removed old sample on keypoints matching and added new one
authorMaria Dimashova <no@email>
Wed, 26 May 2010 15:45:32 +0000 (15:45 +0000)
committerMaria Dimashova <no@email>
Wed, 26 May 2010 15:45:32 +0000 (15:45 +0000)
samples/c/CMakeLists.txt
samples/c/detectors_sample.cpp [deleted file]
samples/cpp/CMakeLists.txt
samples/cpp/keypoints_matching.cpp [new file with mode: 0644]

index 5e2b220..a8cde50 100644 (file)
@@ -48,7 +48,6 @@ if (BUILD_EXAMPLES)
     MY_DEFINE_EXAMPLE(convexhull               convexhull.c)\r
     MY_DEFINE_EXAMPLE(delaunay                 delaunay.c)\r
     MY_DEFINE_EXAMPLE(demhist                  demhist.c)\r
-    MY_DEFINE_EXAMPLE(detectors_sample         detectors_sample.cpp)\r
     MY_DEFINE_EXAMPLE(dft                              dft.c)\r
     MY_DEFINE_EXAMPLE(distrans                 distrans.c)\r
     MY_DEFINE_EXAMPLE(drawing                  drawing.c)\r
diff --git a/samples/c/detectors_sample.cpp b/samples/c/detectors_sample.cpp
deleted file mode 100644 (file)
index 6031e0a..0000000
+++ /dev/null
@@ -1,259 +0,0 @@
-#include <cv.h>
-#include <cvaux.h>
-#include <highgui.h>
-#include <iostream>
-
-using namespace cv;
-using namespace std;
-
-inline Point2f applyHomography( const Mat_<double>& H, const Point2f& pt )
-{
-    double w = 1./(H(2,0)*pt.x + H(2,1)*pt.y + H(2,2));
-    return Point2f( (float)((H(0,0)*pt.x + H(0,1)*pt.y + H(0,2))*w), (float)((H(1,0)*pt.x + H(1,1)*pt.y + H(1,2))*w) );
-}
-
-void drawCorrespondences( const Mat& img1, const Mat& img2, const Mat& transfMtr,
-                          const vector<KeyPoint>& keypoints1, const vector<KeyPoint>& keypoints2,
-                          const vector<int>& matches, float maxDist, Mat& drawImg )
-{
-    Scalar RED = CV_RGB(255, 0, 0);
-    Scalar PINK = CV_RGB(255,130,230);
-    Scalar GREEN = CV_RGB(0, 255, 0);
-    Scalar BLUE = CV_RGB(0, 0, 255);
-
-    /* Output:
-       red point - point without corresponding point;
-       grean point - point having correct corresponding point;
-       pink point - point having incorrect corresponding point, but excised by threshold of distance;
-       blue point - point having incorrect corresponding point;
-    */
-    Size size(img1.cols + img2.cols, MAX(img1.rows, img2.rows));
-    drawImg.create(size, CV_MAKETYPE(img1.depth(), 3));
-    Mat drawImg1 = drawImg(Rect(0, 0, img1.cols, img1.rows));
-    cvtColor(img1, drawImg1, CV_GRAY2RGB);
-    Mat drawImg2 = drawImg(Rect(img1.cols, 0, img2.cols, img2.rows));
-    cvtColor(img2, drawImg2, CV_GRAY2RGB);
-    
-    for(vector<KeyPoint>::const_iterator it = keypoints1.begin(); it < keypoints1.end(); ++it )
-    {
-        circle(drawImg, it->pt, 3, RED);
-    }
-    
-    for(vector<KeyPoint>::const_iterator it = keypoints2.begin(); it < keypoints2.end(); ++it )
-    {
-               Point p = it->pt;
-        circle(drawImg, Point2f(p.x+img1.cols, p.y), 3, RED);
-    }
-    
-    Mat vec1(3, 1, CV_32FC1), vec2;
-    float err = 3;
-    vector<int>::const_iterator mit = matches.begin();
-    assert( matches.size() == keypoints1.size() );
-    for( int i1 = 0; mit < matches.end(); ++mit, i1++ )
-    {
-        Point2f pt1 = keypoints1[i1].pt, pt2 = keypoints2[*mit].pt;
-        Point2f diff = applyHomography(transfMtr, pt1) - pt2;
-        if( norm(diff) < err )
-        {
-            circle(drawImg, pt1, 3, GREEN);
-            circle(drawImg, Point2f(pt2.x+img1.cols, pt2.y), 3, GREEN);
-            line(drawImg, pt1, Point2f(pt2.x+img1.cols, pt2.y), GREEN);
-        }
-        else
