Expert versus multi-sensor evaluation of wood samples after short term weathering
A Sandak, J Sandak, I Burud, L Ross Gobakken, M Noël
Understanding the influence of weathering factors and the material degradation mechanisms are fundamental for modelling the weathering process of wood. The goal of this work was to investigate the combined effect of time and exposure on the physical-chemical mechanisms of wood weathering. Four exposure directions (North, South, East and West) were investigated. Experimental tests were performed for 28 days through July, which according to previous research is considered as the most severe period for weathering of wood micro-sections. Measurements of samples included: photogrammetry, near and mid infrared spectroscopy, colour measurement, SEM observation and visual assessment. Parameters obtained by measuring the weathered surfaces with various sensors were compared with the subjective visual assessment by an expert evaluator. Algorithm based on multi sensor data fusion allowing calculation of the “weathering indicator” was developed. It was concluded that the progress of degradation is clearly correlated to the solar radiation and the exposure direction seems to have a clear effect on the degradation intensity.
Keywords: wood weathering, service life performance, multi-sensor approach, visual assessment