImage;
threshold(grayscaleImage, binarizedImage, thresh, 255, THRESH_BINARY);
//Mat keypointsImage;
//cvtColor( binarizedImage, keypointsImage, CV_GRAY2RGB );
vector<Center> curCenters;
findBlobs(grayscaleImage, binarizedImage, curCenters);
for (size_t i = 0; i < curCenters.size(); i++)
{
//circle(keypointsImage, curCenters[i].location, 1, Scalar(0,0,255),-1);
bool isNew = true;
for (size_t j = 0; j < centers.size(); j++)
{
double dist = norm(centers[j][0].location - curCenters[i].location);
if (params.computeRadius)
isNew = dist >= centers[j][0].radius && dist >= curCenters[i].radius && dist >= params.maxCentersDist;
else
isNew = dist >= params.maxCentersDist;
if (!isNew)
{
centers[j].push_back(curCenters[i]);
// if( centers[j][0].radius < centers[j][ centers[j].size()-1 ].radius )
// {
// std::swap( centers[j][0], centers[j][ centers[j].size()-1 ] );
// }
break;
}
}
if (isNew)
{
centers.push_back(vector<Center> (1, curCenters[i]));
}
}
//imshow("binarized", keypointsImage );
//waitKey();
}
for (size_t i = 0; i < centers.size(); i++)
{
if (centers[i].size() < params.minRepeatability)
continue;
Point2d sumPoint(0, 0);
double normalizer = 0;
for (size_t j = 0; j < centers[i].size(); j++)
{
sumPoint += centers[i][j].confidence * centers[i][j].location;
normalizer += centers[i][j].confidence;
}
sumPoint *= (1. / normalizer);
KeyPoint kpt(sumPoint, params.defaultKeypointSize);
keypoints.push_back(kpt);
}
}

@ -0,0 +1,92 @@
/*M///////////////////////////////////////////////////////////////////////////////////////
//
// IMPORTANT: READ BEFORE DOWNLOADING, COPYING, INSTALLING OR USING.
//
// By downloading, copying, installing or using the software you agree to this license.
// If you do not agree to this license, do not download, install,
// copy or use the software.
//
//
// License Agreement
// For Open Source Computer Vision Library
//
// Copyright (C) 2000-2008, Intel Corporation, all rights reserved.
// Copyright (C) 2009, Willow Garage Inc., all rights reserved.
// Third party copyrights are property of their respective owners.
//
// Redistribution and use in source and binary forms, with or without modification,
// are permitted provided that the following conditions are met:
//
// * Redistribution's of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
//
// * Redistribution's in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
//
// * The name of the copyright holders may not be used to endorse or promote products
// derived from this software without specific prior written permission.
//
// This software is provided by the copyright holders and contributors "as is" and
// any express or implied warranties, including, but not limited to, the implied
// warranties of merchantability and fitness for a particular purpose are disclaimed.
// In no event shall the Intel Corporation or contributors be liable for any direct,
// indirect, incidental, special, exemplary, or consequential damages
// (including, but not limited to, procurement of substitute goods or services;
// loss of use, data, or profits; or business interruption) however caused
// and on any theory of liability, whether in contract, strict liability,
// or tort (including negligence or otherwise) arising in any way out of
// the use of this software, even if advised of the possibility of such damage.
//
//M*/
#ifndef BLOBDETECTOR_HPP_
#define BLOBDETECTOR_HPP_
#include "precomp.hpp"
#include "../../features2d/include/opencv2/features2d/features2d.hpp"
struct BlobDetectorParameters
{
BlobDetectorParameters();
float thresholdStep;
float minThreshold;
float maxThreshold;
float maxCentersDist;
int defaultKeypointSize;
size_t minRepeatability;
bool computeRadius;
bool isGrayscaleCentroid;
int centroidROIMargin;
bool filterByArea, filterByInertia, filterByCircularity, filterByColor, filterByConvexity;
float minArea;
float maxArea;
float minCircularity;
float minInertiaRatio;
float minConvexity;
};
class BlobDetector //: public cv::FeatureDetector
{
public:
BlobDetector(const BlobDetectorParameters &parameters = BlobDetectorParameters());
void detect(const cv::Mat& image, vector<cv::KeyPoint>& keypoints, const cv::Mat& mask = cv::Mat()) const;
