# MATLAB: How to quantify multicolor images

image enhancementImage Processing Toolbox

Hi,
I have to quantify this attached multi-color image. This image (Picture1.png)is an outcome of (Matlab enhanced from Picture4.png) dermascopic image from a broad band light of a microscope. I want to get numbers out of it. Such as what percentage of the signal is red, pink or yellow or green or blue. I basically need free-hand ROI and get Red signal intensity for example). Can you please help me out with this? Thanks Surya

#### Best Answer

• Here's a solution
img = imread('Picture1.png');imh = imshow(img);% Create a mask using freehand ROIh = imfreehand;m = createMask(h, imh);delete(h)% Extract individual color channelsr = img(:,:,1);g = img(:,:,2);b = img(:,:,3);% Get sum of intensity of each channelr_s = sum(r(m));g_s = sum(g(m));b_s = sum(b(m));% Calculate percentage of intensity of each colorr_p = r_s / (r_s + g_s + b_s) * 100;g_p = g_s / (r_s + g_s + b_s) * 100;b_p = b_s / (r_s + g_s + b_s) * 100;