-        {
-            /*if( *dit > maxDist )
-            {
-                circle(drawImg, pt1, 3, PINK);
-                circle(drawImg, Point2f(pt2.x+img1.cols, pt2.y), 3, PINK);
-            }
-            // TODO add key point filter
-            else*/
-            {
-                circle(drawImg, pt1, 3, BLUE);
-                circle(drawImg, Point2f(pt2.x+img1.cols, pt2.y), 3, BLUE);
-                line(drawImg, pt1, Point2f(pt2.x+img1.cols, pt2.y), BLUE);
-            }
-        }
-    }
-}
-
-FeatureDetector* createDetector( const string& detectorType )
-{
-       FeatureDetector* fd = 0;
-    if( !detectorType.compare( "FAST" ) )
-       {
-               fd = new FastFeatureDetector( 1/*threshold*/, true/*nonmax_suppression*/ );
-       }
-    else if( !detectorType.compare( "STAR" ) )
-       {
-               fd = new StarFeatureDetector( 16/*max_size*/, 30/*response_threshold*/, 10/*line_threshold_projected*/,
-                                                                         8/*line_threshold_binarized*/, 5/*suppress_nonmax_size*/ );
-       }
-    else if( !detectorType.compare( "SIFT" ) )
-    {
-        fd = new SiftFeatureDetector(SIFT::DetectorParams::GET_DEFAULT_THRESHOLD(),
-                                     SIFT::DetectorParams::GET_DEFAULT_EDGE_THRESHOLD());
-    }
-    else if( !detectorType.compare( "SURF" ) )
-       {
-               fd = new SurfFeatureDetector( 400./*hessian_threshold*/, 3 /*octaves*/, 4/*octave_layers*/ );
-       }
-    else if( !detectorType.compare( "MSER" ) )
-       {
-               fd = new MserFeatureDetector( 5/*delta*/, 60/*min_area*/, 14400/*_max_area*/, 0.25f/*max_variation*/,
-                               0.2/*min_diversity*/, 200/*max_evolution*/, 1.01/*area_threshold*/, 0.003/*min_margin*/, 
-                               5/*edge_blur_size*/ );
-       }
-    else if( !detectorType.compare( "GFTT" ) )
-       {
-        fd = new GoodFeaturesToTrackDetector( 1000/*maxCorners*/, 0.01/*qualityLevel*/, 1./*minDistance*/,
-                                              3/*int _blockSize*/, true/*useHarrisDetector*/, 0.04/*k*/ );
-       }
-       else
-               fd = 0;
-               
-       return fd;
-}
-
-DescriptorExtractor* createDescExtractor( const string& descriptorType )
-{
-       DescriptorExtractor* de = 0;
-    if( !descriptorType.compare( "CALONDER" ) )
-       {
-               assert(0);
-        //de = new CalonderDescriptorExtractor<float>("");
-       }
-    else if( !descriptorType.compare( "SURF" ) )
-       {
-               de = new SurfDescriptorExtractor( 3/*octaves*/, 4/*octave_layers*/, false/*extended*/ );
-       }
-       else 
-               de = 0;
-       return de;
-}
-
-DescriptorMatcher* createDescMatcher( const string& matherType = string() )
-{
-       return new BruteForceMatcher<L2<float> >();
-}
-
-const string DETECTOR_TYPE_STR = "detector_type";
-const string DESCRIPTOR_TYPE_STR = "descriptor_type";
-
-const string winName = "correspondences";
-
-void iter( Ptr<FeatureDetector> detector, Ptr<DescriptorExtractor> descriptor,
-           const Mat& img1, float maxDist, Mat& transfMtr, RNG* rng = 0 )
-{
-    if( transfMtr.empty() )
-        transfMtr = Mat::eye(3, 3, CV_32FC1);
-    if( rng )
-    {
-        transfMtr.at<float>(0,0) = rng->uniform( 0.7f, 1.3f);
-        transfMtr.at<float>(0,1) = rng->uniform(-0.2f, 0.2f);
-        transfMtr.at<float>(0,2) = rng->uniform(-0.1f, 0.1f)*img1.cols;
-        transfMtr.at<float>(1,0) = rng->uniform(-0.2f, 0.2f);
