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Author Topic: StarAlignment repeatability?  (Read 2775 times)

Offline mschuster

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StarAlignment repeatability?
« on: 2012 December 03 10:41:21 »
When I run StarAlignment on the same files with the same parameter more than once, the results differ slightly (the statistics numbers are slightly different). Is this expected?
Thanks,
Mike
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Offline Juan Conejero

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Re: StarAlignment repeatability?
« Reply #1 on: 2012 December 03 11:05:35 »
Yes. StarAlignment uses a RANSAC routine for robust rejection of false star pair matches. The random component of RANSAC may lead to slightly different sets of star pair matches on each execution. The differences are very small and statistically negligible.
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Juan Conejero
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Offline cs_pixinsight

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Re: StarAlignment repeatability?
« Reply #2 on: 2012 December 03 12:12:55 »
Hmm, so let's say I ran the StarAlignment routine 10-20 times followed by ImageIntegration to get 20 slightly different stacked images.  If I now stack all 20 of these how much do you think noise would be further reduced? 

Craig
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Offline Juan Conejero

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Re: StarAlignment repeatability?
« Reply #3 on: 2012 December 03 12:20:21 »
:) The same as if you convolved it with a Gaussian of, say, sigma = 0.3.
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Juan Conejero
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