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#apertus IRC Channel Logs

2014/01/02

Timezone: UTC


23:25
gcolburn
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gcolburn
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01:52
troy_s_
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se6astian
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07:04
se6astian
good morning
07:04
Bertl
morning se6astian!
07:12
se6astian
the university is deserted like a hospital in your average hollywood horror film :)
07:13
Bertl
hehe
07:14
Bertl
did you seriously expect anything else?
07:20
se6astian
yes, if there are conferences other events or exams, project deadlines for students we get run over even on days like this in the holidays
07:20
se6astian
you never know, expect the unexpected :)
07:53
Bertl
yes, indeed ...
08:13
Bertl
off to bed now ... have a good one everyone!
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17:09
Bertl
morning everyone!
17:13
se6astian
hello!
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18:59
troy_s
Greets from Minneapolis.
18:59
troy_s
guesst: 150 fps is 1/300ths standard.
19:00
troy_s
(180° shutter should always be inferred)
19:02
guesst
troy_s: thats exposure, the delay for readout of last line is 1/150
19:03
troy_s
readout would still be in the 180° shutter off - 1/300th
19:03
troy_s
(assuming read - dump - read - dump etc.
19:04
Bertl
readout solely depends on the transfer rate and channels
19:04
troy_s
Bertl: How does the global shutter work exactly?
19:04
guesst
troy_s: that is rolling shutter
19:04
Bertl
in case of the CMV12k, it is max 64 channels at max 600MHz (with new sensors)
19:04
troy_s
Started on the image viewer.
19:04
troy_s
By the way.
19:04
troy_s
guesst: No.
19:05
troy_s
guesst: You are still always exposing for a full shutter cycle.
19:05
guesst
you can not dump the whole frame at once
19:05
troy_s
Dumping is whatever.
19:05
Bertl
troy_s: what do you want me to tell you about the global shutter?
19:05
troy_s
Doesn't matter.
19:06
troy_s
Bertl: Well I have always wondered how ot works.
19:06
troy_s
Bertl: I mean on some level is the sensel array not charged, and if so, is there not a refresh rate (scanline?) that is unavoidable?
19:07
troy_s
Bertl: So I started in on an image viewer.
19:07
Bertl
basically the cmos sensor works with a photodiode which accumulates a charge when light falls onto it
19:07
troy_s
Bertl: If you look at my github I skeletoned my YCbCr lab app.
19:07
philippej
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19:07
troy_s
Bertl: So the energy is 100% distributed?
19:08
Bertl
by manipulating the potential difference on the diode, you can basically disable the sensel
19:08
Bertl
the 'shutter' itself works by converting the charge to a voltage and storing it in a sample hold capacitor
19:09
troy_s
Bertl: Is there an upper shutter cap then for dumping the data? Throughput will need to be through the roof to dump in a 270° (90° dump) window?
19:09
Bertl
(that happens on a per sensel basis)
19:09
Bertl
the design allows to start sampling long before the previous samples are transferred
19:10
Bertl
so you can sample (i.e. expose) almost back to back
19:10
Bertl
as long as the exposure time is at least as long as the readout time
19:10
troy_s
Bertl: Any forward motion on noise issues?
19:10
Bertl
yes, we are making good progress there
19:12
Bertl
the main problem at the moment is to get good data for the FPN
19:13
Bertl
which basically consists of two components, a static offset and a dynamic gain related pattern
19:15
Bertl
guesst: did you take a series of black frames with the global shutter on the kodak yet?
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