How create plot of intensity versus frequency of image?

imhist function will give a plot of intensity versus frequency, or we can normalize it like follow, but how we can make a plot like attached? it looks like an area plot. any comment appreciated.

 clc;
close all;
clear all;
I = dicomread('IM_0007-Bmode');
for fr = 1:size(I,4)-1
    img(:,:,fr) = rgb2gray(I(:,:,:,fr));
end
im1 = double(img(:,:,1));
%// Create normalized images
Inormalized = double(im1)./double(max(im1(:)));
%// Convert back to uint8
% im2Norm = im2uint8(Inormalized);
imhist (Inormalized);
minVal = min(Inormalized(:));
maxVal = max(Inormalized(:));

Answer 1

[Image Analyst]

Try this:

histogram(I, 'normalization', 'probability')
title('Probability vs. Intensity', 'FontSize', 15);
xlabel('Intensity (gray level)', 'FontSize', 15);
ylabel('Probability', 'FontSize', 15);
grid on;

[Neda]

thank you for this. yes, it provide a histogram of image, but I need to be normalize. In the question and code, I did normalize it, and it is producing the right values. The problem is I need to be like attached file. Is it bar plot? is it area plot? it is not imhist

[Image Analyst]

Histogram produces a bar plot. There are several normalizations methods other than 'probability' such as 'pdf', 'Countdensity', etc. Pick whichever one uses the normalization method that you want.

[Neda Azarmehr]

thank you. Is image attached on my question bar chart?

[Image Analyst]

Yes it is. It also has no edge lines between the bins, which is an option you can have or not have. Excel calls it a column chart but most people, including at the Mathworks, call it a bar chart.

[Neda Azarmehr]

thank you.

Answer 2

[Ameer Hamza]

You can do something like this

[counts bins] = imhist(im1);
% normalize 'bins' and 'counts' here. e.g. 
bins = bins/255; 
counts = counts/sum(counts);
bar(bins, counts);
ax = gca;
ax.Children.BarWidth = 1;

[Neda]

it gave me just two bin, 0 and 4, and if I do this xlim ([0 1]); nothing return back.