| 摘要 |
Image analysis algorithms find the iris in a live video image (10) of a person's face, and encode its texture into an "iris code" (24). Iris texture is extracted from the image at multiple scales of analysis by a self-similar set of quadrature bandpass filters defined in a dimensionless polar coordinate system. The sign of the projection of many different parts of the iris onto these filters determines each bit in an iris code. Comparisons between codes are readily implemented by the Exclusive-OR (XOR) logical operation. Pattern recognition is achieved by combining signal processing methods with statistical decision theory, leading to a statistical test of independence based on a similarity metric (Hamming distance) (26) that is computed from the XOR of any two iris codes. This measure positively establishes, confirms, or disconfirms, the identity of any individual (28). It also generates an objective confidence level (30) associated with the identification decision. |
