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BadPixelMap Files


(@batch)
Molecular Cloud Customer
Joined: 3 years ago
Posts: 6
Topic starter  

I just got a new camera and I am in the process of creating a set of Master Calibration files. As part of this process I am creating a new BadPixelMap. After running the Calibrate module APP output two BPM master files BPM-1 and BPM-2. It's been a while since I did this but I do not recall two files being created in the past. When I examine them it only looks like BPM-1 contains any information (BPM-1 shows a lot of bad pixels and BPM-2 doesn't appear to show any). So I have a couple of questions: What are the two files for and is it ok to delete BPM-2 (no apparent info) and just use BPM-1?  Thanks


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(@wvreeven)
Galaxy Admin
Joined: 4 years ago
Posts: 2035
 

@batch Hi Bill,

What input data are you using for creating the BPM? Are there files that have a different temperature, gain, offset or exposure time than others? Are you loading all data into one session or two? Please try to give us as much information as possible.

Thanks, Wouter


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(@jochen-scharmann)
Main Sequence Star Customer
Joined: 3 years ago
Posts: 72
 

Hi Bill,

have You checked the exposure times in the frame list? I came across a similar issue as the camare reports slightly different exposure times (e.g. 60s vs 61 s), hence APP would create 2 MasterDarks resulting in 2 BPM's.

You can avoid this by unchecking the "seperate darks acc. to exposure time box at the very bottom of tab 2) (You need to watch out not to throw in lights with really different exposure time, though , e.g. 60s vs 120s), which would require individual Masterdarks.

Hope this helps,

Jochen


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(@batch)
Molecular Cloud Customer
Joined: 3 years ago
Posts: 6
Topic starter  

@wvreeven Hi Wouter

I've tried multiple variations by processing individual channels/single session to multiple channels/single session. All temps and gain are the same on a per channel basis and darks match lights. I have tried setting the BPM parameters myself as well as running it with the automatic option selected. I am using vr 2.0.0beta4. Regardless of what iteration I run it still results in two BPMs being produced. One thing of note is that I am reporting a Hot Pixel count of about 2.7% and 0% Cold pixel count so I'm wondering if BPM-1 which clearly shows multiple pixels is the Hot pixels and BPM-2 which shows nothing (flat white) is the Cold pixels. Would this make sense? If so I could discard BPM-2 and just use BPM-1 going forward.


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(@batch)
Molecular Cloud Customer
Joined: 3 years ago
Posts: 6
Topic starter  

@jochen-scharmann Hi Jochen,

Thanks very much for the suggestion. I did check the exposure times and everything matches as well and in every instance only one MasterDark was created. 

Regards,

Bill


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