نتایج جستجو برای: specular

تعداد نتایج: 3089  

Journal: :Computer Vision, Graphics, and Image Processing 1988
Glenn Healey Thomas O. Binford

We show that highlights in images of objects with specularly reflecting surfaces provide significant information about the surfaces which generate them. A brief survey is given of specular reflectance models which have been used in computer vision and graphics. For our work, we adopt the Torrance-Sparrow specular model which, unlike most previous models, considers the underlying physics of spec...

2011
Guohui Wang Wei Su Yugui Song

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...

Journal: :Japanese journal of ophthalmology 2001
M Kubo T Sakuraba Y Arai M Nakazawa

PURPOSE Specular images of the tear film in the central cornea were examined in patients with nasolacrimal duct obstruction to observe changes before and after dacryocystorhinostomy (DCR). METHODS We observed the specular images in 4 patients (5 eyes) by a noncontact observation device and recording system. Observed patterns were classified into five grades. The specular images and tear menis...

2006
Thomas Bonfort Peter F. Sturm Pau Gargallo

We present a method for the reconstruction of a specular surface, using a single camera viewpoint and the reflection of a planar target placed at two different positions. Contrarily to most specular surface reconstruction algorithms, our method makes no assumption on the regularity or continuity of the specular surface, and outputs a set of 3D points along with corresponding surface normals, al...

Journal: :Acta Crystallographica Section A Foundations of Crystallography 2005

1996
Masaki Otsuki Yukio Sato

In this paper, a method for extracting influences of specular reflection and shade from multiple color images is described. As regards extraction, the di-chromatic reflection model is applied. First, the same point on an object is observed from multiple viewpoints, and the pixel values in a window in which the fixation point is being imaged are projected into RGB color space. The shape of each ...

Journal: :Vision Research 2002
Joong Nam Yang Steven K Shevell

Binocular disparity is an aspect of natural viewing. This research investigates whether disparity affects surface color perception. Achromatic settings were obtained and compared for two stereograms of a scene with specular reflections, one stereogram with binocular disparity and one without it (cyclopean view). Binocular disparity was found to improve color constancy. Next, the geometry of spe...

Journal: :Comput. Graph. Forum 2008
Ivo Ihrke Kiriakos N. Kutulakos Hendrik P. A. Lensch Marcus A. Magnor Wolfgang Heidrich

This state of the art report covers reconstruction methods for transparent and specular objects or phenomena. While the 3D acquisition of opaque surfaces with Lambertian reflectance is a well-studied problem, transparent, refractive, specular and potentially dynamic scenes pose challenging problems for acquisition systems. This report reviews and categorizes the literature in this field. Despit...

2015
Naoto Ienaga Hideo Saito Kouichi Tezuka Yasumasa Iwamura Masayoshi Shimizu

We present a novel combination photometric stereo which can estimate surface normals precisely even for images including shadows and specular reflection. We can use photometric stereo if there are more than three input images. Therefore we can employ photometric stereo with nC3 combinations for n input images. We make 3D distribution of albedos and surface normals estimated from pixel intensiti...

1998
DINKAR N. BHAT SHREE K. NAYAR

The problem of accurate depth estimation using stereo in the presence of specular reeection is addressed. Specular reeection, a fundamental and ubiquitous reeection mechanism, is viewpoint dependent and can cause large intensity diierences at corresponding points, resulting in signiicant depth errors. We analyze the physics of specular reeection and the geometry of stereopsis which lead to a re...

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