I'm trying to calculate DCT and IDCT of an input image, and display the IDCT output as resultant image. But my IDCT values are going above 300. My input image is a '.rgb' image. I am also considering the height and width of the input image as constant i.e., 352*288
I am representing my input red, green and blue integers of each pixels as rgb[3][64][1583] where [3] -> index of red/green/blue and [64] -> index of pixel in each block and the [1583]-> index of the 8*8 block i.e., one of the block in 1583 blocks.
And lastly im keeping my quantization table as which has uniform value -> 2^N where N is passed as parameter.In this code the quantLevel is the N above.
Following is my Code:
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.util.Arrays;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class Jpeg {
double rgb[][][]=new double[3][64][1584];
double rgbfinal[][][]=new double[3][64][1584];
double R[][]=new double[64][1584];
double G[][]=new double[64][1584];
double B[][]=new double[64][1584];
public void go(String fname, int quantLevel){
int numBlocks=(352*288)/64;
String fileName = fname;
int width=352,height=288;
BufferedImage img = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
try {
File file = new File(fname);
InputStream is = new FileInputStream(file);
long len = file.length();
byte[] bytes = new byte[(int)len];
int offset = 0;
int numRead = 0;
while (offset < bytes.length && (numRead=is.read(bytes, offset, bytes.length-offset)) >= 0) {
offset += numRead;
}
int ind = 0;
for(int y = 0; y < height; y++){
for(int x = 0; x < width; x++){
byte r = bytes[ind];
byte g = bytes[ind+height*width];
byte b = bytes[ind+height*width*2];
int pix = 0xff000000 | ((r & 0xff) << 16) | ((g & 0xff) << 8) | (b & 0xff);
img.setRGB(x,y,pix);
ind++;
}
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
int indexRow=0,indexCol=0,indexBlock=0,indexBits=0,indexPixelBlock=0,indexPixel=0;
long count=0L;
String binary="";
indexPixel=0;
indexBlock=0;
int i=0;
while(count!=(long)(numBlocks*64)){
int pix = img.getRGB(indexCol, indexRow);
int red = (pix >> 16) & 0x000000FF;
int green = (pix >>8 ) & 0x000000FF;
int blue = (pix) & 0x000000FF;
rgb[0][indexPixel][indexBlock]=red;
rgb[1][indexPixel][indexBlock]=green;
rgb[2][indexPixel][indexBlock]=blue;
count++;
indexPixel++;
if(indexCol==width-1 && indexRow==height-1)
break;
if(indexCol%7==0 && indexCol!=0 && indexPixel%8==0)
{
indexPixel=indexPixelBlock;
indexBlock++;
}
if(indexPixel%8==0 && indexCol%7!=0 && indexBlock!=1583)
{
indexPixel=indexPixelBlock;
indexBlock++;
}
if(indexCol==width-1)
{
indexCol=0;
indexRow++;
}
else
indexCol++;
if((indexPixel)%8==0 && indexBlock==numBlocks-1 && indexCol%7==0)
{
indexBlock=0;
indexPixelBlock=indexPixel;
}
}
calcQuantizedDCT(quantLevel);
calcInverseDCT(quantLevel);
JFrame frame = new JFrame();
frame.setLocation(0,0);
frame.setSize(1024, 720);
frame.getContentPane().setBackground(Color.WHITE);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel p=new JPanel();
p.setLayout(new FlowLayout(FlowLayout.LEFT));
p.setLocation(100,100);
JLabel label = new JLabel(new ImageIcon(img));
label.setLocation(0,0);
label.setSize(352,288);
p.add(label);
frame.add(p);
frame.setVisible(true);
return;
}
void calcQuantizedDCT(int quantLevel)
{
String binary="";
int indexBlock=0,indexPixel=0,indexBits=0,red=0,green=0,blue=0,x=0,y=0,indexPixelTemp=0,u=0,v=0;
double sumRed=0,sumGreen=0,sumBlue=0;
String substr="";
int i=0;
for(indexBlock=0;indexBlock<1584;indexBlock++)
{
indexPixel=0;
//
while(indexPixel!=64 && u<8)
{
while(indexPixelTemp<64 && x<8)
