ISO IEC 39794-6:2021 pdf download – Information technology — Extensible biometric data interchange formats — Part 6: Iris image data.
1 Scope This document specifies: — generic extensible data interchange formats for the representation of iris image data: a tagged binary data format based on an extensible specification in ASN.1 and a textual data format based on an XML schema definition that are both capable of holding the same information, — examples of data record contents, — application specific requirements, recommendations, and best practices in data acquisition, and — conformance test assertions and conformance test procedures applicable to this document. The iris image information is stored as: — an array of intensity values optionally compressed with ISO/IEC 15948 or ISO/IEC 15444-1, or — an array of intensity values optionally compressed with ISO/IEC 15948 or ISO/IEC 15444-1 that can be cropped around the iris, with the iris at the centre, and which can incorporate region-of-interest masking of non-iris regions. This document also specifies elements of conformance testing methodology, test assertions, and test procedures, as applicable to this document. It establishes: — test assertions pertaining to the structure of the iris image data format, as specified in Clauses 6 , 7, 8 and 9 of this document, — test assertions pertaining to internal consistency by checking the types of values that may be contained within each field, and — semantic test assertions. The conformance testing methodology specified in this document does not establish: — tests of other characteristics of biometric products or other types of testing of biometric products (e.g. acceptance, performance, robustness, security), or — tests of conformance of systems that do not produce data records conforming to the requirements of this document. This document does not establish: — requirements on the optical specifications of cameras, or — requirements on photometric properties of iris images, or — requirements on enrolment processes, workflow and use of iris equipment.
3.6 iris radius radius of a circle modelling the boundary between iris (3.4) and sclera (3.12) 3.7 margin distance in an image from the iris-sclera border, when modelled as a circle, to the closest image border, expressed in pixels Note 1 to entry: Throughout this document, margins are defined in terms of the iris radius , R ( 3.6 ). When written as an ordered pair, the order is (horizontal, vertical). EXAMPLE (0,6R , 0,2 R) indicates that for an iris radius of R , there shall be margins of image data 0,6 ·R to the right and left of the iris (3.4) and 0,2·R above and below the iris. 3.8 Modulation Transfer Function MTF ratio of the image modulation to the object modulation as a function of spatial frequency (3.14) 3.9 pupil optical opening in the centre of the eye that serves as a variable light aperture and defines the inner boundary of the iris (3.4) 3.10 pupil centre average of coordinates of all the pixels lying on the boundary of the pupil (3.9) and the iris (3.4)
ISO IEC 39794-6:2021 pdf download – Information technology — Extensible biometric data interchange formats — Part 6: Iris image data