-        transfMtr.at<float>(1,1) = rng->uniform( 0.7f, 1.3f);
-        transfMtr.at<float>(1,2) = rng->uniform(-0.1f, 0.3f)*img1.rows;
-        transfMtr.at<float>(2,0) = rng->uniform( -1e-4f, 1e-4f);
-        transfMtr.at<float>(2,1) = rng->uniform( -1e-4f, 1e-4f);
-        transfMtr.at<float>(2,2) = rng->uniform( 0.7f, 1.3f);
-    }
-
-    Mat img2; warpPerspective( img1, img2, transfMtr, img1.size() );
-
-
-    cout << endl << "< Extracting keypoints... ";
-    vector<KeyPoint> keypoints1, keypoints2;
-    detector->detect( img1, keypoints1 );
-    detector->detect( img2, keypoints2 );
-    cout << keypoints1.size() << " from first image and " << keypoints2.size() << " from second image >" << endl;
-    if( keypoints1.empty() || keypoints2.empty() )
-        cout << "end" << endl;
-
-    cout << "< Computing  descriptors... ";
-    Mat descs1, descs2;
-    if( keypoints1.size()>0 && keypoints2.size()>0 )
-    {
-        descriptor->compute( img1, keypoints1, descs1 );
-        descriptor->compute( img2, keypoints2, descs2 );
-    }
-    cout << ">" << endl;
-
-    cout << "< Matching keypoints by descriptors... ";
-    vector<int> matches;
-    Ptr<DescriptorMatcher> matcher = createDescMatcher();
-    matcher->add( descs2 );
-    matcher->match( descs1, matches );
-    cout << ">" << endl;
-
-    // TODO time
-
-    Mat drawImg;
-    drawCorrespondences( img1, img2, transfMtr, keypoints1, keypoints2,
-                         matches, maxDist, drawImg );
-    imshow( winName, drawImg);
-}
-
-Ptr<FeatureDetector> detector;
-Ptr<DescriptorExtractor> descriptor;
-Mat img1;
-Mat transfMtr;
-RNG rng;
-const float maxDistScale = 0.01f;
-int maxDist;
-
-void onMaxDistChange( int maxDist, void* )
-{
-    float realMaxDist = maxDist*maxDistScale;
-    cout << "maxDist " <<  realMaxDist << endl;
-    iter( detector, descriptor, img1, realMaxDist, transfMtr );
-}
-
-int main(int argc, char** argv)
-{
-    if( argc != 4 )
-    {
-        cout << "Format:" << endl;
-        cout << "./" << argv[0] << " [detector_type] [descriptor_type] [image]" << endl;
-        return 0;
-    }
-    
-    cout << "< Creating detector, descriptor and matcher... ";
-    detector = createDetector(argv[1]);
-    descriptor = createDescExtractor(argv[2]);
-    //Ptr<DescriptorMatcher> matcher = createDescMatcher(argv[3]);
-    cout << ">" << endl;
-    if( detector.empty() || descriptor.empty()/* || matcher.empty() */ )
-    {
-               cout << "Can not create detector or descriptor or matcher of given types" << endl;
-               return 0;
-       }
-               
-    cout << "< Reading the image... ";
-    img1 = imread( argv[3], CV_LOAD_IMAGE_GRAYSCALE);
-    cout << ">" << endl;
-    if( img1.empty() )
-    {
-        cout << "Can not read image" << endl;
-        return 0;
-    }
-
-    namedWindow(winName, 1);
-    maxDist = 12;
-    createTrackbar( "maxDist", winName, &maxDist, 100, onMaxDistChange );
-
-    onMaxDistChange(maxDist, 0);
-    for(;;)
-    {
-        char c = (char)cvWaitKey(0);
-        if( c == '\x1b' ) // esc
-        {
-            cout << "Exiting ..." << endl;
-            return 0;
-        }
-        else if( c == 'n' )
-            iter(detector, descriptor, img1, maxDist*maxDistScale, transfMtr, &rng);
-    }
-    waitKey(0);
-}
index 1a6072f..f5cf8ff 100644 (file)
@@ -40,6 +40,7 @@ if (BUILD_EXAMPLES)
     
     MY_DEFINE_EXAMPLE(connected_components  connected_components.cpp)
     MY_DEFINE_EXAMPLE(contours2  contours2.cpp)
