Thread: Problem with image crop and pixel comparison code

I have got some code to read in an image, crop a region from the image and compare with a reference image.
It seems to compile and work ok until the line

data1 = (int[]) grab1.getPixels();

at which point it crashes
when i run the code. I do previously use pdftk and convert (in Ubuntu) to extract .png images from a pdf file so maybe it is a problem with the output .png?

code:

  if(NAME.endsWith("_1.1.1.png")) {
 //
 //
 //
	println("first filename:");
  	System.out.println(NAME);
        String curDir = System.getProperty("user.dir");
	println("current directory:");
	System.out.println(curDir);
  	int flag = 111;
	System.out.format("flag = %d%n", flag);
	BufferedImage image = null;
        try {
	    // Read from a first image file  
		//hardcoded right now!
          // File file = new File(".../image/2cm.png");
  File file = new File(".../s123456TTT2012-06-2_1.1.1.png"); 
	      //File file = new File(curDir, '/', NAME); 
            image = ImageIO.read(file);  
	   // crop and save output image
	image = image.getSubimage(100, 40, 100, 100);
 	ImageIO.write(image, "png",new File(".../image/out.png"));
	//Comp();
 
        } catch (IOException e) {
        	e.printStackTrace();
        }
 
	// compare the cropped image with the reference image (for 2 cm scale)
	String file1 = ".../image/ref.png";
	String file2 = ".../image/out.png";
 
	Image image1 = Toolkit.getDefaultToolkit().getImage(file1);
	Image image2 = Toolkit.getDefaultToolkit().getImage(file2);
 
	try {
 
	PixelGrabber grab1 =new PixelGrabber(image1, 0, 0, -1, -1, false);
	PixelGrabber grab2 =new PixelGrabber(image2, 0, 0, -1, -1, false);
 
	int[] data1 = null;
 
	if (grab1.grabPixels()) {
	int width = grab1.getWidth();
	int height = grab1.getHeight();
	data1 = new int[width * height];
	data1 = (int[]) grab1.getPixels();
	}
 
	int[] data2 = null;
 
	if (grab2.grabPixels()) {
	int width = grab2.getWidth();
	int height = grab2.getHeight();
	data2 = new int[width * height];
	data2 = (int[]) grab2.getPixels();
	}
 
	System.out.println("The Calypso data has a 2 cm scale: " + java.util.Arrays.equals(data1, data2));
 
	} catch (InterruptedException e1) {
	e1.printStackTrace();
	}

error:

Now running java PNG to ASCII code...
first filename:
s123456TTT2012-06-2_1.1.1.png
current directory:
.../
flag = 111
Exception in thread "Animation Thread" java.lang.ClassCastException: [B cannot be cast to [I
	at CalypsoAnalysis.setup(CalypsoAnalysis.java:104)
	at processing.core.PApplet.handleDraw(Unknown Source)
	at processing.core.PApplet.run(Unknown Source)
	at java.lang.Thread.run(Thread.java:636)

thanks

i figured it out. I perform two Linux 'convert' commands on the original PNG image. this somehow corrupts the data. I have modified my code to crop from the image output after the initial 'convert' and the pixel comparison works ok.