Can anyone please help me about histogram matching without using inbuilt functions like imhist? Because my system shows error for 'im' built-in functions.

Code using im functions is:

I1 = imread('image1.jpg'); I2 = imread('image2.png');

image1 = im2double(I1); % convert images to type double (range from from 0 to 1 instead of from 0 to 255) image2 = im2double(I2);

% Calculate the Normalized Histogram of Image 1 and Image 2 hn1 = imhist(image1)./numel(image1); hn2 = imhist(image2)./numel(image2);

subplot(2,2,1);plot(hn1); subplot(2,2,2);plot(hn2);

f = sum((hn1 - hn2).^2) % Calculate the histogram error

So can you please help me about replacing imhist function?

[Muhammad Barznji]

https://www.mathworks.com/matlabcentral/fileexchange/69323-histogram-matching

Answer 1

[Bhumi Shah]

You can use histogram function with NumBins and BinLimits NV pair in place of imhist. Following steps might be helpful.

I1 = imread(image1); 
I1double = im2double(I1); 
 
I2 = imread(image2); 
I2double = im2double(I2); 
 
H1 = histogram(I1double, 'NumBins', 256, 'BinLimits', [0 1]); 
H2 = histogram(I2double, 'NumBins', 256, 'BinLimits', [0 1]); 
 
Count1 = H1.BinCounts';  
Count2 = H2.BinCounts'; 

 

Refer to the following link for more information: 

https://www.mathworks.com/help/matlab/ref/matlab.graphics.chart.primitive.histogram.html (histogram)