how to extract features using the equation

Please can someone help me in extracting features of an image using the following equation....

http://img443.imageshack.us/img443/176/meanvariancell.png

Please do reply

i tried something which i got while searching....

but wasnt sure whether it matches with the equation in the link..... thats y i gave it like that......

[Matt J]

http://www.mathworks.com/matlabcentral/answers/8626-how-do-i-get-help-on-homework-questions-on-matlab-answers

[Elysi Cochin]

this is what i tried....

mean=conv2(A,ones(3)/9,'same');

Answer 1

[Matt J]

Yes. It matches.