Mean Greyscale Index matrix

How do I calculate mean N x M in 2d pictures?

Is it same is I use mean2() function?

Answer 1

[Aiswarya]

According to my understanding you want to calculate mean of all pixels in the image and it's a greyscale image.

So if your image is given by img you can use the function mean in the manner given below:

meanIntensity = mean(img(:));