Overview
ISO 18251-2:2023 specifies a standardized test method for the integrated performance of infrared (IR) imaging systems and related equipment used in non-destructive testing (NDT). It complements ISO 18251-1 by defining how to measure key performance parameters of a thermal camera system and associated test fixtures, and helps users and purchasers select an appropriate infrared thermography system for a given inspection task.
Key topics and technical requirements
- Scope and environment
- Tests are performed indoors in a stable environment (typical range 20 °C to 25 °C, relative humidity 40–80%) and without shocks, vibrations or interfering radiation.
- Required test equipment
- Blackbody simulator (high emissivity ≥ 0.95; stability and uniformity requirements, e.g. ≤ ±0.1 °C at ≤100 °C)
- Targets: common target, MRTD four‑shot target (metal, black matt paint, aspect ratio 7:1), MDTD disk target (diameter 100–300 mm, hole 20–40 mm)
- Optical table, positioning stage, infrared radiometer (range −20 °C to 500 °C; accuracy ±1 °C or ±1 %), optional collimator
- Performance parameters and test methods
- NETD (Noise Equivalent Temperature Difference) - evaluates sensor noise and thermal sensitivity using blackbody sources and frame statistics.
- MRTD (Minimum Resolvable Temperature Difference) - assesses spatial plus thermal resolving ability using the four‑shot target and visual criteria.
- MDTD (Minimum Detectable Temperature Difference) - evaluates smallest detectable thermal contrast using disk targets.
- Field of View (FOV), IFOV and spatial resolution, minimum working distance, maximum temperature measurement range, temperature measurement uniformity, and operating temperature range.
- Documentation
- Test specification, test report and test record requirements (including environment, instrument info, test data, signatures).
Applications and users
- Who benefits:
- Manufacturers of thermal cameras and thermographic systems - for product verification and performance claims.
- NDT service providers and inspection engineers - to select and validate equipment for industrial inspections (electrical, mechanical, composites, process equipment).
- Test laboratories and calibration facilities - for repeatable, auditable performance testing and acceptance.
- Procurement and quality assurance teams - to define acceptance criteria and compare candidate systems.
- Practical uses:
- Verifying camera sensitivity and resolution before in‑field inspections.
- Matching system capabilities to inspection tasks (detecting small delaminations, hot spots, or sub-surface defects).
- Ensuring traceable measurement procedures and consistent test reporting.
Related standards
- ISO 18251-1 (Characteristics of system and equipment)
- ISO 10878 (Infrared thermography - Vocabulary)
- ISO 10880 (Infrared thermographic testing - General principles)
Keywords: ISO 18251-2:2023, infrared thermography, non-destructive testing, NDT, thermal camera performance, NETD, MRTD, MDTD, blackbody simulator, test method.
Open preview (PDF)Non-destructive testing — Infrared thermography — Part 2: Test method for integrated performance of system and equipment
