initial commit

samples/cpp/lkdemo.cpp

@@ -0,0 +1,151 @@
+#include "opencv2/video/tracking.hpp"
+#include "opencv2/imgproc.hpp"
+#include "opencv2/videoio.hpp"
+#include "opencv2/highgui.hpp"
+
+#include <iostream>
+#include <ctype.h>
+
+using namespace cv;
+using namespace std;
+
+static void help()
+{
+    // print a welcome message, and the OpenCV version
+    cout << "\nThis is a demo of Lukas-Kanade optical flow lkdemo(),\n"
+            "Using OpenCV version " << CV_VERSION << endl;
+    cout << "\nIt uses camera by default, but you can provide a path to video as an argument.\n";
+    cout << "\nHot keys: \n"
+            "\tESC - quit the program\n"
+            "\tr - auto-initialize tracking\n"
+            "\tc - delete all the points\n"
+            "\tn - switch the \"night\" mode on/off\n"
+            "To add/remove a feature point click it\n" << endl;
+}
+
+Point2f point;
+bool addRemovePt = false;
+
+static void onMouse( int event, int x, int y, int /*flags*/, void* /*param*/ )
+{
+    if( event == EVENT_LBUTTONDOWN )
+    {
+        point = Point2f((float)x, (float)y);
+        addRemovePt = true;
+    }
+}
+
+int main( int argc, char** argv )
+{
+    VideoCapture cap;
+    TermCriteria termcrit(TermCriteria::COUNT|TermCriteria::EPS,20,0.03);
+    Size subPixWinSize(10,10), winSize(31,31);
+
+    const int MAX_COUNT = 500;
+    bool needToInit = false;
+    bool nightMode = false;
+
+    help();
+    cv::CommandLineParser parser(argc, argv, "{@input|0|}");
+    string input = parser.get<string>("@input");
+
+    if( input.size() == 1 && isdigit(input[0]) )
+        cap.open(input[0] - '0');
+    else
+        cap.open(input);
+
+    if( !cap.isOpened() )
+    {
+        cout << "Could not initialize capturing...\n";
+        return 0;
+    }
+
+    namedWindow( "LK Demo", 1 );
+    setMouseCallback( "LK Demo", onMouse, 0 );
+
+    Mat gray, prevGray, image, frame;
+    vector<Point2f> points[2];
+
+    for(;;)
+    {
+        cap >> frame;
+        if( frame.empty() )
+            break;
+
+        frame.copyTo(image);
+        cvtColor(image, gray, COLOR_BGR2GRAY);
+
+        if( nightMode )
+            image = Scalar::all(0);
+
+        if( needToInit )
+        {
+            // automatic initialization
+            goodFeaturesToTrack(gray, points[1], MAX_COUNT, 0.01, 10, Mat(), 3, 3, 0, 0.04);
+            cornerSubPix(gray, points[1], subPixWinSize, Size(-1,-1), termcrit);
+            addRemovePt = false;
+        }
+        else if( !points[0].empty() )
+        {
+            vector<uchar> status;
+            vector<float> err;
+            if(prevGray.empty())
+                gray.copyTo(prevGray);
+            calcOpticalFlowPyrLK(prevGray, gray, points[0], points[1], status, err, winSize,
+                                 3, termcrit, 0, 0.001);
+            size_t i, k;
+            for( i = k = 0; i < points[1].size(); i++ )
+            {
+                if( addRemovePt )
+                {
+                    if( norm(point - points[1][i]) <= 5 )
+                    {
+                        addRemovePt = false;
+                        continue;
+                    }
+                }
+
+                if( !status[i] )
+                    continue;
+
+                points[1][k++] = points[1][i];
+                circle( image, points[1][i], 3, Scalar(0,255,0), -1, 8);
+            }
+            points[1].resize(k);
+        }
+
+        if( addRemovePt && points[1].size() < (size_t)MAX_COUNT )
+        {
+            vector<Point2f> tmp;
+            tmp.push_back(point);
+            cornerSubPix( gray, tmp, winSize, Size(-1,-1), termcrit);
+            points[1].push_back(tmp[0]);
+            addRemovePt = false;
+        }
+
+        needToInit = false;
+        imshow("LK Demo", image);
+
+        char c = (char)waitKey(10);
+        if( c == 27 )
+            break;
+        switch( c )
+        {
+        case 'r':
+            needToInit = true;
+            break;
+        case 'c':
+            points[0].clear();
+            points[1].clear();
+            break;
+        case 'n':
+            nightMode = !nightMode;
+            break;
+        }
+
+        std::swap(points[1], points[0]);
+        cv::swap(prevGray, gray);
+    }
+
+    return 0;
+}