Add Java and Python code for ML tutorials.

samples/cpp/tutorial_code/ml/introduction_to_pca/introduction_to_pca.cpp

@@ -21,13 +21,9 @@ double getOrientation(const vector<Point> &, Mat&);
  */
 void drawAxis(Mat& img, Point p, Point q, Scalar colour, const float scale = 0.2)
 {
-//! [visualization1]
-    double angle;
-    double hypotenuse;
-    angle = atan2( (double) p.y - q.y, (double) p.x - q.x ); // angle in radians
-    hypotenuse = sqrt( (double) (p.y - q.y) * (p.y - q.y) + (p.x - q.x) * (p.x - q.x));
-//    double degrees = angle * 180 / CV_PI; // convert radians to degrees (0-180 range)
-//    cout << "Degrees: " << abs(degrees - 180) << endl; // angle in 0-360 degrees range
+    //! [visualization1]
+    double angle = atan2( (double) p.y - q.y, (double) p.x - q.x ); // angle in radians
+    double hypotenuse = sqrt( (double) (p.y - q.y) * (p.y - q.y) + (p.x - q.x) * (p.x - q.x));
 
     // Here we lengthen the arrow by a factor of scale
     q.x = (int) (p.x - scale * hypotenuse * cos(angle));
@@ -42,7 +38,7 @@ void drawAxis(Mat& img, Point p, Point q, Scalar colour, const float scale = 0.2
     p.x = (int) (q.x + 9 * cos(angle - CV_PI / 4));
     p.y = (int) (q.y + 9 * sin(angle - CV_PI / 4));
     line(img, p, q, colour, 1, LINE_AA);
-//! [visualization1]
+    //! [visualization1]
 }
 
 /**
@@ -50,11 +46,11 @@ void drawAxis(Mat& img, Point p, Point q, Scalar colour, const float scale = 0.2
  */
 double getOrientation(const vector<Point> &pts, Mat &img)
 {
-//! [pca]
+    //! [pca]
     //Construct a buffer used by the pca analysis
     int sz = static_cast<int>(pts.size());
-    Mat data_pts = Mat(sz, 2, CV_64FC1);
-    for (int i = 0; i < data_pts.rows; ++i)
+    Mat data_pts = Mat(sz, 2, CV_64F);
+    for (int i = 0; i < data_pts.rows; i++)
     {
         data_pts.at<double>(i, 0) = pts[i].x;
         data_pts.at<double>(i, 1) = pts[i].y;
@@ -70,16 +66,16 @@ double getOrientation(const vector<Point> &pts, Mat &img)
     //Store the eigenvalues and eigenvectors
     vector<Point2d> eigen_vecs(2);
     vector<double> eigen_val(2);
-    for (int i = 0; i < 2; ++i)
+    for (int i = 0; i < 2; i++)
     {
         eigen_vecs[i] = Point2d(pca_analysis.eigenvectors.at<double>(i, 0),
                                 pca_analysis.eigenvectors.at<double>(i, 1));
 
         eigen_val[i] = pca_analysis.eigenvalues.at<double>(i);
     }
+    //! [pca]
 
-//! [pca]
-//! [visualization]
+    //! [visualization]
     // Draw the principal components
     circle(img, cntr, 3, Scalar(255, 0, 255), 2);
     Point p1 = cntr + 0.02 * Point(static_cast<int>(eigen_vecs[0].x * eigen_val[0]), static_cast<int>(eigen_vecs[0].y * eigen_val[0]));
@@ -88,7 +84,7 @@ double getOrientation(const vector<Point> &pts, Mat &img)
     drawAxis(img, cntr, p2, Scalar(255, 255, 0), 5);
 
     double angle = atan2(eigen_vecs[0].y, eigen_vecs[0].x); // orientation in radians
-//! [visualization]
+    //! [visualization]
 
     return angle;
 }
@@ -98,10 +94,10 @@ double getOrientation(const vector<Point> &pts, Mat &img)
  */
 int main(int argc, char** argv)
 {
-//! [pre-process]
+    //! [pre-process]
     // Load image
     CommandLineParser parser(argc, argv, "{@input | ../data/pca_test1.jpg | input image}");
-    parser.about( "This program demonstrates how to use OpenCV PCA to extract the orienation of an object.\n" );
+    parser.about( "This program demonstrates how to use OpenCV PCA to extract the orientation of an object.\n" );
     parser.printMessage();
 
     Mat src = imread(parser.get<String>("@input"));
@@ -122,14 +118,14 @@ int main(int argc, char** argv)
     // Convert image to binary
     Mat bw;
     threshold(gray, bw, 50, 255, THRESH_BINARY | THRESH_OTSU);
-//! [pre-process]
+    //! [pre-process]
 
-//! [contours]
+    //! [contours]
     // Find all the contours in the thresholded image
     vector<vector<Point> > contours;
     findContours(bw, contours, RETR_LIST, CHAIN_APPROX_NONE);
 
-    for (size_t i = 0; i < contours.size(); ++i)
+    for (size_t i = 0; i < contours.size(); i++)
     {
         // Calculate the area of each contour
         double area = contourArea(contours[i]);
@@ -137,14 +133,14 @@ int main(int argc, char** argv)
         if (area < 1e2 || 1e5 < area) continue;
 
         // Draw each contour only for visualisation purposes
-        drawContours(src, contours, static_cast<int>(i), Scalar(0, 0, 255), 2, LINE_8);
+        drawContours(src, contours, static_cast<int>(i), Scalar(0, 0, 255), 2);
         // Find the orientation of each shape
         getOrientation(contours[i], src);
     }
-//! [contours]
+    //! [contours]
 
     imshow("output", src);
 
-    waitKey(0);
+    waitKey();
     return 0;
 }