Overview
ISO/TS 21957:2023 - "Road vehicles - Visibility - Specifications and test procedures for head-up displays (HUD)" provides a technology‑neutral framework of definitions, measurement methods and test procedures for automotive head‑up displays. It covers HUD design, ergonomics evaluation and verification for passenger cars, light trucks and commercial vehicles (including heavy trucks and buses). The specification excludes helmet‑mounted or head‑worn devices (e.g., glasses). Key goals are consistent measurement of HUD virtual image properties and standardized laboratory and dynamic field assessments.
Key topics and technical requirements
- Definitions and reference systems: Establishes vehicle coordinate systems, eyellipse and eyebox definitions to locate driver and passenger eye points for repeatable measurements. (Related: ISO 4130, ISO 4513.)
- HUD image geometry and optics: Procedures to measure virtual image distance (optical accommodation), image orientation, display field of view (DFoV), image location and aspect ratio deviation.
- Visual performance metrics: Measurement of luminance, luminance non‑uniformity, contrast ratio, chromaticity, resolution, ghost images, distortion and rotation.
- Spatial and ergonomic parameters: Look‑down angle (LDA), look‑over angle (LOA), image height adjustment ranges, and geometric adjustability relative to driver head position.
- Test environments and procedures: Static bench tests, laboratory assessments with vehicle setup and mannequin eye points, and dynamic field operational assessments including environmental test conditions and vehicle setup guidance.
- System behavior: Requirements and test procedures for display adjustability, automatic adjustment accuracy and latency.
- Annexes and informative guidance: Subjective evaluation methods (e.g., 3D HUD), environmental interference factors, and alternative image generation technologies.
Applications and who uses this standard
ISO/TS 21957:2023 is intended for:
- Automotive OEMs and integration engineers integrating HUD systems into vehicle cabins.
- HUD suppliers and optical engine manufacturers validating performance (luminance, contrast, DFoV, eyebox).
- Test laboratories and certification bodies performing repeatable lab and field assessments.
- Human factors and ergonomics teams ensuring visibility, sightline alignment and driver comfort.
- Regulatory and safety stakeholders referencing standardized measurements for visibility and in‑vehicle information design.
Practical uses include design validation, bench testing, dynamic performance verification, human‑machine interface (HMI) ergonomics studies, and documentation for procurement or compliance.
Related standards
- ISO 4513 - eyellipse method for driver eye location
- ISO 4130 - vehicle 3‑D reference system
- ISO 16750 (Parts 2–5) - environmental testing for electronic equipment
- SAE J1757‑1 / J1757‑2 and ISO 15008 - referenced for image readability and related visual performance metrics
Keywords: ISO TS 21957, head‑up display standard, HUD testing, HUD measurement, automotive HUD, eyellipse, eyebox, HUD luminance, HUD field of view, HUD ergonomics.