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[Solved] Calibrating data with a Sony BSI IMX183 C/M sensor - ASI183, Altair Hypercam 183, QHY183 - removing the severe Amp-Glow patterns  

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(@rcfmitch)
Red Giant Customer
Joined: 9 months ago
Posts: 57
November 3, 2018 21:45  

the New Sony Hypercam BSI IMX183 C/M star burst doesn't seem be subtracting with 40 darks ,

and I'm too new to guess why.

Im going to try a few more runs and show the results. Doing BPMap also did not seem to solve this.

MD ISO gain 800.0 exp 180.0s 40subs Altair Astro Camera ASCOM Driver 5440x3648 WC 3 3.0 avg StIMX183M
BPM1
Sony BSI IMX 183

 

EDIT by Mabula:

CHECK this post with the solution:

https://www.astropixelprocessor.com/community/main-forum/sony-hypercam-bsi-imx183-c-m-star-burst-not-subtracting/#post-4533

This topic was modified 7 months ago 2 times by Mabula Haverkamp - Admin

(@rafiosso)
Molecular Cloud Customer
Joined: 10 months ago
Posts: 4
November 3, 2018 23:29  

What precisely camera is it? Altair Hypercam? Or something else?


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(@rcfmitch)
Red Giant Customer
Joined: 9 months ago
Posts: 57
November 4, 2018 00:57  

Yes, the Altair Astro 183M  hypercam . 🙂


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(@rafiosso)
Molecular Cloud Customer
Joined: 10 months ago
Posts: 4
November 4, 2018 10:55  
Posted by: rcfmitch

Yes, the Altair Astro 183M  hypercam . 🙂

Well, in that case You don't have precise temperature control built into the camera. AFAIK Altair hypercam has only a cooler, not a precise controlled peltier (like ZWO, QHY) and that is why You cannot get rid of thermal pattern, as temperature changes during photosession.


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(@rcfmitch)
Red Giant Customer
Joined: 9 months ago
Posts: 57
November 4, 2018 20:08  

 

 

Actually that statement is incorrect , ( get rid of thermal patterns) i can completely remove the Starburst in Pixinsight and DSS4.1.1. and Nebulosity 4.

the problem at this point is the way APP interprets the darks and flats as it calibrates the light frame.

thank you for your input , 🙂   Mabula will have a look at this when he has a minute..  

 

Micth 

This post was modified 8 months ago by rcfmitch

(@rafiosso)
Molecular Cloud Customer
Joined: 10 months ago
Posts: 4
November 5, 2018 20:37  
Posted by: rcfmitch

 

Actually that statement is incorrect , ( get rid of thermal patterns) i can completely remove the Starburst in Pixinsight and DSS4.1.1. and Nebulosity 4.

the problem at this point is the way APP interprets the darks and flats as it calibrates the light frame.

thank you for your input , 🙂   Mabula will have a look at this when he has a minute..  

 

Micth 

Oh, glad to see there's a solution for thermal patterns, i suspected the temperature control to be "guilty" 😉


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(@mabula-admin)
Quasar Admin
Joined: 2 years ago
Posts: 2081
November 7, 2018 13:52  

Hi Mitch @rcfmitch, @rafiosso, @vincent-mod,

Thank you Mitch for sending me a dataset shot with the Altair Astro Camera which has the Sony Hypercam BSI IMX183 sensor.

APP can calibrate this data correctly, using the Adaptive Data Pedestal in 2) Calibrate.

To be clear, APP will do this better (at least with the data that I have for testing) than other applications due to this Adaptive Pedestal.

Please have a look at the release notes of APP 1.062, this example shows the issue with an asi183mm-c camera which has the same sensor.:

https://www.astropixelprocessor.com/community/release-information/astro-pixel-processor-1-062-ready-for-download/

  • Improved, data calibration of severe Amp Glow, amp glow does not behave linearly so it's always important to not use dark scaling if your sensor has significant amp glow. You need to create darks of the same offset, gain/ISO, temperature and exposure time as your lights, to properly deal with amp glow. Now, in cases of strong amp glow, it can happen that the glow is so strong when compared to the real photon signal and noise in our data that a large part of these pixels will be calibrated to zero if we subtract a suitable dark frame. This will happen in each frame for different pixels and that will have a cumulative effect in image integration. The statistics of the pixelstacks will actually be skewed to the upside still showing residual amp glow in some cases. In 2) Calibrate, there is now a new option that will adaptively solve this for data were this happens. It's called Adaptive Data Pedestal. If you enable this, it will prevent severe clipping on the black point in calibration, and will therefore prevent skewed pixel statistics in image integration. It's an adaptive algorithm, so it takes a little bit more time in calibration. A case were you probably need to enable this is strong Amp Glow with camera's like the ZWO ASI183. For most camera's and datasets, this setting will have no effect, but in cases where severe black clipping in calibration does occur, for whatever reason, this setting will prevent it and will ensure precise calibration and no-skewed statistics in image integration.

