Undefined function 'rgb2gray' for input arguments of type 'uint8'.

I am using MATLAB 2013 b. It gives the error: Undefined function 'rgb2gray' for input arguments of type 'uint8'

when I am loading an image to do some processing. Help?

A= imread('Saturn.jpg');  
image(A); %show image loaded
B=rgb2gray(A);  % RGB to Gray Level image conversion

Answer 1

[Walter Roberson]

rgb2gray() is part of the Image Processing Toolbox. If you have a Student Version license, you probably have a license for it, but you might not have installed it yet.