Baggage-scanning system minimizes lost luggage — with PC-based control
Modern airport baggagehandling systems quickly route enormous quantities of luggage, but basic computer scans and manual sorting remain significant sources of error. For the latter, airport staff must judge at a glance whether a bag can travel on dedicated conveyor belts without causing problems.
Overly bulky items can jam conveyor tunnels, round luggage can roll off belts, and backpacks with loose straps or handles can get trapped on pinch points. Most nonstandard items are manually segregated during passenger check-in, but they frequently end up back in the general baggage stream when travelers change planes for flight connections.
To address this problem, a new system called Bagcheck was jointly developed by Type22 of Delft, Netherlands, and Vanderlande Industries, the Netherlands, a global package-handling supplier. After luggage has been weighed and stamped with a barcode label, a conveyor moves it to the Bagcheck station for scanning. However, unlike a security check, the system scans the luggage item’s outlines rather than its contents.
How it works
“By using a contour scan camera, Bagcheck generates a detailed 3D image of a bag’s outlines from above. Then a light curtain generates side views, to record how tall the luggage is and whether it has a round shape, for example,” explains Jorick Naber, Type22’s technical director. Luggage unsuitable for the standard conveyor can then be filtered out within 1 or 2 —sec.
The camera scans passing luggage at 4,000 1-mm contours/sec. A CP6502 Panel PC with a 19-in. TFT display from Beckhoff Automation, Burnsville, Minn., leverages feedback from high-resolution encoders to synchronize the camera, lighting, and conveyor belts.
“The design relies on highresolution images, so the line-scan cameras and LED lights must be synchronized very accurately with the conveyor velocity and position,” explains Naber.
Line rates up to 4,000 Hz require 125-ƒsec control cycles — so the camera is linked with the PC via 1-Gbit Ethernet. “Other PLC and soft PLC systems fail to deliver sufficiently short cycle times, but Beckhoff’s Ether- CAT fieldbus components combined with TwinCAT NC PTP software do the job with fast and accurate data communication.”
The Panel PC also delivers on data capacity, integrating controls with an SQL database that stores all scanned-luggage image data. The information is used to evaluate Bagcheck decisions against jam occurrences, allowing adaptive learning to improve future sorting decisions. Items missing their labels can also be identified: Here, Bagcheck matches scanned luggage images with those of the untagged item to trace the luggage to its owner.
Finally, Bagcheck software allows virtual separation of luggage that is stacked or snagged together. In traditional systems, stacked luggage often causes conveyors to stop or, even worse for travelers, mistakenly direct both bags to the same aircraft.
Five Bagchecks are in use at London Heathrow Airport with additional systems on order, and an initial implementation phase at Amsterdam Airport Schiphol is now underway. At existing installations, baggage jams and blockages on conveyor belts have been reduced by 40% and lost luggage instances have been significantly minimized.