Two-dimensional barcodes for mobile phones

Motivated by a number of potential applications for a high data-density barcode that can be easily photographed and decoded by mobile phones, this paper presents the design of a new colour high data-density two-dimensional barcode symbology. The new symbology is designed to exploit the low-pass characteristic of a camera phone channel, and encodes information in the spatial Discrete Cosine Transform domain. A water-filling process and a noise-shaping algorithm enhance performance, while a new fast acquisition method allows for rotational and size invariance. An outer Accumulate-Repeat-Accumulate code is employed, followed by an inner Reed Muller code with a rate varying according to spatial frequency. The final barcode data-density is 3.5 times greater than the leading symbology and has proven robust to various impairments imposed by camera phones.