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A Specular Shape from Shading by Fast Marching Method

Guohui Wang, Wei Su, Fen Gao
2011 Procedia Engineering  
In order to reconstruct a surface which has specular reflection from the grayscale information contained in a single two-dimensional (2D) image, a specular shape from shading (SFS) using the fast marching  ...  surface is derived and it is a first-order nonlinear partial differential equation (PDE).  ...  Now, the solution of the Eikonal PDE (6)  + + − −  − < =   + −  , ≥ (8) The fast marching method for specular shape from shading is summarized in the following: 1) Initialization: All grid points  ... 
doi:10.1016/j.proeng.2011.11.2625 fatcat:k53q3k4njfbkhdzaety6c565hm

A New Shape from Shading Approach for Specular Surfaces [chapter]

Guohui Wang, Wei Su, Yugui Song
2011 Lecture Notes in Computer Science  
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.  ...  Then, it is formulated as an Eikonal PDE which includes the shape of the surfaces. The viscosity solution of the resulting PDE is approximated by using the high-order Godunov fast sweeping method.  ...  Introduction Shape recovery is a basic problem in computer vision. Shape from shading (SFS), presented by Horn [1] , is an approach to get the 3D shape from one single shading image.  ... 
doi:10.1007/978-3-642-23896-3_9 fatcat:3pdco6mq5jgmlk2odtgmmua3fe

A Differential Approach to Shape from Polarisation: A Level-Set Characterisation

Fotios Logothetis, Roberto Mecca, Fiorella Sgallari, Roberto Cipolla
2018 International Journal of Computer Vision  
The inherent ambiguity of the Shape from Polarization problem becomes evident through the impossibility of reconstructing the whole surface with this differential approach.  ...  With the aim of deriving a formulation capable of dealing with as many heterogeneous effects as possible, we propose a differential formulation of the Shape from Polarisation problem that depends only  ...  From the experimental point of view, this new model permits to distinguish diffuse regions from specular region very easily and then characterise the shape through its level-set entirely.  ... 
doi:10.1007/s11263-018-1127-x fatcat:7zjdbvmqhffslajkez3uh62iii

Shape from Shading for Hybrid Surfaces

Abdelrehim Ahmed, Aly Farag
2007 2007 IEEE International Conference on Image Processing  
This paper presents a new method for recovering the shape of hybrid surfaces that have both diffuse reflection and specular reflection using shape from shading (SFS).  ...  Index Terms-Shape from Shading, Ward Model, Lax-Friedrichs sweeping.  ...  The resulting PDE is solved using a fast numerical algorithm based on Lax-Friedrichs sweeping method.  ... 
doi:10.1109/icip.2007.4379208 dblp:conf/icip/AhmedF07 fatcat:vhex54ov3vhwxciis3na7vl4ra

Specularity Removal in Images and Videos: A PDE Approach [chapter]

Satya P. Mallick, Todd Zickler, Peter N. Belhumeur, David J. Kriegman
2006 Lecture Notes in Computer Science  
This is accomplished by evolving a partial differential equation (PDE) that iteratively erodes the specular component at each pixel.  ...  We present results on high-quality images and video acquired in the laboratory in addition to images taken from the Internet.  ...  In practice, the transition from linear to disk-shaped structuring sets in Eq. 19 is controlled by a threshold on ∇θ .  ... 
doi:10.1007/11744023_43 fatcat:kaucd2jxkzg7vonpi2wq2zl5iy

A linear formulation of shape from specular flow

Guillermo D Canas, Yuriy Vasilyev, Yair Adato, Todd Zickler, Steven Gortler, Ohad Ben-Shahar
2009 2009 IEEE 12th International Conference on Computer Vision  
We show that a suitable reparameterization leads to a linear formulation of the shape from specular flow equation.  ...  shape information from other sources.  ...  Acknowledgements The authors thank Peter Sturm for suggesting the link between shape from specular flow and generic camera calibration. This project is funded by the US National Science  ... 
doi:10.1109/iccv.2009.5459164 dblp:conf/iccv/CanasVAZGB09 fatcat:moo56l7ovbfjdcyquzyh74fnpu

A Unified Shape-From-Shading Approach for 3D Surface Reconstruction Using Fast Eikonal Solvers

Guohui Wang, Xuan Zhang, Jin Cheng
2020 International Journal of Optics  
Object shape reconstruction from images has been an active topic in computer vision. Shape-from-shading (SFS) is an important approach for inferring 3D surface from a single shading image.  ...  It comprises two Godunov-based schemes with fast sweeping method that can handle the eikonal-type PDII equation.  ...  , and shape-from-X (X � shading, photometric stereo, texture, focus/defocus, motion, etc.).  ... 
doi:10.1155/2020/6156058 fatcat:7dicd4w3ezcedaco3uzti6yx54

Generic Scene Recovery Using Multiple Images [chapter]

Kuk-Jin Yoon, Emmanuel Prados, Peter Sturm
2009 Lecture Notes in Computer Science  
In this paper, a generative model based method for recovering both the shape and the reflectance of the surface(s) of a scene from multiple images is presented, assuming that illumination conditions are  ...  Based on a variational framework and via gradient descents, the algorithm minimizes simultaneously and consistently a global cost functional with respect to both shape and reflectance.  ...  Also S t shape (from E shape (S)) is the mean curvature flow as S t shape = −2λH.  ... 
doi:10.1007/978-3-642-02256-2_62 fatcat:nwmvktjxufh2bkvgwhbv337xvy

