Max Filter - MATLAB CODE

• To find the brightest points in an image.
•  Finds the maximum value in the area encompassed by the filter.
•  Reduces the pepper noise as a result of the max operation.
•  The 100^th percentile filter is max filter. Check the 50^th percentile filter i.e the median filter.

MATLAB CODE:

%READ AN IMAGE

A = imread('board.tif');

A = rgb2gray(A(1:300,1:300,:));

figure,imshow(A),title('ORIGINAL IMAGE');

%PREALLOCATE THE OUTPUT MATRIX

B=zeros(size(A));

%PAD THE MATRIX A WITH ZEROS

modifyA=padarray(A,[1 1]);

        x=[1:3]';

        y=[1:3]';

       

for i= 1:size(modifyA,1)-2

    for j=1:size(modifyA,2)-2

      

       %VECTORIZED METHOD

       window=reshape(modifyA(i+x-1,j+y-1),[],1);

       %FIND THE MAXIMUM VALUE IN THE SELECTED WINDOW

        

       B(i,j)=max(window);

   

    end

end

%CONVERT THE OUTPUT MATRIX TO 0-255 RANGE IMAGE TYPE

B=uint8(B);

figure,imshow(B),title('IMAGE AFTER MAX FILTERING');