OpenCV繪製圓形

可以使用org.opencv.imgproc包的相應方法在圖像上繪製各種形狀,如圓形,矩形,線條,橢圓,多段線,凸起,多段線,多段線。

可以使用imgproc類的circle()方法在圖像上繪製一個圓形。 以下是這種方法的語法 -

circle(img, center, radius, color, thickness)

該方法接受以下參數 -

  • mat - Mat對象,表示要在其上繪製圓的圖像。
  • point - 代表圓中心的Point對象。
  • radius - 表示圓的半徑的整型變量。
  • scalar - 表示圓的顏色的標量對象(BGR)。
  • thickness - 表示圓的厚度的整數; 默認情況下,厚度值爲1

示例

以下程序演示如何在圖像上繪製圓形並使用JavaFX窗口進行顯示。

package yiibai.com;

import java.awt.image.BufferedImage;

import java.io.ByteArrayInputStream;
import java.io.InputStream;
import javax.imageio.ImageIO;

import javafx.application.Application;
import javafx.embed.swing.SwingFXUtils;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.image.ImageView;
import javafx.scene.image.WritableImage;
import javafx.stage.Stage;

import org.opencv.core.Core;
import org.opencv.core.Mat;
import org.opencv.core.MatOfByte;
import org.opencv.core.Point;
import org.opencv.core.Scalar;
import org.opencv.imgcodecs.Imgcodecs;
import org.opencv.imgproc.Imgproc;

public class DrawingCircle extends Application {
   Mat matrix = null;

   @Override
   public void start(Stage stage) throws Exception {
      // Capturing the snapshot from the camera
      DrawingCircle obj = new DrawingCircle();
      WritableImage writableImage = obj.LoadImage();

      // Setting the image view
      ImageView imageView = new ImageView(writableImage);

      // setting the fit height and width of the image view
      imageView.setFitHeight(600);
      imageView.setFitWidth(600);

      // Setting the preserve ratio of the image view
      imageView.setPreserveRatio(true);

      // Creating a Group object
      Group root = new Group(imageView);

      // Creating a scene object
      Scene scene = new Scene(root, 600, 400);

      // Setting title to the Stage
      stage.setTitle("Drawing Circle on the image");

      // Adding scene to the stage
      stage.setScene(scene);

      // Displaying the contents of the stage
      stage.show();
   }      
   public WritableImage LoadImage() throws Exception {
      // Loading the OpenCV core library
      System.loadLibrary( Core.NATIVE_LIBRARY_NAME );

      // Reading the Image from the file and storing it in to a Matrix object
      String file ="F:/worksp/opencv/images/sample.jpg";
      Mat matrix = Imgcodecs.imread(file);

      //Drawing a Circle
      Imgproc.circle (
         matrix,                 //Matrix obj of the image
         new Point(230, 160),    //Center of the circle
         100,                    //Radius
         new Scalar(0, 0, 255),  //Scalar object for color
         2                      //圓線的厚度
      );

      // Encoding the image
      MatOfByte matOfByte = new MatOfByte();
      Imgcodecs.imencode(".jpg", matrix, matOfByte);

      // Storing the encoded Mat in a byte array
      byte[] byteArray = matOfByte.toArray();

      // Displaying the image
      InputStream in = new ByteArrayInputStream(byteArray);
      BufferedImage bufImage = ImageIO.read(in);
      this.matrix = matrix;

      // Creating the Writable Image
      WritableImage writableImage = SwingFXUtils.toFXImage(bufImage, null);

      return writableImage;
   }
   public static void main(String args[]) {
      launch(args);
   }
}

在執行上述程序時,您將得到以下輸出 -
OpenCV繪製圓形

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