protected:
struct Center
{
cv::Point2d location;
double radius;
double confidence;
};
virtual void detectImpl(const cv::Mat& image, vector<cv::KeyPoint>& keypoints, const cv::Mat& mask = cv::Mat()) const;
virtual void findBlobs(const cv::Mat &image, const cv::Mat &binaryImage, vector<Center> &centers) const;
cv::Point2d computeGrayscaleCentroid(const cv::Mat &image, const vector<cv::Point> &contour) const;
BlobDetectorParameters params;
};
#endif /* BLOBDETECTOR_HPP_ */

@ -60,6 +60,8 @@
\************************************************************************************/
#include "precomp.hpp"
#include "circlesgrid.hpp"
#include "blobdetector.hpp"
#include <stdarg.h>
//#define ENABLE_TRIM_COL_ROW
@ -1933,6 +1935,62 @@ void drawChessboardCorners( Mat& image, Size patternSize,
(int)corners.size(), patternWasFound );
}
bool findCirclesGrid( const Mat& image, Size patternSize,
vector<Point2f>& centers, int flags )
{
Ptr<BlobDetector> detector = new BlobDetector();
//Ptr<FeatureDetector> detector = new MserFeatureDetector();
vector<KeyPoint> keypoints;
detector->detect(image, keypoints);
CirclesGridFinderParameters parameters;
parameters.vertexPenalty = -0.6;
parameters.vertexGain = 1;
parameters.existingVertexGain = 10000;
parameters.edgeGain = 1;
parameters.edgePenalty = -0.6;
const int attempts = 2;
const int minHomographyPoints = 4;
Mat H;
for (int i = 0; i < attempts; i++)
{
centers.clear();
CirclesGridFinder boxFinder(patternSize, keypoints, parameters);
bool isFound = false;
try
{
isFound = boxFinder.findHoles();
}
catch (cv::Exception &e)
{
}
boxFinder.getHoles(centers);
if (isFound)
{
if (i != 0)
{
Mat orgPointsMat;
transform(Mat(centers), orgPointsMat, H.inv());
convertPointsHomogeneous(orgPointsMat, centers);
}
return true;
}
if (i != attempts - 1)
{
if (centers.size() < minHomographyPoints)
break;
H = CirclesGridFinder::rectifyGrid(boxFinder.getDetectedGridSize(), centers, keypoints, keypoints);
}
}
return false;
}
}
/* End of file. */

@ -0,0 +1,850 @@
/*M///////////////////////////////////////////////////////////////////////////////////////
//
// IMPORTANT: READ BEFORE DOWNLOADING, COPYING, INSTALLING OR USING.
//
// By downloading, copying, installing or using the software you agree to this license.
// If you do not agree to this license, do not download, install,
// copy or use the software.
//
//
// License Agreement
// For Open Source Computer Vision Library
//
// Copyright (C) 2000-2008, Intel Corporation, all rights reserved.
// Copyright (C) 2009, Willow Garage Inc., all rights reserved.
// Third party copyrights are property of their respective owners.
//
// Redistribution and use in source and binary forms, with or without modification,
// are permitted provided that the following conditions are met:
//
// * Redistribution's of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
//
// * Redistribution's in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
//
// * The name of the copyright holders may not be used to endorse or promote products
// derived from this software without specific prior written permission.
//
// This software is provided by the copyright holders and contributors "as is" and
// any express or implied warranties, including, but not limited to, the implied
// warranties of merchantability and fitness for a particular purpose are disclaimed.
// In no event shall the Intel Corporation or contributors be liable for any direct,
// indirect, incidental, special, exemplary, or consequential damages
// (including, but not limited to, procurement of substitute goods or services;
// loss of use, data, or profits; or business interruption) however caused
// and on any theory of liability, whether in contract, strict liability,
// or tort (including negligence or otherwise) arising in any way out of
// the use of this software, even if advised of the possibility of such damage.
//
//M*/
#include "circlesgrid.hpp"
using namespace cv;
Graph::Graph(int n)
{
for (int i = 0; i < n; i++)
{
addVertex(i);
}
}
bool Graph::doesVertexExist(int id) const
{
return (vertices.find(id) != vertices.end());
}
