Astro to Astro-art Continuum, 2024 Edition

General discussion about StarTools.
decay
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Re: Astro to Astro-art Continuum, 2024 Edition

Post by decay »

Hi Ivo, thank you much for your detailed and extensive explanations.
admin wrote: Sun Feb 04, 2024 11:41 pm Keep in mind there is always the "scale 0" residual(s) the boundaries beyond which the scales do not operate
This is exactly the point I overlooked. A graphic equalizer covers the whole audible frequency spectrum whereas ST Sharp module leaves the lower spatial frequencies untouched and starts at a distinct detail level which we select on screen one. And this is also exactly the reason why it is somehow reasonable/possible that the sliders are all set to 100% by default. I never understood that … up to now :D

Best regards, Dietmar.
decay
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Re: Astro to Astro-art Continuum, 2024 Edition

Post by decay »

admin wrote: Sun Feb 04, 2024 11:41 pm So, in terms of your tool, it would be helpful to calculate the average brightness for the entire cross-section and subtract that average from what is displayed.
Copy that. ;)
2024-02-05 16_55_19-Window.jpg
2024-02-05 16_55_19-Window.jpg (31.64 KiB) Viewed 820 times
2024-02-05 16_54_56-Window.jpg
2024-02-05 16_54_56-Window.jpg (38.32 KiB) Viewed 820 times
Hey, that's exactly what the AC/DC input coupling switch of an oscilloscope does! :D
I have to think about coding a Y gain control :lol:

Dietmar.
decay
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Re: Astro to Astro-art Continuum, 2024 Edition

Post by decay »

Mike in Rancho wrote: Mon Feb 05, 2024 7:55 am Dietmar I finally downloaded, unquarantined, and played with the brightness app.
Thanks for trying, Mike :)
Mike in Rancho wrote: Mon Feb 05, 2024 7:55 am Gimp's built-in UM indeed worked as expected based on the reading we did, though it seemed slanted towards a deeper darkening than brightening.
I found out exactly the same!
Mike in Rancho wrote: Mon Feb 05, 2024 7:55 am I screenshot each stage with the Viewer in place so I could flip layers when pasted into a new image. I didn't go make a flashing gif, but...I could!
Yes, I thougth about adding such a function into the app. Maybe later :lol:
Mike in Rancho wrote: Mon Feb 05, 2024 7:55 am Before that I tested it using the "manual" method of UM via layer operations -- original + (original - blurred). Interestingly, while it worked, the Viewer showed that it was only brightening the light side of the transitions, not darkening the dark side. So, there must be another step involved. Or probably lots of steps, since the blur-subtract-add is very simplified I'm sure. :confusion-shrug:

I also tried to fool it by drawing a fork in my line and bringing them near to each other, emulating fine structure in close proximity -- thinking the blur would overlap (it did) and ruin the sharpening or create incorrect information (it didn't).
Yeah, I really think this tool might be helpful to get a better view on what's happening. Especially, since we now know, that our eye and brain are fooling us sometimes. I'm looking forward to check out the Contrast module. At a first glance, I suspect, the 'Locality' slider is not (just) what it looks like ;-)
Mike in Rancho wrote: Mon Feb 05, 2024 7:55 am So, I gauss that blurring is smarter than I thought it was.
Really, Mike? 'gauss'? Typo or joke? :lol: :thumbsup:
Mike in Rancho
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Re: Astro to Astro-art Continuum, 2024 Edition

Post by Mike in Rancho »

decay wrote: Mon Feb 05, 2024 1:09 pm Hi Ivo, thank you much for your detailed and extensive explanations.
admin wrote: Sun Feb 04, 2024 11:41 pm Keep in mind there is always the "scale 0" residual(s) the boundaries beyond which the scales do not operate
This is exactly the point I overlooked. A graphic equalizer covers the whole audible frequency spectrum whereas ST Sharp module leaves the lower spatial frequencies untouched and starts at a distinct detail level which we select on screen one. And this is also exactly the reason why it is somehow reasonable/possible that the sliders are all set to 100% by default. I never understood that … up to now :D

Best regards, Dietmar.
Okay, I'm confused. Need you audio and oscilloscope gurus to help me out. :D

Low frequency is the long rolling waves. Bass. In the image, large features, bigger blur. ?
High frequency is the short fast waves. Treble. In the image, small features, tighter blur. ?

