Re: How to average to find 'circular' symmetry in a SQUARE matrix?

[Robert A. Macy]

Doug,

Yes, 1 degree, 10 degrees, or 127 degrees, image that is
represented by x-y data set is perfectly axisymmetric.

How do I use polar notation to average?

       - Robert -

Chris,

How do I use 2D Lagrange interpolation?  Sounds exactly
what I need, but didn't find any functions that looked like
it would do that.  

What were you using it on?

        - Robert -

From: "Chris Zarowski" <address@hidden>
> Maybe I misunderstand, but it sounds like
> you need to do interpolation in 2D.
>
> There is a 2D form of Lagrange interpolation
> that is perhaps the easiest thing.
>
> The idea is to interpolate over a desired circle
> (appropriately centered), and average the interpolants.
>
> I actually had this problem in processing some
> grey-scale images from a thin-film optics experiment.
> 
> Chris Z

On Mon, 15 Jan 2007 19:06:24 -0500
 Doug Stewart <address@hidden> wrote:
> Hi Robert
> 
>  Do you mean by rotational symmetry  that if you rotate
> it 10 deg ( or 
> 20 or 30 etc.) it still has symmetry or do you mean
> rotate by 90 deg. steps.
> 
> 
> If it is by any deg. then maybe you could use polar
> notation?
> 
> Doug Stewart