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Gamma using log

I= imread ("cameraman.tif");
Id= double (I);
[m, c] =size(Id);
J= zeros (size (Id));
for  i 1:m
      for  j= 1:c
            J (i,j) = log (Id (i,j) + 1);
      end;
end;
figure;
subplot (1,2,1);
imshow (I,[]);

subplot (1, 2,2); 
imshow (J, []);


Gamma using power

I=imread ("cameraman.tif");
Id-double (I);
[m, c] = size (Id);
J= zeros (size (Id));
for i 1:m
      for j 1: c
            I(i, j) power (Id (i,j)+1,2);
      end;
end;
figure;
subplot (1,2,1); imshow(I,[]);
subplot (1,2,2), imshow(I,[]);

intensity level slicing 

I=imread("cameraman.tif");
Id = 1 double(I);
[m, c]= size(Id);
J= zeros(size(Id));

for i = 1:m 
      for j = 1:c 
            if ( I(i, j) > 100 && J(i, j) < 150 ) 										J(i, j) = 255;
						 else
										J(i,j)= I(i,j);
						end
			end
end

figure;
subplot(1,2,1); imshow(I);
subplot(1,2,2); imshow(uint8(J));


Thresholding


I = imread('cameraman.tif');
I = double(I);
threshold = 100; 
J = zeros(size(I)); 
J(I > threshold) = 255; 
figure;
subplot(1, 2, 1); imshow(uint8(I)); title('Original Image'); 
subplot(1, 2, 2); imshow(uint8(J)); title('Thresholded Image');



Smoothing 


I= imread('peppers.png');

if size(I , 3) == 3
   I = rgb2gray(I);
end


[m, n] = size(I);

%blank image
J = zeros(m, n);

%defining simple average mask
kernel_size = 7;
pad_size = floor(kernel_size / 2);
kernel=(1/(kernel_size*kernel_size))*ones(kernel_size,kernel_size);


padded_img = padarray(I, [pad_size pad_size], 0, 'both');

%correlation
for i = 1:m
    for j = 1:n
        
        neighborhood = padded_img(i:i+kernel_size-1, j:j+kernel_size-1);
      
      
      %  smoothed_value = sum(neighborhood(:)) / 9;
      sum=0; 
      for k=1:kernel_size
           for l=1:kernel_size
               corrI=kernel(k,l)*neighborhood(k,l); 
               sum=sum+corrI;
           end;
       end;
     
       %output_image=new value
        J(i, j) = sum;
    end;
end;


J = uint8(J);


figure,subplot(1, 2, 1), imshow(I), title('Original Image');
subplot(1, 2, 2), imshow(J), title('Smoothed Image',[]);


Histogram equilization