thorikawa · August 19, 2012 23:37 · Kaushik2017 · Oct 3, 2017 · Kaushik2017 · Oct 3, 2017
diff --git a/matching_sift.cpp b/matching_sift.cpp
 #include <opencv2/opencv.hpp>
 #include <opencv2/nonfree/nonfree.hpp>
 #include <iostream>
 #include <vector>
 #include <cmath>

 using namespace std;
 using namespace cv;

 const double THRESHOLD = 400;

 /**
 * Calculate euclid distance
 */
 double euclidDistance(Mat& vec1, Mat& vec2) {
  double sum = 0.0;
  int dim = vec1.cols;
  for (int i = 0; i < dim; i++) {
    sum += (vec1.at<uchar>(0,i) - vec2.at<uchar>(0,i)) * (vec1.at<uchar>(0,i) - vec2.at<uchar>(0,i));
  }
  return sqrt(sum);
 }

 /**
 * Find the index of nearest neighbor point from keypoints.
 */
 int nearestNeighbor(Mat& vec, vector<KeyPoint>& keypoints, Mat& descriptors) {
  int neighbor = -1;
  double minDist = 1e6;
  
  for (int i = 0; i < descriptors.rows; i++) {
    KeyPoint pt = keypoints[i];
    Mat v = descriptors.row(i);
    double d = euclidDistance(vec, v);
    //printf("%d %f\n", v.cols, d);
    if (d < minDist) {
      minDist = d;
      neighbor = i;
    }
  }
  
  if (minDist < THRESHOLD) {
    return neighbor;
  }
  
  return -1;
 }

 /**
 * Find pairs of points with the smallest distace between them
 */
 void findPairs(vector<KeyPoint>& keypoints1, Mat& descriptors1,
               vector<KeyPoint>& keypoints2, Mat& descriptors2,
               vector<Point2f>& srcPoints, vector<Point2f>& dstPoints) {
  for (int i = 0; i < descriptors1.rows; i++) {
    KeyPoint pt1 = keypoints1[i];
    Mat desc1 = descriptors1.row(i);
    int nn = nearestNeighbor(desc1, keypoints2, descriptors2);
    if (nn >= 0) {
      KeyPoint pt2 = keypoints2[nn];
      srcPoints.push_back(pt1.pt);
      dstPoints.push_back(pt2.pt);
    }
  }
 }

 int main(int argc, char** argv) {
  if (argc < 2) {
    cerr << "Too few arguments" << endl;
    return -1;
  }
  
  const char* filename = argv[1];
  
  printf("load file:%s\n", filename);
  
  // initialize detector and extractor
  FeatureDetector* detector;
  detector = new SiftFeatureDetector(
                                     0, // nFeatures
                                     4, // nOctaveLayers
                                     0.04, // contrastThreshold
                                     10, //edgeThreshold
                                     1.6 //sigma
                                     );
  
  DescriptorExtractor* extractor;
  extractor = new SiftDescriptorExtractor();
  
  // Compute keypoints and descriptor from the source image in advance
  vector<KeyPoint> keypoints2;
  Mat descriptors2;
  
  Mat originalGrayImage = imread(filename, CV_LOAD_IMAGE_GRAYSCALE);
  if (!originalGrayImage.data) {
    cerr << "gray image load error" << endl;
    return -1;
  }
  Mat originalColorImage = imread(filename, CV_LOAD_IMAGE_ANYCOLOR|CV_LOAD_IMAGE_ANYDEPTH);
  if (!originalColorImage.data) {
    cerr << "color image open error" << endl;
    return -1;
  }
  
  detector->detect(originalGrayImage, keypoints2);
  extractor->compute(originalGrayImage, keypoints2, descriptors2);
  printf("original image:%d keypoints are found.\n", (int)keypoints2.size());
  
  VideoCapture capture(0);
  capture.set(CV_CAP_PROP_FRAME_WIDTH,640);
  capture.set(CV_CAP_PROP_FRAME_HEIGHT,480);
  
  namedWindow("mywindow");
  Mat frame;
  while (1) {
    capture >> frame;
    
    // load gray scale image from camera
    Size size = frame.size();
    Mat grayFrame(size, CV_8UC1);
    cvtColor(frame, grayFrame, CV_BGR2GRAY);
    if (!grayFrame.data) {
      cerr << "cannot find image file1" << endl;
      exit(-1);
    }
    
