What Are The Different Sections In A QR Code? - Feb 2017
QR Codes are split into various sections and it's these sections that the scanners use to decode the data. Below is a breakdown of each section.
The image below is a standard QR Code containing plain text. If you scan the code it should be decoded as text and will simply include the string "Sample QR Code".
The image has been split into sections and each section has been given a number and a colour. Each of these sections has a given role which has been covered in more detail.
Section 1 - Finder Pattern
The finder pattern consists of three identical structures that are located in all corners of the QR Code except the bottom right corner. Each pattern is based on a 3x3 matrix of black modules surrounded by white modules that are again surrounded by black modules. The Finder Patterns enable the decoder software to recognize the QR Code and determine the correct orientation.
Section 2 - Separators
The white separators have a width of one pixel and improve the recognizability of the Finder Patters as they separate them from the actual data. They are generally always white
Section 3 - Timing Pattern
Alternating black and white modules in the Timing Pattern enable the decoder software to determine the width of a single module.
Section 4 - Alignment Patterns
Alignment Patterns support the decoder software in compensating for moderate image distortions. Version 1 QR Codes do not have Alignment Patterns. With growing size of the code, more Alignment Patterns are added.
Section 5 - Format Information
The Formation Information section consists of 15 bits next to the separators and stores information about the error correction level of the QR Code and the chosen masking pattern.
Section 6 - Data
Data is converted into a bit stream and then stored in 8 bit parts (called code words) in the data section.
Section 7 - Error Correction
Similar to the data section, error correction codes are stored in 8 bit long code- words in the error correction section.
Section 8 - Remainder Bits
This section consists of empty bits if data and error correction bits can not be divided into 8 bit code words without remainder.
Combined, these sections allow QR Codes to be flexible, reliable and robust.
Keep Reading: 8. QR Code Error Correction