Chapter 56: The End of the Laser Scanner |
Summary Overview: |
For decades, the laser scanner was the workhorse of automatic identification, decoding the language of bars and spaces printed on nearly every product. Its fundamental limitation, however, is that it can only read one-dimensional barcodes by analyzing a single line of reflected light. The world has moved on to two-dimensional codes like QR and Data Matrix, which hold far more data and can be read from any angle. This chapter explores the inevitable decline of the laser scanner, driven by the rise of 2D codes, and explains why image-based readers are now the essential technology for modern industry. |
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56.1 The Last Line of Light |
To understand why the laser scanner is being retired, we must first appreciate its mechanics. For nearly four decades, the ubiquitous red beam was the primary tool for connecting the physical world of goods to the digital world of data. The process was elegant in its simplicity: a laser diode projected a beam of light onto a rapidly oscillating mirror. This created a single, bright line of light that shot across the barcode. As the beam moved, it swept from one side of the code to the other. |
When this laser line hit the black bars of the barcode, the light was absorbed. When it hit the white spaces, the light was reflected back. A photodetector captured this reflected light and converted the fluctuating intensity into an electrical signal. The scanner's electronics then analyzed the width of the bars and spaces, translating the pattern into a data string. |
This system worked beautifully for decades. It was fast, reliable, and relatively inexpensive. However, this mechanism contained an inherent flaw: the laser scanner could only see a single line at a time. It was essentially blind to anything outside that thin slice of light. A barcode that was slightly curved, scratched, smudged, or printed on a reflective surface could baffle a laser scanner because it could not 'see' the whole picture. It only saw a cross-section that might be distorted. |
The architecture of a laser scanner also contained moving parts. The oscillating mirror that created the scan line was subject to mechanical wear and tear. Dust, shock, and vibration would eventually cause these parts to fail, requiring maintenance or replacement. |
These mechanical and optical limitations were acceptable as long as the technology being read was simple: black-and-white lines on a white background. However, the landscape of automatic identification was beginning to change, demanding a more powerful and flexible reader. |
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56.2 The World Shifts to Two Dimensions |
The primary reason for the laser scanner's impending obsolescence is not its own failings, but rather the rise of a superior data carrier: the two-dimensional barcode. |
The 1D barcode is, by nature, a limited database. It can hold, at most, a string of characters that usually acts as a serial number, a stock-keeping unit, or a reference number to look up information in a central database. This is akin to having a key. It unlocks information if you have the door (the database). Without a network connection, the barcode is just a meaningless number. |
The 2D barcode is a different entity entirely. It is not a 'line' but a 'map.' It stores data in a grid of black and white modules, allowing it to hold information in two dimensions: horizontally and vertically. A single 2D code, such as a QR Code or Data Matrix code, can hold hundreds of times more data than a 1D barcode. |
This capacity to encode data is transformative. A 2D code can contain the entire manufacturing history of a part, its batch number, expiry date, unique serial number, website URL, and even a small block of text. This is known as 'carrier data' - the data is physically carried by the product itself. It eliminates the need to access a central database for information, empowering disconnected or mobile workflows. |
Furthermore, 2D codes have built-in error correction. If a portion of the code is damaged or obscured, the scanning software can use the redundant data encoded within the rest of the pattern to reconstruct the missing information. This is a crucial advantage over 1D barcodes, where a single scratch across the code can render it unreadable by a laser scanner. |
Industries are rapidly moving toward 2D codes to meet the demands of modern business. Regulatory pressure, such as the pharmaceutical serialization mandates to combat counterfeiting, require a level of detail that only 2D codes can provide. Consumer expectations are also driving this shift. A QR code on a food package allows a consumer to scan the product with a smartphone and instantly access detailed information about allergens, ingredients, sustainability credentials, and brand provenance. |
The global scanning community has united to support this transition. Major manufacturers like Datalogic, Honeywell, Newland, and Zebra Technologies have aligned to support the global shift to 2D barcodes on product packaging, signaling to retailers and brands that the hardware ecosystem is ready. As one industry leader stated, 'the global scanning community has never been this united'. This concerted effort accelerates the move away from legacy laser technology and toward image-based readers. |
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56.3 The Image-Based Alternative |
The image-based reader, or camera, addresses every weakness of the laser scanner. It does not use a moving beam. Instead, it uses a sophisticated digital camera sensor, often a CMOS or CCD sensor, which captures a full two-dimensional image of the barcode, just like the camera in a smartphone. |
