MATLAB PROGRAM FOR IMAGE ENHANCEMENT USING FILTERS

/*MATLAB PROGRAM FOR IMAGE ENHANCEMENT USING FILTERS*/

clc

clear all

subplot(3,2,1)

A=imread('cameraman.tif')

colormap(gray)

imagesc(A)

title('original image')

B=double(A)

[m n] = size(B)

mask = [1/9 1/9 1/9 1/9 1/9 1/9 1/9 1/9 1/9]

for i= 2:1:m-1

for j=2:1:n-1

L(i,j)=B(i-1,j-1)*mask(1)+B(i-1,j)*mask(2)+B(i-1,j+1)*mask(3)+B(i,j-1)*mask(4)+B(i,j)*mask(5)+B(i,j+1)*mask(6)+B(i+1,j-1)*mask(7)+B(i+1,j)*mask(8)+B(i+1,j+1)*mask(9);

end

end

subplot(3,2,2)

colormap(gray)

imagesc(L)

title('low pass filter image')

mask1 = [-1/9 -1/9 -1/9 -1/9 8/9 -1/9 -1/9 -1/9 -1/9]

for i=2:1:m-1

for j=2:1:n-1

H(i,j)=B(i-1,j-1)*mask1(1)+B(i-1,j)*mask1(2)+B(i-1,j+1)*mask1(3)+B(i,j-1)*mask1(4)+B(i,j)*mask1(5)+B(i,j+1)*mask1(6)+B(i+1,j-1)*mask1(7)+B(i+1,j)*mask1(8)+B(i+1,j+1)*mask1(9);

end

end

subplot(3,2,3)

colormap(gray)

imagesc(H)

title('high pass filter image')

BN=imnoise(A,'salt& pepper')

subplot(3,2,4)

colormap(gray)

imagesc(BN)

title('salt and pepper noise image')

for i=2:1:m-1

for j=2:1:n-1

mr=[BN(i-1,j-1) BN(i-1,j) BN(i-1,j+1) BN(i,j-1) BN(i,j) BN(i,j+1) BN(i+1,j-1) BN(i+1,j) BN(i+1,j+1)];

smr=sort(mr);

M(i,j)=smr(5);

end

end

subplot(3,2,5)

colormap(gray)

imagesc(M)

title('median filter image')

s=2.5;

x=(9*s)-1;

mask1 = [-1/9 -1/9 -1/9 -1/9 x -1/9 -1/9 -1/9 -1/9]

for i=2:1:m-1

for j=2:1:n-1

            H(i,j)=B(i-1,j-1)*mask1(1)+B(i-1,j)*mask1(2)+B(i-1,j+1)*mask1(3)+B(i,j-1)*mask1(4)+B(i,j)*mask1(5)+B(i,j+1)*mask1(6)+B(i+1,j-1)*mask1(7)+B(i+1,j)*mask1(8)+B(i+1,j+1)*mask1(9);

end

end

subplot(3,2,6)

colormap(gray)

imagesc(H)

title('high boost filter image')

OUTPUT