The Project

The project ‘Measurement and characterisation of areal surfaces’ carried out the following activities:

• Development of unambiguous definitions and specifications of algorithms for areal filtering and evaluating areal surface texture parameters;

• Implementation of reference software consistent with those definitions and specifications.

The project, supported by the National Measurement Office of the UK Department of Business, Innovation and Skills as part of its Engineering Measurement Programme, October 2008 − September 2011, was carried out by the National Physical Laboratory in partnership with the Centre for Precision Technologies at the University of Huddersfield.

Functions

The main functions of the reference software are as follows:

• Read data defining an S-F surface, i.e., a surface that has been S-filtered (to remove small scale components) and from which form has been removed (using an F-operator);

• Apply a Gaussian areal filter to the data defining an S-F surface to obtain data defining the corresponding S-L surface;

• Remove points from the data defining an S-L surface, i.e., ‘trim’ the data, to produce a surface defined on an area that has sides with lengths that are integer multiples of the cut-off wavelength for the Gaussian areal filter used to obtain the surface;

• Apply surface interpolation to the data defining the S-F and S-L surfaces to obtain continuous representations of those surfaces;

• Evaluate areal surface texture parameters in terms of these continuous representations of the S-F and S-L surfaces;

• Write the values of the areal surface texture parameters to a simple text output file.

Parameters

The areal surface texture parameters to be evaluated are from the S-parameter set and include height parameters Sq (root mean square height), Ssk (skewness), Sku (kurtosis), Sp (maximum peak height), Sv (maximum pit height), Sz (maximum height) and Sa (arithmetical mean height), spatial parameters Sal (autocorrelation length) and Str (texture aspect ratio), and hybrid parameters Sdq (root mean square gradient) and Sdr (developed interfacial area ratio).

Download

To download the reference software it is necessary to complete a simple registration form.

The reference software is provided as a compressed ZIP folder containing:

• A user manual describing how to install and use the software;

• A software user license agreement (REF: MSC/L/11/003);

• A 'readme' file;

• The executable Areal_SOFTGAUGES.exe;

• The auxiliary files
  • ISO5436_2_XML.dll,
  • xerces-c_2_7_vc80.dll,
  • npl_logo_black_large.jpg,
  • RomIntWeights.mat,
  • openX3P.mexw32,
  • writeX3P.mexw32, and
  • iso5436_2.xsd.

• An example data file with corresponding output file.

Users are encouraged to read the user manual and ‘readme' file before using the software.