Abstract
We present 'Screen codes' - a space- and time-efficient, aesthetically compelling method for transferring data from a display to a camera-equipped mobile device. Screen codes encode data as a grid of luminosity fluctuations within an arbitrary image, displayed on the video screen and decoded on a mobile device. These 'twinkling' images are a form of 'visual hyperlink', by which users can move dynamically generated content to and from their mobile devices. They help bridge the 'content divide' between mobile and fixed computing.