DCT of buffered image using JTransform - Java -

i'm trying dct of bufferedimage using jtransform. when visualise transform looks http://tinypic.com/r/2vcxhzo/8

in order use jtransform need convert bufferedimage 2d double array. i've tried 2 different methods change bufferedimage double array

    public double[][] convertto2darray(bufferedimage image) {          final byte[] pixels = ((databufferbyte) image.getraster()         .getdatabuffer()).getdata();         final int width = image.getwidth();         final int height = image.getheight();          double[][] result = new double[height][width];          final boolean hasalphachannel = image.getalpharaster() != null;         if (hasalphachannel) {            final int pixellength = 4;            (int pixel = 0, row = 0, col = 0; pixel < pixels.length; pixel += pixellength) {                int argb = 0;                argb += (((int) pixels[pixel] & 0xff) << 24); // alpha                argb += ((int) pixels[pixel + 1] & 0xff); // blue                argb += (((int) pixels[pixel + 2] & 0xff) << 8); // green                argb += (((int) pixels[pixel + 3] & 0xff) << 16); // red                result[row][col] = argb;                col++;             if (col == width) {                 col = 0;                 row++;             }         }        } else {           final int pixellength = 3;           (int pixel = 0, row = 0, col = 0; pixel < pixels.length; pixel += pixellength) {             int argb = 0;             argb += -16777216; // 255 alpha             argb += ((int) pixels[pixel] & 0xff); // blue             argb += (((int) pixels[pixel + 1] & 0xff) << 8); // green             argb += (((int) pixels[pixel + 2] & 0xff) << 16); // red             result[row][col] = argb;             col++;             if (col == width) {                 col = 0;                 row++;             }         }     }      return result; } 

i've tried

private double[][] bufferedimagetoarray(bufferedimage image) {     int h = image.getheight();     int w = image.getwidth();     int[][] array = new int[h][w];     double[][] result;          (int count = 0; count < h; count++) {         (int loop = 0; loop < w; loop++) {              int gray = image.getrgb(loop, count) & 0xff;              // add values array             array[count][loop] = gray;         }     }     result = todoublearray(array);     return result; } 

i've implemented transform

public double[][] applydct(double[][] image) {      doubledct_2d transform = new doubledct_2d(image.length, image[0].length);      transform.forward(image, true);      return image; } 

i tried using opencv's dct transform gives same output shown in link.

ty (i kept blue channel simplicity). shows energy compaction in upper left corner of result image.

import java.awt.graphicsconfiguration; import java.awt.graphicsdevice; import java.awt.graphicsenvironment; import java.awt.image; import java.awt.transparency; import java.awt.image.bufferedimage; import javax.swing.imageicon; import javax.swing.jframe; import javax.swing.jlabel;  public class testdct {   public static void main(string[] args)   {     imageicon icon = new imageicon(args[0]);     image image = icon.getimage();     int w = image.getwidth(null);     int h = image.getheight(null);     graphicsdevice gs = graphicsenvironment.getlocalgraphicsenvironment().getscreendevices()[0];     graphicsconfiguration gc = gs.getdefaultconfiguration();     bufferedimage img = gc.createcompatibleimage(w, h, transparency.opaque);     img.getgraphics().drawimage(image, 0, 0, null);     int[] rgb1 = new int[w*h];     img.getraster().getdataelements(0, 0, w, h, rgb1);     double[] array = new double[w*h];      (int i=0; i<w*h; i++)        array[i] = (double) (rgb1[i] & 0xff);      org.jtransforms.dct.doubledct_2d tr = new org.jtransforms.dct.doubledct_2d(w, h);     tr.forward(array, true);      (int i=0; i<w*h; i++)     {        // grey levels        int val= math.min((int) (array[i]+128), 255);        rgb1[i] = (val <<16) | (val << 8) | val;     }      img.getraster().setdataelements(0, 0, w, h, rgb1);     icon = new imageicon(img);     jframe frame = new jframe("fft");     frame.setbounds(20, 30, w, h);     frame.add(new jlabel(icon));     frame.setvisible(true);   } 

}