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OK, Careful what you wish for

Sat Mar 01, 2014 12:10 pm

I have a RPi mounted outside of my house, running motion and feeding ISpy as an IP camera.

It works quite nicely but is no use at night. So I swapped the camera board for a NoIR model and installed some IR lights and it now works quite nicely at night. However it looks horrible during daylight hours - due to the lack of filtering, the colours are unreal.

Is there anything I can do about this - I note that even inexpensive commercial CCTV cameras are able to show good night pictures and switch over based on the light level to show colours which seem representative of what humans perceive, during daylight.

Thanks for any constructive feedback.

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Re: OK, Careful what you wish for

Sat Mar 01, 2014 1:18 pm

Use a servo to move an IR filter over the lens when it's daylight and move it away when you need IR mode.
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Re: OK, Careful what you wish for

Sat Mar 01, 2014 1:20 pm

Better night vision camera have a mechanical ir filter drop down in daylight hours.
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Re: OK, Careful what you wish for

Sat Mar 01, 2014 8:24 pm

I would think a programmatic fix would be the easiest - all the IR filter does is remove information, thus enhancing other information. That probably could be done with software as well.

[nope - haven't tried it, just seems apriori to be possible...]

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Re: OK, Careful what you wish for

Sat Mar 01, 2014 9:13 pm

The problem with CCD / CMOS imagine sensors they're naturally sensitive to Infrared wavelength of light and this is a big problem because it can pass-though the red, green and blue filters in near equal strength.
Not only that but some clothes absorb or reflect Infrared light (or bounce of clothing under a layer of clothing) hence the weird effects and colours you can get.
Unfortunately there is no software solution for colour correcting a camera with missing IR block filter it's not like you can digitally remote Infrared especially when it affects all 3 colour channels.
As already mentioned you'll need a IR block filter if you want any hope of getting realistic colours from your NoIR camera.

Richard S.

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