Noise, Firecapture and imaging questions

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Re: Noise, Firecapture and imaging questions

Post by Montana » Tue Jan 09, 2018 7:08 pm

That is funny you should say that Mark, I have gone back and looked at all my old recordings from Firecapture 2.3 and all are 16 bit ser. Now my camera can't do 16 bit Ser it would seem. These Moon shots which have outputted as 14 bit ser are the best files I have ever seen with this camera. It is so smooth like velvet and I have not even touched brightness or contrast or levels or anything, it looks beautiful as is. This is with Firecapture 2.5 which picked the 14 bit ser, but half are 15 bit ser and they don't process. If only I could force it to always capture at 14 bit ser it would be a dream come true. Here is one of my Moon shots

Image2017-12-28-2020 by Alexandra Hart, on Flickr

I am just processing a comparison of what happens when you try 16 bit and really the camera is only 14 bit. I think Mark if you could get your camera to record a ser file at the correct bit depth and then analyse it in ASK3 on the right setting you will be amazed. I am!

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Re: Noise, Firecapture and imaging questions

Post by PDB » Tue Jan 09, 2018 7:30 pm

Hi Marc,

impossible to get a screenshot, because it one of those pop-up boxes that dissapears when you try to make the schreenshot. But I marked the area where you can find it:
fc.jpg
fc.jpg (58.86 KiB) Viewed 629 times
But this is camera manufacturer dependent, so it might look different for PointGrey cams.

For ZWO there is something called "highspeed". If you mark this the camera will use to the low ADC value (but perform faster) untick it (default) will use the high ADC value. (One exception I know is the ASI120 which will always use 12bit ADC regardless of this setting)

For PointGrey it might be called "Mode 7". (In Genika it is in Options - Aquisition)

What I noticed for ZWO is that in 16 bit mode, it always seems to be upsampled to 16bit, but not from 8bit but either from 10, 12 or 14 bits ADC (not 100% sure but looking at the histogram it is not an 8bit upsampling, that would show more gaps in the histogram) This upsampling seems to take place in the camera (or ZWO SDK). I need to find some documentation on the PGR SDK to see what really happens there.

Rgrds,

Paul

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Re: Noise, Firecapture and imaging questions

Post by PDB » Tue Jan 09, 2018 7:36 pm

Hi Alexandra,
Firecapture 2.5 which picked the 14 bit ser, but half are 15 bit ser and they don't process.
Think I will ask this directly from Torsten Edelmann. It's a pitty I don't own PGR cam, but not that many dealers on the continent.

Regards,

Paul

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Re: Noise, Firecapture and imaging questions

Post by marktownley » Tue Jan 09, 2018 7:44 pm

Thanks Paul, I'll have another play / explore this evening :)
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Re: Noise, Firecapture and imaging questions

Post by PDB » Wed Jan 10, 2018 9:01 am

Asked the question to Torsten Edelmann. He confirms he always writes "16" in the header field of the SER file, not the true bit depth of the camera. Now I wonder how that then shows as 14 or 15 bit in the SERplayer. It makes sense that you then have to force AS!3 to the correct bit depth.

Maybe we should start a separate discussion for these issues?

P.

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Re: Noise, Firecapture and imaging questions

Post by HansH » Wed Jan 10, 2018 10:37 am

Very interesting discussion, eyeopener....

Yesterday morning did some trials on moon as well following this topic... with ZWO ASI 174MM camera.

Looks like Firecapture not consistent in "always writes 16 in header". See my txt files attached.
in AS3 processing 16 rather than lower (10 or 12 my cam should be) giving me the best results.

Another trial done with 2x2 binning on the sun, where at the disk rim all appearing "sawteeth".... 2-3x more frames though.
This phenomena also appearing with anyone else ?

Hans.
Attachments
070537_Gain=0_Exposure=80.4ms_Gamma=69.txt
(688 Bytes) Downloaded 24 times
073759_Gain=182_Exposure=9.2ms_Gamma=50.txt
(741 Bytes) Downloaded 15 times

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Re: Noise, Firecapture and imaging questions

Post by PDB » Wed Jan 10, 2018 10:48 am

Hans,
Don't think you can capture 16bit in AVI files? You should look ar SER files. When 8 bit mode the header will say 8 not 16.

