about the color of pixel

hi can any one tell me how can i count total no of yellow pixel in an image ? i want to find red ,yellow and black pixels value to find the accuracy of wound tissue.So pls help me in this

Answer 1

[Ayush]

Hi,

To count the number of yellow, red, and black pixels in an image using MATLAB, you can convert the image to the HSV colour space for better colour discrimination, and then define thresholds to identify each colour. To convert the image to HSV color space you can use the “rgb2hsv” function. Refer to an example code below for a better understanding:

% Convert the image to HSV color space
hsvImg = rgb2hsv(img);

% Define thresholds for yellow color in HSV space
yellowMin = [0.10, 0.4, 0.4]; % Adjust these values as needed
yellowMax = [0.20, 1.0, 1.0]; % Adjust these values as needed

% Create a binary mask for yellow pixels
yellowMask = (hsvImg(:,:,1) >= yellowMin(1) & hsvImg(:,:,1) <= yellowMax(1)) & ...
             (hsvImg(:,:,2) >= yellowMin(2) & hsvImg(:,:,2) <= yellowMax(2)) & ...
             (hsvImg(:,:,3) >= yellowMin(3) & hsvImg(:,:,3) <= yellowMax(3));

% Count the number of yellow pixels
numYellowPixels = sum(yellowMask(:));

In the above example, I have provided a mask for yellow colour, in a similar way you can get a mask for red and black colour. For more information on the “rgb2hsv" function refer to the below documentation:

https://www.mathworks.com/help/matlab/ref/rgb2hsv.html