+    MY_DEFINE_EXAMPLE(keypoints_matching  keypoints_matching.cpp)
     MY_DEFINE_EXAMPLE(morphology2  morphology2.cpp)
     MY_DEFINE_EXAMPLE(segment_objects  segment_objects.cpp)
 endif(BUILD_EXAMPLES)
diff --git a/samples/cpp/keypoints_matching.cpp b/samples/cpp/keypoints_matching.cpp
new file mode 100644 (file)
index 0000000..553f78a
--- /dev/null
@@ -0,0 +1,259 @@
+#include <cv.h>
+#include <cvaux.h>
+#include <highgui.h>
+#include <iostream>
+
+using namespace cv;
+using namespace std;
+
+inline Point2f applyHomography( const Mat_<double>& H, const Point2f& pt )
+{
+    double z = H(2,0)*pt.x + H(2,1)*pt.y + H(2,2);
+    if( z )
+    {
+        double w = 1./z;
+        return Point2f( (H(0,0)*pt.x + H(0,1)*pt.y + H(0,2))*w, (H(1,0)*pt.x + H(1,1)*pt.y + H(1,2))*w );
+    }
+    return Point2f( numeric_limits<double>::max(), numeric_limits<double>::max() );
+}
+
+Mat warpPerspectiveRand( const Mat& src, Mat& dst, RNG* rng )
+{
+    Mat H(3, 3, CV_32FC1);
+    H.at<float>(0,0) = rng->uniform( 0.8f, 1.2f);
+    H.at<float>(0,1) = rng->uniform(-0.1f, 0.1f);
+    H.at<float>(0,2) = rng->uniform(-0.1f, 0.1f)*src.cols;
+    H.at<float>(1,0) = rng->uniform(-0.1f, 0.1f);
+    H.at<float>(1,1) = rng->uniform( 0.8f, 1.2f);
+    H.at<float>(1,2) = rng->uniform(-0.1f, 0.3f)*src.rows;
+    H.at<float>(2,0) = rng->uniform( -1e-4f, 1e-4f);
+    H.at<float>(2,1) = rng->uniform( -1e-4f, 1e-4f);
+    H.at<float>(2,2) = rng->uniform( 0.8f, 1.1f);
+
+    warpPerspective( src, dst, H, src.size() );
+    return H;
+}
+
+FeatureDetector* createDetector( const string& detectorType )
+{
+    FeatureDetector* fd = 0;
+    if( !detectorType.compare( "FAST" ) )
+    {
+        fd = new FastFeatureDetector( 10/*threshold*/, true/*nonmax_suppression*/ );
+    }
+    else if( !detectorType.compare( "STAR" ) )
+    {
+        fd = new StarFeatureDetector( 16/*max_size*/, 5/*response_threshold*/, 10/*line_threshold_projected*/,
+                                      8/*line_threshold_binarized*/, 5/*suppress_nonmax_size*/ );
+    }
+    else if( !detectorType.compare( "SIFT" ) )
+    {
+        fd = new SiftFeatureDetector(SIFT::DetectorParams::GET_DEFAULT_THRESHOLD(),
+                                     SIFT::DetectorParams::GET_DEFAULT_EDGE_THRESHOLD());
+    }
+    else if( !detectorType.compare( "SURF" ) )
+    {
+        fd = new SurfFeatureDetector( 100./*hessian_threshold*/, 3 /*octaves*/, 4/*octave_layers*/ );
+    }
+    else if( !detectorType.compare( "MSER" ) )
+    {
+        fd = new MserFeatureDetector( 5/*delta*/, 60/*min_area*/, 14400/*_max_area*/, 0.25f/*max_variation*/,
+                0.2/*min_diversity*/, 200/*max_evolution*/, 1.01/*area_threshold*/, 0.003/*min_margin*/,
+                5/*edge_blur_size*/ );
+    }
+    else if( !detectorType.compare( "GFTT" ) )
+    {
+        fd = new GoodFeaturesToTrackDetector( 1000/*maxCorners*/, 0.01/*qualityLevel*/, 1./*minDistance*/,
+                                              3/*int _blockSize*/, true/*useHarrisDetector*/, 0.04/*k*/ );
+    }
+    else
+        assert(0);
+    return fd;
+}
+
+GenericDescriptorMatch* createDescriptorMatch( const string& descriptorType )
+{
+    GenericDescriptorMatch* de = 0;
+    if( !descriptorType.compare( "SIFT" ) )
+    {
+        SiftDescriptorExtractor extractor/*( double magnification=SIFT::DescriptorParams::GET_DEFAULT_MAGNIFICATION(),
+                             bool isNormalize=true, bool recalculateAngles=true,
+                             int nOctaves=SIFT::CommonParams::DEFAULT_NOCTAVES,
