Overview
ISO 13322-1:2014 - Particle size analysis - Image analysis methods - Part 1: Static image analysis methods defines requirements and guidance for using digital images to determine particle size distributions when particles are stationary (zero velocity relative to the optical axis). The standard covers digital images from light or electron detection systems and image evaluation methods based on complete pixel counts. It focuses on image acquisition factors that affect sizing accuracy, image analysis workflows, calibration, traceability and uncertainty estimation.
Key topics and requirements
The standard addresses practical and technical elements essential to robust particle size analysis by image:
- Scope and definitions: terms such as area equivalent diameter, Feret diameters, measurement frame and segmentation methods.
- Preparation for image capture: procedures to ensure particles are appropriately dispersed and fixed in the object plane; guidance on sampling the measurement field without motion effects.
- Sample presentation considerations: comments on sample splitting and the influence of touching particles, particle distribution and the number of particles required to meet precision targets.
- Quality of captured images: criteria such as contrast, pixels per particle, and imaging conditions that affect segmentation and measurement accuracy.
- Image analysis and segmentation: recommendations for edge detection, thresholding and complete-pixel-count evaluation methods for deriving particle metrics.
- Counting procedures: rules for handling particles cut by frame edges, touching particles and measurement conventions.
- Calibration and traceability: requirements for calibration verification, use of reference scales and estimation of systematic uncertainties.
- Accuracy and qualification: guidance on qualification tests, use of reference materials and estimating measurement uncertainty.
- Reporting: essential content for the test report and annexes (e.g., sample size estimation, common segmentation methods, process flow chart).
Applications and users
ISO 13322-1:2014 is applicable wherever static image-based particle sizing is used to produce particle size distributions. Typical applications include:
- Quality control and R&D for powders, suspensions and particulate materials
- Materials science and microscopy labs using light or electron imaging
- Instrument manufacturers, service labs and metrology teams establishing traceable measurements
Primary users:
- Analytical scientists and laboratory technicians performing image-based particle size analysis
- QA/QC managers specifying test methods and acceptance criteria
- Instrument vendors developing or verifying imaging-based particle sizing systems
Related standards
ISO 13322-1:2014 is essential reading for anyone implementing or validating static image analysis methods for particle size distribution with an emphasis on calibration, traceability and reproducible measurement practice.
