Basic Filters in MatLab

Contents

• Adding noice to an Image
• Median Filter
• Minimum filter
• Maximum filter
• Embos Filter
• Sobel Operator

%%This is for training...
%reading image
i = imread('1.png');
figure; imshow(i); title('Original Image');

%%Testing with filters
% Average Filter
averageFilter = fspecial('average', [2, 2]);
averageFilterImage = imfilter(i, averageFilter);
figure; imshow(averageFilterImage); title('Image after average filter');


% Gaussian Filter
gFilter = fspecial('gaussian');
gFilterImage = imfilter(i, gFilter);
figure; imshow(gFilterImage); title('Image after Gaussian filter');

Adding noice to an Image

grayScaleImage = rgb2gray(i);
noiseImage = imnoise(grayScaleImage, 'salt & pepper', 0.02);
figure; imshow(noiseImage); title('After adding noice');

Median Filter

medialnFilterdImage = medfilt2(noiseImage);
figure; imshow(medialnFilterdImage); title('After applying median filter');

Minimum filter

minImage = ordfilt2(grayScaleImage, 1, true(5));
figure; imshow(minImage); title('After applying min filter');

Maximum filter

maxImage  = ordfilt2(grayScaleImage, 9, true(3));
figure; imshow(maxImage); title('After applying max filter');

Embos Filter

kern = [0 0 0; 1 0 -1 ; 0 0 0];
embossImage = imfilter(grayScaleImage, kern);
figure; imshow(embossImage); title('After applying EMBOSS filter');

Sobel Operator

bw = edge(grayScaleImage, 'sobel');
figure; imshow(bw); title('After applying Sobel filter');

% m7 = grayScaleImage*bw;
% figure; imshow(m7); title('After applying Sobel filter');

%%Some other edge filters
% Canny filter
BW1 = edge(grayScaleImage,'Canny');
figure; imshow(BW1); title('After applying canny filter');

% Prewitt filter
BW2 = edge(grayScaleImage,'Prewitt');
figure; imshow(BW2); title('After applying Prewitt filter');

robe = edge(grayScaleImage,'roberts');
figure; imshow(robe); title('After applying roberts filter');

Published with MATLAB® 7.6

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About Mahinda Jayasundara

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