What Is a Micro QR Code?

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QR codes are everywhere, from product packaging to advertisements, making it easy to access information with a quick scan.

But what happens when space is limited? Enter Micro QR Codes.

Micro QR codes are a smaller version of the standard QR code. They offer a practical solution for encoding information in a tiny footprint without sacrificing readability.

In this article, we will take a closer look at Micro QR codes. We will analyse their structure, discuss their information capacity, and compare them to standard QR codes. We will also explore their applications and examine the reasons behind their increasing popularity.

What Are MicroQR Codes?

Micro QR codes are specialised type of QR codes designed for applications with limited space, such as on small products or electronic components.

Despite their smaller size, Micro QR codes can still encode numeric, alphanumeric, binary data, and even Kanji characters (used in Japanese writing).

How to Visually Identify a Micro QR Code?

Identifying a Micro QR code is straightforward. Here are the key visual features distinguishing Micro QR codes from standard QR codes.

Smaller Size: The most obvious characteristic is the smaller size compared to standard QR codes.
Single Position Detection Pattern: Unlike standard QR codes, which have three large squares in three corners, Micro QR codes have only one large square located in the top left corner.
Compact Data Area: The data area in a Micro QR code is more compact. It consists of fewer modules (the black and white squares that make up the code) than a regular QR code, arranged more densely.
Fewer Rows and Columns: Micro QR codes have fewer rows and columns for modules. This reduced grid size is a direct result of their smaller data capacity and overall size.

Structure of a Micro QR Code

Micro QR codes are designed to be compact while still encoding essential information. Understanding their structure helps in appreciating how they maintain functionality despite their small size.

Here are the key components of a Micro QR code.

Data Modules
Finder Pattern
Timing Pattern
Quiet Zone

Data Modules

The data modules are the small square and rectangular components that form the data area of a Micro QR code. These modules represent the encoded information and incorporate the Reed-Solomon Code, which enables error correction functionality.

Typically, data modules are black and white, but colours can also be used.

Data modules encode data as binary values: black (or dark-coloured) modules represent binary 1, while white (or light-coloured) modules represent binary 0. Combining these binary values into a unique pattern allows Micro QR codes to encode different characters.

In a Micro QR code, the data modules are densely packed to maximise the amount of information stored within the limited space. This dense arrangement allows Micro QR codes to store data more densely than normal QR codes

Finder Pattern

The finder pattern, also known as the positioning patterns, is a single, large square located in the top left corner of the Micro QR code. This distinct pattern helps barcode scanners quickly locate and orient the code, ensuring accurate data reading.

Timing Pattern

The timing pattern is a series of alternating black and white modules that run horizontally and vertically within the Micro QR code.

The timing pattern is arranged along two sides surrounding the finder pattern, with one column on the left and one row on the top of the code. This pattern assists the QR code scanner in determining the size, symbol version, and density of the QR code. It also helps correct the central coordinate of the data cell when the symbol is distorted or when errors occur in the cell pitch.

Compared to standard QR codes, Micro QR codes rely on a single timing pattern for horizontal and vertical synchronisation.

Quiet Zone

The quiet zone is the empty, clear margin surrounding all four sides of the Micro QR code. This area creates a buffer that separates the code from other text or graphics, ensuring that the barcode reader can accurately detect and read the code.

Micro QR codes require a quiet zone of at least two modules to function correctly.

Micro QR Code Error Correction Levels

Error correction is a feature that allows data to be accurately recovered even if parts of it are damaged or obscured. This is achieved through mathematical algorithms that add extra information to the original data, enabling the reconstruction of the lost or corrupted portions.

Micro QR codes use Reed-Solomon error correction, a robust method that works by oversampling a polynomial constructed from the existing encoded data.

Micro QR codes support three error correction levels: L, M, and Q, each providing a different level of recovery capacity.

Level L (Low): Restores up to 7% of encoded data.
Level M (Medium): Restores up to 15% of encoded data.
Level Q (Quartile): Restores up to 25% of encoded data.

It is important to note that higher error correction levels occupy more space within the QR code itself. This means that while higher error correction levels increase the reliability and readability of the code, they also reduce the data capacity of the Micro QR code.

Therefore, balancing error correction level and data capacity is essential for optimising the performance of Micro QR codes in different applications.

Tip:

If a Micro QR code will be placed outdoors, where it will face sunlight, moisture, and other environmental factors, choosing a higher error correction level is beneficial. However, if the code will be used indoors, say inside a store, a lower error correction level can be selected leaving more space for data.

Micro QR Code Character Set

Micro QR code has different modes for supporitng a variety of character stes.,. This makes Micro QR Code versatile. Here are the main data character sets that Micro QR codes can encode.

Numeric Mode: Includes digits from 0 to 9
Alphanumeric Mode: Includes numeric digits (0-9), uppercase letters (A-Z), and special characters such as:
- Dollar sign ($)
- Percent sign (%)
- Asterisk (*)
- Plus sign (+)
- Hyphen (-)
- Period (.)
- Slash mark (/)
- Colon (:)
- Space character
Binary Mode*: Enables Micro QR codes to store data in a binary format as 8 bits per character, with the default character set defined as per ISO/IEC 8859.
Kanji Mode*: Encodes kanji characters according to the Shift JIS system, as defined in the Japanese Industrial Standard (JIS) X 0208 7-bit and 8-bit double-byte coded KANJI sets for data interchange.

