Li Han wrote:
Sorry, I oversimplified the question because of my poor english. It is an analog compass whose value we need to read into the computer every second. We use a video camera keep shooting it, and the compass and camera are fixed.
If you have any choice about it, it would be greatly simpler, cheaper, and more effective to throw out the camera and analog compass, and use an electronic compass instead. These are affordable and work quite well provided you keep them level (the same constraint you have with an old-fashioned compass too). You can make some simple interface hardware, or spend a bit more for something with a USB or serial interface built in, like this: <http://www.oceanserver-store.com/osevkitsorus.html>
Best, - Joe -- http://mail.python.org/mailman/listinfo/python-list
