Overview
ISO 16610-30:2015 - "Geometrical product specifications (GPS) - Filtration - Part 30: Robust profile filters: Basic concepts" defines the basic concepts for robust profile filters used in surface metrology and geometrical product specification. The standard explains what makes a filter robust (insensitivity to specific input phenomena such as outliers, scratches or steps), how robustness is measured relative to linear profile filters, and the main approaches used to achieve robustness in profile filtration.
Key topics and technical requirements
- Scope and reference model
- Establishes robust profile filters relative to the reference class of linear profile filters (ISO 16610-20).
- Normative references include ISO 16610-1, ISO 16610-20 and ISO/IEC Guide 99 (VIM).
- Terms and definitions
- Core terms: robustness, profile discontinuity (slope, step, spike), metric, statistical estimator, M-estimator, Bayesian estimator, median absolute deviation (MAD).
- Metric-based methods
- Use of different norms (L1, L2, L∞) to change sensitivity to discontinuities. The document links common roughness parameters to norms: Ra (L1), Rq (L2), Rz (L∞).
- Statistical-based methods
- M‑estimators: weight points using an influence function (Huber, biweight, etc.) - typically implemented iteratively.
- Bayesian estimators: model representative profile and discontinuity components, compute posterior probabilities to weight points.
- MAD as a robust scale estimate for setting scale parameters.
- Pre-processing methods
- Removing or reducing unwanted phenomena before filtration to make standard filters robust.
- Examples include scale-space and wavelet pre-processing (scale-space techniques referenced in ISO 16610-49).
Practical applications and users
- Purpose: to reduce distortion from outliers, scratches, spikes and steps when extracting representative surface profile components (low-pass response) and computing surface texture parameters.
- Typical users:
- Metrologists and quality engineers performing surface texture analysis and filtering.
- Instrument and software manufacturers implementing filtration algorithms in profilometers and surface-analysis tools.
- Standards developers and test laboratories aligning measurement procedures with ISO GPS principles.
- Practical benefits:
- More reliable roughness parameters and profile characterization in the presence of defects.
- Reusable pre-processing approaches that work with different profile filters.
- Guidance for implementing robust filters (metric, statistical, pre-processing strategies).
Related standards
- ISO 16610-1 (Overview and basic concepts)
- ISO 16610-20 (Linear profile filters: Basic concepts)
- ISO 16610-31, -32 (Robust filter implementations: Gaussian regression and spline)
- ISO 16610-49 (Morphological filters: Scale space techniques)
Keywords: ISO 16610-30:2015, robust profile filters, filtration, GPS, profile discontinuities, M-estimator, Bayesian estimator, L1-norm, scale-space, median absolute deviation, surface metrology.