通过OpenCV实现人脸识别，包括图片，视频，摄像头中人脸识别。

首先看一下效果（在网上随便找的一张图片）：

Java使用OpenCV实现人脸识别

下面开始说一下如何实现的：

第一步：需要安装OpenCV

下载链接：https://opencv.org/ 或 https://download.csdn.net/download/u012804490/10813245

第二步：创建一个Java项目

Java使用OpenCV实现人脸识别

第三步：将OpenCV的jar包引入项目（截图演示）

Java使用OpenCV实现人脸识别

然后点OK。

第四步：代码实现

package com.opencv;

import org.opencv.core.*;
import org.opencv.core.Point;
import org.opencv.imgcodecs.Imgcodecs;
import org.opencv.imgproc.Imgproc;
import org.opencv.objdetect.CascadeClassifier;
import org.opencv.videoio.VideoCapture;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.awt.image.DataBufferByte;
import java.awt.image.WritableRaster;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;

import static org.opencv.imgproc.Imgproc.CV_BILATERAL;


public class FaceRecognitionDemo {
    public static void main(String[] args) {
        System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
        // filePath可以是图片路径，也可以是视频路径
        String filePath ="pic1236710b.jpg";
        playVideo(filePath);
        // 调取摄像头，进行人脸识别
//      recording();
    }

    public static void playVideo(String fileName){
        VideoCapture capture = new VideoCapture(fileName);
        System.out.println(capture.get(CV_BILATERAL));
        if (!capture.isOpened()) {
            System.out.println("未能打开文件");
            return;
        }
        showFace(capture);
    }

    public static void recording(){
        VideoCapture capture = new VideoCapture(0);
        System.out.println(capture.get(CV_BILATERAL));
        if (!capture.isOpened()) {
            System.out.println("未能打开文件");
            return;
        }
        showFace(capture);
    }

    public static void showFace(VideoCapture capture){
        //获得视屏流帧的宽度
        int frame_width = (int) capture.get(3);
        //获得视屏流帧的高度
        int frame_height = (int) capture.get(4);
        //将视频显示类进行实例化
        VideoGui videoGui = new VideoGui();
        videoGui.createWin("视频播放",new Dimension(frame_width,frame_height));


        Mat mat = new Mat();
        String file = "haarcascade_frontalface_alt.xml";
        CascadeClassifier classifier = new CascadeClassifier(file);

        MatOfRect faceDetections = new MatOfRect();
        while (capture.read(mat)){
            classifier.detectMultiScale(mat, faceDetections);
            System.out.println(String.format("Detected %s faces",
                    faceDetections.toArray().length));

            for (Rect rect : faceDetections.toArray()) {
                Imgproc.rectangle(mat, new Point(rect.x, rect.y),
                        new Point(rect.x + rect.width, rect.y + rect.height), new Scalar(0, 0, 255)
                );
            }


            BufferedImage bufferedImage = matToBufferedImage(mat);

            //显示视频
            videoGui.imgShow(bufferedImage);
        }

        // 关闭视频文件
        capture.release();
        try {
            Thread.sleep(5000);
            videoGui.imgClose();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    public static BufferedImage matToBufferedImage(Mat mat){
        try {
            MatOfByte matOfByte = new MatOfByte();
            Imgcodecs.imencode(".jpg", mat, matOfByte);
            byte[] byteArray = matOfByte.toArray();

            InputStream in = new ByteArrayInputStream(byteArray);
            BufferedImage bufImage = ImageIO.read(in);
            return bufImage;
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }
}

package com.opencv;

import javax.swing.*;
import java.awt.*;
import java.awt.image.BufferedImage;


public class VideoGui extends JComponent {
    private BufferedImage image;
    private JDialog ui = new JDialog();
    @Override
    public void paintComponent(Graphics g){
        Graphics2D g2d = (Graphics2D) g;
        if(image == null){
            g2d.setPaint(Color.BLACK);
            g2d.fillRect(0,0,this.getWidth(),this.getHeight());
        }else{
            g2d.drawImage(image,0,0,this.getWidth(),this.getHeight(),null);
        }
    }

    public void createWin(String title,Dimension size){
        ui.setTitle(title);
        ui.getContentPane().setLayout(new BorderLayout());
        ui.getContentPane().add(this,BorderLayout.CENTER);
        ui.setSize(new Dimension(size));
        ui.setVisible(true);
    }

    public void imgShow(BufferedImage image){
        this.image = image;
        this.repaint();
    }

    public void imgClose(){
        ui.dispose();
    }
}

第五步：运行：

可能抛异常：Exception in thread "main" java.lang.UnsatisfiedLinkError: no opencv_java400 in java.library.path

Java使用OpenCV实现人脸识别