Error - Zero or Insignificant Signal Detected in Reference Image

reggiej42

reggiej42

Member
Need help here - Using Batch PreProcessing to integrate RGB subs from Telescope Live session and it seems that no matter what file I choose as a reference file, I get the same error each time I attempt (4 tries) to integrate the images and the calibration files in Pixinsight:

*** Error: /Users/reggiejones/Pictures/Astro Imaging/TelescopeLive/NGC 6744/NGC6744 BatchPreprocess/registered/Red/2020-04-02T08-35-34_NGC_6744_Red_T-25_450s_cal_a_c_r.xisf: Zero or insignificant signal detected (empty image?)
<* failed *>

Checked the calibration files and the Master Dark file looked different from what I was expecting - contained a swirling light pattern. I talked to Telescope Live about this and they responded that the swirling pattern in the Master Dark is called "Residual Bulk Current", or RBI (new learning for me). The camera used on this particular telescope is apparently very susceptible to RBI. Not sure if this is related to the problem but I thought I'd mention this.

All ideas welcome
 
RBI is "residual bulk image" and it's a phenomenon where photoelectrons get trapped in the substrate of the chip (which is also known as the bulk.) this is the layer of silicon underlying the other layers of the chip. those trapped electrons influence how the photosites react to new photoelectrons, and so you end up with a residual image of at least the prior exposure when you read out the current image, which messes it up of course.

when certain sensors are run at very cold temps, this can happen. the solution is to do something called "RBI preflash" before every exposure - basically you shine an IR light onto the chip and then whatever residual image of stars/etc. was in the bulk is replaced by something like a flat. you see swirling patterns that correspond with how the silicon was grown into a cylindrical boule.

that image is also a residual image, it's just an image of nothing.

the upshot is that that a dark with RBI preflash can not be scaled, because the RBI does not scale with exposure time of the dark. so all of the above is a very long way of saying make sure that dark optimization is turned off when you use RBI lights/darks.

usually you won't use RBI preflash for flats, so check that and if they havent, they might be providing different darks for the flats. or, maybe they expect you to calibrate the flats with a master bias (or maybe they provide a calibrated master flat?)

rob
 
pfile said:
RBI is "residual bulk image" and it's a phenomenon where photoelectrons get trapped in the substrate of the chip (which is also known as the bulk.) this is the layer of silicon underlying the other layers of the chip. those trapped electrons influence how the photosites react to new photoelectrons, and so you end up with a residual image of at least the prior exposure when you read out the current image, which messes it up of course.

when certain sensors are run at very cold temps, this can happen. the solution is to do something called "RBI preflash" before every exposure - basically you shine an IR light onto the chip and then whatever residual image of stars/etc. was in the bulk is replaced by something like a flat. you see swirling patterns that correspond with how the silicon was grown into a cylindrical boule.

that image is also a residual image, it's just an image of nothing.

the upshot is that that a dark with RBI preflash can not be scaled, because the RBI does not scale with exposure time of the dark. so all of the above is a very long way of saying make sure that dark optimization is turned off when you use RBI lights/darks.

usually you won't use RBI preflash for flats, so check that and if they havent, they might be providing different darks for the flats. or, maybe they expect you to calibrate the flats with a master bias (or maybe they provide a calibrated master flat?)

rob
Click to expand...

Thanks Rob
 
So, I tried it again with the dark optimization off which it usually is and still get the same error. Asked them some questions based on your response and I'll see what they come back with.

Thanks again for responding.

Reggie
 
dont use a bias frame unless the master was precalibrated by them. that might also be a problem.
 
Thanks Astrobin - I ran Batch Preprocessing with only flat frames and it integrated. When I did a quick combine of the RGB masters, it came out with a purple / fuchsia cast to it which I wasn't quite prepared for. Hoping DBE and then ABE will take care of this.

Thanks for the information!
 
the cast will likely be improved by DBE but the real solution to proper color is BackgroundNeutralization + ColorCalibration, or PhotometricColorCalibration.

rob
 
Dear reggiej42,

I face the same issue processing CR3 Raw´s from my EOS RP. I have just open a new thread on this.

BR Rainer
 
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