void Graph::addVertex(int id)
{
assert( !doesVertexExist( id ) );
vertices.insert(pair<int, Vertex> (id, Vertex()));
}
void Graph::addEdge(int id1, int id2)
{
assert( doesVertexExist( id1 ) );
assert( doesVertexExist( id2 ) );
vertices[id1].neighbors.insert(id2);
vertices[id2].neighbors.insert(id1);
}
bool Graph::areVerticesAdjacent(int id1, int id2) const
{
assert( doesVertexExist( id1 ) );
assert( doesVertexExist( id2 ) );
Vertices::const_iterator it = vertices.find(id1);
return it->second.neighbors.find(id2) != it->second.neighbors.end();
}
size_t Graph::getVerticesCount() const
{
return vertices.size();
}
size_t Graph::getDegree(int id) const
{
assert( doesVertexExist(id) );
Vertices::const_iterator it = vertices.find(id);
return it->second.neighbors.size();
}
void Graph::floydWarshall(cv::Mat &distanceMatrix, int infinity) const
{
const int edgeWeight = 1;
const size_t n = getVerticesCount();
distanceMatrix.create(n, n, CV_32SC1);
distanceMatrix.setTo(infinity);
for (Vertices::const_iterator it1 = vertices.begin(); it1 != vertices.end(); it1++)
{
distanceMatrix.at<int> (it1->first, it1->first) = 0;
for (Neighbors::iterator it2 = it1->second.neighbors.begin(); it2 != it1->second.neighbors.end(); it2++)
{
assert( it1->first != *it2 );
distanceMatrix.at<int> (it1->first, *it2) = edgeWeight;
}
}
for (Vertices::const_iterator it1 = vertices.begin(); it1 != vertices.end(); it1++)
{
for (Vertices::const_iterator it2 = vertices.begin(); it2 != vertices.end(); it2++)
{
for (Vertices::const_iterator it3 = vertices.begin(); it3 != vertices.end(); it3++)
{
int val1 = distanceMatrix.at<int> (it2->first, it3->first);
int val2;
if (distanceMatrix.at<int> (it2->first, it1->first) == infinity || distanceMatrix.at<int> (it1->first,
it3->first)
== infinity)
val2 = val1;
else
val2 = distanceMatrix.at<int> (it2->first, it1->first) + distanceMatrix.at<int> (it1->first, it3->first);
distanceMatrix.at<int> (it2->first, it3->first) = std::min(val1, val2);
}
}
}
}
void computeShortestPath(Mat &predecessorMatrix, int v1, int v2, vector<int> &path);
void computePredecessorMatrix(const Mat &dm, int verticesCount, Mat &predecessorMatrix);
CirclesGridFinderParameters::CirclesGridFinderParameters()
{
minDensity = 10;
densityNeighborhoodSize = Size2f(16, 16);
minDistanceToAddKeypoint = 20;
kmeansAttempts = 100;
convexHullFactor = 1.1;
keypointScale = 1;
minGraphConfidence = 9;
vertexGain = 2;
vertexPenalty = -5;
edgeGain = 1;
edgePenalty = -5;
existingVertexGain = 0;
}
CirclesGridFinder::CirclesGridFinder(Size _patternSize, const vector<KeyPoint> &testKeypoints,
const CirclesGridFinderParameters &_parameters) :
patternSize(_patternSize)
{
keypoints = testKeypoints;
parameters = _parameters;
}
bool CirclesGridFinder::findHoles()
{
vector<Point2f> vectors, filteredVectors, basis;
computeEdgeVectorsOfRNG(vectors);
filterOutliersByDensity(vectors, filteredVectors);
vector<Graph> basisGraphs;
findBasis(filteredVectors, basis, basisGraphs);
findMCS(basis, basisGraphs);
return (isDetectionCorrect());
//CV_Error( 0, "Detection is not correct" );
}
bool CirclesGridFinder::isDetectionCorrect()
{
if (holes.size() != patternSize.height)
return false;
set<int> vertices;
for (size_t i = 0; i < holes.size(); i++)
{
if (holes[i].size() != patternSize.width)
return false;
for (size_t j = 0; j < holes[i].size(); j++)
{
vertices.insert(holes[i][j]);
}
}
return vertices.size() == patternSize.area();
}
void CirclesGridFinder::findMCS(const vector<Point2f> &basis, vector<Graph> &basisGraphs)
{
Path longestPath;
size_t bestGraphIdx = findLongestPath(basisGraphs, longestPath);
vector<int> holesRow = longestPath.vertices;
while (holesRow.size() > std::max(patternSize.width, patternSize.height))
{
holesRow.pop_back();
holesRow.erase(holesRow.begin());
}
if (bestGraphIdx == 0)
{
holes.push_back(holesRow);
int w = holes[0].size();
int h = holes.size();
//parameters.minGraphConfidence = holes[0].size() * parameters.vertexGain + (holes[0].size() - 1) * parameters.edgeGain;
//parameters.minGraphConfidence = holes[0].size() * parameters.vertexGain + (holes[0].size() / 2) * parameters.edgeGain;
