Question

remove noise entire noise from this image using matlab code & get the original image

Problem 4 (35 points) 1. Describe in details how would you detect and reduce the periodic noise in the input image shown (you should have received a copy of this image via email) and remove it to get an enhanced image. 2. Use MATLAB to show the results of your answer. Include in your submission your code and resulting image. Sinusoldal Nolse Sinusoidal Noise

Answer 1

Below is the matlab code:

close all,

clear all,

clc,

ProjectPath = pwd;

baseFileName = strcat(ProjectPath,'\NoisyImg.jpg');
fullFileName=baseFileName;
grayImage = imread(baseFileName);
grayImage = rgb2gray(grayImage);
[rows columns numberOfColorBands] = size(grayImage);

subplot(2,2, 1); imshow(grayImage, [0 255]);
set(gcf, 'Name', ['Results for ' fullFileName]);
title('Original Image');
set(gcf, 'units','normalized','outerposition',[0 0 1 1]); % Maximize figure.
grayImage = double(grayImage);
frequencyImage = fftshift(fft2(grayImage));
subplot(2,2, 2);
amplitudeImage = log(abs(frequencyImage));
Minimum = min(min(amplitudeImage));
MaximumVal = max(max(amplitudeImage));
imshow(amplitudeImage, []);
title('Notice the two spikes perpendicular to periodic frequencies');
% zoom(10)
[midpointX, midpointY] = find(amplitudeImage == MaximumVal);
filterWindowHalfWidth = 1;
for row = midpointY-filterWindowHalfWidth:midpointY+filterWindowHalfWidth
for column = midpointX-filterWindowHalfWidth:midpointX+filterWindowHalfWidth
frequencyImage(row-4, column+7) = 0;
frequencyImage(row+4, column-7) = 0;
end
end
amplitudeImage2 = log(abs(frequencyImage));
Minimum = min(min(amplitudeImage2));
MaximumVal = max(max(amplitudeImage2));
subplot(2,2, 3);
imshow(amplitudeImage2, [Minimum MaximumVal]);
title('Two dots zeroed out');

filteredImage = ifft2(fftshift(frequencyImage));
amplitudeImage3 = abs(filteredImage);
Minimum = min(min(amplitudeImage3));
MaximumVal = max(max(amplitudeImage3));
subplot(2,2, 4);
imshow(amplitudeImage3, [Minimum MaximumVal]);
title('Filtered Image');

Original Image Notice the two spikes perpendicular to periodic frequencies Filtered Image Two dots zeroed out