Update documentation ( tutorials )

samples/cpp/houghcircles.cpp

@@ -24,39 +24,48 @@ int main(int argc, char** argv)
         help();
         return 0;
     }
+    //![load]
     string filename = parser.get<string>("@image");
-    if (filename.empty())
-    {
-        help();
-        cout << "no image_name provided" << endl;
-        return -1;
-    }
-    Mat img = imread(filename, 0);
+    Mat img = imread(filename, IMREAD_COLOR);
     if(img.empty())
     {
         help();
         cout << "can not open " << filename << endl;
         return -1;
     }
+    //![load]
 
-    Mat cimg;
-    medianBlur(img, img, 5);
-    cvtColor(img, cimg, COLOR_GRAY2BGR);
+    //![convert_to_gray]
+    Mat gray;
+    cvtColor(img, gray, COLOR_BGR2GRAY);
+    //![convert_to_gray]
 
+    //![reduce_noise]
+    medianBlur(gray, gray, 5);
+    //![reduce_noise]
+
+    //![houghcircles]
     vector<Vec3f> circles;
-    HoughCircles(img, circles, HOUGH_GRADIENT, 1, 10,
+    HoughCircles(gray, circles, HOUGH_GRADIENT, 1,
+                 gray.rows/16, // change this value to detect circles with different distances to each other
                  100, 30, 1, 30 // change the last two parameters
                                 // (min_radius & max_radius) to detect larger circles
                  );
+    //![houghcircles]
+
+    //![draw]
     for( size_t i = 0; i < circles.size(); i++ )
     {
         Vec3i c = circles[i];
-        circle( cimg, Point(c[0], c[1]), c[2], Scalar(0,0,255), 3, LINE_AA);
-        circle( cimg, Point(c[0], c[1]), 2, Scalar(0,255,0), 3, LINE_AA);
+        circle( img, Point(c[0], c[1]), c[2], Scalar(0,0,255), 3, LINE_AA);
+        circle( img, Point(c[0], c[1]), 2, Scalar(0,255,0), 3, LINE_AA);
     }
+    //![draw]
 
-    imshow("detected circles", cimg);
+    //![display]
+    imshow("detected circles", img);
     waitKey();
+    //![display]
 
     return 0;
 }