From: "ike " <>
Newsgroups: comp.soft-sys.matlab
Subject: Re: question about gradient function
Date: Wed, 2 May 2012 07:48:06 +0000 (UTC)
Organization: The MathWorks, Inc.
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"Matt J" wrote in message <jmk2uj$jsb$>...
> "arron" wrote in message <jmi6n4$f6j$>...
> > also when i try what you have said, i get:
> > 
> > subscript indices must be real positive integers or logicals. 
> ============
> If you've set i and j to values that are not real positive integers, it makes sense that you would get an error when trying to subscript with them.

how can i get gradient direction from every pixel ?
so how can i select pixels randomly ?