Abstract: Angle measurement is high frequency. North-Finder is the most precise apparatus, but it is very expensive and so unwieldy that it is not used widely. In this article, we introduced an angle measurement arithmetic based on digital image processing. A special target is imported to make location and measurement simple. First locate the target, and then process the target to measure the angle. Cheap and easy are the advantage. But it is not very nicety when the angle is very small.

Key words: Digital image processing, Region search, Image location, Angle measurement