The very short explanation: * Split source image into red, green, and blue channels * Run through the halftone qr generator[0] * Recombine resulting QR codes

The very short explanation: * Split source image into red, green, and blue channels * Run through the halftone qr generator[0] * Recombine resulting QR codes into an RGB image * Average combined QR codes with the source image I'll probably post an article walking through the process using imagemagick some time next in August. 0. http://vecg.cs.ucl.ac.uk/Projects/SmartGeometry/halftone_QR/halftoneQR_sigga13.html http://vecg.cs.ucl.ac.uk/Projects/SmartGeometry/halftone_QR/...