Overview
EN ISO 16610-61:2015 - Geometrical product specification (GPS) - Filtration - Part 61: Linear areal filters - Gaussian filters (ISO 16610-61:2015) defines metrological rules for linear areal Gaussian filters used in surface texture analysis. The standard specifies rotationally symmetric Gaussian weighting functions and how to separate a surface into long-wave (form/shape) and short-wave (texture) components for nominal planar and nominal cylindrical surfaces.
Key topics
- Filter type and scope
- Linear areal Gaussian filters for nominal planar surfaces and nominal cylindrical surfaces.
- Rotationally symmetric filtration and profile extraction for circumferential lines.
- Weighting function
- The areal weighting function is a rotationally symmetric Gaussian function defined with a cut-off wavelength (λ, nesting index). A constant parameter is specified so that the filter transmits 50% of amplitude at the cut-off.
- Separable weighting functions and implications for implementation are addressed.
- Transmission characteristics
- Defined transmission characteristics for both the long-wave component and the short-wave component - i.e., how different spatial wavelengths are attenuated or passed by the filter.
- Cylindrical filtration
- Definitions for undulations per revolution (UPR) and the undulation cut-off (nesting index) used when filtering circumferential line extractions from cylindrical surfaces.
- Normative references and context
- Built on other parts of ISO 16610 (Parts 1, 20, 21, 60) and uses GPS principles (ISO/TR 14638, ISO 8015). Annexes provide examples, concept diagrams and relationships to GPS matrix models.
Applications
- Surface metrology and roughness analysis for quality control in precision manufacturing.
- Filtering of measured areal data from optical profilers, white-light interferometers and tactile areal scanners.
- Use in industries where surface texture affects function: automotive, aerospace, bearings, seals, medical devices, and optics.
- Standardizes how practitioners separate form and texture for repeatable specification, comparison and process control.
Who should use it
- Metrologists, QA and R&D engineers performing areal surface characterization.
- Calibration and testing laboratories implementing GPS-compliant filtration.
- Manufacturers of surface measurement instruments and analysis software.
- Standards committees and technical authors referencing GPS filtration methods.
Related standards
- ISO 16610-1, -20, -21, -60 (filtration basics, profile filters, Gaussian profile filters, areal filter concepts)
- ISO/IEC Guide 99 (VIM) and ISO/IEC Guide 98-3 (GUM) for metrological vocabulary and uncertainty guidance
Keywords: EN ISO 16610-61:2015, Gaussian filters, linear areal filters, GPS filtration, cut-off wavelength, nesting index, areal surface metrology, UPR.