Removing Noise from a Noisy Corrupted Image using various Filtering Techniques

Lenna = imread('lenna2.jpg');

NoiseLenna = imnoise(Lenna,'salt & pepper',0.02);

GF1 = fspecial('gaussian',[3 3],0.5);

GF2 = fspecial('gaussian',[5 5],0.5);

GF3 = fspecial('gaussian',[7 7],0.5);

AV1 = [1 1 1;

            1 1 1;

            1 1 1]/9;

AV2 = [1 1 1 1 1;

            1 1 1 1 1;

            1 1 1 1 1;

            1 1 1 1 1;      

            1 1 1 1 1]/25;

AV3 = [1 1 1 1 1 1 1;

            1 1 1 1 1 1 1;

            1 1 1 1 1 1 1;

            1 1 1 1 1 1 1;

            1 1 1 1 1 1 1;

            1 1 1 1 1 1 1;      

            1 1 1 1 1 1 1]/49;

  

GaussLenna = imfilter(NoiseLenna,GF1);

subplot(3,4,1);  imshow(GaussLenna);  ylabel('3x3'); title('Gaussian Filter');

GaussLenna = imfilter(NoiseLenna,GF2);

subplot(3,4,5);  imshow(GaussLenna);  ylabel('5x5');

GaussLenna = imfilter(NoiseLenna,GF3);

subplot(3,4,9);  imshow(GaussLenna);  ylabel('7x7');

AvgLenna = imfilter(NoiseLenna,AV1); 

subplot(3,4,2);  imshow(AvgLenna);  title('Averaging Filter');

AvgLenna = imfilter(NoiseLenna,AV2);

subplot(3,4,6);  imshow(AvgLenna);

AvgLenna = imfilter(NoiseLenna,AV3);

subplot(3,4,10);  imshow(AvgLenna);

MedLenna = medfilt2(NoiseLenna,[3 3]); 

subplot(3,4,3);  imshow(MedLenna);  title('Median Filter');

MedLenna = medfilt2(NoiseLenna,[5 5]);

subplot(3,4,7);  imshow(MedLenna);

MedLenna = medfilt2(NoiseLenna,[7 7]);

subplot(3,4,11);  imshow(MedLenna);

OrdLenna = ordfilt2(NoiseLenna,5,ones(3,3)); 

subplot(3,4,4);  imshow(OrdLenna);  title('Ordered Filter');

OrdLenna = ordfilt2(NoiseLenna,5,ones(5,5));

subplot(3,4,8);  imshow(OrdLenna);

OrdLenna = ordfilt2(NoiseLenna,5,ones(7,7));

subplot(3,4,12);  imshow(OrdLenna);