Transferring and inspection unit of a group of elongated elements that are rod-shaped for smoking articles, comprising: - a forming pocket, having a longitudinal axis, which is provided with a hollow housing suitable for housing a group of elongated elements to be inspected and is provided with a first mouth; - a transporting conveyor of the pocket which is configured to advance the pocket along an advancing path through a first inspection position; - a first tridimensional inspecting optical assembly (15, 16) configured to perform in respective successive scanning instants a plurality of first tridimensional optical scans by projecting a first light blade over a first head face of the group, during the advancing of the pocket through the first inspection position; - a processing device configured to obtain, for each first tridimensional scan, a respective first scanning line and to reconstruct a first tridimensional profile of the first head face on the basis of the plurality of the first scanning lines obtained, wherein - each scanning line is positioned in the first tridimensional profile in a respective first reference position indicating a corresponding zone of the first head face of the group inspected at the scanning instant; and in which - the pocket comprises a first front face that comprises a first flat calibration surface (40; 40'), that lies on a plane perpendicular to the longitudinal axis of the pocket and is arranged at a first preset calibration distance from a first outline surface of the first mouth; a second calibration surface (41; 41') that is flat, parallel to the first calibration surface (40; 40') and staggered in relation thereto along the longitudinal axis, which is at a preset second calibration distance from the first outline surface; and in which the first optical assembly (15, 16) is in addition configured to perform at least one first tridimensional scan of the first calibration surface (40; 40') and a second tridimensional scan of the second calibration surface (41; 41') to obtain respectively a first rectilinear calibration line and a second rectilinear calibration line respectively associated with the first calibration distance and with the second calibration distance, which are used as references by the processing device to evaluate possible deformations of each scanning line along the longitudinal axis of the pocket. - a forming pocket, having a longitudinal axis, which is provided with a hollow housing suitable for housing a group of elongated elements to be inspected and is provided with a first mouth; - a transporting conveyor of the pocket which is configured to advance the pocket along an advancing path through a first inspection position; - a first tridimensional inspecting optical assembly (15, 16) configured to perform in respective successive scanning instants a plurality of first tridimensional optical scans by projecting a first light blade over a first head face of the group, during the advancing of the pocket through the first inspection position; - a processing device configured to obtain, for each first tridimensional scan, a respective first scanning line and to reconstruct a first tridimensional profile of the first head face on the basis of the plurality of the first scanning lines obtained, wherein - each scanning line is positioned in the first tridimensional profile in a respective first reference position indicating a corresponding zone of the first head face of the group inspected at the scanning instant; and in which - the pocket comprises a first front face that comprises a first flat calibration surface (40; 40'), that lies on a plane perpendicular to the longitudinal axis of the pocket and is arranged at a first preset calibration distance from a first outline surface of the first mouth; a second calibration surface (41; 41') that is flat, parallel to the first calibration surface (40; 40') and staggered in relation thereto along the longitudinal axis, which is at a preset second calibration distance from the first outline surface;