| 摘要 |
An optical authentication device (Fig. 8, 1) comprising a plurality of elements having optical polarizing properties distributed in a pseudo-random manner over a predetermined area (33); at least three optically detectable markers (29, 30, 31, 32) positioned in predetermined positions with respect to the predetermined area; whereby, when viewing the predetermined area with an optical imaging sensor of a reader under an illumination having specific polarization properties a first image is obtained that is different from one or more other images obtained under one or more illuminations having different polarization properties, thus by comparing two or more images of at least a portion of the device to saved images of the same device or a portion thereof taken under the same illuminations, using the markers (29, 30, 31, 32) for aligning images to be compared, authentication is achieved. |
