ISO/IEC 39794-5:2019

Overview

ISO/IEC 39794-5:2019 defines extensible biometric data interchange formats specifically for face image data. The standard specifies two interoperable representations: a tagged binary format based on an extensible ASN.1 specification and a textual XML schema that can carry the same information. It also provides examples of data record contents, recommended and application‑specific acquisition practices, and conformance test assertions and procedures to validate implementations.

Keywords: ISO/IEC 39794-5:2019, face image data, extensible biometric data interchange formats, ASN.1, XML schema, biometric interoperability, conformance testing

Key Topics and Technical Requirements

• Dual representation formats: a binary tagged format (ASN.1) and an equivalent XML schema for textual interchange.
• Modality‑specific data blocks: structured elements for face images such as image representation, capture device, version, session and derived‑from metadata.
• Image characteristics and measurements: image size, face/head measurements (inter‑eye distance, head width, head length), colour space and reference colour mapping.
• 2D and 3D support: separate blocks for 2D and 3D representations, including 3D vertices, texture maps, coordinate systems and resolution parameters.
• Landmarks and pose: detailed landmark definitions (MPEG4 points, anthropometric landmarks), pose angle and angle uncertainty blocks for accurate geometric description.
• Quality and processing metadata: quality blocks, post‑acquisition processing, lossy transformation attempts, and PAD (presentation attack detection) metadata.
• Identity and biometric attributes: identity metadata and attributes such as gender, eye colour, hair colour, subject height.
• Acquisition best practices and application requirements: recommendations for capture, device specifics and certification identifiers.
• Conformance framework: test assertions and procedures to ensure interoperability and compliance across implementations.

Practical Applications and Who Uses This Standard

ISO/IEC 39794-5:2019 is used where robust, interoperable exchange of face image data is required:

• Biometric device manufacturers (cameras, 3D scanners) implementing standard output formats.
• Software developers and system integrators building face recognition, enrolment, and verification systems.
• Government agencies and border control for standardized face image records in identity documents and immigration workflows.
• Law enforcement and forensics requiring consistent metadata (landmarks, pose, quality) for matching and analysis.
• Test labs and certification bodies conducting conformance testing and interoperability evaluations.

Adopting this standard improves biometric interoperability, preserves rich metadata for analytics, and supports reliable conformance testing.

Related Standards

• Other parts of the ISO/IEC 39794 series and complementary ISO/IEC biometric interchange standards address additional modalities, global interoperability and related conformance frameworks.