How can I detect a color percentage in a picture?

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fatema ali
fatema ali on 20 Nov 2019
Commented: DGM on 17 May 2022
I have a picture with different colors, but I mainly need the precentage of three colors. how can I do that in matlab?
fatema ali
fatema ali on 20 Nov 2019
Edited: fatema ali on 20 Nov 2019
yes exactly, like the precentage of red in a certain picture.
I want a broader sense of colors, like all shades of red are considered as one thing and so on.

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Answers (1)

Kavya Vuriti
Kavya Vuriti on 17 Feb 2020
It would be better if you first determine the RGB triplet limits for a specific color and count the number of pixels lying in the above range. The sample code could look like this:
% Read image
I = imread('your_image');
% Define RGB limits
redLowerLimit = your_value;
redUpperLimit = your_value;
blueLowerLimit = your_value;
blueUpperLimit = your_value;
greenLowerLimit = your_value;
greenUpperLimit = your_value;
% Number of pixels of required colour
requiredColor = ( I(:,:,1) >= redLowerLimit & I(:,:,1) <= redUpperLimit ) & ...
( I(:,:,2) >= greenLowerLimit & I(:,:,2) <= greenUpperLimit ) & ( I(:,:,3) >= blueLowerLimit & I(:,:,3) <= blueUpperLimit );
% Percentage of colour in the image
percentColor = 100*(sum(sum(requiredColor))/(size(I,1)*size(I,2)));
Hope this helps.
DGM on 17 May 2022
You need to define the variables. You need to specify an image and select threshold values that are appropriate for your own needs.

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