THE EFFECT OF GAUSSIAN FILTER LONG WAVELENGTH CUTOFF λc IN TOPOGRAPHY MEASUREMENTS AND COMPARISONS

摘要

Topography measurements play an important role in surface and nano-metrology, production quality control, tribology, bio-technology and forensic science. Dozens of surface parameters are specified in national and international standards. Although none of these are designed for topography comparisons, statistical methods of auto- and cross-correlation function (ACF and CCF) may be adapted to this purpose. At the National Institute of Standards and Technology (NIST), we use the CCF maximum (CCF_(max)) and a new parameter we call the profile (or topography) difference, D_s, to quantify differences between 2D profiles or between 3D topographies. The CCF_(max) is the value of the cross-correlation function when the two correlated 2D profiles or 3D topographies, A and B, are located in their maximum correlation position (or "zero-shift" position) after registration. At this position, profile (or topography) difference, B - A, is calculated.