Surface metrology open profile Gaussian filter

Procedures and functions for surface open profile filtering using Gaussian filter by ISO 16610-21.

ISO 16610-21 Open profile Gaussian filter
The library contains functions which implement open profile Gaussian convolution filter according ISO 16610-21:2011. The filter is intended to use for separation of short and long wave component profiles from primary surface profile in surface metrology. Roughness parameters can be evaluated from short wave component profile. Waviness parameters and form, position and run-out deviations can be evaluated from long wave component profile. Cut-off wavelength lc is the criterion for primary profile separation. The filter uses own function for convolution of open profile and Gaussian weight function. There are available extrapolation methods according ISO/TS 16610-28 for end effects correction; zero padding and linear extrapolation. Other options are end point value padding and profile end connection. Input arguments of filter function are primary profile values line vector P=[y1 y2…yn] and cut-off wavelength lc. An output argument is filtered profile line vector W=[y1 y2…yn]. The library contains a procedure for demonstration of filter application using attached real profile, or a harmonic sine profile generated on the bases of entered parameters. Other library component is the function for standardized transmission calculation and the procedure for standardized transmission characteristic plotting.
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Main function:
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- The function [wprofile] = gfltlin( pprofile,dx,lcut ) for open profile filtering.
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Auxiliary, testing and demonstrating procedures:
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- The function [weight] = gwfisolin( x,lc ) for Gaussian weight function value calculation
- The function [wprofile] = convsym( pprofile,weightfunction,padding ) for profile and weight function convolution.
- The function [yvector,xvector,dx] = linprogen( length,n,lambda,amplitude ) for harmonic open profile generating.
- The procedure gwfisolintest.m for open profile Gaussian filter weight function displaying
- The function [transmission] = gfltlwlint( l,lc ) for open profile Gaussian filter long wave component approximated
transmission calculation.
- The procedure gfltlwlinchar.m for long wave component transmission characteristic displaying.
- The function [transmission] = gfltswlint( l,lc ) for open profile Gaussian filter short wave component approximated
transmission calculation.
- The procedure gfltswlinchar.m for short wave component transmission characteristic displaying.
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and
- The procedure howtousegfltlin for demonstration how to use the function gwfisolin() for open profile filtering