@Alexandra & Mark
I now found a reason why bit depth in SER players shows strange can show different values. Frustrated, I downloaded the sources of SERPlayer and found that after getting the bit depth from the header, Serplayer checks 10 frames to find "True" bit depth. So it really can depend on content of the image (and noise?) to see a different bit depth in the status bar. (did not had a look how exactly that routine works)

P

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Re: Noise, Firecapture and imaging questions

Post by Montana » Wed Jan 10, 2018 11:13 am

Hans, both your SER and AVI are both 8 bit. AVI can only be 8 bit, but if your SER is also 8 bit, is that the maximum your camera can do? in which case I would stick with AVI to save disc space :) just had a look at your camera and it is "High speed imaging with a max of 164.5 fps at 10 bit ADC, and max of 128.2 fps at 12 bit ADC" therefore your SER file should be 10 or 12 bit?

Paul, this gets more and more intriguing :)
Alexandra

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Re: Noise, Firecapture and imaging questions

Post by PDB » Wed Jan 10, 2018 11:44 am

Hi Alexandra,

did some tests this morning with an ASI178 (14-bit ADC) and ASI120 (12 bit ADC). With no lens attached i just overexposed 1 frame (SER) so that the image was completely white and histogram all to the right (no histogram visible anymore). That should give the maximum recordable value per pixel.
The 178 showed value 65528 which is 13-bit. (strange that it is not 14 bit) In highspeed same value. (Where it should be 12 bit)
The only reason I can think of is that the ZWO driver when put in 16bit mode stretches the pixel depth to 13bit regardless of high-speed setting) The data that is written down in the SER file is an exact copy of what comes out of the call to the drivers, so this must happen either in camera or camera driver)

The 120 showed value 65520 which is 12-bit. (as expected, but this cam only has a 12bit ADC)
The ser file headers indicated in all cases 16 bit.

This can, as i said before, be different for every camera maker. Just depends on how the data from the camera is passed to the capturing program.

Regards,

Paul

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Re: Noise, Firecapture and imaging questions

Post by HansH » Wed Jan 10, 2018 1:46 pm

Uffff my bad...
Included 1x avi indeed, instead of the SER.txt file. (numbers almost the same, so mixed)
Add now the correct one... 2x2 binning and giving bid depth 16

Getting more and more in confusion like all of us when reading results of more and more testings done....

Anyone an idea abt the sawteeth on sundisk rim by chance when binning ?

Hans.
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073059_Gain=93_Exposure=5.1ms_Gamma=50.txt
(693 Bytes) Downloaded 11 times

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Re: Noise, Firecapture and imaging questions

Post by PDB » Wed Jan 10, 2018 2:10 pm

happens ...

If you are using the AsI174, that camera has large pixels (5.86 micron) if bin that 2x2 than your f/ratio should be minimal f/40. If not you will be undersampling. Not sure if that will produce saw-tooth rims, probably only when you enlarge over 100%?

P.

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Re: Noise, Firecapture and imaging questions

Post by Montana » Wed Jan 10, 2018 2:45 pm

Thanks Paul this is very interesting info, I am wondering if any of the recordings I made were more exposed so I got 15 bit recordings, and darker files were 14 bit. I need to do some test samples. If I can get the recording right, I would like to capture the 14 bit ones. I don't know why my Firecapture doesn't label everything as 16 bit then?

Alexandra

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Re: Noise, Firecapture and imaging questions

Post by PDB » Wed Jan 10, 2018 3:02 pm

Hi Alexandra,

FireCapture will label everything 16 bit if 16 bit is selected and a SER file. The real bit depth (which according to specs should be there) however will vary with camera, and how it processes data when you turn 16bit capturing on. Serplayer does not trust the header written in the serfile and has some algoritm that looks at pixels in 10 frames to find the real bit depth. (At least that is how I read the code) But that does not seem to be 100% correct. (My 13bit and 12 bit files are shown as 16bit, so ser player did not detect the real bith depth). Then there is AS!3 and there I don't know how the auto function works. I never had dark images with my 16 (13) bit recordings, so maybe something else comes into play. (Maybe the bit-order in the PGR cameras ... running out of ideas)

Very complicated ... to know exactly what is in the header it should be looked at with some other decoder. (I suppose you don't have Python installed on your PC, otherwhise I could send you a small Python program to decode the header and first data-row(s))

Rgrds,

Paul

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Re: Noise, Firecapture and imaging questions

Post by Montana » Fri Jan 12, 2018 8:05 am

Thanks Paul, I am not very good with computers so it might be starting to get out of my league. I think I might write to Emil and ask about ASK3 to see if he knows what is going on.

