US Patent 7973943 Determining track origin

Apparatus is disclosed for determining the track of origin of a cigarette manufactured in a cigarette making machine having a plurality of tracks. The cigarette making machine (60) is arranged such that the circumferential position of the tipping paper seam and the circumferential position of the tobacco wrapping paper seam are different for different tracks. The apparatus comprises a detector (20, 22; 36; 50) arranged to detect radiation from the cigarette (18) and to produce a signal representative of the detected radiation, and a processor (30; 54) arranged to process the signal produced by the detecting means to identify a shadow cast by a tipping paper seam and a shadow cast by a wrapping paper seam. The processor (30; 54) is arranged to determine a difference in the circumferential position of the shadow cast by the tipping paper seam and the circumferential position of the shadow cast by the wrapping paper seam, and to produce a signal indicating the track of origin of the cigarette in dependence thereon.