Toward a Stratification of Helmholtz Stereopsis
نویسندگان
چکیده
Helmholtz stereopsis has been previously introduced as a surface reconstruction technique that does not assume a model of surface reflectance. This technique relies on the use of multiple cameras and light sources, and it has been shown to be effective when the camera and source positions are known. Here, we take a stratified look at uncalibrated Helmholtz stereopsis. We derive a new photometric matching constraint that can be used to establish correspondence without any knowledge of the cameras and sources (except that they are co-located), and we determine conditions under which we can obtain affine and metric reconstructions. An implementation and experimental results are presented.
منابع مشابه
Binocular Helmholtz Stereopsis
Helmholtz stereopsis has been introduced recently as a surface reconstruction technique that does not assume a model of surface reflectance. In the reported formulation, correspondence was established using a rank constraint, necessitating at least three viewpoints and three pairs of images. Here, it is revealed that the fundamental Helmholtz stereopsis constraint defines a nonlinear partial di...
متن کاملA Maximum Likelihood Surface Normal Estimation Algorithm for Helmholtz Stereopsis
Helmholtz stereopsis is a relatively recent reconstruction technique which is able to reconstruct scenes with arbitrary and unknown surface reflectance properties. Conventional implementations of the method estimate surface normal direction at each surface point via an eigenanalysis, thereby optimising an algebraic distance. We develop a more physically meaningful radiometric distance whose min...
متن کاملHelmholtz reciprocity in surface reconstruction: an overview
Reconstructing the 3D point mesh of an object from 2D images is a difficult problem. The task is even more complicated when the object has arbitrary and unknown surface reflectance. Traditional reconstructing techniques make explicit or implicit assumptions about the bidirectional reflectance distribution function (BRDF), which represents the surface reflectance. A widely used assumption is tha...
متن کاملTowards Full 3D Helmholtz Stereovision Algorithms
Helmholtz stereovision methods are limited to binocular stereovision or depth maps reconstruction. In this paper, we extend these methods to recover the full 3D shape of the objects of a scene from multiview Helmholtz stereopsis. Thus, we are able to reconstruct the complete three-dimensional shape of objects made of any arbitrary and unknown bidirectional reflectance distribution function. Unl...
متن کاملOperating Range Expansion in a HCCI Natural Gas Engine Using Charge and Thermal Stratification in Combustion Chamber
HCCI operating window has two distinct boundaries of knock at higher load region and misfiring/partial burning at lower load region. Moreover, there is no conventional direct way of controlling combustion timing in an HCCI engine. In this research, experimental study were carried out to investigate the effect of thermal and charge stratification on expansion of the operating range of a natural ...
متن کامل