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Re: Polynomial Fitting question [message #68142 is a reply to message #68139]

Fri, 02 October 2009 06:24

Andrew Rodger
Messages: 5
Registered: October 2009

Junior Member

>
> I suggest you run the IDL profiler on your code (maybe you did, but it
> is not mentioned in your post) to see what is causing the delay.
>
> Allard

Hi Allard,

shamefully I have not run the profiler yet :(
I will do that first thing monday. I am in fact working with airborne
hyperspectral datasets (HyMap) and am fitting polynomials to various
surface absorption features (Fe, leaf water, cellulose etc). The
polynomial fit is not the ideal and is only the first cut (although it
does work well with the broader features) and I will move to gaussians
at a later date.

This part of the processing is after I have performed the atmospheric
compensation (radiance to reflectance) and a spectral recalibration of
the band centres. I have this whole process running from go to whoa in
3-5 minutes. This latter aspect (the fitting of the surface
absorptions) which allows me to determine content and composition data
based on the surface reflectance is painfully slow compared to the
initial processing and is driving me crazy.

It just seems that there must be others who want/need to fit equations
on a per-pixel basis (yourself included by the sound of it) but do not
want to have to run through the looping process (seems decidedly like
an unIDL way). I am not sure how large your datasets are but mine are
512 pixels by anywhere from 3000-11000 lines. This is probably small
to some folks.

I will give the profiler a go and see if I can chase this down a bit
better.

Cheers
Andrew

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[Message index]

		Re: Polynomial Fitting question By: Andrew Rodger on Sat, 03 October 2009 09:15
		Re: Polynomial Fitting question By: Andrew Rodger on Fri, 02 October 2009 06:24
		Re: Polynomial Fitting question By: wita on Fri, 02 October 2009 04:47

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