{
red=(int)rgb[0][indexPixelTemp][indexBlock];
green=(int)rgb[1][indexPixelTemp][indexBlock];
blue=(int)rgb[2][indexPixelTemp][indexBlock];
// System.out.println(red);
sumRed+=red*Math.cos((Math.PI*(2*y+1)*u)/(2*8))*Math.cos((Math.PI*(2*x+1)*v)/(2*8));
sumGreen+=green*Math.cos((Math.PI*(2*x+1)*u)/(2*8))*Math.cos((Math.PI*(2*y+1)*v)/(2*8));
sumBlue+=blue*Math.cos((Math.PI*(2*x+1)*u)/(16))*Math.cos((Math.PI*(2*y+1)*v)/(16));
indexPixelTemp++;
y++;
if(y==8)
{
x++;
y=0;
}
}
//System.out.println("SumRed :"+sumRed);
if(u==0 && v==0)
{
//System.out.println("U & V & Pixel & Block "+u+" "+v+" "+indexPixel+" "+indexBlock);
R[indexPixel][indexBlock]=(Math.sqrt(1.0/64.0)*sumRed)/Math.pow(2,quantLevel);
G[indexPixel][indexBlock]=(Math.sqrt(1.0/64.0)*sumGreen)/Math.pow(2,quantLevel);
B[indexPixel][indexBlock]=(Math.sqrt(1.0/64.0)*sumBlue)/Math.pow(2,quantLevel);
}
else
{
//System.out.println("U & V & Pixel & Block "+u+" "+v+" "+indexPixel+" "+indexBlock);
R[indexPixel][indexBlock]=(Math.sqrt(2.0/32.0)*sumRed)/Math.pow(2,quantLevel);
G[indexPixel][indexBlock]=(Math.sqrt(2.0/32.0)*sumGreen)/Math.pow(2,quantLevel);
B[indexPixel][indexBlock]=(Math.sqrt(2.0/32.0)*sumBlue)/Math.pow(2,quantLevel);
}
indexPixel++;
if(indexPixel==64)
break;
indexPixelTemp=0;
v++;
if(v==8)
{
v=0;
u++;
}
x=0;y=0;sumGreen=0;sumRed=0;sumBlue=0;
}
u=0;v=0;
}
/* for(int j=0;j<64;j++)
{
System.out.print(R[j][0]+" ");
if(j%7==0 && j!=0)
System.out.println();
}
*/
}
void calcInverseDCT(int quantLevel)
{
String binary="";
int indexBlock=0,indexPixel=0,indexBits=0,u=0,v=0,x=0,y=0,indexPixelTemp=0,sumRed=0,sumGreen=0,sumBlue=0,red=0,green=0,blue=0;
for(indexBlock=0;indexBlock<1584;indexBlock++)
{
for(indexPixel=0;indexPixel<64;indexPixel++)
{
R[indexPixel][indexBlock]=R[indexPixel][indexBlock]*Math.pow(2,quantLevel);
G[indexPixel][indexBlock]=G[indexPixel][indexBlock]*Math.pow(2,quantLevel);
B[indexPixel][indexBlock]=B[indexPixel][indexBlock]*Math.pow(2,quantLevel);
}
}
int i=0;
indexPixelTemp=0;
indexPixel=0;
for(indexBlock=0;indexBlock<1584;indexBlock++)
{
indexPixel=0;
while(indexPixel<64 && x<8)
{
indexPixelTemp=0;
while(indexPixelTemp<64 && u<8)
{
red=(int)R[indexPixelTemp][indexBlock];
if(u==0 && v==0)
sumRed+=Math.sqrt(1.0/2.0)*red*Math.cos((Math.PI*(2*x+1)*u)/(2*8))*Math.cos((Math.PI*(2*y+1)*v)/(2*8));
else
sumRed+=red*Math.cos((Math.PI*(2*x+1)*u)/(2*8))*Math.cos((Math.PI*(2*y+1)*v)/(2*8));
green=(int)G[indexPixelTemp][indexBlock];
if(u==0 && v==0)
sumGreen+=Math.sqrt(1.0/2.0)*green*Math.cos((Math.PI*(2*x+1)*u)/(2*8))*Math.cos((Math.PI*(2*y+1)*v)/(2*8));
else
sumGreen+=green*Math.cos((Math.PI*(2*x+1)*u)/(2*8))*Math.cos((Math.PI*(2*y+1)*v)/(2*8));
blue=(int)B[indexPixelTemp][indexBlock];
if(u==0 && v==0)
sumBlue+=Math.sqrt(1.0/2.0)*blue*Math.cos((Math.PI*(2*x+1)*u)/(2*8))*Math.cos((Math.PI*(2*y+1)*v)/(2*8));
else
sumBlue+=blue*Math.cos((Math.PI*(2*x+1)*u)/(2*8))*Math.cos((Math.PI*(2*y+1)*v)/(2*8));
indexPixelTemp++;
v++;
if(v==8)
{
u++;
v=0;
}
}
rgbfinal[0][indexPixel][indexBlock]=sumRed;
rgbfinal[1][indexPixel][indexBlock]=sumGreen;
rgbfinal[2][indexPixel][indexBlock]=sumBlue;
indexPixel++;
indexPixelTemp=0;
y++;
if(y==8)
{
y=0;
x++;
}
u=0;v=0;sumGreen=0;sumRed=0;sumBlue=0;
}
if(i==3)
break;
x=0;y=0;
}
System.out.println();
/*for(i=0;i<64;i++)
{
System.out.print(rgbfinal[0][i][0]+" ");
if(i%7==0 && i!=0)
System.out.println();
}*/
}
public static void main(String args[]){
Jpeg a = new Jpeg();
a.go("src/image2.rgb",0);
}
}
I am not trying to display the output image as the ouput of IDCT for Red which i checked goes above 255.
Please help.
