COMPREHENSIVE STUDY OF PARAMETERS FOR CHARACTERIZING 3-DIMENSIONAL SURFACE-TOPOGRAPHY .4. PARAMETERS FOR CHARACTERIZING SPATIAL AND HYBRID PROPERTIES

This is the last part in a series of reports describing a comprehensiv e study of parameters to characterise three-dimensional surface topogr aphy. In conjunction with other parts of the report, this paper deals with parameters used to characterise spatial and hybrid properties of surface topography in three dimensions. Some statistical and signal pr ocessing techniques, e.g. two-dimensional autocorrelation function and spectral analysis, which are used to extract spatial and hybrid param eters, are introduced in the paper. Some spatial and hybrid parameters are recommended to be included in a primary set to serve for a compre hensive characterization of surface topography in three dimensions. Th e definitions and algorithms of the parameters are given in the paper. The feasibility and significance of the parameters in characterising surface topography in three dimensions are addressed by conducting exp eriments on a wide range of engineered surfaces. Ah discussions in the paper are based on theoretical and experimental justification.