+                             int nOctaveLayers=SIFT::CommonParams::DEFAULT_NOCTAVE_LAYERS,
+                             int firstOctave=SIFT::CommonParams::DEFAULT_FIRST_OCTAVE,
+                             int angleMode=SIFT::CommonParams::FIRST_ANGLE )*/;
+        BruteForceMatcher<L2<float> > matcher;
+        de = new VectorDescriptorMatch<SiftDescriptorExtractor, BruteForceMatcher<L2<float> > >(extractor, matcher);
+
+    }
+    else if( !descriptorType.compare( "SURF" ) )
+    {
+        SurfDescriptorExtractor extractor/*( int nOctaves=4,
+                             int nOctaveLayers=2, bool extended=false )*/;
+        BruteForceMatcher<L2<float> > matcher;
+        de = new VectorDescriptorMatch<SurfDescriptorExtractor, BruteForceMatcher<L2<float> > >(extractor, matcher);
+    }
+    else
+        assert(0);
+    return de;
+}
+
+void drawCorrespondences( const Mat& img1, const Mat& img2,
+                          const vector<KeyPoint>& keypoints1, const vector<KeyPoint>& keypoints2,
+                          const vector<int>& matches, Mat& drawImg, const Mat& H12 = Mat() )
+{
+    Scalar RED =   CV_RGB(255, 0, 0); // red keypoint - point without corresponding point
+    Scalar GREEN = CV_RGB(0, 255, 0); // green keypoint - point having correct corresponding point
+    Scalar BLUE =  CV_RGB(0, 0, 255); // blue keypoint - point having incorrect corresponding point
+
+    Size size(img1.cols + img2.cols, MAX(img1.rows, img2.rows));
+    drawImg.create(size, CV_MAKETYPE(img1.depth(), 3));
+    Mat drawImg1 = drawImg(Rect(0, 0, img1.cols, img1.rows));
+    cvtColor(img1, drawImg1, CV_GRAY2RGB);
+    Mat drawImg2 = drawImg(Rect(img1.cols, 0, img2.cols, img2.rows));
+    cvtColor(img2, drawImg2, CV_GRAY2RGB);
+
+    // draw keypoints
+    for(vector<KeyPoint>::const_iterator it = keypoints1.begin(); it < keypoints1.end(); ++it )
+    {
+        circle(drawImg, it->pt, 3, RED);
+    }
+    for(vector<KeyPoint>::const_iterator it = keypoints2.begin(); it < keypoints2.end(); ++it )
+    {
+               Point p = it->pt;
+        circle(drawImg, Point2f(p.x+img1.cols, p.y), 3, RED);
+    }
+    
+    // draw matches
+    vector<int>::const_iterator mit = matches.begin();
+    assert( matches.size() == keypoints1.size() );
+    for( int i1 = 0; mit != matches.end(); ++mit, i1++ )
+    {
+        Point2f pt1 = keypoints1[i1].pt,
+                pt2 = keypoints2[*mit].pt,
+                dpt2 = Point2f( std::min(pt2.x+img1.cols, float(drawImg.cols-1)), pt2.y);
+        if( !H12.empty() )
+        {
+            if( norm(pt2 - applyHomography(H12, pt1)) > 3 )
+            {
+                circle(drawImg, pt1, 3, BLUE);
+                circle(drawImg, dpt2, 3, BLUE);
+                continue;
+            }
+        }
+        circle(drawImg, pt1, 3, GREEN);
+        circle(drawImg, dpt2, 3, GREEN);
+        line(drawImg, pt1, dpt2, GREEN);
+    }
+}
+
+const string winName = "correspondences";
+
+void doIteration( const Mat& img1, Mat& img2, bool isWarpPerspective, vector<KeyPoint>& keypoints1,
+                  Ptr<FeatureDetector>& detector, Ptr<GenericDescriptorMatch>& descriptor,
+                  double ransacReprojThreshold = -1, RNG* rng = 0 )
+{
+    assert( !img1.empty() );
+    Mat H12;
+    if( isWarpPerspective )
+    {
+        assert( rng );
+        H12 = warpPerspectiveRand(img1, img2, rng);
+    }
+    else
+        assert( !img2.empty() && img2.cols==img1.cols && img2.rows== img1.rows );
+
+    cout << endl << "< Extracting keypoints from second image..." << endl;
