INTRODUCTION: Ski base structure, i.e., the topography of ski bases, influences their sliding properties. This paper proposes comparison methods for instruments that measure ski base structure using multiscale analyses and characterizations. One is a traditional laboratory instrument, the other can be used in the field. Brown (2021) describes four principles, two axioms on scales and characterizations and two corollaries on measurement and statistics. Value in surface metrology can come from ability to discriminate topographies that are processed or that perform differently. Ski base topographies, similar to most, have important irregular components that defy apt characterization or modeling with conventional methods. METHODS: Multiscale analyses and characterizations (Brown et al. 2018) are used with univariate ANOVA tests to test discrimination strengths. This is done by comparing different kinds of measurements and characterizations on ski bases with different preparations. Conventional laboratory measurements use interferometric, confocal, focus variation, and scanning laser height sensors to interpret light reflected from bases as topographic height data. These generally require stationary measurement instruments installed in laboratories. A new instrument uses ray tracing from multiple light sources to infer fields of vectors normal to topographies and reconstruct height maps. It interposes a gel and membrane between the light and surface. It is portable and could be used in a wax room on at a race start. RESULTS: Area-scale characterizations as well as commonly used height parameters, developed area, and average slope parameters (MountainsMap by Digital Surf, also ISO 251708-2, ASME B46.1) show differences between instruments used for measurements made at similar locations on prepared skis. Confidence levels of discriminations between different bases preps for several measurement devices and different characterization parameters are compared. DISCUSSION/CONCLUSION: The four principles for surface metrology (Brown 2021) are covered in the methods in the context of comparing the methods. It is not known what characterizations might be pertinent for characterizing base structures for correlating with friction. It is suggested that recent work on multiscale curvature characterizations for feature shape and anisotropy might be useful as well as multiscale volumetric capacity, like filling scale.
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