Distortion-invariant ID tags for object identification

摘要

identification and verification of objects are described. We focus our attention on the design of passive ID tags to achieve distortion-invariant authentication of the information included in the optical tag. A passive ID tag will consist of an optical phase code which can be placed in a visible part of an object for remote detection. We aim to authenticate the object even if the reader captures a distorted version of the code due to in-plane rotations. Distortion-invariance is achieved by both multiplexing the information included in the ID tag and the topology of the tag. For security purposes, double-phase encryption has already been shown as an appropriate technique to encode information. By using double-phase encryption, a signature is hidden in a phase-encoded ID tag not visible by visual inspection. Once the ID tag is captured by the reader and is decrypted, a correlation-based processor verifies the decoded information with a previously stored reference signal. The proposed system may have broad applications in transportation, homeland security, and inventory control.