Laser Line Triangulation Profilometry Principles on Continuous Paperboard Substrates
Inline blue laser triangulation measures paperboard surface topography at high speeds by overcoming fiber light penetration and isolating mechanical flutter.
Gaussian Filter
Mathematical Smoothing
A mathematical operator that modifies a signal by weighting neighboring data points according to a normal distribution curve is used to smooth measurement profiles. In paper and paperboard analysis, applying a gaussian filter helps remove high-frequency noise from surface roughness scans. This process allows engineers to evaluate the underlying micro-contour of the sheet without interference from fine-scale surface textures.
The filter uses a specified cutoff wavelength to determine which surface variations are suppressed.
Roughness Separation
Metrology instruments rely on this technique to distinguish between macro-scale waviness and micro-scale roughness. By separating these two components, the gaussian filter provides a clearer picture of how a paperboard surface will interact with printing ink or coatings. Waviness affects how the sheet feeds through a press, while roughness determines the gloss and ink transfer characteristics of the surface.
This dual analysis is essential for maintaining consistent print quality on high-speed presses.
Boundary Limitation
Numerical limitations of the algorithm appear at the ends of the scan line. The gaussian filter cannot process the margins of a dataset without using specialized extrapolation methods. This restriction means that the very edge of a paper sample cannot be profiled with the same accuracy as the center.