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Structure and Geometry of QR Codes
A Quick Response (QR) code is a matrix barcode invented in 1994 by the Japanese company Denso Wave. Unlike standard linear barcodes that store data in a single horizontal dimension, QR codes store data both vertically and horizontally, allowing them to contain significantly more information in a smaller space. The layout of a QR code is highly structured and contains several key geometric patterns:
- Finder Patterns: The three large squares located in the top-left, top-right, and bottom-left corners. They allow scanners to identify the code location and determine the scanning orientation.
- Alignment Patterns: Smaller squares distributed across the grid (in larger versions) to correct for perspective distortion when scanning at an angle.
- Timing Patterns: Alternating black and white modules that connect the finder patterns, allowing the scanner to determine the width and coordinates of the individual grid columns.
- Format Info: Modules surrounding the finder patterns that contain error correction information and print mask settings, allowing the scanner to decode the data correctly.