رسم هیستوگرام تصویر در متلب – راهنمای کاربردی

1% Read an Image in MATLAB Environment 
2img=imread('apple.jpg'); 
3  
4% Convert image to grayscale image 
5# if read image is an RGB image 
6img=rgb2gray(img); 
7  
8% Show histogram of image 
9# using imhist() function
10imhist(img); 

1% Read source image file  
2img = imread('apple.jpg'); 
3  
4% Convert image to grayscale image  
5img=rgb2gray(img); 
6  
7% get the dimension of the image  
8[x, y] = size(img); 
9  
10  
11% Create a frequency array of size 256 
12frequency = 1 : 256; 
13  
14count = 0; 
15  
16% Iterate over grayscale image matrix  
17% for every possible intensity value 
18% and count them 
19    
20for i = 1 : 256 
21    for j = 1 : x 
22        for k = 1 : y 
23  
24            % if image pixel value at location (j, k) is i-1 
25            % then increment count 
26            if img(j, k) == i-1 
27                    count = count + 1; 
28            end
29        end
30    end
31    % update ith position of frequency array with count 
32    frequency(i) = count; 
33  
34    % reset count 
35    count = 0; 
36  
37end
38  
39  
40n = 0 : 255; 
41  
42% Display Histogram 
43stem(n, frequency); 
44  
45grid on; 
46ylabel('Number of pixels with such intensity levels -->'); 
47xlabel('Intensity Levels  -->'); 
48title('HISTOGRAM OF THE IMAGE');