    // Create a image for displaying mathing keypoints
    Size sz = Size(size.width + originalColorImage.size().width, size.height + originalColorImage.size().height);
    Mat matchingImage = Mat::zeros(sz, CV_8UC3);
    
    // Draw camera frame
    Mat roi1 = Mat(matchingImage, Rect(0, 0, size.width, size.height));
    frame.copyTo(roi1);
    // Draw original image
    Mat roi2 = Mat(matchingImage, Rect(size.width, size.height, originalColorImage.size().width, originalColorImage.size().height));
    originalColorImage.copyTo(roi2);
    
    vector<KeyPoint> keypoints1;
    Mat descriptors1;
    vector<DMatch> matches;
    
    // Detect keypoints
    detector->detect(grayFrame, keypoints1);
    extractor->compute(grayFrame, keypoints1, descriptors1);
    
    printf("image1:%zd keypoints are found.\n", keypoints1.size());
    
    for (int i=0; i<keypoints1.size(); i++){
      KeyPoint kp = keypoints1[i];
      circle(matchingImage, kp.pt, cvRound(kp.size*0.25), Scalar(255,255,0), 1, 8, 0);
    }
    // Find nearest neighbor pairs
    vector<Point2f> srcPoints;
    vector<Point2f> dstPoints;
    findPairs(keypoints1, descriptors1, keypoints2, descriptors2, srcPoints, dstPoints);
    printf("%zd keypoints are matched.\n", srcPoints.size());
    
    char text[256];
    sprintf(text, "%zd/%zd keypoints matched.", srcPoints.size(), keypoints2.size());
    putText(matchingImage, text, Point(0, cvRound(size.height + 30)), FONT_HERSHEY_SCRIPT_SIMPLEX, 1, Scalar(0,0,255));
    
    // Draw line between nearest neighbor pairs
    for (int i = 0; i < (int)srcPoints.size(); ++i) {
      Point2f pt1 = srcPoints[i];
      Point2f pt2 = dstPoints[i];
      Point2f from = pt1;
      Point2f to   = Point(size.width + pt2.x, size.height + pt2.y);
      line(matchingImage, from, to, Scalar(0, 255, 255));
    }
    
    // Display mathing image
    imshow("mywindow", matchingImage);
    
    int c = waitKey(2);
    if (c == '\x1b')
      break;
  }
  
  return 0;
 }
	#include <opencv2/opencv.hpp>
	#include <opencv2/nonfree/nonfree.hpp>
	#include <iostream>
	#include <vector>
	#include <cmath>

	using namespace std;
	using namespace cv;

	const double THRESHOLD = 400;

	/**
	* Calculate euclid distance
	*/
	double euclidDistance(Mat& vec1, Mat& vec2) {
	double sum = 0.0;
	int dim = vec1.cols;
	for (int i = 0; i < dim; i++) {
	sum += (vec1.at<uchar>(0,i) - vec2.at<uchar>(0,i)) * (vec1.at<uchar>(0,i) - vec2.at<uchar>(0,i));
	}
	return sqrt(sum);
	}

	/**
	* Find the index of nearest neighbor point from keypoints.
	*/
	int nearestNeighbor(Mat& vec, vector<KeyPoint>& keypoints, Mat& descriptors) {
	int neighbor = -1;
	double minDist = 1e6;

	for (int i = 0; i < descriptors.rows; i++) {
	KeyPoint pt = keypoints[i];
	Mat v = descriptors.row(i);
	double d = euclidDistance(vec, v);
	//printf("%d %f\n", v.cols, d);
	if (d < minDist) {
	minDist = d;
	neighbor = i;
	}
	}

	if (minDist < THRESHOLD) {
	return neighbor;
	}

	return -1;
	}

	/**
	* Find pairs of points with the smallest distace between them
	*/
	void findPairs(vector<KeyPoint>& keypoints1, Mat& descriptors1,
	vector<KeyPoint>& keypoints2, Mat& descriptors2,
	vector<Point2f>& srcPoints, vector<Point2f>& dstPoints) {
	for (int i = 0; i < descriptors1.rows; i++) {
	KeyPoint pt1 = keypoints1[i];
	Mat desc1 = descriptors1.row(i);
	int nn = nearestNeighbor(desc1, keypoints2, descriptors2);
	if (nn >= 0) {
	KeyPoint pt2 = keypoints2[nn];
	srcPoints.push_back(pt1.pt);
	dstPoints.push_back(pt2.pt);
	}
	}
	}

	int main(int argc, char** argv) {
	if (argc < 2) {
	cerr << "Too few arguments" << endl;
	return -1;
	}

	const char* filename = argv[1];

	printf("load file:%s\n", filename);

