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Local Shape from Mirror Reflections

Silvio Savarese, Min Chen, Pietro Perona
2005 International Journal of Computer Vision  
We study the problem of recovering the 3D shape of an unknown smooth specular surface from a single image. The surface reflects a calibrated pattern onto the image plane of a calibrated camera.  ...  Information equivalent to scale and orientation measurements can be also extracted from the reflection of a planar scene patch of arbitrary geometry, provided that the reflections of (at least) 3 distinctive  ...  We use this relationship to estimate the local shape of the mirror surface.  ... 
doi:10.1007/s11263-005-1086-x fatcat:bu6i7jjajvdhfcjrv4sdjqhw4i

Recovering Local Shape of a Mirror Surface from Reflection of a Regular Grid [chapter]

Silvio Savarese, Min Chen, Pietro Perona
2004 Lecture Notes in Computer Science  
The mapping from the scene pattern to its reflected distorted image in the camera changes the local geometrical structure of the scene pattern.  ...  We present a new technique to recover the shape of an unknown smooth specular surface from a single image.  ...  of mirror surface position and shape.  ... 
doi:10.1007/978-3-540-24672-5_37 fatcat:6tdcy3arzvgitl5q4tqv6hwbai

Qualitative shape from shading, specular highlights, and mirror reflections

M. Langer, A. Faisman
2012 Journal of Vision  
Previous work • Highlights improve shape perception [1] • Shape can be perceived from mirror reflections only [2] • Occluding contours provide strong constraints • Monocular cues for local 3D shape are  ...  patterns of local image orientations which depend on 3D surface slope and curvature)  ...  Qualitative shape from shading, specular highlights, and mirror reflections Method: Mark points on rendered surfaces. Observers judge if shape is convex ("bump") or concave ("dent").  ... 
doi:10.1167/12.9.232 fatcat:tryofbj7gngrvlszba6z4yf7uy

Qualitative shape from shading, highlights, and mirror reflections

A. Faisman, M. S. Langer
2013 Journal of Vision  
Surfaces were rendered using standard computer graphics models of matte, glossy, and mirror reflectance and were viewed from a small oblique angle to avoid occluding contour shape cues.  ...  The human visual system has a remarkable ability to perceive three-dimensional (3-D) surface shape from shading and specular reflections.  ...  They found that under monocular viewing, subjects could reliably estimate local surface orientation from these mirror reflections.  ... 
doi:10.1167/13.5.10 pmid:23584631 fatcat:25kwk6fqhfee7g4yiqrprx667m

Analysis of Parabolic Trough Concentrator Mirror Shape Accuracy in different Measurement Setups

S. Meiser, E. Lüpfert, B. Schiricke, R. Pitz-Paal
2014 Energy Procedia  
Local focus deviation values fd are derived from local slope deviation values and the distance of the according reflecting surface elements to the focal line, e.g. in x-direction: d sdx fdx 2 (2) where  ...  the local slope deviation has to be multiplied by 2 because of reflection.  ... 
doi:10.1016/j.egypro.2014.03.226 fatcat:5qzrwy6zjfguxhkdxgtn6jazzq

Specular reflections and the perception of shape

Roland W. Fleming, Antonio Torralba, Edward H. Adelson
2004 Journal of Vision  
We find that these "orientation fields" are (i) diagnostic of 3D shape, (ii) remain surprisingly stable when the world reflected in the surface is changed, and (iii) can be extracted from the image by  ...  Here we explain how specular reflections can provide reliable and accurate constraints on 3D shape.  ...  shape from specular reflections.  ... 
doi:10.1167/4.9.10 pmid:15493971 fatcat:gk32vuldszbrbaibwg2mrezdmu

What do reflections tell us about the shape of a mirror?

Silvio Savarese, Li Fei-Fei, Pietro Perona
2004 Proceedings of the 1st Symposium on Applied perception in graphics and visualization - APGV '04  
Can specular reflections be used as a visual cue for shape perception? Our experiments show that our subjects are very poor at judging the shape of mirror surfaces in absence of other visual cues.  ...  Three-dimensional shape may be perceived from static images. Contours, shading, texture gradients, perspective and occlusion are well-studied cues to this percept.  ...  Conclusion We have studied how humans perceive shape from mirror reflections.  ... 
doi:10.1145/1012551.1012571 dblp:conf/apgv/SavareseFP04 fatcat:nvdnlfb66zhgvfn4m5ahomqfbe

The reflecting surface of the MAGIC-II Telescope [article]

D. Bastieri, O. Citterio, M. Ghigo (7 and 5), E. Giro, M. Mariotti , D. Pascoli, A. Saggion (1 and 2), P. Sartori Dipartimento di Fisica, Università di Padova, Italy I.N.F.N. Sezione di Padova, Italy, Departament de Física, Universitat Autònoma de Barcelona, Spain, Media Lario Technologies S.r.l. (+12 others)
2007 arXiv   pre-print
MAGIC II is being built at 85 m of distance from MAGIC I, and will also feature a huge reflecting surface of 240 m^2 of area.  ...  One of the improvement is the design for the mirror of MAGIC II, that are lighter and larger, being square of 1 m of side and weighting around 15 kg.  ...  Acknowledgements is also due to the LT Ultra company of Alt Holderberg for all their dedication in developing new technologies for the mirror production.  ... 
arXiv:0709.1372v1 fatcat:uzd73jgyhzanrageayeti437ce