//parameters.minGraphConfidence = holes[0].size() * parameters.existingVertexGain + (holes[0].size() / 2) * parameters.edgeGain;
parameters.minGraphConfidence = holes[0].size() * parameters.existingVertexGain;
for (int i = h; i < patternSize.height; i++)
{
addHolesByGraph(basisGraphs, true, basis[1]);
}
//parameters.minGraphConfidence = holes.size() * parameters.existingVertexGain + (holes.size() / 2) * parameters.edgeGain;
parameters.minGraphConfidence = holes.size() * parameters.existingVertexGain;
for (int i = w; i < patternSize.width; i++)
{
addHolesByGraph(basisGraphs, false, basis[0]);
}
}
else
{
holes.resize(holesRow.size());
for (size_t i = 0; i < holesRow.size(); i++)
holes[i].push_back(holesRow[i]);
int w = holes[0].size();
int h = holes.size();
parameters.minGraphConfidence = holes.size() * parameters.existingVertexGain;
for (int i = w; i < patternSize.width; i++)
{
addHolesByGraph(basisGraphs, false, basis[0]);
}
parameters.minGraphConfidence = holes[0].size() * parameters.existingVertexGain;
for (int i = h; i < patternSize.height; i++)
{
addHolesByGraph(basisGraphs, true, basis[1]);
}
}
}
Mat CirclesGridFinder::rectifyGrid(Size detectedGridSize, const vector<Point2f>& centers,
const vector<KeyPoint> &keypoints, vector<KeyPoint> &warpedKeypoints)
{
assert( !centers.empty() );
const float edgeLength = 30;
const Point2f offset(150, 150);
const int keypointScale = 1;
vector<Point2f> dstPoints;
for (int i = 0; i < detectedGridSize.height; i++)
{
for (int j = 0; j < detectedGridSize.width; j++)
{
dstPoints.push_back(offset + Point2f(edgeLength * j, edgeLength * i));
}
}
Mat H = findHomography(Mat(centers), Mat(dstPoints), CV_RANSAC);
//Mat H = findHomography( Mat( corners ), Mat( dstPoints ) );
vector<Point2f> srcKeypoints;
for (size_t i = 0; i < keypoints.size(); i++)
{
srcKeypoints.push_back(keypoints[i].pt);
}
Mat dstKeypointsMat;
transform(Mat(srcKeypoints), dstKeypointsMat, H);
vector<Point2f> dstKeypoints;
convertPointsHomogeneous(dstKeypointsMat, dstKeypoints);
warpedKeypoints.clear();
for (size_t i = 0; i < dstKeypoints.size(); i++)
{
Point2f pt = dstKeypoints[i];
warpedKeypoints.push_back(KeyPoint(pt, keypointScale));
}
return H;
}
int CirclesGridFinder::findNearestKeypoint(Point2f pt) const
{
int bestIdx = -1;
float minDist = std::numeric_limits<float>::max();
for (size_t i = 0; i < keypoints.size(); i++)
{
float dist = norm(pt - keypoints[i].pt);
if (dist < minDist)
{
minDist = dist;
bestIdx = i;
}
}
return bestIdx;
}
void CirclesGridFinder::addPoint(Point2f pt, vector<int> &points)
{
int ptIdx = findNearestKeypoint(pt);
if (norm(keypoints[ptIdx].pt - pt) > parameters.minDistanceToAddKeypoint)
{
KeyPoint kpt = KeyPoint(pt, parameters.keypointScale);
keypoints.push_back(kpt);
points.push_back(keypoints.size() - 1);
}
else
{
points.push_back(ptIdx);
}
}
void CirclesGridFinder::findCandidateLine(vector<int> &line, int seedLineIdx, bool addRow, Point2f basisVec,
vector<int> &seeds)
{
line.clear();
seeds.clear();
if (addRow)
{
for (size_t i = 0; i < holes[seedLineIdx].size(); i++)
{
Point2f pt = keypoints[holes[seedLineIdx][i]].pt + basisVec;
addPoint(pt, line);
seeds.push_back(holes[seedLineIdx][i]);
}
}
else
{
for (size_t i = 0; i < holes.size(); i++)
{
Point2f pt = keypoints[holes[i][seedLineIdx]].pt + basisVec;
addPoint(pt, line);
seeds.push_back(holes[i][seedLineIdx]);
}
}
assert( line.size() == seeds.size() );
}
void CirclesGridFinder::findCandidateHoles(vector<int> &above, vector<int> &below, bool addRow, Point2f basisVec,
vector<int> &aboveSeeds, vector<int> &belowSeeds)
{
above.clear();
below.clear();
aboveSeeds.clear();
belowSeeds.clear();
findCandidateLine(above, 0, addRow, -basisVec, aboveSeeds);
int lastIdx = addRow ? holes.size() - 1 : holes[0].size() - 1;
findCandidateLine(below, lastIdx, addRow, basisVec, belowSeeds);
assert( below.size() == above.size() );
assert( belowSeeds.size() == aboveSeeds.size() );
assert( below.size() == belowSeeds.size() );
}
bool CirclesGridFinder::areCentersNew(const vector<int> &newCenters, const vector<vector<int> > &holes)
{
for (size_t i = 0; i < newCenters.size(); i++)
{
for (size_t j = 0; j < holes.size(); j++)
{
