summaryrefslogtreecommitdiff
path: root/samples/java/tutorial_code/ImgTrans/distance_transformation/ImageSegmentationDemo.java
diff options
context:
space:
mode:
Diffstat (limited to 'samples/java/tutorial_code/ImgTrans/distance_transformation/ImageSegmentationDemo.java')
-rw-r--r--samples/java/tutorial_code/ImgTrans/distance_transformation/ImageSegmentationDemo.java215
1 files changed, 215 insertions, 0 deletions
diff --git a/samples/java/tutorial_code/ImgTrans/distance_transformation/ImageSegmentationDemo.java b/samples/java/tutorial_code/ImgTrans/distance_transformation/ImageSegmentationDemo.java
new file mode 100644
index 0000000000..1a26092f64
--- /dev/null
+++ b/samples/java/tutorial_code/ImgTrans/distance_transformation/ImageSegmentationDemo.java
@@ -0,0 +1,215 @@
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Random;
+
+import org.opencv.core.Core;
+import org.opencv.core.CvType;
+import org.opencv.core.Mat;
+import org.opencv.core.MatOfPoint;
+import org.opencv.core.Point;
+import org.opencv.core.Scalar;
+import org.opencv.highgui.HighGui;
+import org.opencv.imgcodecs.Imgcodecs;
+import org.opencv.imgproc.Imgproc;
+
+/**
+ *
+ * @brief Sample code showing how to segment overlapping objects using Laplacian filtering, in addition to Watershed
+ * and Distance Transformation
+ *
+ */
+class ImageSegmentation {
+ public void run(String[] args) {
+ //! [load_image]
+ // Load the image
+ String filename = args.length > 0 ? args[0] : "../data/cards.png";
+ Mat srcOriginal = Imgcodecs.imread(filename);
+ if (srcOriginal.empty()) {
+ System.err.println("Cannot read image: " + filename);
+ System.exit(0);
+ }
+
+ // Show source image
+ HighGui.imshow("Source Image", srcOriginal);
+ //! [load_image]
+
+ //! [black_bg]
+ // Change the background from white to black, since that will help later to
+ // extract
+ // better results during the use of Distance Transform
+ Mat src = srcOriginal.clone();
+ byte[] srcData = new byte[(int) (src.total() * src.channels())];
+ src.get(0, 0, srcData);
+ for (int i = 0; i < src.rows(); i++) {
+ for (int j = 0; j < src.cols(); j++) {
+ if (srcData[(i * src.cols() + j) * 3] == (byte) 255 && srcData[(i * src.cols() + j) * 3 + 1] == (byte) 255
+ && srcData[(i * src.cols() + j) * 3 + 2] == (byte) 255) {
+ srcData[(i * src.cols() + j) * 3] = 0;
+ srcData[(i * src.cols() + j) * 3 + 1] = 0;
+ srcData[(i * src.cols() + j) * 3 + 2] = 0;
+ }
+ }
+ }
+ src.put(0, 0, srcData);
+
+ // Show output image
+ HighGui.imshow("Black Background Image", src);
+ //! [black_bg]
+
+ //! [sharp]
+ // Create a kernel that we will use to sharpen our image
+ Mat kernel = new Mat(3, 3, CvType.CV_32F);
+ // an approximation of second derivative, a quite strong kernel
+ float[] kernelData = new float[(int) (kernel.total() * kernel.channels())];
+ kernelData[0] = 1; kernelData[1] = 1; kernelData[2] = 1;
+ kernelData[3] = 1; kernelData[4] = -8; kernelData[5] = 1;
+ kernelData[6] = 1; kernelData[7] = 1; kernelData[8] = 1;
+ kernel.put(0, 0, kernelData);
+
+ // do the laplacian filtering as it is
+ // well, we need to convert everything in something more deeper then CV_8U
+ // because the kernel has some negative values,
+ // and we can expect in general to have a Laplacian image with negative values
+ // BUT a 8bits unsigned int (the one we are working with) can contain values
+ // from 0 to 255
+ // so the possible negative number will be truncated
+ Mat imgLaplacian = new Mat();
+ Imgproc.filter2D(src, imgLaplacian, CvType.CV_32F, kernel);
+ Mat sharp = new Mat();
+ src.convertTo(sharp, CvType.CV_32F);
+ Mat imgResult = new Mat();
+ Core.subtract(sharp, imgLaplacian, imgResult);
+
+ // convert back to 8bits gray scale
+ imgResult.convertTo(imgResult, CvType.CV_8UC3);
+ imgLaplacian.convertTo(imgLaplacian, CvType.CV_8UC3);
+
+ // imshow( "Laplace Filtered Image", imgLaplacian );
+ HighGui.imshow("New Sharped Image", imgResult);
+ //! [sharp]
+
+ //! [bin]
+ // Create binary image from source image
+ Mat bw = new Mat();
+ Imgproc.cvtColor(imgResult, bw, Imgproc.COLOR_BGR2GRAY);
