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#apertus IRC Channel Logs

2022/01/10

Timezone: UTC


04:38
Bertl_oO
off to bed now ... have a good one everyone!
04:38
Bertl_oO
changed nick to: Bertl_zZ
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07:36
se6astian
good day
10:51
illwieckz
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11:04
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11:11
Bertl_zZ
changed nick to: Bertl
11:11
Bertl
morning folks!
16:00
se6astian
MEETING TIME!
16:00
se6astian
who is here?
16:00
Bertl
is here ...
16:00
Tr3n4rT
hello I'm here
16:03
se6astian
hi Tr3n4rT! I don't think we have met before, what are you working on?
16:04
Tr3n4rT
Hi sebastian that's right, I'm not working on an apertus project yet
16:05
se6astian
I see, would you like to?
16:06
Tr3n4rT
kinda :) That's more or less the reason I'm here. I'm starting a new carrer in the IT on the softwear developpement side/coding
16:07
Tr3n4rT
and I was a backer of the axiom project a few years ago
16:07
se6astian
I see, great
16:07
se6astian
so quick updates from me for the last work week:
16:08
se6astian
dev kit to belgium has been received by oscar and he has tested it successfully
16:08
se6astian
firmware 2.0 has been flashed and hdmi output and ssh/usb communication is working
16:09
se6astian
I started cleaning up and restructuring the wiki
16:09
se6astian
https://wiki.apertus.org/index.php/Special:RecentChanges
16:09
se6astian
also the raw hdmi documentation moved to wiki (work in progress) from a google doc
16:09
se6astian
I did some hdmi latency tests, will move to wiki soon as well from google doc
16:10
se6astian
the 3rd version axiom recorder 3d print is done, assembled and works now
16:10
se6astian
I think thats it from my side
16:10
se6astian
vup/anuejn do you want to share anything about the recorder/image analysis?
16:12
se6astian
otherwise Bertl I would love to hear your news
16:12
Bertl
sure
16:13
Bertl
I finished testing the two newly assembled ZIF SFEs today and they are both working perfectly!
16:13
se6astian
great!
16:13
Bertl
I also took the opportunity (of having a ZIF socket) to re-test our engineering samples for the CMV12k
16:14
Bertl
it has been quite a while since we used/tested those and the results were interesting
16:15
Bertl
the two color engineering samples are not working, one has an electrical problem, the other one doesn't pass LVDS training
16:15
Bertl
but we also have four monochrome engineering samples, and to my surprise, they seems to be working just fine (from the electrical point of view)
16:16
vup
is is here now
16:16
Bertl
i.e. those do not give a good picture, but it is quite usable for testing sockets and similar, as they pass training and provide some output as well
16:16
se6astian
great
16:17
Bertl
I also started testing the ultra flexible HDMI cables, but the tests are still running there ...
16:17
Bertl
so results will be available later this week
16:17
Bertl
that's it from my side for this week.
16:17
se6astian
many thanks!
16:17
se6astian
you also adapted the raw hdmi firmware a bit IIRC
16:18
Bertl
ah, yes, but that was rather a quick hack to get some additional info nobody actually used/needed
16:19
se6astian
right
16:19
se6astian
vup do you want to talk a bit about your image analysis progress?
16:19
vup
sure
16:19
vup
so anuejn and I did some more tinkering with the hdmi raw output and capture support of the recorder
16:20
vup
and that should now be in a state where it (atleast sometimes) produces the proper output
16:21
vup
so equipped with that we started taking some darkframes to start to reproduce the color correction stuff that a1ex has worked on some time ago
16:22
vup
with the hdmi raw output it is now a lot easier to capture a lot of image data in a short amount of time, so hopefully some of the calibration processes will get a lot quicker
16:22
vup
for now I only started with very basic analysis of the darkframes
16:23
vup
but that already uncoverd some pretty interesting patterns
16:23
vup
so just producing a mean darkframes shows that there is a big gradient from the left to right: https://files.niemo.de/4x_11ms_mean.png
16:24
vup
and this occurs on atleast two different sensor so we can be pretty sure this is not just a artifact on one specific sensor
16:24
vup
furthemore, while at 1x gain the distribution of the pixel values of the darkframes are roughly gaussian: https://files.niemo.de/1x_hist.png
16:25
vup
at higher gains they always look like the addition of two gaussians: https://files.niemo.de/4x_hist.png
