Abstract: In general, the subject matter described in this specification relates to security credentials for documents, such as identification documents. One example is an identification document that includes a photographic image of an individual associated with the document, and a spiral pattern applied to a region of the identification document. The spiral pattern includes an elliptical spiral segmented into a plurality of arc segments, where wherein the arc segments of the spiral pattern encode identification data associated with the individual. Other implementations include corresponding processes, systems, apparatus, and computer programs related to generating and verifying identification documents with spiral patterns.

Abstract: An identification document includes a card structure including a plastic material, a surface of the card structure including a first surface region that includes a plurality of depressions formed in the surface according to a predefined pattern; and a second surface region that includes a majority of a surface area of the identification document, wherein the second surface region is non-porous. A surface energy of the surface in the first surface region is greater than a surface energy of the surface in the second surface region.

Abstract: An identification document includes a card structure including a plastic material, a surface of the card structure including a first surface region that includes a plurality of depressions formed in the surface according to a predefined pattern; and a second surface region that includes a majority of a surface area of the identification document, wherein the second surface region is non-porous. A surface energy of the surface in the first surface region is greater than a surface energy of the surface in the second surface region.

Abstract: In general, the subject matter described in this specification relates to security credentials for documents, such as identification documents. One example is an identification document that includes a photographic image of an individual associated with the document, and a spiral pattern applied to a region of the identification document. The spiral pattern includes an elliptical spiral segmented into a plurality of arc segments, where wherein the arc segments of the spiral pattern encode identification data associated with the individual. Other implementations include corresponding processes, systems, apparatus, and computer programs related to generating and verifying identification documents with spiral patterns.

Abstract: A multilayer laminate identification document including an outer layer having a contoured surface image formed therein via laser ablation. The contoured surface image has contours based on a digital monochrome image, and has a first appearance when viewed in reflected light at a first angle and a second, different appearance when viewed in reflected light at a second, different angle. The multilayer laminate identification document is formed by generating a second digital monochrome image with continuous pixel patterns from a first digital monochrome image, and irradiating the surface of the identification document with a laser using the second digital monochrome image as a guide to form a contoured surface image in the surface of the identification document.

Abstract: A multilayer laminate identification document including an outer layer having a contoured surface image formed therein via laser ablation. The contoured surface image has contours based on a digital monochrome image, and has a first appearance when viewed in reflected light at a first angle and a second, different appearance when viewed in reflected light at a second, different angle. The multilayer laminate identification document is formed by generating a second digital monochrome image with continuous pixel patterns from a first digital monochrome image, and irradiating the surface of the identification document with a laser using the second digital monochrome image as a guide to form a contoured surface image in the surface of the identification document.

Abstract: Personal data may be embedded in a kinegram of an identification document using a suitable low energy laser without compromising the integrity of the kinegram or the identification document. The personal data can be written in a metalized portion of the kinegram in a high definition, high resolution manner such that the personal data may be read by a human without the use of a text-enhancing viewer device (e.g., magnifying glasses). Additional personal data can be written in a reduced text size (e.g., micro-text) in another metalized portion of the kinegram such that a human must use a text-enhancing viewer device to view the micro-text personal data.

Abstract: A cylindrical type automotive barrier filter is adapted to be used in the inlet airflow of a gas turbine engine that is used in an agricultural aircraft. Air is drawn in through an inlet in the upper portion of the aircraft nose body without appreciable disturbance to the aerodynamic contours. The outlet of the filter is connected to a duct in a sealed relationship to direct the airflow to the engine inlet. The airflow passage is sealed by a connecting flange mounted on the filter to which the duct is connected. A longitudinally extending firewall is constructed to separate the filter and connecting duct from the turbine section of the engine. An emergency bypass door is provided to provide an inlet airflow in the event the filters become clogged. The bypass door is designed to provide particle separation of the incoming air.