*Note – Micro QR Code version M1 does not support Alphanumeric Mode, Binary Mode and Kanji Mode.

Micro QR Code Size

Micro QR codes come in four different sizes, referred to as versions. Each version has a specific number of modules that make up the code.

Here’s an overview of the sizes for different versions of Micro QR codes.

Symbol Version	Number of Modules	Dimensions (in modules)	Dimensions (in mm)
M1	11	11 x 11	2.75 x 2.75
M2	13	13 x 13	3.25 x 3.25
M3	15	15 x 15	3.75 x 3.75
M4	17	17 x 17	4.25 x 4.25

To give you an idea of how these sizes compare to standard QR code size, the smallest standard scannable size of QR codes measures 21 x 21 modules. Even the largest Micro QR code (M4) is significantly smaller, reducing the size by approximately 19%

Micro QR Code Data Capacity

The data capacity of a Micro QR code depends on three factors.

The version of the code
The type of data being encoded
The level of error correction chosen

Below is a table summarising the data capacity for each version of Micro QR codes.

Symbol Version	Number of Modules	Error Correction Level	Numeric Characters	Alphanumeric Characters	Binary Bytes	Kanji Characters
M1	11	Not supported	Up to 5	Not supported	Not supported	Not supported
M2	13	L	Up to 10	Up to 6	Not supported	Not supported
		M	Up to 8	Up to 5	Not supported	Not supported
M3	15	L	Up to 23	Up to 14	Up to 9	Up to 6
		M	Up to 18	Up to 11	Up to 7	Up to 4
M4	17	L	Up to 35	Up to 21	Up to 15	Up to 9
		M	Up to 30	Up to 18	Up to 13	Up to 8
		Q	Up to 21	Up to 13	Up to 9	Up to 5

The largest Micro QR code is the M4 version with an L level of error correction. It can encode up to 35 numeric digits, 21 alphanumeric characters, 15 bytes, or 9 Kanji characters.

What is the Difference Between a QR Code and a Micro QR Code?

QR codes and Micro QR codes are both used to store data. However, there are several key differences between the two, primarily in terms of size, structure, data capacity, and typical applications.

Here’s a detailed comparison between the Micro QR code and the QR code.

Feature	Standard QR Code	Micro QR Code
Size	Larger, ranging from 21 x 21 to 177 x 177 modules	Smaller, ranging from 11 x 11 to 17 x 17 modules
Data Capacity	Higher data capacity; The largest size can store up to 2953 bytes of data, 4296 alphanumeric characters, 7089 numeric characters, or 1817 Kanji characters	Lower data capacity; The largest size can store up to 15 bytes of data, 21 alphanumeric characters, 35 numeric characters, or 9 Kanji characters
Error Correction Levels	Four levels (L, M, Q, H), with up to 30% error correction	Three levels (L, M, Q), with up to 25% error correction
Finder Patterns	Three large squares in the top right, top left, and bottom left corners	One large square in the top left corner
Timing Patterns	Multiple horizontal and vertical timing patterns	Single timing pattern for both horizontal and vertical synchronisation
Usage Scenarios	Commonly used in marketing, payments, and product information	Ideal for small products, electronics, and areas with limited space

Where Are Micro QR Codes Used?

Here are some common use cases for Micro QR codes.

Electronics: Micro QR codes are often used on small electronic components like circuit boards to provide tracking information, serial numbers, manufacturing details, and usage instructions.
Small Product Labels: Micro QR codes carry information such as batch numbers, expiration dates, and product descriptions for products with limited labelling space, such as cosmetics, pharmaceuticals, and food products.
Healthcare: In the medical field, Micro QR codes are used on patient wristbands, medical devices, and lab samples to store critical information such as patient identification, medical history, medication details, and test results.
Retail and Inventory Management: Micro QR codes help manage inventory by providing product details, stock levels, and pricing information, especially for small items such as jewellery, cosmetics, and electronics accessories.
Security and Authentication: Micro QR codes are used on ID cards, access passes, and security tags to store encrypted information such as employee details or access permissions in various settings.

Conclusion

Micro QR codes are a powerful and compact alternative to standard QR codes, designed for use in space-constrained environments. Despite their smaller size, they offer robust data encoding capabilities and support various character sets, including numeric, alphanumeric, binary, and Kanji.

With standardised specifications under ISO/IEC 18004 and JIS X 0510, Micro QR codes ensure reliable performance and interoperability. Their versatility makes them ideal for a wide range of applications, from electronics and small product labelling to healthcare and inventory management.

Frequently Asked Questions

Do Smartphones Support Micro QR Codes?

Yes, most modern smartphones can read Micro QR codes using their built-in camera app. However, if the built-in camera does not support barcode scanning, you can download and use a dedicated third-party QR code scanning app.

Are Micro QR Codes Standardised?

Yes, Micro QR codes are standardised according to two key standards:

ISO/IEC 18004: This standard defines the specifications, encoding, decoding, and error correction procedures for Micro QR codes.

JIS X 0510: This standard aligns Japanese Micro QR codes with international practices as defined by ISO/IEC 18004.

How Many Characters Can a Micro QR Code Encode?

The data capacity of a Micro QR code depends on its version. The largest Micro QR code (Version M4) can hold up to 35 numeric data, 21 alphanumeric data, 15 bytes of binary data, or 9 Kanji characters.