jsQR is a JavaScript library for locating and decoding QR codes directly within a browser or Node.js environment. It functions as a client-side scanner and decoder that extracts text and data from images using pixel arrays, removing the need for server-side processing.
The library provides tools for QR code localization to identify the exact coordinates of corners and alignment patterns within a larger image. It uses image pattern recognition to isolate the QR code and extract its encoded content.
Its internal operations cover binarization-based thresholding, geometric pattern localization, and perspective transformation mapping to normalize skewed images. It also utilizes Reed-Solomon error correction to recover corrupted data bits and version-based grid sampling to determine module layout.
