Reflectance parameter estimation and its application to surface inspection

In this paper, we present a reflectance parameter estimation technique by u sing range and brightness and its relation, i.e. reflectance function. Beca use the reflectance function is quite complex and nonlinear, the parameter estimation is not straightforward. Therefore, we choose a coarse-to-fine ap proach to estimate the reflectance parameters. In the coarse step, the surf ace roughness is coarsely estimated by applying the partial linear method t o the simplified Torrance-Sparrow reflectance model. Then the genetic algor ithm is applied to the Wolff's reflectance model for more accurate estimati on. In order to extend the dynamic range of CCD of laser finder, in this pa per, we introduce the pseudo-brightness instead of the brightness. The prop osed reflectance parameter estimation algorithm is tested on the synthesize d and real data. The results show that the estimated parameter using the sy nthesized data is very accurate. We also apply the proposed algorithm to in spect the flaws on shiny surfaces, which would be a promising method to dis criminate between a wide range of surfaces.