Thickness monitoring of thin lamellae by optical measurement method

To date, dial or digital calipers are mostly used for lumber size measurement. The goal of this project was to design a low-cost scanner capable of measuring the thickness of the thin lamellae after a re-sawing operation. The proposed system was able to detect and reject all elements that do not meet dimensional standards in-process. A data-processing algorithm based on sandwiching measurements from four laser displacement sensors was evaluated. It is shown that for measurement of highly porous wood species it is necessary to utilize a special algorithm reducing the effect of anatomical roughness upon the thickness profile. The filtration method proposed excludes all local valleys due to open vessels or other wood anatomical formations from the primary surface profiles.