~uderu bar code r~adin~systemsuse lasersto read fast and accurat~~y in difficultcircumstances
Usingbar code systemsfor productidentification f
by PAUL BERG6
0
the various concepts of auromatic product id~nti~catio~ currently available, bar coding remains the most widely applicable technology for a number of operational and economic reasons. Alternatives with viability in specifit limited situations include, for exradio frequency automatic mPk idenrification, in which a microelectronic device attached to an article transmits a code number to an RF receiver. This can be useful for car bodies and other products on which printed bar codes may be observed by painting or other finishing processes (ahhough alternative forms of bar coding are also successfully being used). However, bar codes are not only much cheaper to produce and to read, but also have the added advantage of being human-readable if
necessary. While optical character reading (OCR) and optical mark reading (OMR) technologies work well under closely controlled conditions, as in form feed readers for cheques and so on, they are not so suitable for handheld reading or industrial environments. Here bar codes allow greater hand freedom.
Application of bar code systems Bar code systems have been applied in a wide variety of industrial and materials handling applications, as welf as the retailing and distribution functions. The scope of these systems
is being broadened by hardware deveiopments specifically the latest generation of laser scanners - which give improved reading performance, greater fle~biIity of use, and, above all, the ability to be fully integrated into automated systems.
Laser scanners are already installed in activities as diverse as photofinishing laboratories (for work-in-progress, sorting and invoicing), automotive assembly and vehicle delivery, fruit packing, libraries and bloodbanks. They are used for order processing in the large flower auction complex at
Absauct: Bar coding systemsare ghe mast citable data entry device where ~~-he~d reading is required. The systemsare laserbased, and can be interfaced w other contputt?re~i~~~. Scanners are b~~~~ng more reItible and less expensive. Verifiers can be used W check the effectiv~ss of scanners. In thefuture bar coding systems wiE become sma&r and will ~~~~ integra&dinto other sp%ms, such as automated manufactuting.
Paul Bergi: is general manager of Symbol TechnoIogies International Inc.
Hand held bm code scumer, h.ked directly to an D3M System 34,
applications Aalsmeer, Holland, for warehousing by Parfums Christian Dior, and for labelling verification in the bottling of Scotch Whisky. Both the hand held and the fixedmount laser scanners can be used with interfaces that enable them to be linked to all types of computer systems, for example, RS 232C communications for transmission of data in ASCII format, parallel and serial interfaces for point-of-sale systems, and even a data interface designed to emulate the widely-used but outdated barcode reading wand. Such an interface can be fitted retrospectively to existing wand-based host systems in industrial, military, medical and retail markets, so that a laser scanner can be connected to any existing wand decoder as a direct replacement for either digital or analogue wands. Many current users of wands find them slow and cumbersome. They also often experience a low ‘first read’ rate compared to the hand-held laser scanner. Such an interface offers them the possibility of updating while making substantial savings by permitting high capital cost items, including decoders, to be retained when replacing the wand itself. Capable of carrying out 40 scans a second, the LS 7000 laser scanning unit from Symbol Technologies International Inc - the world’s first truly portable unit of this type - requires no hand movement, so the possibility of ‘non reads’ due to incorrect scanning methods is eliminated. This scanner can take readings at distances up to 200 mm and does not have to be aimed carefully. The scanner will read codes printed on curved and irregular surfaces and can read through shrink overwraps even if the symbol itself is at a distance from the plastic. An added emulation interface enables the hand-held scanner to replace the conventional slot scanner in most point-of-sale systems. Here the portable unit saves space, and avoids the
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november
1984
need for special checkout furniture. It is equally fast or faster, more convenient and the low-cost decode electronics enable it to be sold at a fraction of the cost of a slot scanner.
any environment. The low power helium-neon lasers of the current generation of scanners are completely safe.
Future applications Verifiers Although the latest laser scanners are capable of good reading performance even when dealing with imperfectlyprinted bar codes on difficult surfaces, symbol readability remains a primary requirement for efficient data collection. Laser scanning technology has been incorporated in a number of verifiers, which provide those responsible for code printing with a sophisticated means of ensuring scannability. Using a low power helium-neon laser of the same type as the laser scanners, these units provide a facility for comprehensively evaluating codes on flat, curved or irregular surfaces, at distances up to 12 mm. The analytical capabilities of the verifiers enable bar/background colour contrast and both relative and absolute reflectance to be assessed, and a detailed diagnostic printout can be provided to give direct predictive analysis of scannability. Users can record the percentage of successful scans, analyse dynamic reflectance, find character bar width deviations and all out-of-tolerance study measurements. In cases of nonrecognition of a symbol, the verifier will show probable reason for the fault. By monitoring symbols in their final printed form the verifiers can eliminate readability problems which occurred through discrepancies between film masters and their eventual printed copies. The verification facilities are important as users need to be sure that their production line will not be brought to a halt by unscannable symbols, and that they will not be forced to revert to the unreliable methods of key entry or handwriting. The value of a portable laser scanner depends to a large degree on the freedom with which it can be used in
Bar coding and scanning technology is combined with robotic and automated manufacturing in the automation of PCB assembly. Here the selection of the appropriate component assembly program is based on the identification of boards and component groups by the bar code reading system. The system can also be used to control automatic test procedures and to monitor work-in-progress throughout the assembly process. High speed scanners are suitable for reading bar codes on moving objects, such as conveyor-transported items. For example, in the scanner from Symbol Technologies, the decoder is switched on when its inbuilt photosensors signal the arrival of a carton. The bar code label is scanned and the data is passed to the computer via a standard communications channel. If the bar code is invalid or absent, an alarm signal stops the conveyor automatically or diverts the article concerned. The specialized expertise in the miniaturization of laser scanning systems, which is growing rapidly, will have a major effect on bar scanning systems in the future. 0
Symbol Technologies International Inc., Rue Gachard 51, BTE 19, 1050 Brussels, Belgium.
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