Specular surface reconstruction from sparse reflection correspondences

Aswin C. Sankaranarayanan, Ashok Veeraraghavan, Oncel Tuzel, Amit Agrawal
2010 2010 IEEE Computer Society Conference on Computer Vision and Pattern Recognition  
We present a practical approach for surface reconstruction of smooth mirror-like objects using sparse reflection correspondences (RCs).  ...  Ours is the first method that allows for reconstruction of mirror surfaces from sparse RCs, obtained from standard algorithms such as SIFT.  ...  Reflection Correspondences from Images: Figure 7 shows reconstructions from rendered images. We used POV-Ray to render mirrors of various shapes, obtaining Figure 6 .  ... 
doi:10.1109/cvpr.2010.5539826 dblp:conf/cvpr/SankaranarayananVTA10 fatcat:5dmlma43ofbszdv6x6xthhfbo4

RAY-TRACING ANALYSIS OF A TWO-STAGE SOLAR CONCENTRATOR

Dominic Groulx, Benjamin Sponagle
2010 Transactions of the Canadian Society for Mechanical Engineering  
The focal length of the secondary mirror determines the maximum local solar energy flux W that can be achieve on the target.  ...  The concentrator concentrates all the incident energy from the sun on the target, and that independently of the secondary mirror's focal length (within the range studied), as long as the target position  ...  Fig. 7 . 7 Maximum local solar energy flux W as a function of the target displacement from the origin d for various secondary mirrors' focal lengths.  ... 
doi:10.1139/tcsme-2010-0016 fatcat:d7e33ixcenhyroeqvpoijookn4

Evaluation and Assessment of Gravity Load on Mirror Shape of Parabolic Trough Solar Collectors

S. Meiser, S. Schneider, E. Lüpfert, B. Schiricke, R. Pitz-Paal
2015 Energy Procedia  
This implies optimizing mirror shape for 0° (zenith) collector angle.  ...  thus making it difficult to find one optimum shape for all types of mirror and collector.  ...  The deviation of the reflected light beam from the ideal focal line, so called local focus deviation, was introduced as a further parameter characterizing mirror shape accuracy [11] .  ... 
doi:10.1016/j.egypro.2015.07.434 fatcat:tp64uqbvabdnhmezy2yaolkqb4

Specular-reflection photonic hook generation under oblique illumination of a super-contrast dielectric microparticle [article]

Yu.E. Geints, A.A. Zemlyanov, I.V. Minin, O.V. Minin
2020 arXiv   pre-print
To this end, the novel geometrical scheme of photonic nanojet generation in "reflection mode" was proposed based on a super-contrast microparticle (n~2) placed near a flat mirror.  ...  of a "specular reflection photonic hook" (s-Hook).  ...  inhomogeneous and asymmetric-shaped microparticles or complex mirror relief [19, 23] .  ... 
arXiv:2009.14012v1 fatcat:oyjftnz2bngxzlpsjqtkfbhrpu

Beam-shaping PEC Mirror Phase Corrector Design

Shaolin Liao
2007 PIERS Online  
The Perfect Electric Conductor (PEC) mirror phase corrector plays an important role in the beam-shaping mirror system design for Quasi-Optical (QO) mode converter (launcher) in the sub-THz high-power gyrotron  ...  In this article, both the Geometry Optical (GO) method and the phase gradient method have been presented for the PEC mirror phase corrector design.  ...  angle α i ) and the local reflection beam (with reflected angle α r ). δn is the PEC mirror surface correction inn direction and δŷ is the PEC mirror surface correction inŷ direction.  ... 
doi:10.2529/piers061005101313 fatcat:aibl3j6gkrhlxmwokw3qxboili

Dynamir

Florent Berthaut, Deepak Ranjan Sahoo, Jess McIntosh, Diptesh Das, Sriram Subramanian
2015 Proceedings of the 2015 International Conference on Interactive Tabletops & Surfaces - ITS '15  
C) Moving the reflection of physical objects with a finger by changing the orientation of a large brush. ABSTRACT Mirror surfaces are part of our everyday life.  ...  Among them, curved mirrors are used to enhance our perception of the physical space, e.g., convex mirrors are used to increase our field of view in the street, and concave mirrors are used to zoom in on  ...  In other words, the HIPS mirror shows good flatness for undistorted reflection, and at the same time good bending, stretching and twisting performance for local shape control.  ... 
doi:10.1145/2817721.2817744 dblp:conf/tabletop/BerthautSMDS15 fatcat:64eebng6hzabzhcbgu3t7egluy

Alignment of 3D models

Mohamed Chaouch, Anne Verroust-Blondet
2009 Graphical Models  
In order to capture the local translational symmetry of a shape along a direction, we introduce a new measure we call the local translational invariance cost (LT IC).  ...  Finding all reflective symmetries of a shape is much more difficult than simply checking whether a given set of symmetries exists.  ...  Plane Reflection Symmetry Analysis A plane reflection symmetry is defined by a mirror plane π that can be parameterized by its unit normal n and its scalar distance δ from the origin.  ... 
doi:10.1016/j.gmod.2008.12.006 fatcat:r2q3jkb4x5gcde4kezuwra3pay
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