Intelligent Decoding: |
Once the image is captured, the magic begins. The image is processed by advanced software, not just hardware. It converts the image to grayscale, reduces digital noise, and uses binarization to differentiate black from white pixels. The software then applies pattern recognition algorithms to locate and decode the barcode. It uses complex decoding algorithms that can often 'guess' the correct information even when the code is damaged, distorted, or printed with low contrast. |
Omnidirectional Reading: |
Because the camera captures a picture of the whole code, it can read barcodes in any orientation. A laser scanner often requires the barcode to be aligned a certain way, or else it fails. This often requires using multiple laser scanners in a single station to cover all angles. An image-based reader can read a code that is upside down, sideways, or at a 45-degree angle in a single view, eliminating the need for complex fixturing and manual alignment. |
No Moving Parts: |
Image-based readers are solid-state devices. They have no oscillating mirrors or delicate moving components to wear out. This results in higher reliability, a longer lifespan, and lower maintenance costs compared to traditional laser scanners. |
The Power of Visualization: |
This is perhaps the most significant advantage in an industrial setting. A laser scanner is a 'blind' device. If it fails to read a code, it simply outputs a 'no read.' The operator has no idea why it failed. Was the code missingWas it damagedWas it smudgedWith an image-based reader, operators can see exactly what the reader sees. They can view images of successful reads and, most importantly, archive images of failed reads. This archival capability provides incontrovertible proof of label quality issues and allows for root-cause analysis. Production line operators can monitor the reader's performance on a screen and make simple adjustments without consulting a manual. |
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56.4 The Fate of Code 39 |
The transition from laser scanners to image-based readers is not just a technical upgrade; it is a fundamental shift in how we interact with the physical world. To see this transition in action, it is helpful to look at one of the most resilient barcode symbologies ever created: Code 39. This code acts as a bridge between the old world of laser scanning and the new world of image-based reading, highlighting why old technology is being replaced despite the code's continued relevance. |
56.4.1 The Technical Characteristics of Code 39 |
Introduced in 1974, Code 39 was a breakthrough. It was the first barcode that could encode alphanumeric data, allowing for more than just numbers. |
Encoding: Each character in Code 39 is represented by a pattern of five bars and four spaces. The '39' in its name comes from the fact that three of these nine elements are wide, and six are narrow. This 'three of nine' structure is simple and reliable. |
Self-Checking: One of its most important features is its self-checking property. Because the code uses a specific ratio of wide and narrow elements, a single printing defect is not likely to be misinterpreted as a different character. If a wide bar is printed too thin, it will often create an invalid pattern, and the scanner will reject it rather than misread it. This feature reduces the risk of data entry errors. |
Character Set: The base Code 39 symbology can encode 43 characters: uppercase letters A-Z, digits 0-9, and several special symbols like a space, period, and dash. It also uses an asterisk (*) as a start and stop character. |
Variable Length: Code 39 can be of any length, making it adaptable for various tracking needs. This flexibility led to its widespread adoption as a standard for internal tracking and inventory management before the standardization of other data structures. |
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56.4.2 How These Characteristics Shaped Its Industry Use |
The Military (LOGMARS): |
The US Department of Defense recognized the utility of Code 39 early on. They developed the Logistics Applications of Automated Marking and Reading Symbols (LOGMARS) program, which mandated that all government property be marked with Code 39 barcodes. The self-checking property was critical here. In a military logistics environment, a misread could mean sending ammunition or critical parts to the wrong location. The self-checking nature of Code 39 helped ensure a high level of data integrity. |
Automotive (AIAG): |
The automotive industry, driven by the need to track thousands of parts through complex supply chains, adopted the AIAG (Automotive Industry Action Group) B-1 standard, which builds on Code 39. The code was used to track everything from engine blocks to seat assemblies. The variable length allowed manufacturers to encode part numbers and serial numbers of different lengths within a single labeling system. |
Healthcare: |
The Health Industry Bar Code (HIBC) standard also leverages Code 39. Medical labels often contain critical data like lot numbers, expiration dates, and unit-of-use identifiers. Code 39's self-checking nature ensures that the nurse administering a drug can confidently identify the patient and the correct medication. Patent filings from the 1990s even describe point-of-care diagnostic systems that rely on a Code 39 barcode printed directly on a test cartridge to calibrate the instrument for that specific test, interpreting codes for the lot number, expiration date, and calibration curve values. |
