SVDecon star selection

Bugs, glitches and unexpected behaviour.
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happy-kat
Posts: 372
Joined: Sun Feb 01, 2015 11:31 am

SVDecon star selection

Post by happy-kat »

Hi, I'm having trouble with my stars in SVDecon, I appreciate my data is not ideal, these are not particularly good stars, but the same occurs for me with better stars then these too.
On the left is 1.8.527MR2 where SVDecon finds the stars and on the right is 1.9.543 though 1.9.544 is the same.
1.9 tends to show these squiggly stars and none of the best round stars are selected so I cannot use them to sample with.
Any help appreciated please, even how to use my own mask in SVDecon might get around this with my data.
stars.jpg
stars.jpg (122.48 KiB) Viewed 13640 times
Mike in Rancho
Posts: 1142
Joined: Sun Jun 20, 2021 10:05 pm
Location: Alta Loma, CA

Re: SVDecon star selection

Post by Mike in Rancho »

I think adjustments to this may be in the works for the next major alpha still, based on last comments in the 1.9 thread?

A couple things you might try -

I think .541a had improvements to this, so depends what version you are using. I still often use .536a as I prefer how it handles deringing, but 541 can be better with sample outlines.

Binning down the dataset can seem to help with sampling also, as long as you retain enough resolution for SVD to get a good deconvolve.

You might try going stronger on your OptiDev final global stretch and/or with enhancing modules just make sure stuff hasn't dimmed out too much. If I recall from discussions of starfishy sampling while still in 1.8, while the colors of the samples are brought from the data's linear state, the white outlining may be coming from stretched states. That's just off the top of my head and I haven't experimented with it, and I may be confusing it with the binning changes allowing better sampling. :think:

I am not aware of any way to trick ST into using manual mask generation in 1.9.

EDIT: Looks like I was wrong about the level of stretch - did a quick test and the apod mask generation was exactly the same regardless. Oops. :oops: Binning, however, did change a full field of unusable little white outlines into actual usable stars.
happy-kat
Posts: 372
Joined: Sun Feb 01, 2015 11:31 am

Re: SVDecon star selection

Post by happy-kat »

Thank you Mike, having tested same data with 1.9.536>1.9544 all needed binning 50% which isn't ideal when starting with just 1396*1096 pixels pre crop. I'll keep testing with new releases as I enjoy the processing with StarTools.
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