This thesis focuses on the use of non-Lambertian reflectance models for curved surface analysis. The contributions are: a) to show how specular and diffuse reflectance models can be used to recover surface normal estimates using shape-from-shading (SFS), b) to show how wave scattering theory can be used to estimate rough surface characteristics, and c) to present a method for surface normal smo...

This paper presents a large set of spectral and directional signatures of the polarized reflectance acquired over various surfaces. Two analytical physically-based models were developed, one for bare soils and the other for simple vegetation cover. They consider that the polarized reflectance is generated by single specular reflection over isotropically distributed facets or leaves. The models ...

In this paper we address the problem of separating Lambertian and specular reflection components in order to improve the quality of surface normal information recoverable using shape-from-shading. The framework for our study is provided by the iterated conditional modes algorithm. We develop a maximum a posteriori probability (MAP) estimation method for estimating the mixing proportions for Lam...

Specular reflections are exhibited by a wide range of materials whose reflectance can be described as a linear combination of specular and diffuse components [5]. There are several benefits to separating an image into the two components. By isolating the diffuse component (which is often well-described by the Lambertian model), powerful Lambertian-based tools for tracking, reconstruction and re...

The photometric sampling method [4] extracts shape and reflectance properties of surfaces (Lambertian, specular, and hybrid) by using multiple illunrination directions and a single viewing direction. This paper describes a complete implementation and a performance evaluation of a three-dimensional version of the photometric sampler. The experimental conducted on Lambertian surfaces, specular su...

Visible surfaces in a natural environment often have multiple components of reflectance, including a diffuse component, by which light is scattered isotropically in all possible directions, and a specular component, by which light is reflected anisotropically within a limited range of directions. The research described in the present article was designed to investigate how these different compo...

For inhomogeneous materials, the standard reflectance model suggests that under all viewing geometries surface reflectance functions can be described as the sum of a constant function of wavelength (specular) and a diffuse function that is characteristic of the material. As the viewing geometry varies, the relative contribution of these two terms varies. In a previous study [J. Opt. Soc. Am. A ...

Shape recovery is a basic problem in computer vision. Shape from shading (SFS) is an approach to get the 3D shape from a single shading image. Diffuse model is usually used to approximate the surface reflectance property. For specular surfaces, however, it is not suitable. In this paper, we propose a new SFS approach for specular surfaces. The Blinn-Phong reflectance model is applied to charact...

In mink production, silkiness refers to a silky fur surface. The sensory evaluation of silkiness may be based on information perceived by the eyes and the hands. Silkiness is assumed to depend on hair fiber properties such as guard hair straightness, glossiness, and smoothness. Our objective was to characterize the dorsal surface of brown mink pelts by means of optical variables and relate thes...

Several techniques have been developed for recovering reflectance properties of real surfaces under unknown illumination conditions. However, in most cases, those techniques assume that the light sources are located at inifinity, which cannot be applied to, for example, photometric modeling of indoor environments. In this paper, we propose two methods to estimate the surface reflectance propert...