1,485 Hits in 3.5 sec

Flexible Image-Based Photometric Reconstruction using Virtual Light Sources

Simon Gibson, Toby Howard, Roger Hubbold
2001 Computer graphics forum (Print)  
Requirements on the amount of user-supplied data must be reduced if image-based photometric reconstruction algorithms are to be applied in practical real-world situations.  ...  This is achieved through the use of virtual light sources which mimic the effect of direct illumination from unknown luminaires, and indirect illumination reflected off unknown geometry.  ...  This research was supported by EPSRC grant number GR/M14531, entitled 'REVEAL: Reconstruction from Video of Environments with Accurate Lighting'.  ... 
doi:10.1111/1467-8659.00513 fatcat:fx6n73h55faclov2lrddzw2zki

A Practical Reflectance Transformation Imaging Pipeline For Surface Characterization In Cultural Heritage

Irene Ciortan, Ruggero Pintus, G Marchioro, Claudia Daffara, Andrea Giachetti, Enrico Gobbetti
2016 Zenodo  
Using a free-form Reflectance Transformation Imaging (RTI) approach, we acquire multiple digital photographs of the studied object shot from a stationary camera.  ...  In each photograph, a light is freely positioned around the object in order to cover a wide variety of illumination directions.  ...  • A flexible and portable solution for image acquisition with RTI, based on a low-cost hardware kit, flexible and easy to arrange in either a research lab or on-site. • An image processing pipeline & software  ... 
doi:10.5281/zenodo.177891 fatcat:szouycvsozguxmco7oeu35xywi

A Self-Calibrating Method for Photogeometric Acquisition of 3D Objects

D.G. Aliaga, Yi Xu
2010 IEEE Transactions on Pattern Analysis and Machine Intelligence  
Our key enabling observation is that a digital projector can be simultaneously used as either an active light source or as a virtual camera (as opposed to a digital camera which cannot be used for both  ...  Acquisition processing freely alternates between using a geometric setup and using a photometric setup with the same hardware configuration.  ...  We demonstrate (1) using the projectors as light sources and then as virtual cameras to produce a fast geometric reconstruction whereby an uncalibrated photometric-based initialization obtains estimates  ... 
doi:10.1109/tpami.2009.202 pmid:20224128 fatcat:sm4koflrxvbrnkzlpjcs76j2ha

Photogeometric structured light: A self-calibrating and multi-viewpoint framework for accurate 3D modeling

Daniel G. Aliaga, Yi Xu
2008 2008 IEEE Conference on Computer Vision and Pattern Recognition  
Structured-light methods actively generate geometric correspondence data between projectors and cameras in order to facilitate robust 3D reconstruction.  ...  In this paper, we present Photogeometric Structured Light whereby a standard structured light method is extended to include photometric methods.  ...  (c) Photometric reconstruction using 3 images illuminated from 3 directions. (d-e) Two corresponded virtual views between two projectors and the camera picture in b.  ... 
doi:10.1109/cvpr.2008.4587709 dblp:conf/cvpr/AliagaX08 fatcat:4l4vgdl5c5gmjeymhuv3ddaqnu


A. Martos, R. Cachero
2015 The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences  
Software tools for photogrametric and multi-view stereo reconstruction are nowadays of generalized use in the digitization of architectural cultural heritage.  ...  Methods based on systematic sampling with commuting light patterns in a laboratory set-up are not suitable.  ...  Instead it represents a texture image which, unlike a typical photograph, can be re-lighted using a virtual light source.  ... 
doi:10.5194/isprsarchives-xl-5-w4-139-2015 fatcat:dt5aigbhlnh45mhx5foin3t6qa

[Paper] Textured 3D Reconstruction Using Photometric Stereo for Projection-based Display Systems

Isao Miyagawa, Hiroyuki Arai, Yukinobu Taniguchi
2013 ITE Transactions on Media Technology and Applications  
We propose a new textured 3D reconstruction method that uses image sequences output by projection-based display systems.  ...  So that image sequences can recreate convex objects on a planar display, we extend the photometric model used in photometric stereo to handle full color images.  ...  Yabushita, who was a colleague of our laboratories, for her help in measuring 3D points on the surface of real objects by using a 3D laser scanner.  ... 
doi:10.3169/mta.1.292 fatcat:iczqmkg3qrd67ek4wa64weuaje

Digital inspection

Daniel G. Aliaga
2008 Proceedings of the 2008 symposium on Interactive 3D graphics and games - SI3D '08  
Our approach uses photometric and geometric processing, combined with a set of visualization methods tuned to the interactive inspection and analysis of objects.  ...  In this paper, we demonstrate our system using several real-world objects.  ...  (a) A video-frame of an object under a single light source. (b) A synthesized and re-lit rendering with a different virtual light. (c-d) View using our depth-light visualization tool.  ... 
doi:10.1145/1342250.1342258 dblp:conf/si3d/Aliaga08 fatcat:zuvgxitngjdjfgvmfoydzkq6du

Shape and Reflectance Reconstruction in Uncontrolled Environments by Differentiable Rendering [article]

