4 Essential Barcode Reading Technologies You Need to Know
How to Read a Barcode: Top 4 Essential Technologies
Barcodes have been in use since the early 1970s, inspired in inventor Joe Woodland’s mind by the dots and dashes of Morse code he had learned as a Scout.
The simplicity and elegance of the barcode revolutionized retail inventory management. Since its introduction in 1974, barcoding has been indispensable for reducing human error and ensuring visibility, traceability, connectivity, and control over manufacturing and supply chains worldwide.
The composition of a barcode is simple, and different barcode types can encode information for a wide range of applications.
A barcode is made up of a visual pattern of parallel black and white lines (and more recently, more complex geometrical arrangements). The bars are arranged to represent digits, and often also letters and symbols. The information represented in a barcode can be simple or complex, depending on the user’s needs and system requirements.
But these systems only work when a barcode is read by a scanner. In this article, we’ll take a look at how bar codes and barcode scanning devices work together.
How Do Barcode Scanners Work?
So, what do barcode scanners read, anyway?
All barcode readers use a light source and sensors to detect and measure the intensity of light reflected back by the white spaces within the unique pattern of parallel bars. The reflected light is detected through a photodiode, producing an electronic signal that corresponds to the barcode pattern.
The electronic signal passes through circuits, which translate it back into the original digits (and possibly also letters and symbols, depending on the barcode type) that the barcode was generated to represent.
The digits are converted by the system into meaningful text that works within the user’s database, providing essential information at incredible speed. But different types of barcode readers are suited for different applications.
An evaluation of barcode scanning technologies begins with a closer look at the four major types of barcode readers available on the market.
What Are the Most Common Types of Barcode Scanners?
Each different scanner type has advantages and disadvantages. The right type of barcode reader depends on the barcoding system followed, the working environment, range, cost, and much more.
Pen readers are shaped like a pen or wand, the tip of which houses both a light source and a photodiode. To read a barcode, the user drags the tip of the barcode wand across the bars in an even motion.
Dark bars absorb light and white spaces reflect it back. The photo diode measures the light intensity and generates a voltage waveform that is an exact duplicate of the black and white, bar and space pattern in the barcode. The reader decodes the waveform into digital data.
Pen readers are typically lowest in price, making them an accessible way to incorporate bar coding into inventory management. At the same time, they can be more temperamental to use than other scanner types, because the pen tip needs to directly contact and pass smoothly over the barcode. This can introduce user error.
Laser readers are incredibly popular, including for retail and point of sale environments. They are easy to use whether hand-held or mounted, and they can read barcodes from longer ranges — from 6 inches to 30 feet, depending on the device.
Laser readers use a laser as their light source. A reciprocating or oscillating mirror or rotating prism scans the laser beam back and forth across a barcode. A photodiode inside the scanner measures the intensity of light reflected back from the white spaces within the barcode, and generates a specific frequency that translates into the digital information.
CCD (Charge Coupled Device) Readers
CCD readers use an array of hundreds of light sensors in single row formation. They act together like a single photo diode to measure the intensity of ambient light that reflects off the barcode pattern.
Each tiny sensor generates a voltage pattern, and the reader assembles the individual patterns into a whole that corresponds to the barcode. Unlike laser and pen barcode readers, CCD scanners do not rely on an internal light source.
CCD devices are especially accurate, and they are popular for use in retail applications. But one disadvantage they present is that they need to be close to the barcode being scanned. In addition, they can’t scan barcodes larger or longer than their own sensor array.
Camera Based Readers
A camera based scanner uses a small video camera to capture the barcode image. The device applies advanced digital image processing technology to decode the barcode pattern.
The technology is similar to CCD readers, but CCD scanners use sensors arranged in a single line, and camera-based readers use a two-dimensional sensor arrangement. This enables the scanner to generate an image of the barcode.
Camera-based readers enable easy deployment and faster scanning of both 1D and 2D barcodes. Omni-directional camera based scanners can easily read barcodes even when not ideally presented or aligned. Unlike laser readers, they have no moving parts, which can mean better durability. They’re also able to read more data-robust codes than other readers.
Common Challenges to Reading Barcodes
Besides the pros and cons of barcode scanner technologies, barcodes themselves can sometimes present challenges. Preventable printing errors can include:
- Ink bleed
- Inadequate light margins
- Missing horizontal line
- Insufficient color contrast
- Barcodes printed too large or too small
- Issues with transparent, dull, or metallic substrates
- Issues with vertical edges, round shapes, or distortion
- Creased or peeling barcode labels
- Bands, labels, and stickers obscuring barcodes
- And more
If your scanner isn’t reading your barcode, it’s important to remember the barcode itself could be the problem. Labels, printing technologies, software, and other factors can also contribute to problems. It’s essential to make sure all aspects of your system are selected and designed to work together.
Every factor that goes into choosing a barcoding system and reader technology is important in its own right, from cost and maintenance to the types, levels and quantities of data you need to handle.
But the most important factor in your decision is the expert you choose to partner with. For more than 20 years, we’ve delivered unparalleled efficiency, accuracy, and connectivity with our end-to-end solutions for customers around the world. So if you’ve got questions, don’t hesitate to use our contact form to get in touch. We look forward to reaching out to you directly.