Camera boosts barcode reading rate

During the final production trials of the Accu-Vision Camera Tunnel, Tesco's Pat Morgan did all he could to spoil the system's 100% barcode reading record.

During the final production trials of the Accu-Vision Camera Tunnel, Tesco's Pat Morgan did all he could to spoil the system's 100% barcode reading record.

He wrote his name across one barcode and stuck masking tape over another, completely obliterating it.

He even ripped a code so that the remaining image was only 8mm in height.

Yet despite all these 'spanners in the works', Accu-Sort's camera maintained its 100% read rate.

Every valid code that was presented, was read and the product sorted.

This superior performance is now standard at Tesco's Composite Distribution Centre in Southampton.

This major hub supporting Tesco's southern England stores with chilled products was in fact the first pick-by-line facility in Europe.

It was opened in 1995 and equipped with the latest automation technology available.

This included Accu-Sort laser scanners that were - and still are in Morgan's opinion - "the best in the world".

It is a fact of life however that even the best laser scanners still have an average mis-scan rate of between 3 and 6%.

"This means that rejects have to be manually resolved and that represents a huge cost", Morgan explained.

Although the laser scanners were operating to the best of their ability, the technology involved is now more than 30 years old.

Quite simply, the barcode problems being presented to Tesco today demands better.

Clearly the Tesco distribution network needs to deliver to its stores, the products they have ordered, in optimum condition and on time.

If a significant number of those products have to be sorted manually at the distribution centre, delays are introduced and customer service can be compromised.

Tesco's automation process has to accommodate a wide variety of barcode standards presented by its suppliers and Morgan thought that camera technology could offer a solution.

Although around since the 1980s, camera-based systems had not been suited to high-speed sortation.

Nevertheless Morgan decided to pose the question to long-term partner Accu-Sort who coincidentally had just perfected its compact, third-generation Accu-Vision system.

The proposed accu-vision Tunnel Camera System for Tesco was designed to provide five-sided scanning of supplier cartons, totes and trays.

It comprises one AV-3700 camera for scanning the left side of the object, one for the right and two further units for the front/top and back/top faces.

This configuration achieves five-sided scanning from just four cameras, reducing Tesco's capital costs.

The AV-3700's typical scan-rate is 20,000 scan/s, whereas traditional laser scanners can only offer 500 scan/s.

Each camera is equipped with its own processing system - the Accu-Sort APC-100 - and illumination array - the Accu-Sort SI-20.

The Accu-Sort DM-3000 overhead dimensioning system is responsible for profiling and dimensioning each item.

The application requires the camera system to be integrated into the existing Vanderlande Industries main line sorters that handle containers coded with UCC.EAN-128 or Interleaved Two of Five type barcodes.

Sorter speed through the camera tunnels would typically be 1.85m/s.

Barcodes may be on any of the five sides and in any orientation.

The Vanderlande Industries sorters operate in a chilled environment at a temperature of 0-3C.

This range is well within the capability of the standard Accu-Vision package; a cold-store specification system is also available for lower temperatures at frozen foods distribution centres.

Thanks to the co-operation of Vanderlande Industries a week's trial of the proposed camera system was subsequently organised at the company's test centre in Holland during which it was put through its paces on products from the Southampton operation.

These products included known 'trouble-makers'.

The results were exceptional.

"It gave us 100% even on nonconforming codes", Morgan confirmed.

The Accu-Sort camera was able to read all bar codes presented to it, including those that were poorly printed, ripped, marked with a felt-tipped pen or with bars that were wavy.

The system even read EAN codes on outers down to 10mm and proved able to achieve excellent read rates when cases were presented at wide skew angles.

Readability was consistent at angles of 30 degrees even when case spacing was not uniform.

It also had no problem reading codes through plastic shrink-wrap, a requirement that often proved to be beyond the capability of Tesco's old laser scanners.

As the camera works by taking a picture of the whole bar code it is immune to reflected light and is therefore far more efficient at reading codes on shiny surfaces.

The technology proven, Tesco ordered Accu-Vision camera tunnels to equip both main line sorters at Southampton.

A team comprising Tesco, Accu-Sort and Vanderlande Industries ensured that the day-to-day operations onsite continued while the new camera tunnels were installed.

The entire system was then subject to an acceptance test that confirmed mis-scans to be just 0.6%.

An impressive result by any standards but even more so when one learns that the 0.6% accounts for products with the wrong barcode, those with no barcodes at all and those with two different barcodes on the same package.

"The outcome was far better than we expected", Morgan admits.

"When supplier faults are taken out of the equation, we're achieving a 100% read rate".

The manpower savings are equally significant.

One operator is required to oversee the new system whereas its forerunner required eight.

The acceptance test also revealed other benefits too.

Tesco discovered that the dimensioning unit can also 'cube' the cage into which products are packed for delivery to the store.

In this way, it can determine how many boxes the cage can accommodate.

"It does all the calculation for us so we get a better vehicle fill", Morgan continues.

It is also clear that Tesco's investment in Accu-Vision camera tunnels will provide benefits to all barcode users in the grocery supply chain; a better communication with suppliers is another major benefit of this installation.

A barcode may be beautifully printed but if it's the wrong code, it will be a mis-scan and this information needs to be conveyed to the supplier as soon as possible in order that the error may be rectified.

To enable Tesco to export relevant information to its suppliers, Accu-Sort is currently linking Southampton's Accu-Vision camera tunnels to monitoring and recording stations.

"We will soon be able to show a supplier a coding problem as soon as it happens", Morgan concludes.

"It'll make it so much easier and quicker for the rogue code to be tracked and corrected.

The camera system will provide all the evidence we need".

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