Overview
ISO/IEC 19794-6:2005 - Information technology - Biometric data interchange formats - Part 6: Iris image data defines standardized interchange formats for storing and transmitting iris images used in biometric authentication. The standard enables interoperability among vendors by specifying two alternative iris image representations, associated headers and data structures, and conformance rules for embedding iris data in a CBEFF-compliant Biometric Data Block (BDB).
Key topics and technical requirements
- Two image formats
- Rectilinear format: full-image storage in Cartesian coordinates - can be a raw, uncompressed array (at least 8 bits per pixel for greyscale) or a compressed continuous-tone image.
- Polar format: compact representation derived from preprocessing and segmentation that contains only the unwrapped iris region (more storage- and bandwidth-efficient).
- Image compression options
- Pre-processing and segmentation
- Polar format requires specified preprocessing (pupil/limbus localization, cropping, normalization) before encoding to achieve the compact iris-only data structure.
- CBEFF embedding and headers
- Iris records must be embedded in a CBEFF Biometric Data Block per ISO/IEC 19785-1.
- Registered CBEFF BDB format type values: 0x0009 for rectilinear and 0x000B for polar records; BDB format owner for SC37 is 0x0101.
- Image quality and conformance
- Annex A defines recommended image quality levels (four tiers) covering resolution, contrast, focus, illumination, noise and other capture criteria to suit different security and cost needs.
- Security and IP
- The standard recommends encrypting and signing iris data for privacy and integrity. It also notes potential patent claims (as disclosed in the standard).
Applications and who uses it
- Iris recognition system vendors - to ensure stored/transmitted iris images interoperate across devices and software.
- Biometric SDK and algorithm developers - to standardize input/output formats for matching and template generation.
- System integrators and identity management providers - for integration into access control, border control, national ID and e‑passport systems.
- Government agencies and high-security deployments - when consistent, high-quality iris data exchange and compact storage are required.
- Device manufacturers (cameras/scanners) - to implement capture, preprocessing and quality grading compatible with ISO/IEC 19794-6:2005.
Related standards
Keywords: ISO/IEC 19794-6:2005, iris image data, biometric data interchange formats, iris recognition, CBEFF, rectilinear iris format, polar iris format, image compression, JPEG2000, image preprocessing.
