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#apertus IRC Channel Logs

2016/12/16

Timezone: UTC


00:41
jucar
joined the channel
02:55
jucar
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04:02
Spirit532
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08:00
se6astian|away
changed nick to: se6astian
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pusle
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11:50
slikdigit
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slikdigit
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12:20
Bertl_zZ
changed nick to: Bertl
12:20
Bertl
morning folks!
12:42
se6astian
hello!
14:37
jucar
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jucar
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15:56
intracube
hello :)
16:22
intracube
any new news from apertusland?
17:25
Bertl
nothing worth mentioning on my side ...
17:33
intracube
hi Bertl
17:33
intracube
I was wondering how many prototypes/betas have been made so far
17:42
Bertl
about 20
17:50
intracube
ah ok
18:38
se6astian
18 I counted
18:41
intracube
and what's the current state of the sensor calibration/colour?
18:45
intracube
is the processing still all done 'off-camera'?
18:51
se6astian
some steps are already possible to do camera internally
18:51
se6astian
FPN calibration for the FPGA for example
18:52
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
18:52
se6astian
the process takes a few minutes
19:03
Spirit532
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19:03
se6astian
changed nick to: se6astian|away
19:04
se6astian|away
changed nick to: se6astian
19:05
intracube
is the FPN fairly static for a given chip?
19:05
intracube
so the process would only have to be done occasionally (or during initial calibration)
19:06
intracube
I remember reading there were issues around different gain settings for the CMV chip requiring different FPN correction
19:07
se6astian
changed nick to: se6astian|away
19:07
se6astian|away
changed nick to: se6astian
19:07
Bertl
off for now ... bbl
19:07
Bertl
changed nick to: bertl_oO
19:23
alexML
intracube: you know this page, right? https://wiki.apertus.org/index.php/Pattern_Noise
19:24
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)
19:24
alexML
but this part is currently done in post, and the black column data is not yet recorded on HDMI
19:25
alexML
so, it only works best on raw12 stills
19:26
intracube
alexML: qute a lot of the dynamic row noise was caused by an early power supply design iirc?
19:27
intracube
and yep, I read through those docs a while back :)
19:29
alexML
possible, I'm not aware of power supply changes related to this issue (but didn't really follow the hardware side)
19:29
alexML
a while ago we found a possible connection between fan rotation and row noise (on top of what's on the wiki)
19:30
intracube
think it Bertl mentioned a change to the power supply design some months back and that it reduced row noise
19:30
alexML
have a link?
19:31
intracube
no - I'll see if a search brings up anything
19:31
intracube
alexML: https://www.apertus.org/axiom-beta-hello-world-article-may-2015
19:32
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. "
19:33
intracube
looks like this pre-dates your work, so it's not relevant
19:33
alexML
ah, thought it's a recent improvement on the beta hardware
19:33
intracube
didn't realise it was quite so long ago o.o
19:37
intracube
fans are PWM controlled, I guess?
19:37
intracube
choppy output might be to blame for the noise
19:38
intracube
it's a problem for sensitive rf applications
19:41
se6astian
changed nick to: se6astian|away
19:41
se6astian|away
changed nick to: se6astian
19:44
intracube
installed some 1000Hz PWM controlled LED lights in his parents kitchen
19:44
intracube
then the kitchen radio stopped working. oops.
19:58
se6astian
changed nick to: se6astian|away
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arpu
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arpu
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danieeel
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danieel
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