	// initialize detector and extractor
	FeatureDetector* detector;
	detector = new SiftFeatureDetector(
	0, // nFeatures
	4, // nOctaveLayers
	0.04, // contrastThreshold
	10, //edgeThreshold
	1.6 //sigma
	);

	DescriptorExtractor* extractor;
	extractor = new SiftDescriptorExtractor();

	// Compute keypoints and descriptor from the source image in advance
	vector<KeyPoint> keypoints2;
	Mat descriptors2;

	Mat originalGrayImage = imread(filename, CV_LOAD_IMAGE_GRAYSCALE);
	if (!originalGrayImage.data) {
	cerr << "gray image load error" << endl;
	return -1;
	}
	Mat originalColorImage = imread(filename, CV_LOAD_IMAGE_ANYCOLOR\|CV_LOAD_IMAGE_ANYDEPTH);
	if (!originalColorImage.data) {
	cerr << "color image open error" << endl;
	return -1;
	}

	detector->detect(originalGrayImage, keypoints2);
	extractor->compute(originalGrayImage, keypoints2, descriptors2);
	printf("original image:%d keypoints are found.\n", (int)keypoints2.size());

	VideoCapture capture(0);
	capture.set(CV_CAP_PROP_FRAME_WIDTH,640);
	capture.set(CV_CAP_PROP_FRAME_HEIGHT,480);

	namedWindow("mywindow");
	Mat frame;
	while (1) {
	capture >> frame;

	// load gray scale image from camera
	Size size = frame.size();
	Mat grayFrame(size, CV_8UC1);
	cvtColor(frame, grayFrame, CV_BGR2GRAY);
	if (!grayFrame.data) {
	cerr << "cannot find image file1" << endl;
	exit(-1);
	}

	// Create a image for displaying mathing keypoints
	Size sz = Size(size.width + originalColorImage.size().width, size.height + originalColorImage.size().height);
	Mat matchingImage = Mat::zeros(sz, CV_8UC3);

	// Draw camera frame
	Mat roi1 = Mat(matchingImage, Rect(0, 0, size.width, size.height));
	frame.copyTo(roi1);
	// Draw original image
	Mat roi2 = Mat(matchingImage, Rect(size.width, size.height, originalColorImage.size().width, originalColorImage.size().height));
	originalColorImage.copyTo(roi2);

	vector<KeyPoint> keypoints1;
	Mat descriptors1;
	vector<DMatch> matches;

	// Detect keypoints
	detector->detect(grayFrame, keypoints1);
	extractor->compute(grayFrame, keypoints1, descriptors1);

	printf("image1:%zd keypoints are found.\n", keypoints1.size());

	for (int i=0; i<keypoints1.size(); i++){
	KeyPoint kp = keypoints1[i];
	circle(matchingImage, kp.pt, cvRound(kp.size*0.25), Scalar(255,255,0), 1, 8, 0);
	}
	// Find nearest neighbor pairs
	vector<Point2f> srcPoints;
	vector<Point2f> dstPoints;
	findPairs(keypoints1, descriptors1, keypoints2, descriptors2, srcPoints, dstPoints);
	printf("%zd keypoints are matched.\n", srcPoints.size());

	char text[256];
	sprintf(text, "%zd/%zd keypoints matched.", srcPoints.size(), keypoints2.size());
	putText(matchingImage, text, Point(0, cvRound(size.height + 30)), FONT_HERSHEY_SCRIPT_SIMPLEX, 1, Scalar(0,0,255));

	// Draw line between nearest neighbor pairs
	for (int i = 0; i < (int)srcPoints.size(); ++i) {
	Point2f pt1 = srcPoints[i];
	Point2f pt2 = dstPoints[i];
	Point2f from = pt1;
	Point2f to = Point(size.width + pt2.x, size.height + pt2.y);
	line(matchingImage, from, to, Scalar(0, 255, 255));
	}

	// Display mathing image
	imshow("mywindow", matchingImage);

	int c = waitKey(2);
	if (c == '\x1b')
	break;
	}

	return 0;
	}
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