Abstract: The invention relates to a method and an arrangement for optically detecting the measurements, in particular the diameters, of a long object during or after its production, which object moves forward continuously at high speed in lengthwise direction. With this method, one light beam intersects with the object at a measuring location at a flat angle (&agr;) and a second light beam intersects with the object at the same measuring location at a flat angle (&bgr;) and the shadows formed in the process are detected. The light beams are offset relative to each other in the cross-sectional plane that extends perpendicular to the longitudinal axis of the object by a specific angle (&ggr;), and the angle (&agr;) corresponds to the angle (&bgr;) and preferably measures 10 to 40°, in particular essentially 20°.

Abstract: The invention relates to a method and an arrangement for optically detecting the measurements, in particular the diameters, of a long object during or after its production, which object moves forward continuously at high speed in lengthwise direction. With this method, one light beam intersects with the object at a measuring location at a flat angle (&agr;) and a second light beam intersects with the object at the same measuring location at a flat angle (&bgr;) and the shadows formed in the process are detected. The light beams are offset relative to each other in the cross-sectional plane that extends perpendicular to the longitudinal axis of the object by a specific angle (&ggr;), and the angle (&agr;) corresponds to the angle (&bgr;) and preferably measures 10 to 40°, in particular essentially 20°.