Please complete the provided Matlab code to implement Histogram equalization. Pl

Question

Please complete the provided Matlab code to implement Histogram equalization.
Please use the follow program to test your function.

J is output of the histogram equalization function provided by Matlab. Please compare your output and Matlab’s output.

function OutIm = HistogramEq(InIm)

HistogramEq Code:

% Input:
% InIm - input image
%
% Output:
% OutIm - output image
%

%%%%%%%%
%%%%%%%%

% get the size of input image;
[row, col] = size(InIm);
% initalize the histogram array;
H = zeros(1,256);
% initalize the output image;
OutIm = uint8(zeros(row, col));

% Step 1: computer histogram (note the index starts from 1 but gray level starts from 0);
for i=1:row
for j=1:col
% Your code here!  
end
end

% Step 2: compute PDF;
PDF= % Your code here!

% Step 3: compute CDF (Hint: use 'cumsum' function, type 'help cumsum' to see help)
CDF= % Your code here!

% Step 4: compute transformation T (T=CDF*(L-1) and L=256);
T= % Your code here!

% Step 5: generate output image using transformation T;
for i=1:row
for j=1:col
OutIm(i,j)= % Your coder here!
end
end

>>clear all >>close all >> I=imread ('tire . tif' ); >> J=histeg (1); >> Out 1m=HistogramEg(1); >>figure (1) >>subplot (1,2,1) >>subplot (1,2,2)

Explanation / Answer

GIm=imread('tire.tif');
numofpixels=size(GIm,1)*size(GIm,2);
figure,imshow(GIm);
title('Original Image');
HIm=uint8(zeros(size(GIm,1),size(GIm,2)));
freq=zeros(256,1);
probf=zeros(256,1);
probc=zeros(256,1);
cum=zeros(256,1);
output=zeros(256,1);
%freq counts the occurrence of each pixel value.
%The probability of each occurrence is calculated by probf.
for i=1:size(GIm,1)
    for j=1:size(GIm,2)
        value=GIm(i,j);
        freq(value+1)=freq(value+1)+1;
        probf(value+1)=freq(value+1)/numofpixels;
    end
end
sum=0;
no_bins=255;
%The cumulative distribution probability is calculated.
for i=1:size(probf)
   sum=sum+freq(i);
   cum(i)=sum;
   probc(i)=cum(i)/numofpixels;
   output(i)=round(probc(i)*no_bins);
end
for i=1:size(GIm,1)
    for j=1:size(GIm,2)
    HIm(i,j)=output(GIm(i,j)+1);
    end
end
figure,imshow(HIm);
title('Histogram equalization');

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