MATLAB: Histogram-based RGB segmentation

digital image processinghistogramimage analysisimage processingimage segmentationMATLAB

Hi All,
I'm trying to segment an RGB image based on it's histograms; my code is as follows: 
    %Split into RGB Channels
    Red = img(:,:,1);
    Green = img(:,:,2);
    Blue = img(:,:,3);
    %Get histValues for each channel
    [yRed, x] = imhist(Red);
    [yGreen, x] = imhist(Green);
    [yBlue, x] = imhist(Blue);
    %Plot them together in one plot
    plot(x, yRed, 'Red', x, yGreen, 'Green', x, yBlue, 'Blue');
    
    histRGB = hist([imhist(Red), imhist(Green), imhist(Blue)]);
    histMask = img.*uint8(histRGB);
    imshow(histMask)
I get the following error when compiling this section: "Array dimensions must match for binary array op." I'm not sure how to fix this, as I'm not well versed in Matlab currently.
Any help will be appreciated!
Thanks

Best Answer

I am not sure about which algorithm you are trying to implement but below is an example of histogram based segmentation using Otsu's method.
clc; close all;
% Read image into the workspace
img = imread('peppers.png');
% Calculate a 255-bin histogram for the image
[counts, ~] = imhist(rgb2gray(img), 255);
% Compute a global threshold using the histogram counts
T = otsuthresh(counts);
% Create a binary image using the computed threshold
BW = imbinarize(rgb2gray(img), T);
% Display the image
figure; imshowpair(img, BW, 'montage');
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