Question

write a matlab code for histogram and histogram equallization code without built in commands

Answer 1

Question:

write a matlab code for histogram and histogram equalization code without built in commands.

Answer:

Histogram - Its are a type a bar plot for numeric data that group the data into bins.

Syntax for the same is as follows:

histogram(X)

histogram(X,nbins)

histogram(X,edges)

histogram('BinEdges',edges,'BinCounts',counts)

Below is the matlab code for Histogram Equalization without any in-built commands

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close all;
clear all;
clc
GIm=imread('myImage.png');
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);
cum1=zeros(256,1);
output=zeros(256,1);
n=1:256;
%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
figure,stem(n,probf)
title('Probability Distribution Function')
sum=0;
no_bins=255;
%The cumulative distribution probability is calculated.
for i=1:size(probf)
sum=sum+freq(i);
cum1(i)=sum;
probc(i)=cum1(i)/numofpixels;
output(i)=round(probc(i)*no_bins);
end
cum1
figure,stem(n,output)
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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