Alexandra

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Re: Noise, Firecapture and imaging questions

Post by marktownley » Mon Jan 15, 2018 5:25 pm

I was having a bit of a play yesterday; I can't get firecapture with my chameleon 3 or the blackfly to run in 12bit - 8 bit by default, if I ask FC to run in 16 bit it is not running in true 16 bit, just upsampled 8bit - hence why I see no difference when comparing the 2 files side by side.
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Re: Noise, Firecapture and imaging questions

Post by marktownley » Tue Jan 16, 2018 6:48 am

Reading on the PGR website, when cameras are put into '16 bit mode' as i'm describing ticking the 16 bit box in firecapture, all that happens is the extra bits are given a value of zero. So, still 8 bit data effectively in a 16 bit carrier. Intrigued as to how you got your PGR to output at 14 bit Alexandra?
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Re: Noise, Firecapture and imaging questions

Post by PDB » Tue Jan 16, 2018 7:45 am

Mark,

this is getting more and more fuzzy, and even conflicting. (Manufacturer vs what I see) Maybe I need to review my testing procedure.
It is strange that on another page (https://www.ptgrey.com/astrophotography) the cameras are marketed under unique features:

"Support for 16 bit video important for DSO imaging, doing Photometry for Exoplanet transits and teasing subtle details such as clouds on Venus using UV bandpass filters."

But that is probably just marketing ...

rgrds,

Paul

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Re: Noise, Firecapture and imaging questions

Post by Montana » Tue Jan 16, 2018 8:42 am

Yes I would like to know Mark because those files are my best ever!
I have written to Emil but currently waiting for a response.

Alexandra

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Re: Noise, Firecapture and imaging questions

Post by marktownley » Tue Jan 16, 2018 10:25 am

Montana wrote:
Tue Jan 16, 2018 8:42 am
Yes I would like to know Mark because those files are my best ever!
I have written to Emil but currently waiting for a response.

Alexandra
I'm guessing you captured them in FC2.3?
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Re: Noise, Firecapture and imaging questions

Post by Montana » Tue Jan 16, 2018 12:49 pm

No in Firecapture 2.5
In all my Firecapture 2.3 they are across the board 16 bit. The 2.5 version is giving 50/50 14 or 15 bit recordings.

Alexandra

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Re: Noise, Firecapture and imaging questions

Post by marktownley » Tue Jan 16, 2018 2:09 pm

strange... :/
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Re: Noise, Firecapture and imaging questions

Post by PDB » Tue Jan 16, 2018 8:45 pm

Alexandra,

do you still have the firecapture recording parameters (.txt file) for that file? If yes, what are the histogram values?

Rgrds,

Paul

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Re: Noise, Firecapture and imaging questions

Post by Montana » Sun Jan 21, 2018 4:11 pm

Sorry for not getting back to you Paul, here are a couple of text files from 2 of the 14 bit recordings. I've not heard anything back from Emil yet :(
14 bit.PNG
14 bit.PNG (23.01 KiB) Viewed 344 times
14 bit.PNG
14 bit.PNG (23.01 KiB) Viewed 344 times
Alexandra
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14 bit v1.PNG
14 bit v1.PNG (20.19 KiB) Viewed 344 times

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Re: Noise, Firecapture and imaging questions

Post by MapleRidge » Sun Jan 21, 2018 4:59 pm

HI Alexandra and all those contributing to this post...

I see in the settings that you have posted, about 3/4 way down the list of parameters is a 'Mode 7' that is listed as off. I am trying to remember back to when I first go the camera that there was a change to be made on my FireWire Grasshopper Express to change this to on in order to get the greater bit depth on the camera.

This was set in the Point Grey FlyCap 2 software...I googled it and the link is listed below. Reference to the bit setting is is in the Custom Video Settings box, the 3rd screen shot shown.

https://www.ptgrey.com/tan/10340

Not sure if this helps or not, and if already covered my apologies for not catching it earlier.

Brian
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Re: Noise, Firecapture and imaging questions

Post by PDB » Sun Jan 21, 2018 5:33 pm

Hi,

According to what I read in the AiryLab AstroGenika manual: mode 7 on = slower but better quality, mode 7 off = faster but lower quality. (Looks a lot like ZWO's high speed mode, on=faster but lower bit depth in ADC) So then i would really not expect 14 bit then. Probably you can control this in FireCapture from the "More" options just below Gamma. (See higher in an answer to Mark). Can't test that because those fields are camera dependent.

Alexandra: No problem (lots of things to do while waiting for some sunshine)

I noticed the histogram is very low (to the left). Now I need to understand how SER player tries to guess the bit depth, and how PointGrey handles the 16 bit values. (ZWO shifts the bits towards the higher values so that there are added 0 in the "black", but no idea how Ptgrey does) This could explain why some programs have difficulties stretching the image.

Regards,

Paul

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