Using Specularities for Recognition
Margarita Osadchy, David Jacobs, Ravi Ramamoorthi · 2003
Recognition systems have generally treated specular high-lights as noise. We show how to use these highlights as a positive source of information that improves recognition of shiny objects. This also enables us to recognize very challenging shiny transparent objects, such as wine glasses. Specifically, we show how to find highlights that are consis-tent with an hypothesized pose of an object of known 3D shape. We do this using only a qualitative description of highlight formation that is consistent with most models of specular reflection, so no specific knowledge of an object’s reflectance properties is needed. We first present a method that finds highlights produced by a dominant compact light source, whose position is roughly known. We then show how to estimate the lighting automatically for objects whose re-flection is part specular and part Lambertian. We demon-strate this method for two classes of objects. First, we show that specular information alone can suffice to identify ob-jects with no Lambertian reflectance, such as transparent wine glasses. Second, we use our complete system to recog-nize shiny objects, such as pottery. 1