Xue: open source reconfigurable network camera

Wolfgang Spraul wolfgang at sharism.cc
Sat Jul 24 02:10:27 EDT 2010


Andres,

> A simple CMOS sensors comparison table:
> http://en.qi-hardware.com/wiki/Xue/sensor

Great! One thing I noticed are the small pixel sizes, around 2 micron.
>From my visit to Azure Photonics (lense makers) recently I have heard the
term 'lines per millimeter' several times. Lenses in normal digital cameras
should go up to 30-50 lines/mm, megapixel M12 board lenses maybe 80-110,
higher-end 5 megapixel c-mount lenses maybe 150 lines/mm. I don't know how
this translates to pixel sizes, of course we can just choose the most
economic CIS, even if it has more pixels than our lense can support?

I googled a bit and added what I found to the Xue page:

http://www.luminous-landscape.com/tutorials/understanding-series/understanding-mtf.shtml
http://www.gpsinformation.org/jack/photo-test/pics/lens-tests.html
http://old.photodo.com/art/Lens6.shtml
http://www.imatest.com/docs/sharpness.html 

If our goal is to come out with a functioning and cheap camera PCBA asap,
maybe a PCB-mounted M12 connector is a good start, we can even leave out
the separate sensor board in the first version. What do you think?
A common CIS size for M12 lenses seems to be 1/3'' optical format.

SIDE NOTE: Andres told he is trying to use KiCad for the entire design,
both schematics and layout. He is using some of the scripts and footprint
editor that Werner developed for gta02-core. I don't know where this will
all go, but it's definitely an ambitious goal in the right direction! :-)

Wolfgang




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