[WM]: Problems understanding this algorithm...

[tan haisiang <siang3333@yahoo.com>]

i am trying to do a watermarking on image, i facing
some problems in image processing...

*******************************************************
  public static int[] extractGreyValues(int pixels[])
  {

//   int pixels[] = extractPixelValues(image,ob);
   /* int alpha=0;*/
     int newClr =0;
     int [] clr = new int [NO_OF_CHANNEL];
 
    newClr =(int) (0.2125*(double)clr[ImageData.RED] +

    0.7154*(double)clr[ImageData.GREEN] + 0.0721*
double)clr[ImageData.BLUE]) ;


    for (int k = 0; k < pixels.length; k++)
    {
//   red = clr = extractColourValue(pixels[k]);

/*uses ITU-R Recommendation BT.709, "Basic Parameter
Values for the Studio and for International Programme
Exchange (1990) [formerly CCIR Rec.709]*/
	
        newClr =(int) (0.2125*(double)clr[RED] + 0.7154*(double)clr[GREEN] + 
			0.0721*(double)clr[BLUE]) ;

        pixels[k] = 0xff000000 | (newClr << 16) |
(newClr << 8) | (newClr);

    }
     return pixels;
  }
******************************************************

CAn anyone explain to me how is it working here:
******************************************************
        newClr =(int) (0.2125*(double)clr[RED] + 0.7154*(double)clr[GREEN] + 
			0.0721*(double)clr[BLUE]) ;

        pixels[k] = 0xff000000 | (newClr << 16) |
(newClr << 8) | (newClr);
******************************************************


Thanks.
From:Siang



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