if (holes[j].end() != std::find(holes[j].begin(), holes[j].end(), newCenters[i]))
{
return false;
}
}
}
return true;
}
void CirclesGridFinder::insertWinner(float aboveConfidence, float belowConfidence, float minConfidence, bool addRow,
const vector<int> &above, const vector<int> &below, vector<vector<int> > &holes)
{
if (aboveConfidence < minConfidence && belowConfidence < minConfidence)
return;
if (addRow)
{
if (aboveConfidence >= belowConfidence)
{
if (!areCentersNew(above, holes))
CV_Error( 0, "Centers are not new" );
holes.insert(holes.begin(), above);
}
else
{
if (!areCentersNew(below, holes))
CV_Error( 0, "Centers are not new" );
holes.insert(holes.end(), below);
}
}
else
{
if (aboveConfidence >= belowConfidence)
{
if (!areCentersNew(above, holes))
CV_Error( 0, "Centers are not new" );
for (size_t i = 0; i < holes.size(); i++)
{
holes[i].insert(holes[i].begin(), above[i]);
}
}
else
{
if (!areCentersNew(below, holes))
CV_Error( 0, "Centers are not new" );
for (size_t i = 0; i < holes.size(); i++)
{
holes[i].insert(holes[i].end(), below[i]);
}
}
}
}
/*
bool CirclesGridFinder::areVerticesAdjacent(const Graph &graph, int vertex1, int vertex2)
{
property_map<Graph, vertex_index_t>::type index = get(vertex_index, graph);
bool areAdjacent = false;
graph_traits<Graph>::adjacency_iterator ai;
graph_traits<Graph>::adjacency_iterator ai_end;
for (tie(ai, ai_end) = adjacent_vertices(vertex1, graph); ai != ai_end; ++ai)
{
if (*ai == index[vertex2])
areAdjacent = true;
}
return areAdjacent;
}*/
float CirclesGridFinder::computeGraphConfidence(const vector<Graph> &basisGraphs, bool addRow,
const vector<int> &points, const vector<int> &seeds)
{
assert( points.size() == seeds.size() );
float confidence = 0;
const int vCount = basisGraphs[0].getVerticesCount();
assert( basisGraphs[0].getVerticesCount() == basisGraphs[1].getVerticesCount() );
for (size_t i = 0; i < seeds.size(); i++)
{
if (seeds[i] < vCount && points[i] < vCount)
{
if (!basisGraphs[addRow].areVerticesAdjacent(seeds[i], points[i]))
{
confidence += parameters.vertexPenalty;
}
else
{
confidence += parameters.vertexGain;
}
}
if (points[i] < vCount)
{
confidence += parameters.existingVertexGain;
}
}
for (size_t i = 1; i < points.size(); i++)
{
if (points[i - 1] < vCount && points[i] < vCount)
{
if (!basisGraphs[!addRow].areVerticesAdjacent(points[i - 1], points[i]))
{
confidence += parameters.edgePenalty;
}
else
{
confidence += parameters.edgeGain;
}
}
}
return confidence;
}
void CirclesGridFinder::addHolesByGraph(const vector<Graph> &basisGraphs, bool addRow, Point2f basisVec)
{
vector<int> above, below, aboveSeeds, belowSeeds;
findCandidateHoles(above, below, addRow, basisVec, aboveSeeds, belowSeeds);
float aboveConfidence = computeGraphConfidence(basisGraphs, addRow, above, aboveSeeds);
float belowConfidence = computeGraphConfidence(basisGraphs, addRow, below, belowSeeds);
insertWinner(aboveConfidence, belowConfidence, parameters.minGraphConfidence, addRow, above, below, holes);
}
void CirclesGridFinder::filterOutliersByDensity(const vector<Point2f> &samples, vector<Point2f> &filteredSamples)
{
if (samples.empty())
CV_Error( 0, "samples is empty" );
filteredSamples.clear();
for (size_t i = 0; i < samples.size(); i++)
{
Rect_<float> rect(samples[i] - Point2f(parameters.densityNeighborhoodSize) * 0.5,
parameters.densityNeighborhoodSize);
int neighborsCount = 0;
for (size_t j = 0; j < samples.size(); j++)
{
if (rect.contains(samples[j]))
neighborsCount++;
}
if (neighborsCount >= parameters.minDensity)
filteredSamples.push_back(samples[i]);
}
if (filteredSamples.empty())
CV_Error( 0, "filteredSamples is empty" );
}
void CirclesGridFinder::findBasis(const vector<Point2f> &samples, vector<Point2f> &basis, vector<Graph> &basisGraphs)
{
basis.clear();
Mat bestLabels;
TermCriteria termCriteria;
Mat centers;
int clustersCount = 4;
kmeans(Mat(samples).reshape(1, 0), clustersCount, bestLabels, termCriteria, parameters.kmeansAttempts,
KMEANS_RANDOM_CENTERS, &centers);
assert( centers.type() == CV_32FC1 );
vector<int> basisIndices;
//TODO: only remove duplicate
for (int i = 0; i < clustersCount; i++)
{
int maxIdx = (fabs(centers.at<float> (i, 0)) < fabs(centers.at<float> (i, 1)));
