ISO 13322-2:2021

Overview

ISO 13322-2:2021 - "Particle size analysis - Image analysis methods - Part 2: Dynamic image analysis methods" - specifies procedures and guidance for measuring particle size and shape from images of particles in relative motion. The standard covers how to transfer captured images of moving particles into binary images for downstream analysis (with static-image processing described in ISO 13322-1). It addresses instrument design, image capture, motion-related artifacts, and qualification of dynamic image analysers for reliable particle size distribution measurements.

Key topics and technical requirements

• Dynamic image capture: Guidance on creating images of moving particles using optical capture devices while minimizing or correcting motion effects (e.g., motion blur).
• Illumination and optics: Requirements and recommendations for illumination timing, direction, spectral properties, stability, lens design, magnification and optical resolution to ensure accurate imaging.
• Image acquisition devices: Considerations for matrix and line-scan cameras, exposure time, frame/line rate and sensor resolution.
• Particle motion & positioning: Handling relative particle movement, depth of field (axial position), orientation and segregation during capture.
• Image processing: Segmentation methods, image correction, particle classification and conversion of binary images to meaningful particle descriptors (size, shape).
• Calibration and instrument qualification: Use of particulate reference materials, tests for trueness, repeatability and intermediate precision, and operational qualification procedures.
• Sample preparation and dispersion: Guidelines on sample splitting, reducing touching particles, number of particles to count, and dispersing techniques to achieve representative results.
• Statistical reporting and test reports: Requirements for reporting particle size distributions (by number and by volume), system-specific corrections and comprehensive test reporting.
• Supporting annexes: The standard includes annexes on theoretical background, recommended particle velocities/exposure times, threshold effects, reference material requirements, robustness, and typical capture systems.

Practical applications

ISO 13322-2 is applied wherever high-throughput, image-based particle characterization is needed:

• Quality control and R&D in pharmaceuticals, powders, food, cosmetics, ceramics and mining
• Process monitoring in manufacturing lines and material handling
• Research labs studying aerosols, suspensions or particulate blends Dynamic image analysis is especially valuable when large particle counts and particle shape information are required in addition to size distributions.

Who should use this standard

• Instrument manufacturers designing dynamic image analysers
• Analytical and QA/QC laboratories validating particle size measurement methods
• Process engineers and researchers needing standardized procedures for image-based particle sizing

Related standards

• ISO 13322-1 - Image analysis methods (static image analysis) - complementary for post-processing.
• Other particle sizing standards (e.g., sieving, laser diffraction) can be used alongside ISO 13322-2 depending on material and measurement goals.

Keywords: ISO 13322-2, dynamic image analysis, particle size analysis, image analysis methods, motion blur, depth of field, instrument qualification, particle size distribution.