PACER is a system that allows users to interact with paper documents using a cell phone in a seamless way. It uses computer vision techniques and hybrid camera-touch gestures to link physical paper to digital information and interactions. Some key features include allowing fine-grained interaction at the word/character level, semi-real-time processing to handle camera inputs, and hybrid gestures combining embodied gestures and touch inputs. A preliminary user study found the approach was well received and recognition accuracy was over 80%, though further work is needed to improve interactions.