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56.4.3 The Inevitable End for Laser Scanners |
Despite the continued utility of Code 39, the old laser scanners are being retired. This is because the advantages of image-based reading are not just about reading 2D codes; they offer superior performance on the 1D codes that defined the old world. |
An image-based reader is simply better at reading a Code 39 label than a laser scanner is. If the Code 39 label is placed on a curved surface, smudged, or has a damaged quiet zone, a laser scanner will often fail. An image-based reader can 'see' the entire label, process the image, and almost always decode it. An image-based reader can also provide operators with a picture of the label to grade its print quality, ensuring that poor labels are identified before they leave the factory floor and disrupt the supply chain. |
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56.5 Real-World Applications: The End of the Line |
The impact of this technology shift is felt across virtually every industry. |
Logistics and E-Commerce: |
The explosive growth of e-commerce has created a demand for high-speed, high-volume package sorting that laser scanners cannot keep up with. In a modern distribution center, image-based readers can scan packages at high speeds, reading both the 1D tracking barcode and the 2D QR code on the shipping label simultaneously. The cameras are omnidirectional, meaning the package does not need to be perfectly aligned for the system to read it, increasing throughput and reducing labor costs. For instance, a warehouse handling 10,000 packages a day with a manual laser scanner might take 6 seconds per package. An operator using a camera-based system can do the same job in roughly 3 seconds, saving over $26,000 a year just on throughput, while also achieving read rates closer to 99% compared to 98% for lasers. |
Pharmaceuticals and Healthcare: |
Pharmaceutical serialization mandates require each product unit to have a unique serial number. This data must be tracked from manufacturing to the pharmacy counter. 2D Data Matrix codes are the standard for this application, as they can encode the product code, serial number, lot number, and expiration date in a tiny space that fits on a small vial or ampoule. Laser scanners cannot read these codes. A camera-based reader can easily decode the Data Matrix code, verifying the authenticity and tracking the product through the supply chain. The image also creates a permanent record of the label at the point of inspection, valuable for auditing and traceability. |
Manufacturing (Electronics and Automotive): |
Manufacturing often uses a process called 'direct part marking,' where a permanent Data Matrix code is laser-etched or dot-peened directly onto the metal or plastic surface of a part. This creates a 2D code with very low contrast that is extremely difficult for a laser scanner to read. A camera-based reader, with specialized lighting and algorithms, can reliably decode these direct marks, tracking a component from its creation through the assembly process and throughout its service life. |
Consumer Goods and Retail: |
The retail sector is undergoing a massive transition to 'next-generation barcodes.' The standard UPC barcode is being replaced by 2D QR codes that can link to nutritional information, expiration dates, promotion videos, and ingredient sourcing details. The Australian SmartFacts platform, for example, uses GS1 QR codes to allow consumers instant access to standardized, real-time product information. This shift, supported by GS1 and major technology providers, will require a massive investment in new point-of-sale and warehouse scanning infrastructure, inevitably replacing millions of legacy laser scanners. |
Aviation and Aerospace: |
Aerospace manufacturing uses an exceptionally high number of parts, each with a demanding set of safety and traceability requirements. The industry was an early adopter of Code 39 for asset tracking, but it has now moved to 2D codes to contain extensive lifecycle data on critical components. The image-based reader's ability to provide 'proof of read' - a photo of the scanned part showing the exact moment it was processed - provides the auditable trail required by aviation regulators. |
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56.6 Conclusion |
The laser scanner is not being replaced simply because it is old technology; it is being replaced because it is functionally obsolete. The world has moved to 2D codes, data-rich carriers that enable mobile commerce, product intelligence, and end-to-end supply chain traceability. The laser scanner, with its single line of light, cannot read these codes. |
The image-based reader is more than just a solution for 2D codes. It is a superior device for the entire spectrum of barcodes. It provides faster read rates, higher accuracy, improved reliability, and unprecedented visibility into the scanning process. The ability to visualize, archive, and analyze reads and failures allows for a level of process control that was impossible with the 'blind' laser scanner. |
While Code 39 will likely remain in use for many years due to its historical inertia and self-checking properties, its applications will increasingly be serviced by cameras. The small, incremental cost of an image-based reader is far outweighed by the cost of a 'no read' on a high-speed production line or the operational headaches caused by damaged labels. The retirement of the laser scanner is not a question of 'if' but 'when,' as every modern industry updates its infrastructure to meet the demands of a data-rich, transparent, and traceable future. |
cs@easiersoft.com