What Is a Micro QR Code?
Barcodes continue to be an essential tool for today’s organizations, whether they’re using them for managing supply chains or sorting documents within a complex digital workflow. Since the early 1990s, however, the potential use cases of barcodes have expanded tremendously. That’s largely due to the invention of the quick response barcode, better known as the QR Code. Developed by the Japanese manufacturer Denso Wave in 1994, this two-dimensional barcode revolutionized the way data was encoded and scanned. Today, QR Codes can be found practically everywhere, along with their smaller cousins, the Micro QR Code.
What Is a Micro QR Code?
Although the standard QR Code could hold a tremendous amount of information, that ability occasionally created challenges for specialized use cases where space was at a premium. Small components like circuit boards or machinery parts, for example, often couldn’t accommodate a QR Code. Even when they could, much of the QR Code’s storage capacity wasn’t being used to its full potential. For use cases where space was at a premium and only a small amount of data needed to be encoded, a more compact version of the QR Code was needed.
The Micro QR Code was designed to solve this specific challenge. Roughly half the size of the conventional QR Code, this smaller version still provided many of the benefits of its bigger cousin, including finder patterns to orient the image properly, multiple levels of error correction, and support for Japanese Kanji, Kana, and Hiragana characters.
The Anatomy of a Micro QR Code
A Micro QR Code consists of four elements that allow it to encode data and provide a barcode reader with instructions for how to read the contents.
Like any other QR Code, Micro QR Codes store binary data in square modules. While the human eye only registers the black modules, a computer scanner also registers white modules when reading the code. A black square represents a binary 1 while white squares are read as a binary 0. The amount of information that can be encoded into these modules changes depending upon the size of the barcode. Micro QR Codes can be written in four different sizes (more on that in a moment), allowing them to store up to 35 numeric digits, 21 alphanumeric characters, or 128 data bits.
The finder pattern is the square “bull’s eye” that appears in the upper-left hand corner of a Micro QR Code. This pattern ensures that the barcode is oriented and scanned correctly when read by an application. Since Micro QR Codes contain less complex data, they only require a single pattern finder while a conventional QR Code uses three. While many QR Codes also require an alignment pattern to correct for crookedness or distortion, Micro QR Codes are not large enough for these problems to create much of an issue during scanning.
A series of alternating black and white modules running vertically along the left side and horizontally along top of the barcode, the timing pattern is used to configure the rest of the data grid for the scanner. By reading the timing pattern, the scanner software can quickly determine the size of the barcode’s data matrix, as well as the symbol and version density.
A clear margin space surrounding the rest of the barcode elements, the quiet zone makes the boundaries easy for scanning software to detect and identify. While a conventional QR Code requires four or more modules of empty space, a Micro QR Code only needs a two module-wide space. This helps to keep the barcode compact regardless of how much data is encoded within it.
Micro QR Code Sizes and Error Correction
Depending upon the amount of data encoded, Micro QR Codes can be written in one of four sizes. The smallest version, M1, consists of 11×11 modules, while the largest, M4, is 17×17 modules. Each size above M1 can support different levels of error correction, although the more thorough the error correction, the less data can be encoded.
Error correction is based on the Reed-Solomon algorithm and allows scanning software to recover lost, poorly printed, or damaged barcode data. Versions M2 and M3 offer two levels of error correction:
- Level L (Low): Capable of recovering up to seven percent of encoded data.
- Level M (Medium): Capable of recovering up to 15 percent of encoded data.
As mentioned above, higher levels of error correction impact the amount of data that can be encoded into Micro QR Code modules. That’s because the redundancies necessary to support error correction algorithms take up available space. Increasing an M3 barcode’s error correction from level L to Level M, for instance, would reduce the number of numeric characters that could be supported from 23 to 18.
An M4 Micro QR Code contains enough modules to support a third level of error correction:
- Level Q (Quartile): Capable of recovering up to 25 percent of encoded data.
Although level Q provides excellent durability, it leaves much less space for encoding data. An M4 barcode with this level of error correction actually holds less data than an M3 barcode with level L error correction. When writing a Micro QR Code, it’s important to determine what level of error correction is actually necessary for the use case at hand rather than simply defaulting to the most robust option.
Differences Between Micro QR Codes and Conventional QR Codes
While Micro QR Codes use many of the same 2d barcode principles as traditional QR Codes, it’s not quite accurate to think of them as a condensed version. They have some notable differences that make them more or less suited to specific use cases.
Micro QR Codes
- Provide up to three levels of error correction.
- Needs only a single finder pattern for orientation.
- Can encode up to 128 bits.
Conventional QR Codes
- Provide up to four levels of error correction.
- Requires three finder patterns for orientation.
- Can encode up to 23,658 bits.
Enhance Your Barcode Capabilities with Barcode Xpress
Adding barcode recognition capabilities to an application can help to streamline document management workflows and allow organizations to route files more efficiently. Developers can easily integrate the ability to read and write barcodes into their platforms using a barcode SDK like Accusoft’s Barcode Xpress. With support for more than 30 unique barcode types, including Micro QR Barcodes, this versatile SDK provides the tools to support a wide range of use cases that call for fast, accurate barcode recognition.
For a hands-on evaluation of how Barcode Xpress will perform in your development environment, download a free trial today or start a conversation with one of our SDK specialists.