16:25
vup
if anybody has theories why this might be the case I would be interested to hear them
16:25
Bertl
are those monochrome or color sensors?
16:26
vup
color
16:26
Bertl
can you do the evaluations per channel there?
16:26
vup
sure, I can do those later today
16:27
Bertl
would be interesting whether they match up or not
16:27
vup
yeah I also was wondering about that aswell
16:27
Bertl
in theory they should, as monochrome and color sensors should not differe electrically
16:27
Bertl
*differ
16:27
vup
yeah
16:28
se6astian
and ultimately there should be no light "input"
16:28
Bertl
no visible light, yes
16:29
Bertl
what would also be quite interesting is to do separate analysis over the column blocks
16:29
vup
that another thing, the exposure time seems to only have a really small influence on the mean dark current, and a rather weird one, the extreme exposure times (~0ms and 11ms) seem to have the biggest dark current and the further you get to the "middle" the dark current reduces
16:29
vup
finally when one subtracts the column wise means from each column some more patterns are visible: https://files.niemo.de/1x_10ms_mean_by_column.png
16:29
vup
Bertl: what do you mean by column blocks?
16:30
Bertl
well, we get sensel 0,128,256,... first, then 1,129,257 ...
16:30
vup
ah right
16:30
Bertl
so I'd expect some time based difference there
16:31
vup
so in column and row block?
16:32
Bertl
yeah, I'd summ up all the columns we get first, then the columns we get second, and so on
16:33
Bertl
and see whether they differ based on 'when' they were transferred compared to the exposure
16:33
vup
you mean the columns where we get the pixel first in each row, the columns where we get the pixel second in each row, etc?
16:34
Bertl
yes, i.e. sum over 0,128,256,384,512, ...
16:34
Bertl
then sum over 1,129,257,385,513, ...
16:34
vup
yeah that could be interesting
16:34
Bertl
and so on, up to 127,255,383,511,...
16:34
se6astian
you expect noise to "accumulate" when the data stays longer in the sensor memory?
16:35
Bertl
yes, that is what I'd expect when the data gets 'shifted' out
16:35
se6astian
interesting
16:36
se6astian
great progress vup! let me know if there is anything else I can help with other than capture more darkframes soon?
16:36
Bertl
same goes for the rows of course (i.e. I'd also expect some row pattern there)
16:36
Bertl
increasing noise from top to bottom
16:37
vup
Bertl: some row patterns are already visible in the last link i posted
16:37
vup
se6astian: well images of a homogeneous light source would be pretty interesting aswell
16:37
se6astian
thats quite tricky as the lens always vignettes
16:38
se6astian
and without lens the center of the sensor receives more light
16:38
se6astian
or what did you have in mind?
16:38
se6astian
out of focus mid grey wall?
16:38
vup
thats what a1ex recommended
16:38
Bertl
it should not be too hard to get even light exposure on a sensor without lens
16:39
se6astian
I will see what I can do
16:39
Bertl
all you need is a reasonably far diffuse light source
16:39
Bertl
(in an otherwise dark room ;)
16:40
se6astian
anything else for the meeting?
16:41
se6astian
or anyone else who wants to report?
16:42
Bertl
vup: do you have the mean_by_column.png in a size which doesn't cause aliasing effects?
16:42
Bertl
i.e. where the data is one value per pixel
16:42
vup
yeah, one sec
16:43
vup
do you want to read the file and process it or just look at it?
16:43
vup
i have pdfs ready that have per pixel data
16:43
Bertl
just look at it for now
16:43
vup
https://files.niemo.de/darkframe_pdfs/
16:44
vup
(these are always the average of 256 darkframes, the 2x for example is the gain, the number after that the exposure time in ms)
16:44
mecrisp
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16:45
Bertl
understood
16:45
Bertl
tx
16:46
se6astian
I have to leave for another videoconference so if its alright for you I would conclude this weeks meeting
16:47
se6astian
and leave you to discuss calibration details as desired
16:47
Bertl
yeah, I think we are done for today
16:47
se6astian
great
16:47
vup
yeah fine with we
16:47
vup
s/we/me/
16:47
se6astian
then MEETING CONCLUDED, many thanks
16:47
Bertl
thanks for moderating!
16:48
Tr3n4rT
thqnk you, have a nice evening
16:48
Tr3n4rT
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16:57
Bertl
off for now ... bbl
16:57
Bertl
changed nick to: Bertl_oO
22:06
vup
se6astian: also pretty interesting would be full width darkframes with the dark columns present