SubscribeToday's logistics and IT managers in the airport industry are faced with a daunting challenge - how to choose an automatic identification and data collection (AIDC) technology, and handheld scanners and mobile computers, that will not only allow their companies to survive throughout the next decades, but also give them a headstart on the competition.
This paper presents a short description of the various AIDC technologies available today and outlines the advantages and challenges of each technology.
Laser
What’s it all about
Laser scanners emit a laser beam, which is reflected by the barcode and then captured by a small mirror in the scanner. Because the black bars don't reflect light as well as the white bars, the scanner is able to discern the pattern of the barcode.
How it all began
The first contactless barcode scanners were introduced in 1982 and were based on laser technology. The main reason for adopting bar code scanners was the need to replace manual systems, which would increase efficiency and decrease errors.
The first laser scanners were adopted in retail applications, but they quickly spread to any application that could benefit from moving away from manual processes, especially in warehousing.
Market share and growth
Laser scanners have traditionally dominated the Auto ID industry and still held 48% of the handheld scanner market in 2004 (VDC report). However, laser scanners are reaching maturity in the technology life cycle. Their sales growth is slowly declining (5.4% CAGR), and laser technology is expected to continue losing market share relative to other AIDC technologies in the future.
Challenges and advantages
The biggest advantage of laser technology is the distance at which barcodes can be read.
Some major disadvantages of laser scanners are durability and speed. A laser scanner has a mechanically moving mirror for capturing the reflection of the laser beam, which is easily damaged. Because of the mechanical mirror, the speed of a portable laser scanner is also limited to 25 to 40 scans per second.
In addition, laser scanners can have difficulties reading damaged or dirty codes, as well as 2D codes or OCR.
Imaging
What’s it all about
Linear imagers are based on CCD technology.They receive as input light from an object and take this optical input and convert it into an electronic signal - the output. The electronic signal is then processed to read the barcode.
Area imagers using imaging technology take a digital picture of the barcode, which is analyzed by graphical software. Devices using imaging technology allow users to capture signatures, take photos, read virtually all barcodes (1D and 2D) – even damaged ones, and more.
How it all began
The Charged Coupled Device (or CCD) was initially conceived in 1970 at Bell Labs by W. Boyle and G. Smith. In the same year Welch Allyn delivered the first handheld, fiber optic solid state contact scanner in the world. Since then, the company has pioneered many advances in barcode scanning technology, including linear and area imagers, auto discrimination of multiple symbologies, advanced linear and 2-dimensional decoding algorithms and the world’s first 2D-capable portable data terminal.
The first handheld imagers arrived on the market in 1992 and were seen as innovative, but not immediately as a viable alternative to laser. The major driver behind their implementation was speed as imagers were much faster than laser scanners. Imaging technology evolved rapidly and in addition to linear (1D) imagers, area (2D) imagers were developed.
Their success was accelerated by the implementation of 2D barcodes, which can contain up to 2000 characters. Users began to demand scanners that were able to read several types of barcodes, as well as capture images and signatures.
The first industry segments that adopted 2D imaging applications in large scale were postal and parcel delivery. In addition, various other markets - such as logistics, retail, government and utilities - are more and more using imaging for short-range scanning applications. They also benefit from the added versatility that the imagers offer. For example, an area imager can read barcodes in any direction (omni-directional reading) and linear imagers are useful when reading poor quality and damaged barcodes.
Market share and growth
Imaging technology is gaining ground in many AIDC applications due to its versatility and durability. At the moment, imaging technology (1D and 2D) holds almost 40% of the total handheld scanner market, and it is growing rapidly, at an average of 14% year (CAGR).
Challenges and advantages
Because imaging technology is based on digital photography, the main challenges for it are scanning in very dark environments and scanning at very long distances.
On the other hand, imagers contain no moving parts and are better able to withstand the rough treatment scanners have to endure in industrial applications. An imager can make up to 270 scans per second, which results in noticeably faster barcode scanning than with laser.
An imager is also fault-tolerant. It takes a picture of the whole barcode and is able to pick out the most readable section, making it suitable for reading damaged or poor quality codes. An additional advantage of area (2D) imagers is that they can easily handle any type of barcode, both 1D and 2D codes, as well as OCR.
On top of that, the area imager’s ability to take pictures allows for a variety of new applications. A parcel delivery company could use an imager to scan both the barcode of a parcel and the signature of the recipient at delivery, after which the signature is automatically filed in the appropriate archive. That way, a separate system for processing signatures is no longer necessary. It is also possible to configure the imager to scan multiple barcodes at once.
With the maturing of imaging technology, prices can be expected to decrease over time which will further increase the adoption of the technology.
