Pi Camera

Hi,

Looking at using a Raspberry with the camera module as a pretty reasonable webcam that'll FTP a still exterior view to a web site. Looking through the command line options for raspistill I noticed a "night" mode, what does that actually do over the default?

Are there any sample Pi camera images taken at night (full moon, no streetlights?) on the web anywhere? Not IR illuminated ones from the Pi-noIR camera

I can't actually find sensitivity spec for the Pi Cam other than calculated guesstimates. Not that "1 lux" would mean a great deal in relation to real light levels to me...

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Cheers 
Dave.
Reply to
Dave Liquorice
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I have thought of doing something similar but with video. Have you seen the following link? It looks useful.

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I couldn't find any such images but IIRC I have seen one before.

According to the above link the sensor used in the camera module is the OmniVision OV5647. One source of info is

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From that link the sensor apparently has a sensitivity of 680-mV/lux-sec. Frankly, that means nothing to me. It's even worse than a simple 1 lux measure that you mentioned! I did see that the sensor will "bin" pixels. Not sure what that means. Possibly it will combine pixels so as to collect more photons per pixel but at the cost of larger and fewer effective points.

If there is no way to relate the spec to how the camera will perform in practice for your application why not just go buy a module and try it out?

AIUI there are two camera modules: normal and noir. The latter has no IR filter (and is appropriately on a black PCB) It has worse colour rendering but is better for low-light nighttime shots. About right?

James

Reply to
James Harris

Video might be available on the LAN.

no

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I later found a few but all taken in towns with loads of street lighting about. Nearest street light to here is a mile and half away...

in

Yeah, and people who presumably understand the number/units used in the spec say it could 0.02 Lux and a full moon is 0.25 lux. How ever there is some dispute about what will happen in reality as one figure is probably derived with the amp gain at minimum and another at maximum so noise levels will be considerably different.

That's how I interpret it.

I only have one Raspberry ATM, that is running XBMC and I'd get into trouble if I "stole" it for development work. B-)

There seem to a shortage of single box solutions take a Pi and camera module. A plastic one in the US or a diecast water resistant one in the UK both are almost as much a Pi...

More interested in proper daylight colours than night. I might still get a Pi noIR though as I believe they come with an separate IR filter. Thinking that with some basic image analysis (or even just time based) one could bring in the -night "effect" and use a GPIO to operate a small solenoid to remove the filter from in front of the lens.

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Cheers 
Dave.
Reply to
Dave Liquorice

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