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This paper presents development and application of a new software solution for stitching surface three-dimensional topography data where best matching positions are detected through maximization of a cross-correlation function. Differently from other stitching software tools developed in the past, the one here presented is based not on colour gradients but on matching of physical coordinates. The developed routine fully compensates positioning errors occurring when the measuring instrument is displaced relative to the surface. Qualitative as well as quantitative analyses were carried out in order to verify the applicability of the stitching process. Both synthetic and real scanned surfaces were used for testing. It was demonstrated that misalignments after software compensation are negligible: sub-pixel level inaccuracies, with absolute deviations <0.2%, were in fact verified when stitching two images. The method was developed specifically for atomic force microscopy, but can be effectively applied to any 3D topography measuring instrument. [ABSTRACT FROM AUTHOR]

The paper presents implementation and validation of a method for accurate imaging of three-dimensional surface topographies, developed for AFM metrology but in principle applicable to the whole family of scanning probe microscopes. The method provides correction of the vertical drift, and can be applied to any AFM scanner system, without need for modification of the instrument hardware. Surface correction is performed based on two topographies taken with mutually orthogonal scanning directions. Reconstruction is rapidly achieved through the use of an automatic routine developed for the purpose. The proposed method has been tested by using an optical and a silicon flat and a high precision cylindrical artefact. Examples of successful reconstructions on different samples are also reported within the paper. [ABSTRACT FROM AUTHOR]

In this work, the interaction between 3D optical scanners and objects realized with different materials and colours was investigated. The interaction is mainly related to the translucency of some materials, such as polymers, which is a category of materials in ever-increasing demand by industry. At the same time, the increase of the geometrical complexity of manufactured parts raises the need for the use of 3D optical scanners thanks to their rapidity and effectiveness. Translucency causes a subsurface scattering effect that has been modelled for certain cases and affects the dimensional accuracy of measurements, as well as the quality of reconstruction. Recently, an investigation considered its effect in dimensional verification using a structured light scanner with fringe projection. In this work, the investigation is extended to other 3D optical scanners exploiting different measuring principles: laser, structured light based on phase shifting and gray code, and photogrammetry. This was done in order to study how the subsurface scattering effect can vary with the materials, colours, and also the measuring principle used. To this end, five miniature step gauges made of different polymers and colours were used, and the effects due to their different optical properties investigated. The analysis focused on dimensional verification of bidirectional lengths, first calibrated with a traceable coordinate measuring machine. The quality of the reconstruction was also evaluated through the flatness values. According to the results obtained, translucency of materials has a dual and significant effect: a measurement bias and an increase of the uncertainty due to the different quality of reconstruction retrieved. Thus, it has to be considered properly for each case. [ABSTRACT FROM AUTHOR]

Engineered surfaces containing lubrication pockets and directional surface texture can decrease wear and friction in sliding or rolling contacts. A new generation of multifunctional (MUFU) surfaces has been created by hard machining followed by robot-assisted polishing. The production method allows for a large degree of freedom in specifying surface topography defined by frequency, depth and volume of the lubricant retention valleys, as well as the amount of load bearing area and the surface roughness. The surfaces cannot readily be characterized by means of conventional roughness parameters due to the multi-process production method involved. A series of MUFU surfaces were characterized by using the ISO 13565 standard for stratified surfaces and it is shown that the standard in some cases is inadequate for the characterization of a MUFU surface. To improve the filtering of MUFU surfaces, the robust Gaussian regression filtering technique described in ISO 16610-31 is analyzed and discussed. By slight modifications it is shown how the robust Gaussian regression filter can be applied to remove the form and find a suitable reference surface for further characterization of the MUFU surfaces--even for surfaces with a moderate to small plateau region. [ABSTRACT FROM AUTHOR]