A Laser Microreliefmeter

Abstract

ABSTRACT Alaser microreliefmeter was developed for field and laboratory measurements of surface roughness. The microreliefmeter is a laser probe which is moved along a transect by a microprocessor-based motion control device. The vertical surface coordinate is determined with the laser instrument with a maximum accuracy of 0.25 mm using the principle of triangulation. The horizontal surface coordinates, representing the position of the laser probe on the transect and the transect position on the plot, are respectively determined by the motion control device with an accuracy of about 0.001 mm or better and a metric tape measure with accuracy of about 0.5 mm. Performance tests on soil surfaces yielded more consistent and reproducible values relative to those obtained by point gauge measurements. Small errors in elevation measurements are made on surfaces with rapidly varying, non-uniform or discontinuous slopes. The microreliefmeter is capable of measuring 2.6 m long transects, having different data point densities, and taking data at a rate of 27 observations/s. It is not affected by differences in soil surface albedo or temperature.