+ Imgproc.threshold(bw, bw, 40, 255, Imgproc.THRESH_BINARY | Imgproc.THRESH_OTSU);
+ HighGui.imshow("Binary Image", bw);
+ //! [bin]
+
+ //! [dist]
+ // Perform the distance transform algorithm
+ Mat dist = new Mat();
+ Imgproc.distanceTransform(bw, dist, Imgproc.DIST_L2, 3);
+
+ // Normalize the distance image for range = {0.0, 1.0}
+ // so we can visualize and threshold it
+ Core.normalize(dist, dist, 0, 1., Core.NORM_MINMAX);
+ Mat distDisplayScaled = dist.mul(dist, 255);
+ Mat distDisplay = new Mat();
+ distDisplayScaled.convertTo(distDisplay, CvType.CV_8U);
+ HighGui.imshow("Distance Transform Image", distDisplay);
+ //! [dist]
+
+ //! [peaks]
+ // Threshold to obtain the peaks
+ // This will be the markers for the foreground objects
+ Imgproc.threshold(dist, dist, .4, 1., Imgproc.THRESH_BINARY);
+
+ // Dilate a bit the dist image
+ Mat kernel1 = Mat.ones(3, 3, CvType.CV_8U);
+ Imgproc.dilate(dist, dist, kernel1);
+ Mat distDisplay2 = new Mat();
+ dist.convertTo(distDisplay2, CvType.CV_8U);
+ distDisplay2 = distDisplay2.mul(distDisplay2, 255);
+ HighGui.imshow("Peaks", distDisplay2);
+ //! [peaks]
+
+ //! [seeds]
+ // Create the CV_8U version of the distance image
+ // It is needed for findContours()
+ Mat dist_8u = new Mat();
+ dist.convertTo(dist_8u, CvType.CV_8U);
+
+ // Find total markers
+ List<MatOfPoint> contours = new ArrayList<>();
+ Mat hierarchy = new Mat();
+ Imgproc.findContours(dist_8u, contours, hierarchy, Imgproc.RETR_EXTERNAL, Imgproc.CHAIN_APPROX_SIMPLE);
+
+ // Create the marker image for the watershed algorithm
+ Mat markers = Mat.zeros(dist.size(), CvType.CV_32S);
+
+ // Draw the foreground markers
+ for (int i = 0; i < contours.size(); i++) {
+ Imgproc.drawContours(markers, contours, i, new Scalar(i + 1), -1);
+ }
+
+ // Draw the background marker
+ Imgproc.circle(markers, new Point(5, 5), 3, new Scalar(255, 255, 255), -1);
+ Mat markersScaled = markers.mul(markers, 10000);
+ Mat markersDisplay = new Mat();
+ markersScaled.convertTo(markersDisplay, CvType.CV_8U);
+ HighGui.imshow("Markers", markersDisplay);
+ //! [seeds]
+
+ //! [watershed]
+ // Perform the watershed algorithm
+ Imgproc.watershed(imgResult, markers);
+
+ Mat mark = Mat.zeros(markers.size(), CvType.CV_8U);
+ markers.convertTo(mark, CvType.CV_8UC1);
+ Core.bitwise_not(mark, mark);
+ // imshow("Markers_v2", mark); // uncomment this if you want to see how the mark
+ // image looks like at that point
+
+ // Generate random colors
+ Random rng = new Random(12345);
+ List<Scalar> colors = new ArrayList<>(contours.size());
+ for (int i = 0; i < contours.size(); i++) {
+ int b = rng.nextInt(256);
+ int g = rng.nextInt(256);
+ int r = rng.nextInt(256);
+
+ colors.add(new Scalar(b, g, r));
+ }
+
+ // Create the result image
+ Mat dst = Mat.zeros(markers.size(), CvType.CV_8UC3);
+ byte[] dstData = new byte[(int) (dst.total() * dst.channels())];
+ dst.get(0, 0, dstData);
+
+ // Fill labeled objects with random colors
+ int[] markersData = new int[(int) (markers.total() * markers.channels())];
+ markers.get(0, 0, markersData);
+ for (int i = 0; i < markers.rows(); i++) {
+ for (int j = 0; j < markers.cols(); j++) {
+ int index = markersData[i * markers.cols() + j];
+ if (index > 0 && index <= contours.size()) {
+ dstData[(i * dst.cols() + j) * 3 + 0] = (byte) colors.get(index - 1).val[0];
+ dstData[(i * dst.cols() + j) * 3 + 1] = (byte) colors.get(index - 1).val[1];
+ dstData[(i * dst.cols() + j) * 3 + 2] = (byte) colors.get(index - 1).val[2];
+ } else {
+ dstData[(i * dst.cols() + j) * 3 + 0] = 0;
+ dstData[(i * dst.cols() + j) * 3 + 1] = 0;
+ dstData[(i * dst.cols() + j) * 3 + 2] = 0;
+ }
+ }
+ }
+ dst.put(0, 0, dstData);
+
+ // Visualize the final image
+ HighGui.imshow("Final Result", dst);
+ //! [watershed]
+
+ HighGui.waitKey();
+ System.exit(0);
+ }
+}
+
+public class ImageSegmentationDemo {
+ public static void main(String[] args) {
+ // Load the native OpenCV library
+ System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
+
+ new ImageSegmentation().run(args);
+ }
+}