gaurav007
Newbie level 4
![Newbie level 4](/styles/images/ranks/blevel1.gif)
sir I am a research scholar, and currently working on lossy image compression using FFT.
The proposed FFT/IFFT algorithm is also folIows:
So far i have done this
now i want to recombine Fblock (fft of each block) after taking inverse fft plz help me out i am confused a lot
The proposed FFT/IFFT algorithm is also folIows:
- Read the input file from the host system.
- Evaluate the (8x8) Cosine and Sine matrix using Equations.
C(u+l, x+l) = cos(pi / 4)*(u* x))
S(u + 1, x + 1) = sin(pi / 4) * (u * x))
- The image is accessed as (8x8) block successively, and the Cosine and Sine transforms are obtained.
- Compute the FFT of the image using basic equation.
- Verify the obtained FFT values with buiIt in FFT functional values of MATLAB.
- Compute the IFFT of the processed image in step 4 using the Eq.
- Verify visually the reconstructed image with the original image.
- Calculate the Power Signal to Noise Ratio (PSNR) of the processed signals for validation.
So far i have done this
clc;
clear all;
close all;
I_color=imread('lena.jpg');
I=rgb2gray(I_color);
[r,c,p]= size(I);
subplot(2,2,1);
imshow(I_color);
title('Original Image');
subplot(2,2,2);
imshow(I);
title('Grayscaled');
bs=8;
nob=r/bs;
xx=0;
% creating cos and sine matrix
for u=0:7
for x=0:7
C(u+1,x+1)= cos((pi/4)*(u*x)); %cos matrix
S(u+1,x+1)= sin((pi/4)*(u*x)); %sine matrix
C= im2uint8(C);
S= im2uint8(S);
end
end
%Ctransform = zeros(8,8,64);
for k=1:r/bs
for j=1:c/bs
block,:,xx+j)= I(bs*(k-1)+1:bs*(k-1)+bs,bs*(j-1)+1:bs*(j-1)+bs);
Ctransform,:,xx+j)= immultiply(C,block
,:,xx+j));
Stransform,:,xx+j)= immultiply(S,block
,:,xx+j));
end
xx=xx+(r/bs);
end
yy=0;
%F=im2uint8(zeros(512,512));
Fblock=im2uint8(zeros(8,8,64));
for M=1:64
for N=1:64
Fblock,:,yy+N)=Ctransform
,:,yy+N) +imag((Stransform
,:,yy+N)));
% F(bs*(M-1)+1:bs*(M-1)+bs,bs*(N-1)+1:bs*(N-1)+bs) = Fblock;
end
yy=yy+64;
end
now i want to recombine Fblock (fft of each block) after taking inverse fft plz help me out i am confused a lot