Patent ID: 8913251
Filing Date: 2014-12-16
Classification: G01B,G01N

Abstract:
1. A method of estimating both of a surface roughness value and a sub-surface scattering property of a material, the method comprising: illuminating the material with a light beam with controlled coherence properties at multiple incident angles; recording multiple speckle patterns, each speckle pattern being recorded for a respective one of the multiple incident angles; and estimating both of a surface roughness value and a sub-surface scattering property of the material by calculations using the multiple speckle patterns and the incident angle for each such speckle pattern, wherein the estimating step comprises: calculating, for each of the multiple speckle patterns, a numeric value for a parameter; fitting the numeric values to a model, wherein the model defines relatedness amongst all of the parameter, surface roughness, the sub-surface scattering property, and the incident angle; and estimating both of the surface roughness value and the sub-surface scattering property of the material from the fitted model.