if (centers.at<float> (i, maxIdx) > 0)
{
Point2f vec(centers.at<float> (i, 0), centers.at<float> (i, 1));
basis.push_back(vec);
basisIndices.push_back(i);
}
}
if (basis.size() != 2)
CV_Error( 0, "Basis size is not 2");
if (basis[1].x > basis[0].x)
{
std::swap(basis[0], basis[1]);
std::swap(basisIndices[0], basisIndices[1]);
}
const float minBasisDif = 2;
if (norm(basis[0] - basis[1]) < minBasisDif)
CV_Error( 0, "degenerate basis" );
vector<vector<Point2f> > clusters(2), hulls(2);
for (size_t k = 0; k < samples.size(); k++)
{
int label = bestLabels.at<int> (k, 0);
int idx = -1;
if (label == basisIndices[0])
idx = 0;
if (label == basisIndices[1])
idx = 1;
if (idx >= 0)
{
clusters[idx].push_back(basis[idx] + parameters.convexHullFactor * (samples[k] - basis[idx]));
}
}
for (size_t i = 0; i < basis.size(); i++)
{
convexHull(Mat(clusters[i]), hulls[i]);
}
basisGraphs.resize(basis.size(), Graph(keypoints.size()));
for (size_t i = 0; i < keypoints.size(); i++)
{
for (size_t j = 0; j < keypoints.size(); j++)
{
if (i == j)
continue;
Point2f vec = keypoints[i].pt - keypoints[j].pt;
for (size_t k = 0; k < hulls.size(); k++)
{
if (pointPolygonTest(Mat(hulls[k]), vec, false) >= 0)
{
basisGraphs[k].addEdge(i, j);
}
}
}
}
}
void CirclesGridFinder::computeEdgeVectorsOfRNG(vector<Point2f> &vectors, Mat *drawImage) const
{
vectors.clear();
//TODO: use more fast algorithm instead of naive N^3
for (size_t i = 0; i < keypoints.size(); i++)
{
for (size_t j = 0; j < keypoints.size(); j++)
{
if (i == j)
continue;
Point2f vec = keypoints[i].pt - keypoints[j].pt;
float dist = norm(vec);
bool isNeighbors = true;
for (size_t k = 0; k < keypoints.size(); k++)
{
if (k == i || k == j)
continue;
float dist1 = norm(keypoints[i].pt - keypoints[k].pt);
float dist2 = norm(keypoints[j].pt - keypoints[k].pt);
if (dist1 < dist && dist2 < dist)
{
isNeighbors = false;
break;
}
}
if (isNeighbors)
{
vectors.push_back(keypoints[i].pt - keypoints[j].pt);
if (drawImage != 0)
{
line(*drawImage, keypoints[i].pt, keypoints[j].pt, Scalar(255, 0, 0), 2);
circle(*drawImage, keypoints[i].pt, 3, Scalar(0, 0, 255), -1);
circle(*drawImage, keypoints[j].pt, 3, Scalar(0, 0, 255), -1);
}
}
}
}
}
void computePredecessorMatrix(const Mat &dm, int verticesCount, Mat &predecessorMatrix)
{
assert( dm.type() == CV_32SC1 );
predecessorMatrix.create(verticesCount, verticesCount, CV_32SC1);
predecessorMatrix = -1;
for (int i = 0; i < predecessorMatrix.rows; i++)
{
for (int j = 0; j < predecessorMatrix.cols; j++)
{
int dist = dm.at<int> (i, j);
for (int k = 0; k < verticesCount; k++)
{
if (dm.at<int> (i, k) == dist - 1 && dm.at<int> (k, j) == 1)
{
predecessorMatrix.at<int> (i, j) = k;
break;
}
}
}
}
}
void computeShortestPath(Mat &predecessorMatrix, int v1, int v2, vector<int> &path)
{
if (predecessorMatrix.at<int> (v1, v2) < 0)
{
path.push_back(v1);
return;
}
computeShortestPath(predecessorMatrix, v1, predecessorMatrix.at<int> (v1, v2), path);
path.push_back(v2);
}
size_t CirclesGridFinder::findLongestPath(vector<Graph> &basisGraphs, Path &bestPath)
{
vector<Path> longestPaths(1);
vector<int> confidences;
size_t bestGraphIdx = 0;
const int infinity = -1;
for (size_t graphIdx = 0; graphIdx < basisGraphs.size(); graphIdx++)
{
const Graph &g = basisGraphs[graphIdx];
Mat distanceMatrix;
g.floydWarshall(distanceMatrix, infinity);
Mat predecessorMatrix;
computePredecessorMatrix(distanceMatrix, g.getVerticesCount(), predecessorMatrix);
double maxVal;
Point maxLoc;
assert (infinity < 0);
minMaxLoc(distanceMatrix, 0, &maxVal, 0, &maxLoc);
if (maxVal > longestPaths[0].length)
{
longestPaths.clear();
confidences.clear();
bestGraphIdx = graphIdx;
}
if (longestPaths.empty() || (maxVal == longestPaths[0].length && graphIdx == bestGraphIdx))
{
Path path = Path(maxLoc.x, maxLoc.y, maxVal);
computeShortestPath(predecessorMatrix, maxLoc.x, maxLoc.y, path.vertices);
longestPaths.push_back(path);
int conf = 0;
for (size_t v2 = 0; v2 < path.vertices.size(); v2++)
{
conf += basisGraphs[1 - (int)graphIdx].getDegree(v2);
}
confidences.push_back(conf);
}
}
//if( bestGraphIdx != 0 )
//CV_Error( 0, "" );
int maxConf = -1;
int bestPathIdx = -1;
