Multi-factor Analysis of Reflection from Granite Surfaces

Many earlier experiments have shown that reflection from rock surfaces depends upon surface roughness, incidence zenith angle, viewing zenith angle, incidence azimuth and viewing azimuth. However, no research exists showing the interaction effects of these variables. Using granite as a model surface, we have designed an orthogonal, two level test having seven factors. Analysis of variance shows that surface roughness, relative viewing azimuth, and the interaction between these two factors are the largest sources of variance in our experiment. Hence we should include the interaction term in reflection models of granite.