Rui Li, Guangmin Zang, Miao Qi, Wolfgang Heidrich
2022 arXiv   pre-print
In this paper, we propose an efficient method to reconstruct the scene's 3D geometry and reflectance from multi-view photography using conventional hand-held cameras.  ...  Our method automatically builds a virtual scene in a differentiable rendering system that roughly matches the real world's scene parameters, optimized by minimizing photometric objectives alternatingly  ...  In our virtual scene, an environment light source emits light to the virtual scene and bounces when hitting a 3D object. This environment light is represented as a set of isotropic point sources.  ... 
arXiv:2110.12975v2 fatcat:uosmgsv5ivhbbkuejz44xsn2oa

DECHO—a framework for the digital exploration of cultural heritage objects

Daniel G. Aliaga, Elisa Bertino, Stefano Valtolina
2011 ACM Journal on Computing and Cultural Heritage  
To this end, we present a complete framework that is easy to use, does not require expensive/custom equipment, and has been designed for helping archaeology researchers and educators reconstruct and analyze  ...  Our main inspiration is that archaeology today would benefit significantly from having spur-of-the-moment access to information from a variety of heterogeneous data sources and being able to have multiple  ...  In this scenario the data sources are accessed using specific webservices and the OMS is used for coordinating them according to the conceptual ontology.  ... 
doi:10.1145/1921614.1921619 fatcat:3l2hdotruzb55cq7wwery3ygjm

Virtual reality in GI endoscopy: intuitive zoom for improving diagnostics and training

Alexander Hann, Benjamin M Walter, Niklas Mehlhase, Alexander Meining
2018 Gut  
In this work, we used VR in flexible GI endoscopy by implementing different image sources into a virtual endoscopy cockpit.  ...  Assuming Endoscopy news that brighter areas are closer to the light source of the endoscope, we were able to generate 3D images using the regular 2D endoscopic image.  ... 
doi:10.1136/gutjnl-2018-317058 pmid:30228217 fatcat:q3kc3foomzehlnjtrejvicdyry

A full photometric and geometric model for attached webcam/matte screen devices

Yvain Quéau, Richard Modrzejewski, Pierre Gurdjos, Jean-Denis Durou
2016 Signal processing. Image communication  
These theoretical contributions are experimentally validated in a photometric stereo application with extended sources, where a colored scene is reconstructed while watching a collection of graylevel images  ...  composed of both a matte screen and an attached camera, where it is shown that the light emitted by an image displayed on the monitor can be expressed in closed-form at any point facing the screen, and  ...  In this section, we show how to use images displayed on the screen as extended light sources for photometric stereo (Fig. 13 ).  ... 
doi:10.1016/j.image.2015.11.006 fatcat:7x5tjnq55zfmvffeizgmpsbuly

Shape and spatially-varying BRDFs from photometric stereo

D.B. Goldman, B. Curless, A. Hertzmann, S.M. Seitz
2005 Tenth IEEE International Conference on Computer Vision (ICCV'05) Volume 1  
Using this representation we can f) re-render the object under novel lighting.  ...  We also show examples of interactive lighting and editing operations made possible by our method.  ...  Since we use multiple fixed light sources, we only calibrate the light sources once each capture session.  ... 
doi:10.1109/iccv.2005.219 dblp:conf/iccv/GoldmanCHS05 fatcat:tgsl3iwqkfc3vezibaeuqhmfdq

Shape and Spatially-Varying BRDFs from Photometric Stereo

Dan B Goldman, Brian Curless, Aaron Hertzmann, Steven M Seitz
2010 IEEE Transactions on Pattern Analysis and Machine Intelligence  
Using this representation we can f) re-render the object under novel lighting.  ...  We also show examples of interactive lighting and editing operations made possible by our method.  ...  Since we use multiple fixed light sources, we only calibrate the light sources once each capture session.  ... 
doi:10.1109/tpami.2009.102 pmid:20431131 fatcat:ncvjod6xgzd5hblvuoetmvgqq4

Depth enhancement using a scanning fiber optical endoscope

Quinn Y. J. Smithwick, Eric J. Seibel, Robert R. Alfano
2002 Optical Biopsy IV  
A novel method for interactive virtual lighting allows the surface to be illuminated from any virtual lighting direction, even those not physically possible with endoscope, for use with either monocular  ...  A radiometric dual exists between array and scanning acquisition systems, so scanning acquisition images appear to have the light source originating from the sensors and the viewpoint at the scanner location  ...  and Deguchi [7]) c. reconstructed shape using photometric stereo.  ... 
doi:10.1117/12.465249 fatcat:hefauylkobadrov7yb5lklcboa

An improved photometric stereo through distance estimation and light vector optimization from diffused maxima region

Jahanzeb Ahmad, Jiuai Sun, Lyndon Smith, Melvyn Smith
2014 Pattern Recognition Letters  
a novel method to allow us to calculate the 37 distance of an object based on the same photometric stereo imaging setup, 38 i.e. one camera and four lights, without a requirement for any additional  ...  calculating the light vector of every 125 pixel based on its distance from the camera and light source.  ... 
doi:10.1016/j.patrec.2013.09.005 fatcat:dg2di4klvrgj5o37sndqikfhse
« Previous Showing results 1 — 15 out of 1,485 results