Merge pull request #214 from LaurentBerger/bugfix4269

bugfix4269 included remarks in http://answers.opencv.org/question/59293/...

modules/optflow/samples/motempl.cpp

@@ -13,21 +13,20 @@ using namespace cv::motempl;
 static void help(void)
 {
     printf(
-            "\nThis program demonstrated the use of motion templates -- basically using the gradients\n"
-            "of thresholded layers of decaying frame differencing. New movements are stamped on top with floating system\n"
-            "time code and motions too old are thresholded away. This is the 'motion history file'. The program reads from the camera of your choice or from\n"
-            "a file. Gradients of motion history are used to detect direction of motoin etc\n"
-            "Usage :\n"
-            "./motempl [camera number 0-n or file name, default is camera 0]\n"
-            );
+        "\nThis program demonstrated the use of motion templates -- basically using the gradients\n"
+        "of thresholded layers of decaying frame differencing. New movements are stamped on top with floating system\n"
+        "time code and motions too old are thresholded away. This is the 'motion history file'. The program reads from the camera of your choice or from\n"
+        "a file. Gradients of motion history are used to detect direction of motion etc\n"
+        "Usage :\n"
+        "./motempl [camera number 0-n or file name, default is camera 0]\n"
+        );
 }
 // various tracking parameters (in seconds)
-const double MHI_DURATION = 1;
+const double MHI_DURATION = 5;
 const double MAX_TIME_DELTA = 0.5;
 const double MIN_TIME_DELTA = 0.05;
 // number of cyclic frame buffer used for motion detection
 // (should, probably, depend on FPS)
-const int N = 4;
 
 // ring image buffer
 vector<Mat> buf;
@@ -41,9 +40,9 @@ vector<Rect> regions;
 //  img - input video frame
 //  dst - resultant motion picture
 //  args - optional parameters
-static void  update_mhi( const Mat& img, Mat& dst, int diff_threshold )
+static void  update_mhi(const Mat& img, Mat& dst, int diff_threshold)
 {
-    double timestamp = (double)clock()/CLOCKS_PER_SEC; // get current time in seconds
+    double timestamp = (double)clock() / CLOCKS_PER_SEC; // get current time in seconds
     Size size = img.size();
     int i, idx1 = last;
     Rect comp_rect;
@@ -55,57 +54,54 @@ static void  update_mhi( const Mat& img, Mat& dst, int diff_threshold )
 
     // allocate images at the beginning or
     // reallocate them if the frame size is changed
-    if( mhi.size() != size )
+    if (mhi.size() != size)
     {
         mhi = Mat::zeros(size, CV_32F);
         zplane = Mat::zeros(size, CV_8U);
-        
-        buf.resize(N);
-        for( i = 0; i < N; i++ )
-        {
-            buf[i] = Mat::zeros(size, CV_8U);
-        }
+
+        buf[0] = Mat::zeros(size, CV_8U);
+        buf[1] = Mat::zeros(size, CV_8U);
     }
 
-    cvtColor( img, buf[last], COLOR_BGR2GRAY ); // convert frame to grayscale
+    cvtColor(img, buf[last], COLOR_BGR2GRAY); // convert frame to grayscale
 
-    int idx2 = (last + 1) % N; // index of (last - (N-1))th frame
+    int idx2 = (last + 1) % 2; // index of (last - (N-1))th frame
     last = idx2;
 
     Mat silh = buf[idx2];
-    absdiff( buf[idx1], buf[idx2], silh ); // get difference between frames
+    absdiff(buf[idx1], buf[idx2], silh); // get difference between frames
 
-    threshold( silh, silh, diff_threshold, 1, THRESH_BINARY ); // and threshold it
-    updateMotionHistory( silh, mhi, timestamp, MHI_DURATION ); // update MHI
+    threshold(silh, silh, diff_threshold, 1, THRESH_BINARY); // and threshold it
+    updateMotionHistory(silh, mhi, timestamp, MHI_DURATION); // update MHI
 
     // convert MHI to blue 8u image
-    mhi.convertTo( mask, CV_8U, 255./MHI_DURATION, (MHI_DURATION - timestamp)*255./MHI_DURATION );
-    
-    Mat planes[] = {mask, zplane, zplane};
+    mhi.convertTo(mask, CV_8U, 255. / MHI_DURATION, (MHI_DURATION - timestamp)*255. / MHI_DURATION);
+
+    Mat planes[] = { mask, zplane, zplane };
     merge(planes, 3, dst);
 
