2D imagers capture a “picture” of two-dimensional or linear codes and process them using advanced decoding algorithms. For linear codes, 2D imagers provide omnidirectional reading of linear barcodes, so orientating the code for scanning is unnecessary.
2D codes carry more information in a smaller space than linear barcodes, making them ideal for applications like printed circuit board manufacturing, healthcare/clinical and retail.
2D imagers can be produced using either charge-coupled device (CCD) technology or the more sophisticated complementary metal-oxide-semiconductor (CMOS) technology, which uses dramatically less power while providing advanced performance. CMOS-based 2D imagers are ideal for applications where changing or recharging batteries in mid-shift reduces productivity, like portable data collection in warehouse, manufacturing and distribution applications.
Active Pixel CMOS Sensors (APS) replace the CCD used in many of today’s linear imagers. The APS sensor combines the light detector and the digital signal processor into one application-specific integrated circuit (ASIC).
This APS sensor allows for linear imagers to have the same performance as those that used CCD sensors. However, these linear imagers are smaller, lower power, more reliable and offer many other advantages over conventional CCD-based linear imagers.
Also, APS enables individual pixels on the sensors to be programmed, making it easier to read a variety of different symbologies from the same device.
A sequence of rectangular shapes and intervening spaces used to encode a string of data. A barcode symbol typically consists of five parts:
- A leading quiet zone
- A start character
- Data character(s) including an optional check character
- A stop character
- A trailing quiet zone
Characteristic of some barcodes that allows decoding of the symbol regardless of whether it is scanned in a forward or backward direction.
Charge-Coupled Device. The solid state component found in a wide variety of products –from simple scanners and fax machines, to highly sophisticated devices, like linear imagers, video cameras and digital cameras.
Contact to 5 inches (12.7 centimeters)
Complementary Metal-Oxide-Semiconductor (pronounced “see-moss”). CMOS is a widely used type of semiconductor that leverages both NMOS (negative polarity) and PMOS (positive polarity) circuits. Since only one of the circuit types is on at any given time, CMOS chips require less power than chips using just one type of transistor. This makes them particularly attractive for use in battery-powered devices, such as portable computers.
2 feet (61 centimeters) to 35 feet (11 meters)
Light Amplification by Stimulated Emission of Radiation. Laser scanners read barcodes with a laser beam in conjunction with oscillating mirrors to automatically move the beam back and forth across the symbol.
Laser scanners read barcodes with a laser beam in conjunction with oscillating mirrors to automatically move the beam back and forth across a barcode. Laser engines come in a variety of configurations (e.g. standard range, wide angle, high density, long range and high visibility) to meet the needs of different scanning applications. The major advantage to lasers is their scan range; they can read barcodes from several feet away. In fact, if the symbol is printed large enough, the laser can read it from as far away as 35 feet (11 meters). For applications such as scanning from a forklift in a warehouse, the ability to read a barcode without having to constantly get off the forklift is a distinct advantage.
The underlying technology of a linear imager is called a charge coupled-device (CCD). These solid state components are found in a wide variety of products from simple scanners and image capture devices, such as fax machines, to highly sophisticated devices, like linear imagers, video cameras and digital cameras. In a linear imager, the CCD captures different levels of reflected light from a barcode’s bars and spaces and converts them into a video signal. For optimum performance, linear imagers need their own light source, which is provided by low-power, long-life LEDs (light emitting diodes). Their low power consumption and long life means that the light can be on all the time, eliminating the need for a trigger. However, some scanners do incorporate triggers and sleep/wake modes for power saving, especially when connected to battery-operated devices.
Linear imagers are solid state scanners which use a charge-coupled device (CCD) as their underlying technology. Linear imagers have generally better performance and reliability at a lower price than laser scanners.
Light Emitting Diodes are special diodes that emit light when connected in a circuit. They are frequently used as “pilot” lights in electronic appliances to indicate whether the circuit is closed or not.
An arrangement of regular polygon shaped cells where the center to center distance of adjacent elements is uniform. The arrangement of the elements represents data or symbology functions. Matrix symbols may include recognition patterns that do not follow the same rule as the other elements within the symbol.
Radio Frequency Identification. The use of radio frequency signals to provide automatic identification of items. RFID uses a reader (or interrogator) and special RFID tags that can be read and written to hundreds of times.
RFID is similar in concept to barcoding, but instead of a printed label with static information that requires line-of-sight scanning, RFID tags contain an application-specific integrated circuit (ASIC). The ASIC acts as a dynamic portable database that can be read and/or written to every step along the supply chain. RFID does not require line of sight to read tags, speeding the process of data collection. And, RFID devices, such as a tag or label, can be attached to virtually anything – from a vehicle to a pallet of merchandise. In addition, because the technology is difficult to counterfeit, RFID provides a high level of security.
2 to 9 inches (5 to 23 centimeters).
A long, multi-row symbol that is broken into sections, which are stacked upon another, in a fashion similarto sentences in a paragraph.
Barcode language, i.e. Code39, UPC, EAN, including linear, stacked matrix and matrix barcodes. Learn more about barcode symbologies.
A machine-readable symbol composed of rows of encrypted data arranged in a rectangular or square pattern. The rows of data may be composed of barcode strips, “stacked” to form the two dimensional block pattern or arranged as a checkerboard “matrix” of typically square elements.
The nominal dimension of the narrow bars and spaces in linear and 2D stacked codes. In 2D matrix symbols, the X-dimension is the height and width dimension of the smallest element because each module is square, except for MaxiCode modules, which are hexagonal.