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From: "Bruno Luong" <b.luong@fogale.findmycountry>
Newsgroups: comp.soft-sys.matlab
Subject: Re: Implementing splines in a microcontroller
Date: Wed, 18 Nov 2009 21:14:20 +0000 (UTC)
Organization: FOGALE nanotech
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"Tom E" <tom.elliot@students.fhv.at> wrote in message <he1kh0$26s$1@fred.mathworks.com>...
> Hi folks,
> 
> I have a reasonably simple task to do for uni:
> Take an image
> Extract the edges
> Display this using a microcontroller.
> 
> Because the display method is as a vector, I have chosen to interpret the edges as splines.
> 
> So far I have managed to extract the edges and convert to a series of splines.
> 
> Now i've come to the problem of how to implement the resultant data in a microcontroller. I don't really understand how splines are stored in matlab. As far as I understand, splines are a series of curves, all joined together (Bezier curves, paths, however you'd like to call them).
> 
> So given a spline in ppform, or B-form, how do I know what the equations are for each of the curves?

Spline is a polynomial on each subinterval (piecewise polynomials). On each interval, the polynomial is computed with respect to the relative abscissa to its left bound  (leftbound := 0). The coefficients of the polynomials are ranged in each columns of the field COEFS (highest to lowest order - same as used by polyval/polyfit). Consecutive subintervals are separated by the subdivision of the entire interval stored in the field BREAKS.

Bruno