     // calculate motion gradient orientation and valid orientation mask
-    calcMotionGradient( mhi, mask, orient, MAX_TIME_DELTA, MIN_TIME_DELTA, 3 );
+    calcMotionGradient(mhi, mask, orient, MAX_TIME_DELTA, MIN_TIME_DELTA, 3);
 
     // segment motion: get sequence of motion components
     // segmask is marked motion components map. It is not used further
-
+    regions.clear();
     segmentMotion(mhi, segmask, regions, timestamp, MAX_TIME_DELTA);
 
     // iterate through the motion components,
     // One more iteration (i == -1) corresponds to the whole image (global motion)
-    for( i = -1; i < (int)regions.size(); i++ ) {
+    for (i = -1; i < (int)regions.size(); i++) {
 
-        if( i < 0 ) { // case of the whole image
-            comp_rect = Rect( 0, 0, size.width, size.height );
-            color = Scalar(255,255,255);
+        if (i < 0) { // case of the whole image
+            comp_rect = Rect(0, 0, size.width, size.height);
+            color = Scalar(255, 255, 255);
             magnitude = 100;
         }
         else { // i-th motion component
             comp_rect = regions[i];
-            if( comp_rect.width + comp_rect.height < 100 ) // reject very small components
+            if (comp_rect.width + comp_rect.height < 100) // reject very small components
                 continue;
-            color = Scalar(0,0,255);
+            color = Scalar(0, 0, 255);
             magnitude = 30;
         }
 
@@ -116,22 +112,22 @@ static void  update_mhi( const Mat& img, Mat& dst, int diff_threshold )
         Mat mask_roi = mask(comp_rect);
 
         // calculate orientation
-        angle = calcGlobalOrientation( orient_roi, mask_roi, mhi_roi, timestamp, MHI_DURATION);
+        angle = calcGlobalOrientation(orient_roi, mask_roi, mhi_roi, timestamp, MHI_DURATION);
         angle = 360.0 - angle;  // adjust for images with top-left origin
 
-        count = norm( silh, 0, NORM_L1, 0 ); // calculate number of points within silhouette ROI
+        count = norm(silh_roi, NORM_L1);; // calculate number of points within silhouette ROI
 
         // check for the case of little motion
-        if( count < comp_rect.width*comp_rect.height * 0.05 )
+        if (count < comp_rect.width*comp_rect.height * 0.05)
             continue;
 
         // draw a clock with arrow indicating the direction
-        center = Point( (comp_rect.x + comp_rect.width/2),
-                          (comp_rect.y + comp_rect.height/2) );
+        center = Point((comp_rect.x + comp_rect.width / 2),
+            (comp_rect.y + comp_rect.height / 2));
 
-        circle( dst, center, cvRound(magnitude*1.2), color, 3, 16, 0 );
-        line( dst, center, Point( cvRound( center.x + magnitude*cos(angle*CV_PI/180)),
-                cvRound( center.y - magnitude*sin(angle*CV_PI/180))), color, 3, 16, 0 );
+        circle(img, center, cvRound(magnitude*1.2), color, 3, 16, 0);
+        line(img, center, Point(cvRound(center.x + magnitude*cos(angle*CV_PI / 180)),
+            cvRound(center.y - magnitude*sin(angle*CV_PI / 180))), color, 3, 16, 0);
     }
 }
 
@@ -142,28 +138,29 @@ int main(int argc, char** argv)
 
     help();
 
-    if( argc == 1 || (argc == 2 && strlen(argv[1]) == 1 && isdigit(argv[1][0])))
-        cap.open( argc == 2 ? argv[1][0] - '0' : 0 );
-    else if( argc == 2 )
-        cap.open( argv[1] );
+    if (argc == 1 || (argc == 2 && strlen(argv[1]) == 1 && isdigit(argv[1][0])))
+        cap.open(argc == 2 ? argv[1][0] - '0' : 0);
+    else if (argc == 2)
+        cap.open(argv[1]);
 
-    if( !cap.isOpened() )
+    if (!cap.isOpened())
     {
         printf("Could not initialize video capture\n");
         return 0;
     }
-    
+    buf.resize(2);
     Mat image, motion;
-    for(;;)
+    for (;;)
     {
         cap >> image;
-        if( image.empty() )
+        if (image.empty())
             break;
 
-        update_mhi( image, motion, 30 );
-        imshow( "Motion", motion );
+        update_mhi(image, motion, 30);
+        imshow("Image", image);
+        imshow("Motion", motion);
 
-        if( waitKey(10) >= 0 )
+        if (waitKey(10) >= 0)
             break;
     }