ArrayIndexOutOfBoundsException

[pushgod]

hey in my code im processing 2 imgs....both around 200x200....while processing d first one i dont ve ne prob......but wen aplyin d same steps on other img its giving ArrayIndexOutOfBoundsException....

byte[][] R = new byte[200][200];
 byte[][] s = new byte[200][200];
 double m1[] = new double[FP_TEMPLATE_MAX_SIZE];
 double m2[] = new double[FP_TEMPLATE_MAX_SIZE];
 		
 R = grayScale(ip);
 R = ThinningHilditch(R,ip);
 R = ThinningHitAndMiss(R,ip);
 m1 = getFingerPrintTemplate(R,ip);
 printFeatures(m1);
    	
 s = grayScale(ip2);
 s = ThinningHilditch(s,ip2);
 s = ThinningHitAndMiss(s,ip2);
 m2 = getFingerPrintTemplate(s,ip2);

the grayScale function is i think d source of problem

public byte[][] grayScale(Image img)
	{
		
		byte P[][] = new byte[200][200];
		int red1,green1,blue1,cl,clr,clg,clb;
	
		//int[]rgbData = new int[img.getWidth() * img.getHeight()]; //array containin rgb of each pixel
        img.getRGB(rgbData, 0, img.getWidth(), 0, 0, img.getWidth(), img.getHeight()); //rgb of each pixel goin in the array
        
    	int [][]rgbData_two_d = new int [img.getWidth()][img.getHeight()];
		
		for(i1 = 0; i1 < img.getWidth(); i1++)
        {
        	
        	for(j1= 0; j1 <img.getHeight(); j1++)
            	{
                	
                	rgbData_two_d[i1][j1] = rgbData[temp];
                    temp++;
                }       
                
                System.out.println("");
   		}
 
      	for(i1 = 0; i1 < img.getWidth(); i1++)
      	{
    		for(j1= 0; j1 <img.getHeight(); j1++)
            { 
            	cl= rgbData_two_d[i1][j1];
           		clr= rgbData_two_d[i1][j1];
               	clb= rgbData_two_d[i1][j1];
              	clg= rgbData_two_d[i1][j1];
                       	
               	clr= clr & 0x00ff0000;
             	red1= clr>>16;
              	clg= clg & 0x0000ff00;
           		green1= clg>>8;
               	clb= clb & 0x000000ff;
          		blue1= clb;
                       	
               	if ((blue1<= 127) && (red1<= 127) && (green1 <= 127))        
              	{
                   	P[i1][j1] = 1;
              	}
                       	
           		else
              	{
           			P[i1][j1] = 0;
            	}
                   
       		}
                    
     	}
               
      	for( i1 = 0; i1<= img.getWidth() - 1;i1++)
		{
  			P[i1][0] = 0;
  			P[i1][img.getHeight()- 1] = 0;
  		}
  			  
  		for( j1 = 0 ; j1<= img.getHeight() - 1 ; j1++)
  		{
   			P[0][j1] = 0;
     		P[ img.getWidth() - 1][j1] = 0;
    	
		}
		
		return P;	
	}

here is d stack trace

java.lang.ArrayIndexOutOfBoundsException
java.lang.ArrayIndexOutOfBoundsException
at LoginMIDlet.grayScale(+99)
at LoginMIDlet.allFun(+87)
at LoginMIDlet.startApp(+12)
at javax.microedition.midlet.MIDletProxy.startApp(+7)
at com.sun.midp.midlet.Scheduler.schedule(+270)
at com.sun.midp.main.Main.runLocalClass(+28)
at com.sun.midp.main.Main.main(+116)

plzzzzz help!!!!

[grahamhughes]

I think it is because you do not initialize the variable "temp".

You use lots of non-local variables, and this will cause you endless problems. Declare your variables where you use them, in the smallest possible scope.

You call getWidth() and getHeight() often. The return the same values each time, so it is much more efficient to call them once, and store the values.

Also, there is no need to re-organize the data into a 2D array, then convert to bytes. You can do both as one step. Otherwise, you could be using a very large amount of memory.

I've simplified the code a little. Try to keep your code as simple as you can, and it will be easier for you to find problems.

public byte[][] grayScale(Image img) {
    int width = img.getWidth();
    int height = img.getHeight();

    int[] rgbData = new int[width * height];
    img.getRGB(rgbData, 0, width, 0, 0, width, height);

    byte[][] P = new byte[width][height];

    for (int x = 0; x < width; x++) {
        for (int y = 0; y < height; y++) {
            int p = rgbData[(y * width) + height];
            int alpha = (p >> 24) & 0xff;
            int red   = (p >> 16) & 0xff;
            int green = (p >>  8) & 0xff;
            int blue  =  p        & 0xff;

            if ((blue <= 127) && (red <= 127) && (green <= 127)) {
                P[x][y] = 1;
            } else {
                P[x][y] = 0;
            }
        }
    }

    for (int x = 0; x < width; x++) {
        P[x][0] = 0;
        P[x][height - 1] = 0;
    }

    for (int y = 0 ; y < height; y++) {
        P[0][y] = 0;
        P[width - 1][y] = 0;
    }

    return P;    
} 

[arpit2agrawal]

You can store 8 bits in 1 byte. So better do it like this:

byte[][] P = new byte[(width + 7) >>> 3][(height + 7) >>> 3];