OpenCV - Java - 臉部辨識

OpenCV 是一個是一個跨平台的電腦視覺庫，其可讓我們方便的做許多圖像方面的處理，
在這裡我參考了網路上的資料加上修改實測，展示一個簡單的OpenCV範例：

程式語言 : Java
需求：
調用電腦本身的攝影機，在UI上顯示即時截取的畫面，並在辨視出人臉的地方加上方框，並將人臉部份儲存至本地電腦上。

到這裡下載OpenCV，我下載的是 3.4.1 的Win pack版本，下載後執行，它會解壓縮生成一個opencv資料，打開它後，
會看到所須的jar檔及dll檔:
opencv-341.jar
並且在x64和x86資料夾內有不同位元的windows dll檔：
opencv_java341.dll

以Eclipse來示範，除了加入opencv0341.jar到lib後，還要如下圖設定Native library location為dll檔所在的資料夾路徑

接下來是程式的部份

import java.io.ByteArrayInputStream;
import java.io.FileInputStream;
import java.util.Calendar;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

import org.opencv.core.Core;
import org.opencv.core.Mat;
import org.opencv.core.MatOfByte;
import org.opencv.core.MatOfRect;
import org.opencv.core.Point;
import org.opencv.core.Rect;
import org.opencv.core.Scalar;
import org.opencv.imgcodecs.Imgcodecs;
import org.opencv.imgproc.Imgproc;
import org.opencv.objdetect.CascadeClassifier;
import org.opencv.videoio.VideoCapture;
import org.opencv.videoio.Videoio;

import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.HBox;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

public class OpenCV_Test extends Application{

 //是否正在截取攝影機影像
    private boolean isStart = false;
 
    private VideoCapture videoCapture;
    private ScheduledExecutorService scheduledExecutorService;
 
    // JavaFX 元件
    private BorderPane rootNode;
    private VBox vbox;
    private ImageView imageView;
    private Button startStopBtn;
    String startText = "Start";
    String stopText = "Stop";
 
 public static void main(String[] args) {
  Application.launch(args);
 }

 @Override
 public void start(Stage primaryStage) throws Exception {
  
  startStopBtn.setOnAction(new EventHandler<ActionEvent>() {

   @Override
   public void handle(ActionEvent event) {
    if (!isStart) {
     startStopBtn.setText(stopText);
     videoCapture.open(0);
     videoCapture.set(Videoio.CAP_PROP_FRAME_WIDTH, 640);
     videoCapture.set(Videoio.CAP_PROP_FRAME_HEIGHT, 480);
     
     if (videoCapture.isOpened()) {
      isStart = true;
      
      //建立設定截取攝影機的thread
      scheduledExecutorService = Executors.newSingleThreadScheduledExecutor();
      scheduledExecutorService.scheduleAtFixedRate(new Runnable() {

       @Override
       public void run() {
        imageView.setImage(captureImage());
       }
       
      }, 0, 16, TimeUnit.MILLISECONDS);
     }else {
      System.err.println("Error: Can not open camera.");
     }
     
    }else {
     startStopBtn.setText(startText);
     isStart = false;
     
     scheduledExecutorService.shutdown();
     try {
      //確保scheduledExecutorService有正確關閉排程
      while(!scheduledExecutorService.awaitTermination(30, TimeUnit.MILLISECONDS)) {
       System.out.println("Not close thread yet");
      }
     } catch (InterruptedException e) {
      System.err.println(e.getMessage());
      e.printStackTrace();
     }
     
     videoCapture.release();
     imageView.setImage(null);
    }
   }
   
  });
  
  //UI畫面
  Scene scene = new Scene(rootNode, 800, 640);
        primaryStage.setTitle("OpenCV Test");
        primaryStage.setScene(scene);
        primaryStage.show();
 }

 //UI畫面設定
 @Override
 public void init() throws Exception {
  super.init();
  
  System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
  videoCapture = new VideoCapture();
  
  rootNode = new BorderPane();
  
  vbox = new VBox();
  vbox.setAlignment(Pos.CENTER);
  rootNode.setCenter(vbox);
  
  imageView = new ImageView();
  imageView.setFitWidth(640);
  imageView.setFitHeight(480);
  imageView.setPreserveRatio(true);
  
  startStopBtn = new Button(startText);
  vbox.getChildren().addAll(imageView, startStopBtn);
  
 }

 //程式關閉時關閉攝影機
 @Override
 public void stop() throws Exception {
  if (videoCapture.isOpened()) {
   videoCapture.release();
  }
  super.stop();
 }
 
 private Image captureImage() {
  Image capturedImage = null;
 
  if (videoCapture.isOpened()) {
   Mat mat = new Mat();
   videoCapture.read(mat);
   if (!mat.empty()) {
    MatOfByte buffer = new MatOfByte();
    //偵測人臉，截取人臉部份存圖，
    //並在要顯示在畫面上的影像用矩形標示人臉部份
    detectDrawAndSaveFace(mat);
          Imgcodecs.imencode(".png", mat, buffer);
          capturedImage = new Image(new ByteArrayInputStream(buffer.toArray()));
   }
  }   
        return capturedImage;
 }
 
 //臉部偵測
    private void detectDrawAndSaveFace(Mat image) {
     CascadeClassifier faceDetector = new CascadeClassifier();
        faceDetector.load("D:\\JavaLib\\opencv\\sources\\data\\haarcascades_cuda\\haarcascade_frontalface_alt2.xml");

        MatOfRect faceDetections = new MatOfRect();
        faceDetector.detectMultiScale(image, faceDetections);
        for (Rect rect : faceDetections.toArray())
        {
         //截detect到人臉的區域，將區域內的圖存檔
            Mat faceImage = new Mat(image, rect);
            String outputDir = "D:\\detectedFaces";
            String outputFilePath = outputDir + "\\detectedFace_" + Calendar.getInstance().getTimeInMillis() + ".png";
            Imgcodecs.imwrite(outputFilePath, faceImage);
            
            //在detect到人臉的區域上畫上矩形邊框，顯示在螢幕上的ImageView上
            Imgproc.rectangle(image, new Point(rect.x, rect.y), new Point(rect.x + rect.width, rect.y + rect.height), new Scalar(0, 255, 0));
        } 
    }
}

Opencv 3.4.1 Win pack 下載分享

參考資料：

1. Java+opencv3.2.0之人脸检测
2. [OpenCV] 人臉偵測 (Face Detection)
3. [OpenCV] 人臉偵測2 (Face Detection)
4. 利用Java调用OpenCV进行人脸识别OpenCV on Raspberry Pi - Using Java（7）- 使用 OpenCV 截取與顯示影片