This is a work-in-progress javascript DataMatrix detector and decoder.

The goal is to make a module suitable for in-browser real-time DataMatrix scanning using phone/tablet cameras.

There are two existing open source projects that can scan 2D barcodes:

• libdmtx: Written in C. Robust to changes in rotation but less robust to lighting/contrast changes. Fairly complicated codebase.
• ZXing: Writen in Java. Robust to lighting/contrast changes. Does not work if DataMatrix code is rotated.

It uses code from the following projects:

• jsqrcode: Re-used some parts of this javascript port of the QR code scanning functionality from ZXing (License: Apache v2)
• ZXing: Ported some additional DataMatrix-related functionality from ZXing to javascript (License: Apache v2)
• LSD: a Line Segment Detector: Compiled reference implementation in C to javascript using emscripten. (License: AGPLv3)

The algorithm as implemented in this code is partially inspired by the algorithm described in this article:

• "Data Matrix Code Location Based on Finder Pattern Detection and Bar Code Border Fitting" by Huang et al, Mathematical Problems in Engineering, 2012

It makes use of the following algorithm:

• "LSD: a Line Segment Detector" by Gioi et al, Image Processing On Line, 2012

Getting started

npm install
cp settings.js.example settings.js
npm run build
firefox index.html

Future ToDo

• Detect image sharpness and only apply blur if sharpness above some threshold. This should improve scanning robustness when code is in/out of focus.
• Before detection find and extract candidate regions that may contain DataMatrix codes. This will allow scanning of codes at a variety of distances and scanning of multiple codes at once.
• Add perspective correction.

License

Various parts of this code is available under different licenses as described in individual source files. This includes MIT license, Apache v2 license and AGPLv3.