Overview
ISO/IEC 19794-6:2011 - "Information technology - Biometric data interchange formats - Part 6: Iris image data" defines a standardized iris image data format for biometric enrolment, verification and identification systems. The standard specifies how iris images and associated metadata are stored and exchanged so devices and systems from different vendors can interoperate. It covers uncompressed and compressed image representations, cropped and masked variants, and the structure of biometric data records and headers.
Key topics and technical requirements
- Image types defined: UNCROPPED, VGA (640×480), CROPPED (iris-centered), and CROPPED_AND_MASKED (with non-iris regions masked).
- Image content rules: Geometric structure, margins relative to the iris radius (R), and required pixel organization (row-major order). Margins are expressed in units of R (e.g., ≥0.6R horizontally, ≥0.2R vertically).
- Pixel and color requirements: Uncompressed images use 8‑bit pixel depth (grayscale). Other bit depths must be encoded using PNG or JPEG2000.
- Compression: Supports lossless PNG (ISO/IEC 15948) and JPEG 2000 (ISO/IEC 15444) as normative compression options. Typical compressed sizes are provided (e.g., VGA uncompressed ~307 kB, cropped/compact JPEG2000 in the single-digit kB range for some use cases).
- Record and header structure: Clause 7 defines the biometric data record (BDIR) layout, image representation headers and metadata required for conformance and interoperability.
- Conformance and testing: Systems and records must meet normative structure and value relationships; conformance criteria and testing methodology are addressed (Annex A). Implementation Conformance Statements (ICS) describe supported features.
- What it does not specify: Optical camera specifications, photometric capture conditions, or enrolment workflows-those are out of scope.
Practical applications and typical users
ISO/IEC 19794-6 is used to ensure consistent exchange and storage of iris imagery across systems:
- System integrators and software developers building iris recognition systems and middleware.
- Device manufacturers (iris cameras, access control terminals, kiosks, smartcards) needing interoperable image formats.
- Government and border-control agencies implementing biometric enrolment, ID programs, e-passports, and watchlists.
- Biometric vendors and labs conducting matching, evaluation, and forensic analysis.
- Standards and compliance teams creating Implementation Conformance Statements and test suites.
The standard is especially useful where storage space or transmission bandwidth is constrained (smartcards, mobile ID, networked enrolment) and when interoperability across vendors is required.
Related standards
Keywords: ISO/IEC 19794-6:2011, iris image data, biometric data interchange formats, JPEG2000, PNG, iris recognition, cropped iris image, region-of-interest masking, biometric enrolment, VGA iris image.
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