Capture the webcam video in Java with OpenCV

I am going to capture the video from webcam of the computer/laptop in our Java program. I am using OpenCV for this. For this first obtain a fresh release of OpenCV and extract it under some location like C:\opencv\. I am using version 3.0.0.

Now, we will define OpenCV as a user library in Eclipse, so we can reuse the configuration for any project. Launch Eclipse and select Window –> Preferences from the menu.

Navigate under Java –> Build Path –> User Libraries and click New....

Enter a name, e.g. OPENCV-3.0.0 for new library.

Now select your new user library and click Add External JARs....

Browse through C:\opencv\build\java and select opencv-300.jar. After adding the jar, extend the opencv-300.jar and select Native library location and press Edit....

Select External Folder... and browse to select the folder C:\opencv\build\java\x64. If you have a 32-bit system you need to select thex86 folder instead of x64.

My user library configuration should look like this:

Testing the configuration

Now start creating a new Java project.

On the Java Settings step, under Libraries tab, select Add Library... and select OpenCV-3.0.0, then click Finish.

Libraries should look like this:

Now once our setup is done, we are gonna write our Java Program using Swing, having a Frame, a Pane, and two button for 'Start' and 'Pause'. The pane is used to capture the webcam video.

CaptureCamVideo.java

package com.rohan.opencvtest;

import java.awt.EventQueue;

import java.awt.Graphics;

import java.awt.Image;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import java.awt.image.BufferedImage;

import java.io.ByteArrayInputStream;

import javax.imageio.ImageIO;

import javax.swing.GroupLayout;

import javax.swing.JButton;

import javax.swing.JFrame;

import javax.swing.JPanel;

import javax.swing.LayoutStyle;

import javax.swing.WindowConstants;

import org.opencv.core.Core;

import org.opencv.core.Mat;

import org.opencv.core.MatOfByte;

import org.opencv.imgcodecs.Imgcodecs;

import org.opencv.videoio.VideoCapture;

@SuppressWarnings("serial")

public class CaptureCamVideo extends JFrame {

// definitions

private DaemonThread myThread = null;

int count = 0;

VideoCapture webSource = null;

Mat frame = new Mat();

MatOfByte mem = new MatOfByte();

// class of thread

class DaemonThread implements Runnable {

protected volatile boolean runnable = false;

@Override

public void run() {

synchronized (this) {

while (runnable) {

if (webSource.grab()) {

try {

webSource.retrieve(frame);

Imgcodecs.imencode(".bmp", frame, mem);

Image im = ImageIO.read(new ByteArrayInputStream(mem.toArray()));

BufferedImage buff = (BufferedImage) im;

// Image jPanel1;

Graphics g = jPanel1.getGraphics();

if (g.drawImage(buff, 0, 0, getWidth(),

getHeight() - 150, 0, 0, buff.getWidth(),

buff.getHeight(), null))

if (runnable == false) {

System.out.println("Going to wait()");

this.wait();

}

} catch (Exception ex) {

System.out.println("Error");

}

}

}

}

}

}

public CaptureCamVideo() {

initComponents();

}

private void initComponents() {

        jPanel1 = new JPanel();

        jButton1 = new JButton();

        jButton2 = new JButton();

        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

        GroupLayout jPanel1Layout = new GroupLayout(jPanel1);

        jPanel1.setLayout(jPanel1Layout);

        jPanel1Layout.setHorizontalGroup(

            jPanel1Layout.createParallelGroup(GroupLayout.Alignment.LEADING)

            .addGap(0, 383, Short.MAX_VALUE)

        );

        jPanel1Layout.setVerticalGroup(

            jPanel1Layout.createParallelGroup(GroupLayout.Alignment.LEADING)

            .addGap(0, 276, Short.MAX_VALUE)

        );

        jButton1.setText("Start");

        jButton1.addActionListener(new ActionListener() {

            public void actionPerformed(ActionEvent evt) {

                jButton1ActionPerformed(evt);

            }

        });

        jButton2.setText("Stop");

        jButton2.addActionListener(new ActionListener() {

            public void actionPerformed(ActionEvent evt) {

                jButton2ActionPerformed(evt);

            }

        });

        GroupLayout layout = new GroupLayout(getContentPane());

        getContentPane().setLayout(layout);

        layout.setHorizontalGroup(

            layout.createParallelGroup(GroupLayout.Alignment.LEADING)

            .addGroup(layout.createSequentialGroup()

                .addGroup(layout.createParallelGroup(GroupLayout.Alignment.LEADING)

                    .addGroup(layout.createSequentialGroup()

                        .addGap(136, 136, 136)

                        .addComponent(jPanel1, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE))

                    .addGroup(layout.createSequentialGroup()

                        .addGap(179, 179, 179)

                        .addComponent(jButton1)

                        .addGap(165, 165, 165)

                        .addComponent(jButton2)))

                .addContainerGap(225, Short.MAX_VALUE))

        );

        layout.setVerticalGroup(

            layout.createParallelGroup(GroupLayout.Alignment.LEADING)

            .addGroup(layout.createSequentialGroup()

                .addContainerGap()

                .addComponent(jPanel1, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)

                .addPreferredGap(LayoutStyle.ComponentPlacement.UNRELATED)

                .addGroup(layout.createParallelGroup(GroupLayout.Alignment.LEADING)

                    .addComponent(jButton2)

                    .addComponent(jButton1))

                .addContainerGap(169, Short.MAX_VALUE))

        );

        pack();

    }

private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {

webSource = new VideoCapture(0);

myThread = new DaemonThread();

Thread t = new Thread(myThread);

t.setDaemon(true);

myThread.runnable = true;

t.start();

jButton1.setEnabled(false); // start button

jButton2.setEnabled(true); // stop button

}

private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {

myThread.runnable = false;

jButton2.setEnabled(false);

jButton1.setEnabled(true);

webSource.release();

}

public static void main(String[] args) {

System.loadLibrary(Core.NATIVE_LIBRARY_NAME); // load native library of opencv

EventQueue.invokeLater(new Runnable() {

@Override

public void run() {

CaptureCamVideo javaCam = new CaptureCamVideo();

javaCam.setVisible(true);

}

});

}

JButton jButton1;

JButton jButton2;

JPanel jPanel1;

}

Now, its time to run the program,

Run it and you will get the below screen:

Click on the Start button to view the live video capture by your webcam.

References:
http://docs.opencv.org/2.4/doc/tutorials/introduction/java_eclipse/java_eclipse.html
http://sourceforge.net/projects/opencvlibrary/?source=typ_redirect