mõõtevahend, milles valgusvihk valgusallikast peegeldub peegli poolt, mis pöörleb pidevalt konstantse kiirusega ümber oma telje, ning peegeldunud kiir kompab objekti ja läbib objekti pinna etteantud punkti
beam of light from a light source is reflected by a polyhedral mirror which is continuously rotating in a constant speed around its axis, and the reflected beam sweeps on an object and passes a predetermined point of the object surface
