Abstract: An optical sensing assembly (20) detects media (32) carried by a traveling mesh or suction belt (34) having material portions (82) that define therebetween open portions (84). An emitter (22) is disposed opposite and spaced apart from the first side of the belt (34). The emitter (22) emits light in a direction from the first side toward the second side of the belt (34). A detector (24) is disposed opposite and spaced apart from the second side of the belt (34) and generally opposite the emitter (22). A portion of the light emitted by the emitter (22) passes through the open portions (84) of the mesh belt (34) and impinges upon the detector (24). The detector (24) issues a detect signal (DET_SIG) indicative of a reduction in the detected portion of light. The detect signal (DET_SIG) is filtered to reject reductions in the detected portion of light that are not due to the presence of media (32) on the belt (34).