RFID
What’s it all about
Radio Frequency Identification (RFID) is a method of storing and remotely retrieving data using devices called RFID tags or transponders. An RFID tag is a small object that can be attached to or incorporated into a product, animal, or person. RFID tags contain antennas to enable them to receive and respond to radio-frequency queries from an RFID reader. Passive tags require no internal power source, whereas active tags require a power source.
There are four different kinds of tags commonly in use. They are categorized by their radio frequency: low frequency tags (125 or 134.2 kHz), high frequency tags (13.56 MHz), UHF tags (868 to 956 MHz), and microwave tags (2.45 GHz). UHF tags cannot be used globally as there aren't global regulations for their usage.
How it all began
RFID was first used in World War II to identify enemy aircraft, which makes RFID a fairly old technology that has only recently become an alternative to barcodes because of advances in chip development.
At the moment, RFID is mostly used in closed-loop systems, such as animal identification and building access. RFID in supply chain applications is still very much in its infancy, with only pilot projects taking place at the moment.
Market share and growth
As mentioned earlier, looking at the scanner market, RFID is only used in a few pilot projects. The future is also uncertain.
Although several large retailers and defense organizations have introduced mandates to their suppliers (on pallet level), it is not widely adopted due to lack of standards and high costs, as well as technical difficulties in reading tags in the vicinity of certain materials, such as metal and liquids.
In the foreseeable future, it is likely that the use of RFID in the supply chain will be restricted to high value items and containers or pallets. It is not certain if low-value products will ever be tagged individually.
Challenges and advantages
The biggest hurdle that RFID technology has to overcome is price. The cheapest tags available still cost around 30 eurocents each and RFID tags with rewriteable memory and/or batteries cost even more - up to tens of euros per tag. Furthermore, a company considering a shift from barcode to RFID also faces a considerable investment in readers and infrastructure.
Some major technical limitations in RFID reading, especially with passive tags, are products containing metal or water, such as canned items, which tend to distort or even block RFID signals.
Two other issues with RFID are privacy and security. RFID tags don't have the computing power necessary for high-end encryption and can, in theory, be read and even rewritten by those with malicious intent.
The major advantage of RFID is that the scanner doesn't actually have to 'see' the tags in order to read them. Some more advanced tags possess a rewriteable memory, which opens the way for more functionality that barcodes cannot match. A product with such an RFID tag could be tracked all along the value chain, from production to the customer, with information about its particulars added to the tag at various stages in the process. Another example would be incorporating RFID in electronic article surveillance systems or using it to trace fresh produce. RFID tags can also store more data than traditional barcodes.
What does the future hold
It is not likely that either laser, imaging or RFID will be pushed out of the AIDC market in the foreseeable future. Each technology has unique qualities that make it best suited for certain applications. Laser, for instance, will most likely remain the technology of choice for long-distance warehouse AIDC, where forklift drivers need to scan pallet barcodes at distances of several meters.
Most AIDC users (about 80%) don’t require long-distance scanning, however, and are likely to consider moving to imaging technology in the coming years, due to the fact that imaging meets and exceed the features and benefits of laser, and also offers more versatility. Moreover, the required investment is relatively low compared to investment needed in RFID, as the underlying infrastructure doesn't need to be changed. Imagers are even making inroads in warehouses - the traditional domain of laser scanners - where they are used for various short-distance applications like order picking.
RFID will continue to develop in specific segments of the AIDC market that have an urgent need for 'sightless' scanning and/or other additional functionalities that RFID offers, for example tracing valuable items. However, the technology is still quite costly and immature to become a credible alternative to barcode scanning methods for the mass market. With lacking standards, it's not yet clear when and if these issues will be resolved. Also, if users need to store additional information, they may find a solution in 2D barcodes combined with imagers, which in many cases may be a viable alternative to RFID.
Companies looking to update their AIDC infrastructure would do best to investigate imaging alternatives, or if the situation demands it, a hybrid solution that combines imaging with RFID. That way, they'll gain a proven AIDC infrastructure at an affordable price, which will not only improve their primary business processes, but also guide them through the first decades of the 21st century.
Summary
Laser is a mature technology that has probably reached it’s limits of technical innovation and versatility and is losing ground to imaging
- Biggest advantage of laser is reading distance, which is important in some warehousing applications
- Imaging is enjoying growth and the technology is continuously improving, finding new innovative applications every day
- Imaging is durable and versatile – no moving parts, reads all 1D and 2D codes, takes photos, captures signatures, allows omni-directional reading
- RFID does not require line of sight
- RFID allows in some cases re-writing information on tags
- Lack of standards (regarding frequencies etc) and high costs and some technical difficulties are a major problem for RFID in supply chain applications
- 2D codes that can be read with area imagers can contain up to 2000 characters of information
- Imagers exceed laser performance in most short-distance applications