Dense specular shape from multiple specular flows

Yuriy Vasilyev, Yair Adato, Todd Zickler, Ohad Ben-Shahar
2008 2008 IEEE Conference on Computer Vision and Pattern Recognition  
We show that while the 'shape from specular flow' PDE for a single motion is non-linear, we can combine observations of multiple specular flows from distinct relative motions to yield a linear set of equations  ...  However, this approach requires solving a non-linear PDE (the 'shape from specular flow equation') and analytic solutions are only known to exist for very constrained motions.  ...  Environment motion induces a specular flow on the image plane, and this is related to shape through a non-linear PDE (the shape from specular flow equation).  ... 
doi:10.1109/cvpr.2008.4587685 dblp:conf/cvpr/VasilyevAZB08 fatcat:ti7zbz6tnfenxbmfsjl5n7wteq

Variational Shape and Reflectance Estimation Under Changing Light and Viewpoints [chapter]

Neil Birkbeck, Dana Cobzas, Peter Sturm, Martin Jagersand
2006 Lecture Notes in Computer Science  
Fitting parameterized 3D shape and general reflectance models to 2D image data is challenging due to the high dimensionality of the problem.  ...  In particular, we present a variational method implemented as a PDE-driven surface evolution interleaved with reflectance estimation.  ...  The gradient flow PDE is derived from the Euler-Lagrange equation of Eq. 1. The PDE contains higher order terms [2] resulting from the general form of g being a function of n.  ... 
doi:10.1007/11744023_42 fatcat:ig46hyrnyzdevhmmgjqwxp3miu

Specular Surface Recovery from Reflections of a Planar Pattern Undergoing an Unknown Pure Translation [chapter]

Miaomiao Liu, Kwan-Yee K. Wong, Zhenwen Dai, Zhihu Chen
2011 Lecture Notes in Computer Science  
Previous works have demonstrated that a specular surface can be recovered from the reflections of two calibrated planar patterns.  ...  This paper addresses the problem of specular surface recovery, and proposes a novel solution based on observing the reflections of a translating planar pattern.  ...  In [9] , Canas et al. linearized this non-linear PDE in order to make it easier for practical use. The aforementioned works are regarded as shape from specular flow (SFSF) methods.  ... 
doi:10.1007/978-3-642-19309-5_11 fatcat:334vxdjyrfeanirxwhrxxfrpyi

Unifying diffuse and specular reflections for the photometric stereo problem

Roberto Mecca, Yvain Queau
2016 2016 IEEE Winter Conference on Applications of Computer Vision (WACV)  
After thirty years of researching, the photometric stereo technique for 3D shape recovery still does not provide reliable results if it is not constrained into very well-controlled scenarios.  ...  It is provided by making the ratio of irradiance equations holding both diffuse and specular reflections as well as non-linear light propagation features simultaneously.  ...  Reflectance Shape recovery from specular shading still remains a challenging goal since very common materials provide specular highlights that prevent reasonable reconstructions from the PS technique.  ... 
doi:10.1109/wacv.2016.7477643 dblp:conf/wacv/MeccaQ16 fatcat:ymgbjigx4vaxhipesgd6fq2xcm

Metric depth recovery from monocular images using Shape-from-Shading and specularities

Marco Visentini-Scarzanella, Danail Stoyanov, Guang-Zhong Yang
2012 2012 19th IEEE International Conference on Image Processing  
Despite recent advances in modeling the Shape-from-Shading (SFS) problem and its numerical solution, practical applications have been limited.  ...  We also show how knowledge of the light source position can enable the recovery of depth information in a metric space by triangulating specular highlights.  ...  INTRODUCTION Shape-from-Shading (SFS) as a technique for 3D reconstruction from single frames presents some obvious advantages.  ... 
doi:10.1109/icip.2012.6466786 dblp:conf/icip/ScarzanellaSY12 fatcat:zg4p6ejijbbadorwn3kqf4573m

Reflectivity and PDE of VUV4 Hamamatsu SiPMs in Liquid Xenon [article]

P. Nakarmi, I. Ostrovskiy, A.K. Soma, F. Retiere, S. Al Kharusi, M. Alfaris, G. Antone, I.J. Arnquist, I. Badhrees, P.S. Barbeau, D. Beck, V. Belov (+136 others)
2019 arXiv   pre-print
Specular reflectivity and relative photodetection efficiency (PDE) of Hamamatsu VUV4 silicon photomultipliers (SiPMs) with 50 um micro-cells have been measured with xenon scintillation light (~175 nm)  ...  Both the reflectivity and PDE decrease as the angle of incidence increases.  ...  The shaped signals are digitized by a 250 MS/s CAEN DT5725 digitizer [23] and analyzed by a custom-made ROOT [24] based software. Table 1 : 1 Stability check results.  ... 
arXiv:1910.06438v1 fatcat:jahlptm6pne75nikiwe43i5jpi

Shape from Specular Flow

Y Adato, Y Vasilyev, T Zickler, O Ben-Shahar
2010 IEEE Transactions on Pattern Analysis and Machine Intelligence  
In this paper, we study the shape from specular flow problem and show that observable specular flow is directly related to surface shape through a nonlinear partial differential equation.  ...  An image of a specular (mirror-like) object is nothing but a distorted reflection of its environment. When the environment is unknown, reconstructing shape from such an image can be very difficult.  ...  (b) One image from a captured sequence. (c) Estimated specular flow. (d) Shape recovered by solving the 3D shape from specular flow equation as described in Section 5.  ... 
doi:10.1109/tpami.2010.126 pmid:20847393 fatcat:xiuycz22xbgntksrwhyw5qqg7u
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