how to find a intensity of the color image?

i need to find the mean intensity value of the colour image. i dont know how to do it? pls help me

[Henric Rydén]

The mean of the entire image? mean(A(:))

[Image Analyst]

What is your definition of intensity (there are multiple definitions)? The actual units of an image are kind of like energy, or more exactly (candela steradian second) in all SI base units - basically Lux * time * area.

Or better yet, what do you really need, and why do you think you need the mean intensity to achieve that?

Answer 1

[Walter Roberson]

intensities = rgb2gray(YourImage);
meanint = mean(intensities(:));