Sharp screen 1 sets absolute pixel scaling ranges for our 5 sliders (so binning matters), large, medium, small.
Screen 2 scales though, are 1 (small, high freq) through 5 (large, low freq).

So since it's absolute and 1 is about a pixel, Scale 0 would be sub-pixel which is out of range, okay. But wouldn't the low frequency outside of the largest range chosen be..."6"? :?
decay
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Re: Astro to Astro-art Continuum, 2024 Edition

Post by decay »

Mike in Rancho wrote: Mon Feb 05, 2024 5:34 pm But wouldn't the low frequency outside of the largest range chosen be..."6"?
Oh yes, your're right Mike. Ivo mentioned both, frequencies too low and too high. (For me, I'm not sure, if 'too high' is possible in our case?!)

I generated two synthetic images, one with square waves and the other one with sine waves with sweeping frequencies. It's very interesting to play around and to see what's happening. I will upload them and write a few words, but I'm afraid, not until tomorrow ...

Best regards, Dietmar.
decay
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Re: Astro to Astro-art Continuum, 2024 Edition

Post by decay »

I created a folder and moved the new version of the tool into it:
https://c.web.de/@334960167135216273/Rx ... kgEbEa4R7w

In addition, there are the two synthetic images mentioned above:
sine-sweep.tif
square-sweep.tif

The brightness levels of the waves shown are between 25 % and 75 %. The new version of the tools shows reference lines at 25, 50 and 75 % so that any change in the amplitudes is easily visible.

You can open the images in ST (linear) and then go straight on to the Sharp module. I used Structure Size = large (default) in this case. For example, I set the Scale sliders to 0 except Scale 3 and increased the amount to 1000%. Now you can see, that the low frequencies remain untouched, with level between 25 and 75 %:
2024-02-07 18_39_37-Window.jpg
2024-02-07 18_39_37-Window.jpg (91.61 KiB) Viewed 557 times
But if you scroll to the right to higher frequencies, you will see that their amplitude has increased:
2024-02-07 18_43_57-Window.jpg
2024-02-07 18_43_57-Window.jpg (51.44 KiB) Viewed 557 times
And the highest frequencies remain mainly untouched, just as the lower frequencies:
2024-02-07 18_49_41-Window.jpg
2024-02-07 18_49_41-Window.jpg (37.86 KiB) Viewed 557 times
(to be continued)
Last edited by decay on Wed Feb 07, 2024 6:10 pm, edited 1 time in total.
decay
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Re: Astro to Astro-art Continuum, 2024 Edition

Post by decay »

Interesting to see what happens when you turn off protection (yes, it clips! :D )
2024-02-07 19_02_47-Window.jpg
2024-02-07 19_02_47-Window.jpg (54.29 KiB) Viewed 549 times
Or what happenes levering the Dark/Light Enhace slider:
2024-02-07 19_06_51-Window.jpg
2024-02-07 19_06_51-Window.jpg (51.37 KiB) Viewed 549 times
2024-02-07 19_08_21-Window.jpg
2024-02-07 19_08_21-Window.jpg (49.03 KiB) Viewed 549 times
(to be continued)
decay
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Re: Astro to Astro-art Continuum, 2024 Edition

Post by decay »

For me, it was interesting to see, what happens to the square wave:
2024-02-07 19_14_24-Window.jpg
2024-02-07 19_14_24-Window.jpg (70.54 KiB) Viewed 542 times
The sharp edges contain a great amount of high frequencies (as explained in a post above) and these components get amplified, even if the base freqency is very low. Playing around with different settings will maybe help to get a better sense of how this all works.

I would like to apologise for all these screenshots, but a picture can say more than 1000 words ... I hope. :oops:

Best regards, Dietmar.
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admin
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Re: Astro to Astro-art Continuum, 2024 Edition

Post by admin »

This is brilliant Dietmar - I love seeing people dive deep into what's happening (and taking others along for the ride). :bow-yellow:
Ivo Jager
StarTools creator and astronomy enthusiast
Startrek
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Re: Astro to Astro-art Continuum, 2024 Edition

Post by Startrek »

Dietmar ,
Absolutely brilliant !!!
I must be showing my age
The closest thing I got to electronics and computers as a young fella in my last year of high school was using punch cards in a mechanical encoder and building a Wheatstone bridge in the engineering class ( early 70’s)
I didn’t get into computers until Windows 98 hit the globe
Well done !!
Martin
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