ISO 25178-71:2017

Overview

ISO 25178-71:2017 - part of the ISO 25178 areal surface texture series - defines software measurement standards for verifying the software components of areal surface texture measuring instruments. The standard specifies two types of etalons: Type S1 (softgauge / reference data) and Type S2 (reference software), and it standardizes the SDF file format used for Type S1 reference data. ISO 25178-71 supports calibration and software verification in the areal surface texture chain (chain link G).

Key topics and requirements

• Type S1 (softgauge): A computer data file containing a digital representation of a scale-limited areal surface. S1 files are used as input to the software under test; results are compared to certified values from the softgauge.
• Type S2 (reference software): Traceable reference implementations that produce certified parameter results from common data sets. S2 software establishes traceability back to mathematically designed synthetic data where possible.
• SDF file format: The standard defines the SDF extension and a three-record file protocol (Header, Data area, Trailer). Header fields include version, instrument manufacturer identifier, creation/modification timestamps, number of points per profile (M) and number of profiles (N), X/Y/Z scale factors, Z resolution, data/compression types and checksum type.
• Measurement intent: Files and reference software are considered scale-limited surfaces (S-F or S-L); no form removal is to be applied prior to testing the software under test.
• Traceability and uncertainty: Reference software and certified S1 data are intended to support traceable comparisons with known specification uncertainty.

Applications and users

ISO 25178-71:2017 is applicable for:

• Instrument manufacturers validating filter algorithms, parameter calculations and other software modules in areal surface texture instruments.
• Calibration laboratories and accreditation bodies performing software verification and issuing certificates for softgauges.
• Metrology engineers and quality teams ensuring measurement software conforms to GPS (geometrical product specification) requirements.
• Research and academia using standardized areal datasets and reference implementations for method development and cross-lab comparisons.

Keywords: ISO 25178-71, surface texture areal, software measurement standards, softgauge, SDF file format, Type S1, Type S2, areal surface texture calibration, reference software, metrology.

Related standards

• ISO 25178-2 (terms and parameters)
• ISO 25178-3 (specification operators)
• ISO 5436-2 (profile method software measurement standards)
• ISO 16610 (filtration)
• ISO 17450-2, ISO/IEC Guide 98-1, ISO/IEC Guide 99 (metrology concepts and uncertainty)