Robin2:
This sounds like one of those projects that you might be able to implement on an Arduino after hours of hard work and many many optimizations and simplifications.And it could be done relatively easily on, say, a Raspberry PI or, perhaps, a Yun.
...R
Yes, this does indeed look easier:
http://raspberrypi.rsdelivers.com/product/rs/picamera-2/pi-a-type-a-camera-4gb-sd-os/7902708.aspx
Since i already have the webcam, wouldn't this be the easiest solution for me? It's about 40$.
http://dk.farnell.com/raspberry-pi/raspberry-pi-8gb-usd/sbc-raspberry-pi-8gb-sd-bundle/dp/2334982#