Computer assignment 6 - EE114 Speech and Image Processing...

EE114 Speech and Image Processing Systems Design – Computer Assignment 6
Speech and Image Processing System Design
Computer Assignment 6
- Simple Image compression(LPF) -
Subject : EE114
Professor : Flavio Lorenzelli
Department : EE Engineering
Name : Jong Hyun Lee Si Hyun Park
Student number : 804-111-081 503-693-067
Due date : February 27(Wednesday), 2013
Abstract
We perform simple image compression using 2D-DFT(2D-FFT) and reduction of
frequency components of the image.(Low pass filter)

EE114 Speech and Image Processing Systems Design – Computer Assignment 6
%% Initiation
clear all close all clc;
image = imread( 'image.tif' );
figure(1)
imagesc(image); colormap(gray);
title( 'Original' );
axis square
%% 2D-FFT
c = 6;
image_fft = fft2(image);
image_fft_LogScale = (log10( abs(image_fft)/max(max(abs(image_fft))) ) +c) *
255/c;
image_fft_LogScale_shift = fftshift(image_fft_LogScale);
figure(2)
imagesc(image_fft_LogScale_shift); colormap(gray);
title( 'FFT of Original' );
axis square
%% Modification of the coefficients(128)
% Reduction
image_fft_reduce = image_fft;
[length_a, length_b] = size(image_fft_reduce);
reduction_size = 128;
image_fft_reduce(reduction_size : length_a - reduction_size, :) = 0.0001;
image_fft_reduce(:, reduction_size : length_b - reduction_size) = 0.0001;
image_fft_reduce_LogScale = (log10(
abs(image_fft_reduce)/max(max(abs(image_fft_reduce))) ) +c) * 255/c;