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#apertus IRC Channel Logs

2016/12/16

Timezone: UTC


23:41
jucar
joined the channel
01:55
jucar
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03:02
Spirit532
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07:00
se6astian|away
changed nick to: se6astian
07:09
pusle
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10:50
slikdigit
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slikdigit
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11:20
Bertl_zZ
changed nick to: Bertl
11:20
Bertl
morning folks!
11:42
se6astian
hello!
13:37
jucar
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14:50
jucar
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14:56
intracube
hello :)
15:22
intracube
any new news from apertusland?
16:25
Bertl
nothing worth mentioning on my side ...
16:33
intracube
hi Bertl
16:33
intracube
I was wondering how many prototypes/betas have been made so far
16:42
Bertl
about 20
16:50
intracube
ah ok
17:38
se6astian
18 I counted
17:41
intracube
and what's the current state of the sensor calibration/colour?
17:45
intracube
is the processing still all done 'off-camera'?
17:51
se6astian
some steps are already possible to do camera internally
17:51
se6astian
FPN calibration for the FPGA for example
17:52
se6astian
camera captures 64 darkframes, raw2dng inside camera averages them, adjust levels and the output profile is loaded into memory for compensation by the FPGA
17:52
se6astian
the process takes a few minutes
18:03
Spirit532
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18:03
se6astian
changed nick to: se6astian|away
18:04
se6astian|away
changed nick to: se6astian
18:05
intracube
is the FPN fairly static for a given chip?
18:05
intracube
so the process would only have to be done occasionally (or during initial calibration)
18:06
intracube
I remember reading there were issues around different gain settings for the CMV chip requiring different FPN correction
18:07
se6astian
changed nick to: se6astian|away
18:07
se6astian|away
changed nick to: se6astian
18:07
Bertl
off for now ... bbl
18:07
Bertl
changed nick to: bertl_oO
18:23
alexML
intracube: you know this page, right? https://wiki.apertus.org/index.php/Pattern_Noise
18:24
alexML
the static part is easy to remove; the problem is the dynamic row noise component, which is still an issue (although a very large part of it can be corrected using the black reference columns)
18:24
alexML
but this part is currently done in post, and the black column data is not yet recorded on HDMI
18:25
alexML
so, it only works best on raw12 stills
18:26
intracube
alexML: qute a lot of the dynamic row noise was caused by an early power supply design iirc?
18:27
intracube
and yep, I read through those docs a while back :)
18:29
alexML
possible, I'm not aware of power supply changes related to this issue (but didn't really follow the hardware side)
18:29
alexML
a while ago we found a possible connection between fan rotation and row noise (on top of what's on the wiki)
18:30
intracube
think it Bertl mentioned a change to the power supply design some months back and that it reduced row noise
18:30
alexML
have a link?
18:31
intracube
no - I'll see if a search brings up anything
18:31
intracube
alexML: https://www.apertus.org/axiom-beta-hello-world-article-may-2015
18:32
intracube
"image sensor support and power supply circuit design are clearly visible in the images. The dynamic row noise is barely noticeable anymore compared to the first AXIOM Alpha test images. "
18:33
intracube
looks like this pre-dates your work, so it's not relevant
18:33
alexML
ah, thought it's a recent improvement on the beta hardware
18:33
intracube
didn't realise it was quite so long ago o.o
18:37
intracube
fans are PWM controlled, I guess?
18:37
intracube
choppy output might be to blame for the noise
18:38
intracube
it's a problem for sensitive rf applications
18:41
se6astian
changed nick to: se6astian|away
18:41
se6astian|away
changed nick to: se6astian
18:44
intracube
installed some 1000Hz PWM controlled LED lights in his parents kitchen
18:44
intracube
then the kitchen radio stopped working. oops.
18:58
se6astian
changed nick to: se6astian|away
20:09
arpu
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arpu
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danieeel
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danieel
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