If you took a ride along with your parcel, where do you think the bottlenecks might occur? If you answer at the sortation hubs, you would be right. And that's just why the United States Postal Service continually invests in technology improvements to eliminate the bottleneck and speed your parcel along its course. Most recently, the Postal Service has implemented a sophisticated combination of optical character recognition (OCR), barcode reading (BCR) and video coding systems (VCS) to help reduce operational costs and enhance accuracy, which benefits shippers by keeping postal rates down.
Technology Making the Difference
The Postal Service is migrating its parcel sortation operations from traditional laser-based barcode reading solutions to state-of-the-art camera-based solutions where the images captured are processed using sophisticated OCR and BCR algorithms. In cases where the algorithms fail to produce a "sort" result, the images are sent to a VCS in an off-site
Previous efforts to automate parcel sorting in the Postal Service have relied solely on the presence of a destination barcode. In a mixed barcode and non-barcode mail stream, an operator was required to switch from a facing operation (finding the address side of the parcel and placing that side face up for the barcode reader) to a facing and keying operation. Frequent toggling between these operational modes would significantly impact throughput. In cases where there was uncertainty regarding the presence of a valid destination barcode, an operator might unnecessarily key in the destination information.
The application of the OCR/BCR/VCS combination takes the decision away from an operator and ensures that the recognition will be accomplished in the most efficient manner. The use of VCS for the unresolved images effectively decouples the recognition from the induction process. With this combination, the maximum benefit of the barcode is achieved, eliminating a bottleneck.
Camera's Critical Role
The use of cameras to capture images and produce destination information provides a wealth of information about the physical mailpiece and the address quality. A detailed evaluation of the images and results provides an insight into opportunities for improved readability and more accurate processing.
The Postal Service's typical parcel process includes a device for the automatic singulation of a bulk stream of parcels. The output of the singulator is a single file stream of parcels in random orientation. The parcel is then sent through a dimensioning device that automatically detects doubles. Next, the successfully singulated mail is sent through a multi-sided camera tunnel for the image lift. Images are then captured by cameras using single line charge coupled devices. The motion of the parcel and repeated single line scans generate a 2D image of the piece. Additional sophistication employing dynamic focusing is required to capture the images of the front and back surface.
The resulting images are gray-scale images (8 bits per pixel). A portion of the recognition (barcode reading) is performed using these relatively large gray-scale images. The gray-scale images are then binarized (substantially smaller images where each pixel is black or white) to be sent to the OCR engines for processing. In cases where the BCR and OCR fail to produce a result with sufficient confidence, the compressed binarized images are sent via telecommunications to the Remote Encoding Center where a pool of operators stationed at computer workstations select the appropriate image (top, bottom, front, back or either side) for processing. For images that can be resolved, results are keyed in and sent back over the telecommunications link to the processing equipment. In cases where the images are not of sufficient quality, the encoding operator will reject the mailpiece, and the physical piece will be diverted at the plant to an area for manual processing.
Leveraging Technology
There is a direct correlation between implementing advanced technology, proper package preparation and the cost of doing business. The Postal Service's latest parcel processing technology investments drive efficiency and accuracy, and with proper package preparation, shippers will only boost that efficiency and accuracy. The end result: lower costs for the Postal Service and hence, lower costs for shippers.
Scott Bombaugh is the Manager of Material Handling Technology for the U.S. Postal Service. Scott's group is responsible for package sortation equipment design as well as material handling system design and deployment. He can be contacted at scott.r.bombaugh@usps.gov.
