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Old 22-09-2019, 02:45 PM
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Peter Ward
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Fixed Pattern Noise

The question of fixed pattern noise came up elsewhere, which I found interesting, so I decided to test the two cameras I am using at the moment.

Hopefully this won't be perceived as how to suck eggs, but I made up a web page with a few words on the subject plus some test results here

Maybe useful? or at least food for thought on things to look for when you pick your next camera.

Last edited by Peter Ward; 22-09-2019 at 03:26 PM. Reason: clarification
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Old 22-09-2019, 04:18 PM
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jwoody (Jeremy)
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Most useful, thank you
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Old 22-09-2019, 05:28 PM
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multiweb (Marc)
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Good reference.
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Old 22-09-2019, 07:57 PM
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Peter Ward
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Quote:
Originally Posted by multiweb View Post
Good reference.
Quote:
Originally Posted by jwoody View Post
Most useful, thank you
My pleasure. As it turned out my 9 year old SBIG STX16803 was showing signs of old age.

The input PCB/cooler driver board were suffering from corrosion, which was causing odd spikes in the light and dark frame data.

The replacement PCB from SBIG wasn't cheap, but effectively renewed the camera's noise profile to that of a freshly minted model.

Rather than ship the camera to the USA, with help from the tech guru's at SBIG I did all the work Sydney and ended up learning more about the camera than I really wanted to in the process.
The read noise and gain values had to be measured, calibrated and re-written to the camera's EPROM. The calibrated frames are again absolutely and clinically clean.

So much so, and to paraphrase Mark Twain... rumours of the death of CCD's are greatly exaggerated IMHO
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Old 24-09-2019, 08:46 AM
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Thanks Peter, thatís very interesting.
Where/what is an FFT filter?
Cheers
Andy
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Old 24-09-2019, 09:24 AM
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I reckon that will be a Pixinsight routine, it goes deeper in to image analysis than I would expect Photoshop to do.

https://pixinsight.com/forum/index.php?topic=1494.0
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Old 24-09-2019, 12:21 PM
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Peter Ward
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Quote:
Originally Posted by Andy01 View Post
Thanks Peter, thatís very interesting.
Where/what is an FFT filter?
Cheers
Andy
MaxImCCD > Analyse > FFT analysis

The routine looks for repeating patterns or at various spatial frequencies, or harmonics in the data, and graphically shows these as symmetrical spikes or patterns, which vary in width and amplitude.
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