+    vector<KeyPoint> keypoints2;
+    detector->detect( img2, keypoints2 );
+    cout << keypoints2.size() << " >" << endl;
+
+    cout << "< Computing and matching descriptors..." << endl;
+    vector<int> matches;
+    //if( keypoints1.size()>0 && keypoints2.size()>0 )
+    {
+        descriptor->clear();
+        descriptor->add( img2, keypoints2 );
+        descriptor->match( img1, keypoints1, matches );
+    }
+    cout << ">" << endl;
+
+    if( !isWarpPerspective && ransacReprojThreshold >= 0 )
+    {
+        cout << "< Computing homography (RANSAC)..." << endl;
+        vector<Point2f> points1(matches.size()), points2(matches.size());
+        for( int i = 0; i < matches.size(); i++ )
+        {
+            points1[i] = keypoints1[i].pt;
+            points2[i] = keypoints2[matches[i]].pt;
+        }
+        H12 = findHomography( Mat(points1), Mat(points2), CV_RANSAC, ransacReprojThreshold );
+        cout << ">" << endl;
+    }
+
+    Mat drawImg;
+    drawCorrespondences( img1, img2, keypoints1, keypoints2, matches, drawImg, H12 );
+    imshow( winName, drawImg );
+}
+
+int main(int argc, char** argv)
+{
+    if( argc != 4 && argc != 6 )
+    {
+        cout << "Format:" << endl;
+        cout << "case1: second image is obtained from the first (given) image using random generated homography matrix" << endl;
+        cout << argv[0] << " [detectorType] [descriptorType] [image1]" << endl;
+        cout << "case2: both images are given. If ransacReprojThreshold>=0 then homography matrix are calculated" << endl;
+        cout << argv[0] << " [detectorType] [descriptorType] [image1] [image2] [ransacReprojThreshold]" << endl;
+        cout << endl << "Mathes are filtered using homography matrix in case1 and case2 (if ransacReprojThreshold>=0)" << endl;
+        return 0;
+    }
+    bool isWarpPerspective = argc == 4;
+    double ransacReprojThreshold = -1;
+    if( !isWarpPerspective )
+        ransacReprojThreshold = atof(argv[5]);
+
+    cout << "< Creating detector, descriptor..." << endl;
+    Ptr<FeatureDetector> detector = createDetector(argv[1]);
+    Ptr<GenericDescriptorMatch> descriptor = createDescriptorMatch(argv[2]);
+    cout << ">" << endl;
+    if( detector.empty() || descriptor.empty() )
+    {
+               cout << "Can not create detector or descriptor or matcher of given types" << endl;
+               return 0;
+       }
+               
+    cout << "< Reading the images..." << endl;
+    Mat img1 = imread( argv[3], CV_LOAD_IMAGE_GRAYSCALE), img2;
+    if( !isWarpPerspective )
+        img2 = imread( argv[4], CV_LOAD_IMAGE_GRAYSCALE);
+    cout << ">" << endl;
+    if( img1.empty() || (!isWarpPerspective && img2.empty()) )
+    {
+        cout << "Can not read images" << endl;
+        return 0;
+    }
+
+    cout << endl << "< Extracting keypoints from first image..." << endl;
+    vector<KeyPoint> keypoints1;
+    detector->detect( img1, keypoints1 );
+    cout << keypoints1.size() << " >" << endl;
+
+    namedWindow(winName, 1);
+    RNG rng;
+    doIteration( img1, img2, isWarpPerspective, keypoints1, detector, descriptor, ransacReprojThreshold, &rng );
+    for(;;)
+    {
+        char c = (char)cvWaitKey(0);
+        if( c == '\x1b' ) // esc
+        {
+            cout << "Exiting ..." << endl;
+            return 0;
+        }
+        else if( isWarpPerspective )
+        {
+            doIteration( img1, img2, isWarpPerspective, keypoints1, detector, descriptor, ransacReprojThreshold, &rng );
+        }
+    }
+    waitKey(0);
+}