for (size_t i = 0; i < confidences.size(); i++)
{
if (confidences[i] > maxConf)
{
maxConf = confidences[i];
bestPathIdx = i;
}
}
//int bestPathIdx = rand() % longestPaths.size();
bestPath = longestPaths.at(bestPathIdx);
bool needReverse = (bestGraphIdx == 0 && keypoints[bestPath.lastVertex].pt.x < keypoints[bestPath.firstVertex].pt.x)
|| (bestGraphIdx == 1 && keypoints[bestPath.lastVertex].pt.y < keypoints[bestPath.firstVertex].pt.y);
if (needReverse)
{
std::swap(bestPath.lastVertex, bestPath.firstVertex);
std::reverse(bestPath.vertices.begin(), bestPath.vertices.end());
}
return bestGraphIdx;
}
void CirclesGridFinder::drawBasis(const vector<Point2f> &basis, Point2f origin, Mat &drawImg) const
{
for (size_t i = 0; i < basis.size(); i++)
{
Point2f pt(basis[i]);
line(drawImg, origin, origin + pt, Scalar(0, i * 255, 0), 2);
}
}
void CirclesGridFinder::drawBasisGraphs(const vector<Graph> &basisGraphs, Mat &drawImage, bool drawEdges,
bool drawVertices) const
{
//const int vertexRadius = 1;
const int vertexRadius = 3;
const Scalar vertexColor = Scalar(0, 0, 255);
const int vertexThickness = -1;
const Scalar edgeColor = Scalar(255, 0, 0);
//const int edgeThickness = 1;
const int edgeThickness = 2;
if (drawEdges)
{
for (size_t i = 0; i < basisGraphs.size(); i++)
{
for (size_t v1 = 0; v1 < basisGraphs[i].getVerticesCount(); v1++)
{
for (size_t v2 = 0; v2 < basisGraphs[i].getVerticesCount(); v2++)
{
if (basisGraphs[i].areVerticesAdjacent(v1, v2))
{
line(drawImage, keypoints[v1].pt, keypoints[v2].pt, edgeColor, edgeThickness);
}
}
}
}
}
if (drawVertices)
{
for (size_t v = 0; v < basisGraphs[0].getVerticesCount(); v++)
{
circle(drawImage, keypoints[v].pt, vertexRadius, vertexColor, vertexThickness);
}
}
}
void CirclesGridFinder::drawHoles(const Mat &srcImage, Mat &drawImage) const
{
//const int holeRadius = 4;
//const int holeRadius = 2;
//const int holeThickness = 1;
const int holeRadius = 3;
const int holeThickness = -1;
//const Scalar holeColor = Scalar(0, 0, 255);
const Scalar holeColor = Scalar(0, 255, 0);
if (srcImage.channels() == 1)
cvtColor(srcImage, drawImage, CV_GRAY2RGB);
else
srcImage.copyTo(drawImage);
for (size_t i = 0; i < holes.size(); i++)
{
for (size_t j = 0; j < holes[i].size(); j++)
{
if (j != holes[i].size() - 1)
line(drawImage, keypoints[holes[i][j]].pt, keypoints[holes[i][j + 1]].pt, Scalar(255, 0, 0), 2);
if (i != holes.size() - 1)
line(drawImage, keypoints[holes[i][j]].pt, keypoints[holes[i + 1][j]].pt, Scalar(255, 0, 0), 2);
//circle(drawImage, keypoints[holes[i][j]].pt, holeRadius, holeColor, holeThickness);
circle(drawImage, keypoints[holes[i][j]].pt, holeRadius, holeColor, holeThickness);
}
}
}
Size CirclesGridFinder::getDetectedGridSize() const
{
if (holes.size() == 0)
return Size(0, 0);
return Size(holes[0].size(), holes.size());
}
void CirclesGridFinder::getHoles(vector<Point2f> &outHoles) const
{
outHoles.clear();
for (size_t i = 0; i < holes.size(); i++)
{
for (size_t j = 0; j < holes[i].size(); j++)
{
outHoles.push_back(keypoints[holes[i][j]].pt);
}
}
}

@ -0,0 +1,156 @@
/*M///////////////////////////////////////////////////////////////////////////////////////
//
// IMPORTANT: READ BEFORE DOWNLOADING, COPYING, INSTALLING OR USING.
//
// By downloading, copying, installing or using the software you agree to this license.
// If you do not agree to this license, do not download, install,
// copy or use the software.
//
//
// License Agreement
// For Open Source Computer Vision Library
//
// Copyright (C) 2000-2008, Intel Corporation, all rights reserved.
// Copyright (C) 2009, Willow Garage Inc., all rights reserved.
// Third party copyrights are property of their respective owners.
//
// Redistribution and use in source and binary forms, with or without modification,
// are permitted provided that the following conditions are met:
//
// * Redistribution's of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
//
// * Redistribution's in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
//
// * The name of the copyright holders may not be used to endorse or promote products
// derived from this software without specific prior written permission.
