Current Server Time: 19:09 (Central Europe)

#apertus IRC Channel Logs

2014/01/02

Timezone: UTC


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