A wireless phone is equipped with a 2D optical sensor, enabling a variety of applications. For example, such a phone may also be provided with a digital watermark decoder, permitting decoding of steganographic data on imaged objects. Movement of a phone may be inferred by sensing movement of an imaged...http://www.google.com/patents/US7174031?utm_source=gb-gplus-sharePatent US7174031 - Methods for using wireless phones having optical capabilities