//
// This software is provided by the copyright holders and contributors "as is" and
// any express or implied warranties, including, but not limited to, the implied
// warranties of merchantability and fitness for a particular purpose are disclaimed.
// In no event shall the Intel Corporation or contributors be liable for any direct,
// indirect, incidental, special, exemplary, or consequential damages
// (including, but not limited to, procurement of substitute goods or services;
// loss of use, data, or profits; or business interruption) however caused
// and on any theory of liability, whether in contract, strict liability,
// or tort (including negligence or otherwise) arising in any way out of
// the use of this software, even if advised of the possibility of such damage.
//
//M*/
#ifndef CIRCLESGRID_HPP_
#define CIRCLESGRID_HPP_
#include <fstream>
#include <iostream>
#include <string>
#include <set>
#include "precomp.hpp"
#include "../../features2d/include/opencv2/features2d/features2d.hpp"
class Graph
{
public:
typedef set<int> Neighbors;
struct Vertex
{
Neighbors neighbors;
};
typedef map<int, Vertex> Vertices;
Graph( int n);
bool doesVertexExist( int id ) const;
void addVertex( int id );
void addEdge( int id1, int id2 );
bool areVerticesAdjacent( int id1, int id2 ) const;
size_t getVerticesCount() const;
size_t getDegree( int id ) const;
void floydWarshall(cv::Mat &distanceMatrix, int infinity = -1) const;
private:
Vertices vertices;
};
struct Path
{
int firstVertex;
int lastVertex;
int length;
vector<int> vertices;
Path(int first = -1, int last = -1, int len = -1)
{
firstVertex = first;
lastVertex = last;
length = len;
}
};
struct CirclesGridFinderParameters
{
CirclesGridFinderParameters();
cv::Size2f densityNeighborhoodSize;
float minDensity;
int kmeansAttempts;
int minDistanceToAddKeypoint;
int keypointScale;
int minGraphConfidence;
float vertexGain;
float vertexPenalty;
float existingVertexGain;
float edgeGain;
float edgePenalty;
float convexHullFactor;
};
class CirclesGridFinder
{
public:
CirclesGridFinder(cv::Size patternSize, const vector<cv::KeyPoint> &testKeypoints,
const CirclesGridFinderParameters &parameters = CirclesGridFinderParameters());
bool findHoles();
static cv::Mat rectifyGrid(cv::Size detectedGridSize, const vector<cv::Point2f>& centers,
const vector<cv::KeyPoint> &keypoint, vector<cv::KeyPoint> &warpedKeypoints);
void getHoles(vector<cv::Point2f> &holes) const;
cv::Size getDetectedGridSize() const;
void drawBasis(const vector<cv::Point2f> &basis, cv::Point2f origin, cv::Mat &drawImg) const;
void drawBasisGraphs(const vector<Graph> &basisGraphs, cv::Mat &drawImg, bool drawEdges = true, bool drawVertices =
true) const;
void drawHoles(const cv::Mat &srcImage, cv::Mat &drawImage) const;
private:
void computeEdgeVectorsOfRNG(vector<cv::Point2f> &vectors, cv::Mat *drawImage = 0) const;
void filterOutliersByDensity(const vector<cv::Point2f> &samples, vector<cv::Point2f> &filteredSamples);
void findBasis(const vector<cv::Point2f> &samples, vector<cv::Point2f> &basis, vector<Graph> &basisGraphs);
void findMCS(const vector<cv::Point2f> &basis, vector<Graph> &basisGraphs);
size_t findLongestPath(vector<Graph> &basisGraphs, Path &bestPath);
float computeGraphConfidence(const vector<Graph> &basisGraphs, bool addRow, const vector<int> &points, const vector<
int> &seeds);
void addHolesByGraph(const vector<Graph> &basisGraphs, bool addRow, cv::Point2f basisVec);
int findNearestKeypoint(cv::Point2f pt) const;
void addPoint(cv::Point2f pt, vector<int> &points);
void findCandidateLine(vector<int> &line, int seedLineIdx, bool addRow, cv::Point2f basisVec, vector<int> &seeds);
void findCandidateHoles(vector<int> &above, vector<int> &below, bool addRow, cv::Point2f basisVec,
vector<int> &aboveSeeds, vector<int> &belowSeeds);
static bool areCentersNew( const vector<int> &newCenters, const vector<vector<int> > &holes );
bool isDetectionCorrect();
static void insertWinner(float aboveConfidence, float belowConfidence, float minConfidence,
bool addRow,
const vector<int> &above, const vector<int> &below, vector<vector<int> > &holes);
static bool areVerticesAdjacent(const Graph &graph, int vertex1, int vertex2);
vector<cv::KeyPoint> keypoints;
vector<vector<int> > holes;
const cv::Size patternSize;
CirclesGridFinderParameters parameters;
};
#endif /* CIRCLESGRID_HPP_ */
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