Search found 431 matches

by decay
Thu Mar 28, 2024 9:01 am
Forum: Image Processing Troubleshooting
Topic: Donut stars
Replies: 39
Views: 814

Re: Donut stars

and thus the scale of the stretch is such that it would likely be hard to discern the minor fluctuations around regions of detail [...]. Maybe? I wonder if zooming in to a more narrow region would reveal adjustments made away from smooth curving. I don't think so. :think: My example delivered about...
by decay
Thu Mar 28, 2024 8:22 am
Forum: Image Processing Troubleshooting
Topic: Donut stars
Replies: 39
Views: 814

Re: Donut stars

But, I need some help understanding what we are looking at. :think: You said there's a comparison of pixel mapping per file, resulting in....? :confusion-shrug: It's quite simple, I probably just messed up the explanation. The word 'comparision' I used is simply wrong in this context, sorry. So yes...
by decay
Wed Mar 27, 2024 3:37 pm
Forum: Image Processing Troubleshooting
Topic: Donut stars
Replies: 39
Views: 814

Re: Donut stars

Hi all, I was not sure about posting this here in Ron’s thread, but I think I can add some points with reference. I hope that’s OK, Ron. This is a very early stage (aka: a quick hack), but I already want to share. I wrote a small tool (once again ;-) ) that should help us analyzing OptiDev’s behavio...
by decay
Sun Mar 24, 2024 9:56 pm
Forum: Image Processing Troubleshooting
Topic: Donut stars
Replies: 39
Views: 814

Re: Donut stars

Dietmar, I started trying to write out how our different analogies could point in the same direction, but I got stuck because I don't think I understand how it works Hi Ron, that's my problem as well. There's something Ivo wrote, that I do not understand (as I wrote in my reply to Ivo). Maybe Ivo w...
by decay
Sun Mar 24, 2024 5:26 pm
Forum: Image Processing Troubleshooting
Topic: Donut stars
Replies: 39
Views: 814

Re: Donut stars

Take the notion of decreasing the resolution of the curve to the absurd extreme and give it just one bit. Now every pixel in the 'stretched' image will either be On or Off and (obviously) all the detail in the original data is lost. Thanks, Ron. This is probably not my day. :( Ivo wrote "the amount...
by decay
Sun Mar 24, 2024 3:10 pm
Forum: Image Processing Troubleshooting
Topic: Donut stars
Replies: 39
Views: 814

Re: Donut stars

But really this pops up across a large cohort, with many different optics, sensors, and stackers. I would assume the same. But I cannot prove, of course. And Ivo's testsets don't seem to be affected that much, as he wrote. I wonder if it would be helpful to reread some older threads to identify som...
by decay
Sat Mar 23, 2024 11:03 am
Forum: Image Processing Troubleshooting
Topic: Donut stars
Replies: 39
Views: 814

Re: Donut stars

Dietmar I was curious what you used to create the profile viewer app? At first I was thinking that adding a checkbox or toggle button to set TopMost on the form would be handy, so that we could watch the profile change as we altered stretching parameters. But, the viewer doesn't react to live chang...
by decay
Sat Mar 23, 2024 9:47 am
Forum: Image Processing Troubleshooting
Topic: Donut stars
Replies: 39
Views: 814

Re: Donut stars

Yes, it seems only two distinct values are assigned to the core regions of bright stars. The max value to the 'inner core' and then just one slightly lower value out for a distance surrounding it. The max value of the inner core is caused by saturation in your and in my example. But for non-saturat...
by decay
Fri Mar 22, 2024 5:16 pm
Forum: Image Processing Troubleshooting
Topic: Donut stars
Replies: 39
Views: 814

Re: Donut stars

Now we have to think about why this is happening. A 'plateau' means, that a range of input brightness levels is mapped onto the same output brightness level. I suspect that OptiDev constructs its stretching curve depending on the distribution and weighting of the input brightness levels. So OptiDev ...
by decay
Fri Mar 22, 2024 4:59 pm
Forum: Image Processing Troubleshooting
Topic: Donut stars
Replies: 39
Views: 814

Re: Donut stars

No need to share, Ron. I was able to reproduce this easily with my latest own dataset containing saturated stars: Stellar profile as displayed in Fitswork (this is independed of the actual active stretch!): 2024-03-22 17_52_53-Fitswork.jpg FilmDev: 2024-03-22 17_45_48-StarTools.jpg OptiDev (full ROI...