imageprocessor.java

a zipped example for using a USB camera directly from Java

/**	
 *	JMF Image Processor.  Provides methods to process frames ripped
 *	from live video streams.  It allows access to each pixel within
 *	the image and the images could also be saved to disk in JPEG format.
 *	
 *	@author		Zhenlan Jin
 *	@version	%I%, %G%
 *	@since		1.0
 */

import java.io.*;
import java.util.*;
import java.awt.*;
import java.awt.image.*;
import javax.media.*;
import javax.media.format.*;
import javax.media.control.*;
import javax.media.util.*;
import com.sun.image.codec.jpeg.*; // jpeg encoder

public class ImageProcessor {

	/**
	 *	Returns the current frame in the live video stream specified by Player.
	 *	This method is meant for players in the started state.
	 *	
	 *	@param	player	Player object currently playing the live video stream.
	 *	@return	Image	Image object representing the current frame.
	 */
	public Image getFrame(Player player) {
 	
 		// Grab a frame      
		FrameGrabbingControl fgc = (FrameGrabbingControl)
			player.getControl("javax.media.control.FrameGrabbingControl");
		Buffer buf = fgc.grabFrame();
	
		// Convert it to an image      
		BufferToImage btoi = new BufferToImage((VideoFormat)buf.getFormat());
		Image img = btoi.createImage(buf);
		
		return img;
 	}
 	
 	/**
 	 *	Allows acess to the pixels inside a Java.awt.Image.  Returns an int array
 	 *	with values in each pixel within the rectangle specified by the parameters
 	 *	x, y, w and h.  (x,y) represents the coordinates of the upper left hand corner
 	 *	of the rectangle, while (w,h) represents the coordinates of the lower right
 	 *	hand corner.  Throws InterruptedException if the pixel grab process is
 	 *	interrupted.
 	 *
 	 *	@param	img		the image to be processed.
 	 *			x		the x coordinate of the upper left hand corner.
 	 *			y		the y coordinate of the upper left hand corner.
 	 *			w		the width of the rectangle
 	 *			h		the height of the rectangle.
 	 *	@return	int[]	the integer array representing the value of each pixel in the rectangle.
 	 *	@exception	InterruptedException	thrown if the method is interrupted.
 	 */
 	
 	public int[] getPixel(Image img, int x, int y, int w, int h) throws InterruptedException {
 		int[] iArray = new int[(w-x) * (h-y)];
 	
 		PixelGrabber pg = new PixelGrabber(img, x, y, w, h, iArray, 0, (w-x));
		pg.grabPixels();
		
		return iArray;
 	}
 	
 	/**
 	 *	Finds a video capture device that supports the specified VideoFormat.  Starts
 	 *	streaming the live video and returns the player.  Returns null if a video
 	 *	source with the specified format could not be found or started.
 	 *	
 	 *	@param	vFormat		the desired format of the live video stream
 	 *	@return	Player		the player representing the video stream
 	 */
 	
 	public Player initPlayer(VideoFormat vFormat) {
 		CaptureDeviceInfo cdInfo = null;
 		Player newPlayer = null;
		
		// find all available video capture devices and use the first one found.
		Vector devices= CaptureDeviceManager.getDeviceList(vFormat);
		if (devices.size() > 0) {
 			cdInfo = (CaptureDeviceInfo) devices.elementAt(0);
 		}
 		else {
 			System.out.println("Error: failed to find appropriate capture device");
 			return null;
 		}
 		
 		try {
 			newPlayer = Manager.createRealizedPlayer(cdInfo.getLocator());
			newPlayer.start();
		}
		catch (Exception e) {
			if (e instanceof NoPlayerException)
				System.out.println("Player could not be created");
			else if (e instanceof CannotRealizeException)
				System.out.println("Player could not be realized");
			else if (e instanceof IOException)
				System.out.println("IOException: problem connecting with source.");
			else
				System.out.println("unknown error: Player could not be initialized");
			
			return null;
		}
		
		while (newPlayer.getState() != Controller.Started) {
			try {
				Thread.sleep(1);
			}
			catch (InterruptedException e) {}
		}
		return newPlayer;
 	}
 	
 	
 	/**
 	 *	Saves the image to disk in JPEG format.
 	 *
 	 *	@param	img		the image to save to disk
 	 *			s		the name of the file to save to
 	 *	@return	void
 	 */
 	public static void saveJPG(Image img, String s)  {
		
		FileOutputStream out = null;
		
		// create a buffered Image
 		BufferedImage bi = new BufferedImage(img.getWidth(null), img.getHeight(null), BufferedImage.TYPE_INT_RGB);
 		Graphics2D g2 = bi.createGraphics();
 		g2.drawImage(img, null, null);
 		
 		try {
 			out = new FileOutputStream(s);
 		}
 		catch (java.io.FileNotFoundException io)    {
 			System.out.println("File Not Found");
 			return;
 		}
 		
 		// encode the data with JPEG format and save to file.
 		JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
 		JPEGEncodeParam param = encoder.getDefaultJPEGEncodeParam(bi);
 		param.setQuality(0.5f,false);
 		encoder.setJPEGEncodeParam(param);
 		try {
 			encoder.encode(bi);
 			out.close();
 		}
 		catch (java.io.IOException io) {
 			System.out.println("IOException: JPEG encoding failed");
 			return;
 		}  
 	}
}