Author Topic: BUG REPORT - No Image output at certain Gain-Settings at high framerates.  (Read 2032 times)

Nikon1

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I was just Testing a bunch of gain settings to try to figure out a good and propperly reproduceable way of comparing Noise performance on the Chronos 2.1 for a possible personal future Project, comparing Noise vs Sensor Temperature with different Cooling on the Sensor.
 While i did that, i came across a bunch of Gain Settings, that wherent working at all. So i decided to just test them all. For the Sake of time and my sanity, i limited myself to test just the Preset Resolutions at Max. framerate and maximal exposure time. Full list of the Test Results is attached as Excel List, small part of the list is also posted as screenshot. Testing setup was as follows: Resolution was picked, Black Calibration was done for every single Setting, for the ones that Failed i did at least two to 5 Tries at a Black-Calibration. Result was then written down. All testing was performed after allowing the camera to warm up for more than an hour, and the Camera was pluged into the Power adapter the whole duration of the Testing. This is not an test about image Quality, just to see if its even working at all, and surprisingly many of the Gain-Resolution-Framerate Combinations (especially High framerates + High gain, which would be really, really good to have for stuff that doesnt need to look particularly good, but you have to see them Anyways and dont have a ton of light to work with for some Reason) from the Presets wont work.
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 So now, after seeing those results, i wonder, if this is just some mistake on my side (results are VERY reproduceable on my camera, so i doubt that), something wrong with my unit, or an Actuall Bug in firmware. Can someone Confirm the results i got from my test on his camera? please also post if you get completely different results, or have to add any weird bugs like this to this List. I guess there are many more settings which are pretty glitchy, but i think the Preset ones are propably the most used ones, and because of that the most important. Also noticed there are about as many Bugs for Really low framerates and some Custom Resolutions, but didnt want to also test that today, if i do any more Testing like this, i will propably also post it here or start another thread, if its too much off topic to be included here.
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#EDIT: Removed the Partial Screenshot from the List and Replaced it with an Screenshot of the Complete List. Screenshot is a bit broken at the bottom, Excel seems to not like huge resolution Monitor setups, but should still be readable.
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 #EDIT: My Browser also freaks out when trying to display that long image, and wont display it completely, so maybe just download it to view it, if your Browser wont display that correctly also, or look at the Excel file.

« Last Edit: October 29, 2020, 04:23:58 PM by Nikon1 »

chrissie_c

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I think it's a bug, I'm having similar problems with some combinations of resolutions and gain - though I didn't test as thoroughly as you did!

http://forum.krontech.ca/index.php?topic=569.msg3507#msg3507

Bian

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Re: BUG REPORT - No Image output at certain Gain-Settings at high framerates.
« Reply #2 on: November 01, 2020, 01:09:07 AM »
I did a few tests based on your table and get same results at higher gains.

Nikon1

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Re: BUG REPORT - No Image output at certain Gain-Settings at high framerates.
« Reply #3 on: November 01, 2020, 01:22:39 AM »
I did a few tests based on your table and get same results at higher gains.
Thanks a lot for your tests!

Nikon1

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Re: BUG REPORT - No Image output at certain Gain-Settings at high framerates.
« Reply #4 on: November 01, 2020, 01:47:49 AM »
@chrissie_c: Thanks for that link, read that topic, when it was new, but completely forgot it existed. This is the absolutely same issue you got back then.
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 I also found this:
 https://forum.krontech.ca/index.php?topic=559.0
 This old topic is about some issues one user got with clipping also. This, and the reason behind those lines, tesla500 explained there should also cause all of the cases of Overexposed areas showing various amounts of Line patterns. I think this maybe can be solved with some kind of more advanced Look-Up-Tables inside the camera, allowing for those inconsistent values coming from the sensor, but remapping them to values more accurate to the real world, while beeing aware that this will change a lot with gain, framerate, and Temperature. I dont know how, but it should be possible to be done. maybe not only a Black-Calibration, but also a (optional) Grey- and White-Calibration should provide enough data for This, to improove Image Quality significantly, avoiding having to Hard-Code it into the Firmware for every possible Combination of settings. Fixing this issue with the Vertical Lines and generally very visible Fixed pattern noise in the Overexposed Areas at some resolutions, should also improove overall image-Quality by quite a bit, if done propperly. Because most Noise currently visible is actually those Lines and Fixed Pattern noise, which seems strangely similar to that from the Overexposed Areas in my tests, so the Most of the other Lines and Noise is also most likely caused by the same or similar problems with readout timing or propper remapping of Pixel Brightness values.
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 As far as the Resolution/ Framerate/ Gain Combinations go, which arent working AT ALL currently, which are basicaly all gain settings over 12dB analog Gain at 1024px Horizontal Resolution and all Gain Settings over 6dB Analog Gain for resolutions of 800px Horizontal or smaller, basically forcing you to use 0dB Gain (6dB (and 12dB for 1024px) is working and kinda useable, but image Quality is mostly pretty bad because of those Lines explained above) at the Highest framerates, demanding crazy amounts of light for those usecases. Since this is now obviously no faulty unit on my end, but an Bug in Firmware as it seems right now, this should really be fixed. Would really be great to have higher Sensitivity Options for High Framerate stuff.
« Last Edit: November 01, 2020, 01:49:50 AM by Nikon1 »

chrissie_c

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Re: BUG REPORT - No Image output at certain Gain-Settings at high framerates.
« Reply #5 on: November 01, 2020, 08:18:20 AM »
> I also found this:
> https://forum.krontech.ca/index.php?topic=559.0


Ahh, another good find.

It would be hugely helpful to be able to use sensor gain at those settings higher-frame rate settings - especially as the sensor analogue gain does seem to work really rather well (at least at lower frame rates). My budget doesn't quite run to another 300d at the moment :)