How to implement this plateau limit histogram equalization algorithm

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Mustafa Uysal 2019-12-25

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https://ww2.mathworks.cn/matlabcentral/answers/497985-how-to-implement-this-plateau-limit-histogram-equalization-algorithm

编辑： Mustafa Uysal 2019-12-25

Hi,

i would like to implement and simple alghoritm. i compare my result's histogram with original result's histogram and there is always a huge difference.

i reviewed my code again and again. but i couldn't see what is the problem. can you take a look to my code, please?

histogram_of_image = imhist(input_image);
modified_histogram = zeros(1,256);
modified_histogram(1:256)  = (log(histogram_of_image(1:256)+(a))).^(beta);

these_elements_are_not_zero = modified_histogram~= 0;
sum2 = sum(modified_histogram(these_elements_are_not_zero));
cnt2 = size(these_elements_are_not_zero,2);
tcl = sum2/cnt2;
clipped_histogram = zeros(1,256);
for i=1:256
    if((modified_histogram(i)) >= tcl)
    clipped_histogram(i) = tcl;    
    else 
    clipped_histogram(i) = (modified_histogram(i));   
    end
end

PDa = zeros(1,256);
PDa = clipped_histogram / (sum(clipped_histogram)); 
CDa = zeros(1,256);  %create CDa in formula
CDa(1) = PDa(1) ;
for i=2:256
     CDa(i) =  PDa(i) +  CDa(i-1);  
end
value_after_enhancement =  zeros(1,256); 
value_after_enhancement = (255 * CDa); 
b=uint8(0);
output_image=zeros(width,height);
output_image =   value_after_enhancement(input_image+1);
figure;imshow(uint8(output_image));
original_result=imread('testsonuc.bmp');
original_result=double(rgb2gray(original_result));
image_of_dif= zeros(width,height);
figure;imshow(uint8(original_result));