ISO/IEC 39794-9:2021

Overview

ISO/IEC 39794-9:2021 specifies extensible biometric data interchange formats for vascular image data (for example, palm vascular images). It defines parallel encodings - a tagged binary format based on ASN.1 and a textual format based on an XML Schema - that are capable of representing the same information. The standard also provides examples of data records, capture recommendations and best practices, and conformance test assertions and procedures to ensure interoperability.

Keywords: ISO/IEC 39794-9, vascular image data, extensible biometric data interchange formats, ASN.1, XML, biometric interoperability

Key topics and technical requirements

• Dual encoding support: Tagged binary encoding using ASN.1 (TLV) and XML encoding via XML Schema Definition to support both constrained (bandwidth/storage) and modern IT environments.
• Data model and blocks: Abstract data elements and structured blocks such as Version, Representation, Position, Image data format, Capture date/time, Capture device (model, technology, certification), Quality, Scan resolution, Bit-depth, Pixel aspect ratio, Rotation/flip, Illumination, Imaging method, Background, PAD, Segmentation, Annotation, Comment, and Vendor-specific blocks.
• Capture recommendations: Guidelines on image area, illumination, normalization of projection, and handling occlusions by opaque artifacts to improve acquisition consistency and matching performance.
• Image coordinate system: Standard pose and object coordinate system considerations for consistent spatial referencing across devices.
• Image representation constraints: Requirements and recommendations for pixel aspect ratio, bit-depth, spatial sampling rate and supported image formats to preserve vascular detail.
• Conformance: Test assertions and conformance test methodology to validate compliant implementations and ensure interoperability between systems.

Applications and practical value

• Biometric enrollment and verification: Exchange of raw or processed vascular images between capture devices, identification systems, and verification systems.
• Interoperability across vendors: Enables storage and transfer of vascular images (e.g., on ID documents or databases) so diverse algorithms and systems can interoperate.
• Forensics, healthcare access control, and secure ID: Useful where vascular pattern-based identification is required and image-level detail is necessary.
• Flexible implementation: Supports both high-fidelity image storage (for algorithm development) and compact binary representations (for constrained environments).

Who should use this standard

• Biometric system integrators and vendors implementing vascular image capture, storage, or matching
• Government and identity authorities issuing biometric documents
• Software developers creating biometric middleware, matching algorithms, or interchange tools
• Test labs validating conformance and interoperability

Related standards

• ISO/IEC 39794-1 (Framework)
• Prior parts in ISO/IEC 19794 series (earlier biometric interchange formats)
• ISO/IEC 15444-1 (JPEG 2000), ISO/IEC 14495-1, ISO/IEC 15948 (PNG) - referenced for image coding and compression

This standard is essential for implementing interoperable, extensible vascular image data exchange in biometric systems.