My goal is to get the RGB values of the image taken with the webcam and I need the matlab code to accomplish this purpose. I am a new matlab user, please help me.
See https://www.mathworks.com/help/supportpkg/usbwebcams/ug/acquire-images-from-webcams.html on how to work with webcams.
Once you have done the snapshot(), then just index into the resulting array to get the RGB values. For example,
img(183, 17, :)
would extract the R, G, and B components (in that order) of row 183 column 17 of the image.
The imread function will read any image and give you the RGB values like this:
A = imread('myimage.jpg');
Then the red layer is the first slice of A, blue is the second slice, and green is the third:
R = A(:,:,1); G = A(:,:,2); B = A(:,:,3);
If you need the RGB values of a specific pixel, say, row 22, column 50, it would be:
[R(22,50) G(22,50) B(22,50)]
If you're not sure what the row and column numbers are of the pixel you want, display the image with the image function, then use ginput to click around and get the coordinates you want:
image(A) [col,row] = ginput
To build on what the others said, you should look at impixelinfo() which is a function that puts a status bar on your figure that gives you the (x,y) location and RGB values as you mouse over the displayed image.
There is also a function called impixel() that gives you the RGB value but I never use it.