New (Digital) Technique for Areal Measurements of Stonewall Surface Roughness

Abstract

This study revisits a method introduced in the 1990 s that was deployed to measure surface roughness through profiles on rock blocks. Measurements were originally taken directly in the field using a micro-roughness meter or a simple profile gauge. The roughness index was obtained in the "deviograms" method utilizing the standard deviation of differences between 38 adjacent height measurements. The original method used four profiles of depth, each 19 cm in length taken at 5 mm intervals, for each block. A minimum of 10 surfaces are needed to measure the magnitude and scale of roughness, as of boulders. In the current study, this recognized method is applied to a newly introduced method employing the O-IDIP method, which measures areal surface coloration, including standard deviation of lightness and chroma, enabling for roughness estimation. An analysis of the results obtained using both methods conveys similar and statistically significant linear correlations at the 95 and 99% levels of significance. This indicates that the O-IDIP method can be employed for areal measurement of surface roughness and can be deployed on stonewalls.