Tutorial Morph Lines Detection

2017-08-21 18:51:50 +01:00
parent 18bc4db75c
commit d068e27420
6 changed files with 527 additions and 119 deletions
@@ -0,0 +1,152 @@
+/**
+ * @file Morphology_3.java
+ * @brief Use morphology transformations for extracting horizontal and vertical lines sample code
+ */
+
+import org.opencv.core.*;
+import org.opencv.highgui.HighGui;
+import org.opencv.imgcodecs.Imgcodecs;
+import org.opencv.imgproc.Imgproc;
+
+class Morphology_3Run {
+
+    public void run(String[] args) {
+
+        //! [load_image]
+        // Check number of arguments
+        if (args.length == 0){
+            System.out.println("Not enough parameters!");
+            System.out.println("Program Arguments: [image_path]");
+            System.exit(-1);
+        }
+
+        // Load the image
+        Mat src = Imgcodecs.imread(args[0]);
+
+        // Check if image is loaded fine
+        if( src.empty() ) {
+            System.out.println("Error opening image: " + args[0]);
+            System.exit(-1);
+        }
+
+        // Show source image
+        HighGui.imshow("src", src);
+        //! [load_image]
+
+        //! [gray]
+        // Transform source image to gray if it is not already
+        Mat gray = new Mat();
+
+        if (src.channels() == 3)
+        {
+            Imgproc.cvtColor(src, gray, Imgproc.COLOR_BGR2GRAY);
+        }
+        else
+        {
+            gray = src;
+        }
+
+        // Show gray image
+        showWaitDestroy("gray" , gray);
+        //! [gray]
+
+        //! [bin]
+        // Apply adaptiveThreshold at the bitwise_not of gray
+        Mat bw = new Mat();
+        Core.bitwise_not(gray, gray);
+        Imgproc.adaptiveThreshold(gray, bw, 255, Imgproc.ADAPTIVE_THRESH_MEAN_C, Imgproc.THRESH_BINARY, 15, -2);
+
+        // Show binary image
+        showWaitDestroy("binary" , bw);
+        //! [bin]
+
+        //! [init]
+        // Create the images that will use to extract the horizontal and vertical lines
+        Mat horizontal = bw.clone();
+        Mat vertical = bw.clone();
+        //! [init]
+
+        //! [horiz]
+        // Specify size on horizontal axis
+        int horizontal_size = horizontal.cols() / 30;
+
+        // Create structure element for extracting horizontal lines through morphology operations
+        Mat horizontalStructure = Imgproc.getStructuringElement(Imgproc.MORPH_RECT, new Size(horizontal_size,1));
+
+        // Apply morphology operations
+        Imgproc.erode(horizontal, horizontal, horizontalStructure);
+        Imgproc.dilate(horizontal, horizontal, horizontalStructure);
+
+        // Show extracted horizontal lines
+        showWaitDestroy("horizontal" , horizontal);
+        //! [horiz]
+
+        //! [vert]
+        // Specify size on vertical axis
+        int vertical_size = vertical.rows() / 30;
+
+        // Create structure element for extracting vertical lines through morphology operations
+        Mat verticalStructure = Imgproc.getStructuringElement(Imgproc.MORPH_RECT, new Size( 1,vertical_size));
+
+        // Apply morphology operations
+        Imgproc.erode(vertical, vertical, verticalStructure);
+        Imgproc.dilate(vertical, vertical, verticalStructure);
+
+        // Show extracted vertical lines
+        showWaitDestroy("vertical", vertical);
+        //! [vert]
+
+        //! [smooth]
+        // Inverse vertical image
+        Core.bitwise_not(vertical, vertical);
+        showWaitDestroy("vertical_bit" , vertical);
+
+        // Extract edges and smooth image according to the logic
+        // 1. extract edges
+        // 2. dilate(edges)
+        // 3. src.copyTo(smooth)
+        // 4. blur smooth img
+        // 5. smooth.copyTo(src, edges)
+
+        // Step 1
+        Mat edges = new Mat();
+        Imgproc.adaptiveThreshold(vertical, edges, 255, Imgproc.ADAPTIVE_THRESH_MEAN_C, Imgproc.THRESH_BINARY, 3, -2);
+        showWaitDestroy("edges", edges);
+
+        // Step 2
+        Mat kernel = Mat.ones(2, 2, CvType.CV_8UC1);
+        Imgproc.dilate(edges, edges, kernel);
+        showWaitDestroy("dilate", edges);
+
+        // Step 3
+        Mat smooth = new Mat();
+        vertical.copyTo(smooth);
+
+        // Step 4
+        Imgproc.blur(smooth, smooth, new Size(2, 2));
+
+        // Step 5
+        smooth.copyTo(vertical, edges);
+
+        // Show final result
+        showWaitDestroy("smooth - final", vertical);
+        //! [smooth]
+
+        System.exit(0);
+    }
+
+    private void showWaitDestroy(String winname, Mat img) {
+        HighGui.imshow(winname, img);
+        HighGui.moveWindow(winname, 500, 0);
+        HighGui.waitKey(0);
+        HighGui.destroyWindow(winname);
+    }
+}
+
+public class Morphology_3 {
+    public static void main(String[] args) {
+        // Load the native library.
+        System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
+        new Morphology_3Run().run(args);
+    }
+}