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Image Processing and Pattern Recognition
Experiment VI
11bce022
Objective: For the same image set enhanced using frequency
domain filter find closest spatial domain filter to obtain similar
images.
List of Frequency Domain Filters I have used:
(1) Arithmetic Filter (2) Harmonic Filter (3) Geometric Filter
(4) Contra harmonic Filter (5) Alpha Trimmed Filter
Implementation Code: I =
imread('C:\Users\Niks_$marty\Desktop\Lena.jpg'); I =
imnoise(I,'gaussian'); figure; subplot(2,3,1); imshow(I);
title('Gaussian Noise Image'); [m,n] = size(I); m_size=input('Mask
Size'); mn=(m_size)*(m_size); p=floor(m_size/2); disp(p); %padding
for i = 1:m+(m_size-1) for j = 1:n+(m_size-1) for i=1:p B(i,j) = 0;
end
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for j=1:p B(i,j) = 0; end q=m+p+1; r=(2*p+m); for i=q : r B(i,j)
= 0; end for j=q : r B(i,j) = 0; end end end % Arithmetic Filter
for i = 1:m-2 for j = 1:n-2 A(i,j) = uint8(I(i,j)/mn + I(i,j+1)/mn
+ I(i,j+2)/mn + I(i+1,j)/mn + I(i+1,j+1)/mn + I(i+1,j+2)/mn +
I(i+2, j)/mn + I(i+2,j+1)/mn + I(i+2,j+2)/mn); end end
subplot(2,3,2); imshow(A); title('Arithmetic Filter'); for i =
1:m+2 for j = 1:n+2 if (i==1)||(j==1) C(i,j) = 0; elseif
(i==m+2)||(j==m+2) C(i,j) = 0; else C(i,j) = I(i-1,j-1); end end
end % Harmonic Filter
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for i = 1:m for j = 1:n D(i,j) = uint8(9/(1/C(i,j) + 1/C(i,j+1)
+ 1/C(i,j+2) + 1/C(i+1,j) + 1/C(i+1,j+1) + 1/C(i+1,j+2) + 1/C(i+2,
j) + 1/C(i+2,j+1) + 1/C(i+2,j+2))); end end subplot(2,3,3);
imshow(D); title('Harmonic Filter'); for i = 1:m+2 for j = 1:n+2 if
(i==1)||(j==1) E(i,j) = 0; elseif (i==m+2)||(j==m+2) E(i,j) = 0;
else E(i,j) = I(i-1,j-1); end end end % Geometric Filter for i =
1:m for j = 1:n F(i,j) = uint8((E(i,j) * E(i,j+1) * E(i,j+2) *
E(i+1,j) * E(i+1,j+1) * E(i+1,j+2) * E(i+2, j) * E(i+2,j+1) *
E(i+2,j+2))^(1/9-2)); end end subplot(2,3,4); imshow(F);
title('Geometric Filter'); Q = input('Order of filter:'); for i =
1:m+2 for j = 1:n+2 if (i==1)||(j==1) G(i,j) = 0; elseif
(i==m+2)||(j==m+2)
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G(i,j) = 0; else G(i,j) = I(i-1,j-1); end end end % Contra
Harmonic Filter for i = 1:m for j = 1:n H(i,j) = uint8(((G(i,j) +
G(i,j+1) + G(i,j+2) + G(i+1,j) + G(i+1,j+1) + G(i+1,j+2) + G(i+2,
j) + G(i+2,j+1) + G(i+2,j+2))^(Q+1))/(G(i,j) + G(i,j+1) + G(i,j+2)
+ G(i+1,j) + G(i+1,j+1) + G(i+1,j+2) + G(i+2, j) + G(i+2,j+1) +
G(i+2,j+2))^(Q)); end end subplot(2,3,5); imshow(H);
title('Contraharmonic Filter'); for i = 1:m+2 for j = 1:n+2 if
(i==1)||(j==1) J(i,j) = 0; elseif (i==m+2)||(j==m+2) J(i,j) = 0;
else J(i,j) = I(i-1,j-1); end end end % Alpha Trimmed Filter for i
= 1:m-2 for j = 1:n-2 K(i,j) = uint8((J(i,j) * J(i,j+1) * J(i,j+2)
* J(i+1,j) * J(i+1,j+1) * J(i+1,j+2) * J(i+2, j) * J(i+2,j+1) *
J(i+2,j+2))^(1/7)); end
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end subplot(2,3,6); imshow(K); title('Alpha Trimmed
Filter');
Output:
Conclusion: Closest Filter are Arithmetic and Harmonic
Filter
