Need Help with CatalogStarGenerator and StarAlignment

[smccully]

I am trying to generate a StarField using CatalogStarGenerator that is 50% bigger then the calibration subs to retain more in the final Integration image. If I generate a star field the same size of the image then I can get star alignment to work but once I try generating a field bigger then the image nothing seems to work. Am I doing something wrong?

Everything gets to matching 5 stars, but needs 6. Whether I use a preview window or not. Any help is greatly appreciated.


Example Image https://www.dropbox.com/s/ukdbq769n42dswx/Lum-1x-60s-140_c_a.xisf?dl=0








 

Code: [Select]

StarAlignment: Processing view: Lum_1x_60s_140_c_a
CatalogStars:
Structure map: done
Detecting stars: done
3345 stars found.
Lum_1x_60s_140_c_a:
Structure map: done
Detecting stars: done
2600 stars found.
* Reference image: Limiting to 2000 brightest stars.
* Target image: Limiting to 2000 brightest stars.
Matching stars: done
581 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #2
useScaleDifferences=false
* Reference image: Limiting to 2000 brightest stars.
* Target image: Limiting to 2000 brightest stars.
Matching stars: done
626 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #3
useScaleDifferences=true
* Reference image: Limiting to 250 brightest stars.
* Target image: Limiting to 250 brightest stars.
Matching stars: done
81 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #4
useScaleDifferences=false
* Reference image: Limiting to 250 brightest stars.
* Target image: Limiting to 250 brightest stars.
Matching stars: done
72 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #5
useScaleDifferences=true
* Reference image: Limiting to 125 brightest stars.
* Target image: Limiting to 125 brightest stars.
Matching stars: done
52 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #6
useScaleDifferences=false
* Reference image: Limiting to 125 brightest stars.
* Target image: Limiting to 125 brightest stars.
Matching stars: done
37 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #7
useScaleDifferences=true
* Reference image: Limiting to 60 brightest stars.
* Target image: Limiting to 60 brightest stars.
Matching stars: done
22 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #8
useScaleDifferences=false
* Reference image: Limiting to 60 brightest stars.
* Target image: Limiting to 60 brightest stars.
Matching stars: done
24 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #9
useScaleDifferences=true
* Reference image: Limiting to 30 brightest stars.
* Target image: Limiting to 30 brightest stars.
Matching stars: done
10 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #10
useScaleDifferences=false
* Reference image: Limiting to 30 brightest stars.
* Target image: Limiting to 30 brightest stars.
Matching stars: done
13 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #11
useScaleDifferences=true
* Reference image: Limiting to 15 brightest stars.
* Target image: Limiting to 15 brightest stars.
Matching stars: done
*** 5 star pair matches found - need at least six matched stars.
* Previous attempt failed - this is try #12
useScaleDifferences=false
* Reference image: Limiting to 15 brightest stars.
* Target image: Limiting to 15 brightest stars.
Matching stars: done
*** 5 star pair matches found - need at least six matched stars.
* Previous attempt failed - this is try #13
useScaleDifferences=true
* Reference image: Limiting to 8 brightest stars.
* Target image: Limiting to 8 brightest stars.
Matching stars: done
*** 0 star pair matches found - need at least six matched stars.
* Previous attempt failed - this is try #14
useScaleDifferences=false
* Reference image: Limiting to 8 brightest stars.
* Target image: Limiting to 8 brightest stars.
Matching stars: done
*** 0 star pair matches found - need at least six matched stars.
* Previous attempt failed - this is try #15
useScaleDifferences=true
* Reference image: Limiting to 500 brightest stars.
* Target image: Limiting to 500 brightest stars.
Matching stars: done
166 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #16
useScaleDifferences=false
* Reference image: Limiting to 500 brightest stars.
* Target image: Limiting to 500 brightest stars.
Matching stars: done
157 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #17
useScaleDifferences=true
* Reference image: Limiting to 1000 brightest stars.
* Target image: Limiting to 1000 brightest stars.
Matching stars: done
303 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #18
useScaleDifferences=false
* Reference image: Limiting to 1000 brightest stars.
* Target image: Limiting to 1000 brightest stars.
Matching stars: done
323 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #19
useScaleDifferences=true
* Reference image: Limiting to 3000 brightest stars.
Matching stars: done
857 putative star pair matches.
Performing RANSAC: done
* Previous attempt failed - this is try #20
useScaleDifferences=false
* Reference image: Limiting to 3000 brightest stars.
Matching stars: done
833 putative star pair matches.
Performing RANSAC: done
*** Error: Unable to find an initial set of putative star pair matches.
<* failed *>


[smccully]

It seems i am able to finally get a registered image IF i use a preview window which only works on active windows and not disk files which isn't much help trying to run star alignment on a lot of images. Even using CatalogStarGenerator to generate an enlarged field and then running against a single image to generate a frame with the enlarged field and then trying to run star alignment against the rest of the images doesn't really appear to work either.

[smccully]

Generating a large StarField with a preview window and using that to register a calibrated frame, then using that registered frame as the reference for the star alignment routine ran with a 50% success rate against all the calibrated frames. Where as that same reference frame ran with 99% success rate with the default image size. This is with all the StarAlgnment parameters maxed out.

[pfile]

just so i understand, the reference image is huge and the subs are small, correct?

cant you set the reference to a view with the preview drawn on it and then do global apply to the file list? it's been a while since i tried that so i'm not sure if it works but it seems like it should? i just tried it myself with a view as the reference, no preview though, and it worked ok as long as i hit the global apply button.

rob

[smccully]

That does work, the problem i am having is that the star alignment is being very finicky when trying to do this. Luckily it does appear to be deterministic, but i am just not sure how best to generate the star field and which parameters to tune in Star-Alignment to be the most robust.

Half of the subs, i was able to align and the other half are being more problematic even with the preview windows.
The frustating part is i see a lot of "5 star pair matches found - need at least six matched pairs". Over and Over again, something is stopping it from getting over that threshold and but i am not sure what.

[pfile]

one thing you can try is to open one of the problematic images and then switch the StarAlignment mode to "detected stars". apply StarAlignment to that view, and instead of an aligned image, you'll get a diagnostic image with crosshairs over every star that was detected in the image. if you see a bunch of markers where there are no stars, then the tool is probably finding hot pixels instead of stars and then RANSAC is completely overwhelmed with bogus stars.

if not, then you can play with the star detection controls even more to see if you can get SA to pick up stars that are being missed. the feedback from the detected stars mode is pretty useful for that too.

rob

[smccully]

This definitely helped to visualize the star alignment process, I am not sure how much hot pixels were playing a role in the failures. But turning on the hot pixel and noise reduction appeared to help the robustness of the star alignment process.

I was able to get all the subs aligned, it turned into a piece meal activity. 50 images here, 30 images there. Mostly had to do with moving the preview window orientation to help match the various offsets from the intended center.