Astro Module Liveview suggestion

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Wolsley
Posts: 19
Joined: Tue Oct 06, 2015 6:09 pm

Astro Module Liveview suggestion

Post by Wolsley » Tue Mar 20, 2018 10:01 pm

Duka,
Would it be possible to add a "Contrast" slider to the astro module Liveview display? This would give this Liveview display the equivalent of a real-time image stacking ability. A while ago you added an "Average image count" feature at my request. This helped to reduce high ISO noise but the display lacked contrast. If you add a contrast slider with 5 times the normal contrast range this, along with the existing brightness slider, would allow users to see very faint details that are common in astrophotography. This would allow astrophotographers to easily center their subject even in very faint situations.

The only caution I would add is that all of the Image averaging, contrast and brightness adjustments need to be performed using floating point values. Contrast would be applied after brightness adjustment is performed. Only once all of these calculations are done should you convert the image to an integer data type for display.

Regards,

Peter Wolsley

Astro Module Liveview suggestion

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Wolsley
Posts: 19
Joined: Tue Oct 06, 2015 6:09 pm

Re: Astro Module Liveview suggestion

Post by Wolsley » Wed Mar 21, 2018 10:20 pm

Duka,
If you are able to make this change...I did some research to demonstrate why I will need lots of contrast. I have written a program that displays what are called FLATs. These are images taken with my telescope of an evenly illuminated nearby surface. The telescope is focused on infinity as it would when taking astrophotos. These FLATs appear as grey images with no details. Typically I will take 10 to 15 images this way and generate an averaged master FLAT. The following image is what a master FLAT looks like with no contrast adjustment...not much to look at?
Averaged Image no contrast.jpg
FLAT displayed with no contrast adjustment
Averaged Image no contrast.jpg (20.72 KiB) Viewed 883 times
The magic comes when very high contrast is applied to the image. The 2nd image is the same master FLAT but here I have increased the contrast so that the equivalent of only one or two pixel levels can result in a swing of 100 to 120 pixel levels. This assumes that the full grey level range is from 0 to 255.
Averaged Image HIGH contrast.jpg
Averaged Image HIGH contrast
Averaged Image HIGH contrast.jpg (251.17 KiB) Viewed 883 times
The black circles are commonly called dust donuts. The ones you see here are microscopic specs of dust on the imaging chip of my Nikon D5300. Astrophotographers use FLATs to detect where dust specs are located and whether the optics need to be cleaned. We also use FLATs to calibrate our astrophotos to account for dust on the optics.

I hope this demonstrates how the averaging needs to have a contrast adjustment to pull out the faint details when using Liveview for centering faint galaxies etc.

Peter

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Re: Astro Module Liveview suggestion

Post by admin » Fri Mar 23, 2018 12:46 pm

Hi check this version https://s3.amazonaws.com/download.digic ... 0.76.2.exe

If you have any other sugestion just let me know ..

Wolsley
Posts: 19
Joined: Tue Oct 06, 2015 6:09 pm

Re: Astro Module Liveview suggestion

Post by Wolsley » Fri Mar 23, 2018 5:27 pm

Duka,
Thank-you for replying so fast. I will test it out and let you know.

Peter

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