Adaptive Data Pedestal

Example of an integration of ZWO ASI183mm-c Oxygen-III data provided by Warren Landis @orangemaze, with and without the setting enabled in calibration:

APP 1062 ampglow fix
APP 1061 ampglow asi183

In this case, the amp glow is not calibrated out with the Adaptive Data Pedestal disabled, because the amp glow simply overpowers the real OIII data on the location of the amp-glow. By enabling the Adaptive Data Pedestal, the amp glow is properly calibrated.

I received a nice Hydrogen-Alpha data set from Mitch of IC405. Details are:

60x180sec lights

40x180sec darks to calibrate the lights

50x flats to calibrate the lights

60x bias to calibrate the flats. (not used for the light frame calibration)

To see the extreme amp-glow problem of this sensor, this is the stretched MasterDark:

MD ISO gain 1000.0 exp 180.0s 40subs Altair Astro Camera ASCOM Driver 5440x3648 NR avg St

You can see the extreme amp-glow on the right side of the sensor, and a little bit in both bottom corners of the sensor.

These are the results with and without the Adaptive Data Pedestal enabled in calibration, off course, highly stretched to show the data calibration performance in an integration of 60x180 seconds Hydrogen-Alpha frames (3 hours total exposure time):

Without Adaptive Data Pedestal:

Without AdaptiveDataPedestal
Integration without AdaptiveDataPedestal

With the Adaptive Data Pedestal enabled, where is the Amp-Glow ?? 😉 :

With AdaptiveDataPedestal
Integration with AdaptiveDataPedestal

Direct comparison:

Without With AdaptiveDataPedestal

 

What happens without the Adaptive Data Pedestal: the residual amp-glow that you see in the integration without the adaptive data pedestal enabled, is the result of skewed data integration (to the upside) due to black clipping of the light frames after the subtraction of the MasterDark. This means that the provided lights are not sufficiently illuminated for this sensor. This sounds strange perhaps for such a BSI cmos sensor, but the illumination really is not enough to have the light/photon signal overcome the severe amp-glow on the right side of the sensor. The Amp-Glow signal is so strong, that after subtracting a masterdark from the light frames, a lot of pixels are still black clipped... The Hydrogen-Alpha signal (in this case) is too weak to overcome the Amp-Glow. This has a degrading effect on the data, once properly calibrated with the Adaptive Data Pedestal enabled, the image data will always have worse noise characteristics in the areas where the Amp-Glow resides on the sensor

The Adaptive Data Pedestal is an adaptive algorithm that will prevent the black clipping of pixels after masterdark subtraction and therefore the integration results are no longer skewed to the upside, thus properly removing the amp-glow signal if the provided darks are of  the same temperature, same exposure and same gain + offsett as the light frames.

This post was modified 7 months ago 2 times by Mabula Haverkamp - Admin

Main developer of Astro Pixel Processor and owner of Aries Productions


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(@rafiosso)
Molecular Cloud Customer
Joined: 10 months ago
Posts: 4
November 7, 2018 14:02  

Wow, that is impressive!

Thank You Mabula for lots of effort and clear explanation!!!


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(@mabula-admin)
Quasar Admin
Joined: 2 years ago
Posts: 2081
November 7, 2018 14:06  
Posted by: rafiosso

Wow, that is impressive!

Thank You Mabula for lots of effort and clear explanation!!!

You're most welcome @rafiosso ;-(

Main developer of Astro Pixel Processor and owner of Aries Productions


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(@rcfmitch)
Red Giant Customer
Joined: 9 months ago
Posts: 57
November 7, 2018 16:21  

I agree , WOW , thank you for making a program that will allow us to push the envelope on this new Sony BSI chip without fear of horrible amp glow and damaged data sets. 

More data and images to come in the coming weeks processed with APP.

 

Thanks again Mabula H.


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