Abstract: A continuous cigarette rod advancing along a set path is directed through an electro-optical scanning station where its entire cylindrical surface is inspected by a unit comprising an illumination device of which the function is to shed light in substantially uniform manner on a given annular area of the surface, a line scan television camera positioned relative to the path in such a way as to enable acquisition of a direct image from a first portion of the annular area, and a reflecting element located on the side of the path opposite to the camera, embodied and oriented in such a way as to reflect two images back toward the camera which combine with the direct image to make up the entire annular area.

Abstract: A method of measuring the intensity of radiation transmitted through a body of given shape and material, the method including the steps of directing an incident beam of electromagnetic radiation crosswise onto the body to obtain an output beam coaxial with the incident beam; and measuring the energy of the output beam by correcting the energy transmitted by each of the rays of at least one of the two beams as a function of the length (d) of an optical path through the body and aligned with the ray.

Abstract: A method of controlling the endfill of elongated tobacco articles, whereby at least one collimated beam of electromagnetic radiation is directed on to a series of photosensors aligned in a direction parallel to a longitudinal axis of an article, and is partially intercepted by one end of the article; the signal emitted by each photosensor struck by the nonintercepted portion of the beam is rejected by means of a threshold measurement; and the signal emitted by each photosensor struck by the portion of the beam intercepted by and penetrating the article is compared with a range of limit values characteristic of the endfill.