ISO/IEC 39794-6:2021

Overview

ISO/IEC 39794-6:2021 - "Information technology - Extensible biometric data interchange formats - Part 6: Iris image data" defines an extensible, interoperable data format for exchanging iris image data. The standard specifies both a tagged binary (ASN.1 / DER) encoding and an XML schema encoding capable of holding the same iris image information. It covers image representations (raw intensity arrays, optional compression), record structure, examples, acquisition recommendations, and conformance test assertions and procedures.

Key topics and technical requirements

• Extensible encodings: Formal structure described in ASN.1 (binary TLV) and an equivalent XML Schema for textual exchange. (Annex A contains the formal schemas.)
• Image storage formats: Iris images are stored as arrays of intensity values, optionally compressed with ISO/IEC 15948 (PNG) or ISO/IEC 15444-1 (JPEG 2000).
• Cropped and masked images: Supports uncropped full-eye images, cropped images centered on the iris, and cropped+masked images with region-of-interest masking (e.g., to exclude sclera or eyelids).
• Record elements: Defines abstract data elements such as eye label, bit depth, orientation, capture date/time, capture device block, quality metrics, localization, roll angle and PAD (presentation attack detection) data.
• Conformance testing: Specifies test assertions and procedures to verify structural correctness, internal consistency (field types/values), and semantic assertions for data records (Annex C). It does not cover biometric performance, security robustness, or non-compliant system testing.
• Scope limitations: The standard explicitly does not impose camera optical specs, photometric image requirements, nor enrollment/workflow constraints.

Applications and who uses it

• Biometric system vendors - produce interoperable iris image records for exchange between devices and back-end systems.
• System integrators & solution architects - standardize storage, transmission and parsing of iris data across components.
• Governments & border control agencies - exchange iris records in enrolment, watchlist, and identity verification systems.
• Test labs & QA teams - implement conformance tests to validate data records and interoperability.
• Researchers & forensic analysts - use standardized representations to compare algorithms and datasets.

Practical benefits include improved interoperability, options for compact representations to reduce storage/bandwidth, and an extensible framework that accommodates future attributes like PAD and image-quality metadata.

Related standards

• ISO/IEC 39794-1 (framework)
• ISO/IEC 15948 (PNG)
• ISO/IEC 15444-1 (JPEG 2000)
• ISO/IEC 8824‑1 / 8825‑1 (ASN.1 and encoding rules)
• ISO/IEC 2382-37 (biometrics vocabulary)

Using ISO/IEC 39794-6:2021 helps organizations implement robust, future-proof, and interoperable iris image interchange consistent with modern biometric data interchange practices.