An identification mark may have a calibration color, a predetermined authentication color, and a predetermined difference between the calibration color and the predetermined authentication color that is associated with a product; and a visual code with a mechanism that identifies the predetermined difference.

Embodiments described herein provide for terahertz tags and methods of making and using them. A tag may include a terahertz reflective material; and a saturated hygroscopic material positioned on the terahertz reflective material. A tag may include a terahertz reflective material; and an anhydrous hygroscopic material positioned on the terahertz reflective material. A humidity sensor may include a terahertz reflective material; and an anhydrous hygroscopic material positioned on the terahertz reflective material. A temperature sensor may include a terahertz reflective material; an anhydrous hygroscopic material positioned on the terahertz reflective material; and a polymer overlay having thermally controlled water permeability disposed on the anhydrous hygroscopic material. Some embodiments relate to a tag identification device configured to transmit an incident signal toward the tag, and to receive a reply signal from the tag in response to the incident signal.

The present invention provides a method and apparatus for the production and labeling of objects in a manner suitable for the prevention and detection of counterfeiting. Thus, the system incorporates a variety of features that make unauthorized reproduction difficult. In addition, the present invention provides a system and method for providing a dynamically reconfigurable watermark, and the use of the watermark to encode a stochastically variable property of the carrier medium for self-authentication purposes.

A method for encoding information includes specifying a digital value and providing a symbol (28, 70, 80, 90, 100) comprising a plurality of polygons (72, 82, 92, 94, 102) meeting at a common vertex (74, 84, 96, 98, 104) and having different, respective colors selected so as to encode the specified digital value.

An article includes a substrate having a physical surface, a multi-dimensional machine-readable code embodied on the physical surface, wherein the multi-dimensional machine-readable optical code includes a static data (SD) optical element set and a dynamic lookup data (DLD) optical element set. Each of the SD and the DLD sets are embodied on the physical surface. The DLD optical element set encodes a look-up value that references dynamically changeable data, wherein the SD optical element set encodes static data that does not reference other data. The DLD optical element set is not decodable at the distance greater than the threshold distance.

A method for visual transmission and reception of repeatedly changing information comprises repeatedly performing the following set of actions, receiving a first set of information to transmit, the first set of information is an update of a previously received set of information, generating an information carrying first pattern representing the first set of information; displaying the information carrying first pattern in a first color; receiving a second set of information to transmit, the second set of information is an update of the first set of information; generating an information carrying second pattern representing the second set of information; displaying the information carrying second pattern in a second color, the second color differs from the first color; and wherein one of the information carrying patterns is statically displayed when another one of the information carrying patterns is updated.

The present document describe monocular machine vision systems and methods for determining locations of target elements when the three dimensional orientation of the monocular machine vision system relative to the target system is unknown. The machine vision system described herein captures and uses information gleaned from the captured target elements to determine the locations of these captured target elements relative to the vision system, or reversely, the location and orientation of the vision system relative to the target elements.

Systems, methods and apparatus are provided for light-based authentication of a payment card. The payment card may include a randomized mix of materials. The materials may include transparent or translucent materials. A light source may shine light on a surface of the payment card. Light passing through the card may generate a light pattern that is unique to the payment card. The light pattern may be captured and compared to a reference light pattern to authenticate the payment card. In some embodiments, photodetectors may detect light patterns generated through interactions with the card materials.

An information bearing device comprising a data bearing pattern, wherein the data bearing pattern comprises a plurality of data defining elements, the data defining elements being spatially distributed to define a set of spatial frequency data, and the set of spatial frequency data comprising a plurality of frequency data elements (F.sub.1, F.sub.2, . . . , F.sub.n); and wherein each frequency data (F.sub.i) has a data frequency magnitude (f.sub.i) and a data frequency angle(θ.sub.i), the data frequency magnitude being above a first characteristic spatial frequency (f.sub.A) which corresponds to a characteristic frequency of a staple or commonplace image reproduction apparatus, the characteristic frequency representing an image data frequency above which reproduction quality by the staple or commonplace image reproduction apparatus begins to drop substantially.

An article having an invisible infrared pattern is disclosed. The article includes at least one infrared pattern printed onto a surface. The infrared pattern includes regions of high absorption and high reflection for a plurality of wavelengths of infrared radiation ranging between 700 and 2000 nm. A coating is overlaid over the infrared pattern. The coating is made of a material and has a thickness that is penetrable by infrared radiation and that has an average opacity of at least 20 for light in the visible range.