Indoor Non-directed Optical Wireless Communications Optimization of the Lambertian Order Z. Ghassemlooy1,*, D. Wu1, M. A. Khalighi2, and X. Tang3 1Optical Communications Research Group, Faculty of Engineering and Environment, Northumbria University, Newcastle Upon Tyne, UK 2Ecole Centrale Marseille, Institute Fresnel, Marseille, France 3 Department of Electronic Engineering, Tsinghua University...

Existing radiometric compensation methods are based on the assumption that the projection surface (screen) is Lambertian, i.e. there exists no specular reflection. Thus the methods cannot be applied to non-Lambertian surfaces which are ubiquitous in our everyday environment. In this paper, we try to faithfully display an image onto non-Lambertian surfaces using multiple overlapping projectors a...

It is well known that many surfaces exhibit reflectance that is not well modelled by Lambert’s law. This is the case not only for surfaces that are rough or shiny, but also those that are matte and composed of materials that are particle suspensions. As a result, standard Lambertian shape-from-shading methods can not be applied directly to the analysis of rough and shiny surfaces. In order to o...

Human faces are neither exactly Lambertian nor entirely convex and hence most models in literature which make the Lambertian assumption, fall short when dealing with specularities and cast shadows. In this paper, we present a novel anti-symmetric tensor spline (a spline for tensorvalued functions) based method for the estimation of the Apparent BRDF (ABRDF) field for human faces that seamlessly...

One of the problems that hinders conventional methods for shape-from-shading is the presence of local specularities which may be misidenti.ed as high curvature surface features. In this paper we address the problem of estimating the proportions of Lambertian and specular re1ection components in order to improve the quality of surface normal information recoverable using shape-from-shading. The ...

In this paper, we present a new mathematical foundation for image-based lighting. Using a simple manipulation of the local coordinate system, we derive a closed-form solution to the light integral equation under distant environment illumination. We derive our solution for different BRDF’s such as lambertian and Phong-like. The method is free of noise, and provides the possibility of using the f...

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...

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...

All existing shape extraction techniques that are based on photometric measurements rely on assumed surface reflection properties. We propose a method for determining the shape of surfaces whose reflectance properties may vary from Lambertian to specular without prior knowledge of the relative strengths of the Lambertian and specular components of reflection. The object surface is illuminated u...