On-site surface reflectometry

The rapid development of Augmented Reality (AR) and Virtual Reality (VR) applications over the past years has created the need to quickly and accurately scan the real world to populate immersive, realistic virtual environments for the end user to enjoy. While geometry processing has already gone a long way towards that goal, with self-contained solutions commercially available for on-site acquisition of large scale 3D models, capturing the appearance of the materials that compose those models remains an open problem in general uncontrolled environments. The appearance of a material is indeed a complex function of its geometry, intrinsic physical properties and furthermore depends on the illumination conditions in which it is observed, thus traditionally limiting the scope of reflectometry to highly controlled lighting conditions in a laboratory setup. With the rapid development of digital photography, especially on mobile devices, a new trend in the appearance modelling community has emerged, that investigates novel acquisition methods and algorithms to relax the hard constraints imposed by laboratory-like setups, for easy use by digital artists. While arguably not as accurate, we demonstrate the ability of such self-contained methods to enable quick and easy solutions for on-site reflectometry, able to produce compelling, photo-realistic imagery. In particular, this dissertation investigates novel methods for on-site acquisition of surface reflectance based on off-the-shelf, commodity hardware. We successfully demonstrate how a mobile device can be utilised to capture high quality reflectance maps of spatially-varying planar surfaces in general indoor lighting conditions. We further present a novel methodology for the acquisition of highly detailed reflectance maps of permanent on-site, outdoor surfaces by exploiting polarisation from reflection under natural illumination. We demonstrate the versatility of the presented approaches by scanning various surfaces from the real world and show good qualitative and quantitative agreement with existing methods for appearance acquisition employing controlled or semi-controlled illumination setups.Open Acces

Unifying diffuse and specular reflections for the photometric stereo problem

This is the author accepted manuscript. The final version is available from IEEE via http://dx.doi.org/10.1109/WACV.2016.7477643After 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. In fact, dealing with realistic materials and lightings yields a non-linear bidirectional reflectance distribution function which is primarily difficult to parametrize and then arduous to solve. With the aim to let the photometric stereo approach face more realistic assumptions, in this work we firstly introduce a unified irradiance equation describing both diffuse and specular reflection components in a general lighting setting. After that, we define a new equation we call unifying due to its basic features modeling the photometric stereo problem for heterogeneous materials. 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. Performing a wide range of experiments, we show that this new approach overcomes state-of-the-art since it leads to a system of unifying equations which can be solved in a very robust manner using an efficient variational approach.Experimental setups were provided by Toulouse Tech Transfer, and this collaboration was funded by CNRS GdR 2286 (MIA)

Multiple View Geometry For Video Analysis And Post-production

Multiple view geometry is the foundation of an important class of computer vision techniques for simultaneous recovery of camera motion and scene structure from a set of images. There are numerous important applications in this area. Examples include video post-production, scene reconstruction, registration, surveillance, tracking, and segmentation. In video post-production, which is the topic being addressed in this dissertation, computer analysis of the motion of the camera can replace the currently used manual methods for correctly aligning an artificially inserted object in a scene. However, existing single view methods typically require multiple vanishing points, and therefore would fail when only one vanishing point is available. In addition, current multiple view techniques, making use of either epipolar geometry or trifocal tensor, do not exploit fully the properties of constant or known camera motion. Finally, there does not exist a general solution to the problem of synchronization of N video sequences of distinct general scenes captured by cameras undergoing similar ego-motions, which is the necessary step for video post-production among different input videos. This dissertation proposes several advancements that overcome these limitations. These advancements are used to develop an efficient framework for video analysis and post-production in multiple cameras. In the first part of the dissertation, the novel inter-image constraints are introduced that are particularly useful for scenes where minimal information is available. This result extends the current state-of-the-art in single view geometry techniques to situations where only one vanishing point is available. The property of constant or known camera motion is also described in this dissertation for applications such as calibration of a network of cameras in video surveillance systems, and Euclidean reconstruction from turn-table image sequences in the presence of zoom and focus. We then propose a new framework for the estimation and alignment of camera motions, including both simple (panning, tracking and zooming) and complex (e.g. hand-held) camera motions. Accuracy of these results is demonstrated by applying our approach to video post-production applications such as video cut-and-paste and shadow synthesis. As realistic image-based rendering problems, these applications require extreme accuracy in the estimation of camera geometry, the position and the orientation of the light source, and the photometric properties of the resulting cast shadows. In each case, the theoretical results are fully supported and illustrated by both numerical simulations and thorough experimentation on real data

Capturing and Reconstructing the Appearance of Complex {3D} Scenes

In this thesis, we present our research on new acquisition methods for reflectance properties of real-world objects. Specifically, we first show a method for acquiring spatially varying densities in volumes of translucent, gaseous material with just a single image. This makes the method applicable to constantly changing phenomena like smoke without the use of high-speed camera equipment. Furthermore, we investigated how two well known techniques -- synthetic aperture confocal imaging and algorithmic descattering -- can be combined to help looking through a translucent medium like fog or murky water. We show that the depth at which we can still see an object embedded in the scattering medium is increased. In a related publication, we show how polarization and descattering based on phase-shifting can be combined for efficient 3D~scanning of translucent objects. Normally, subsurface scattering hinders the range estimation by offsetting the peak intensity beneath the surface away from the point of incidence. With our method, the subsurface scattering is reduced to a minimum and therefore reliable 3D~scanning is made possible. Finally, we present a system which recovers surface geometry, reflectance properties of opaque objects, and prevailing lighting conditions at the time of image capture from just a small number of input photographs. While there exist previous approaches to recover reflectance properties, our system is the first to work on images taken under almost arbitrary, changing lighting conditions. This enables us to use images we took from a community photo collection website

Optical techniques for 3D surface reconstruction in computer-assisted laparoscopic surgery

One of the main challenges for computer-assisted surgery (CAS) is to determine the intra-opera- tive morphology and motion of soft-tissues. This information is prerequisite to the registration of multi-modal patient-specific data for enhancing the surgeon’s navigation capabilites by observ- ing beyond exposed tissue surfaces and for providing intelligent control of robotic-assisted in- struments. In minimally invasive surgery (MIS), optical techniques are an increasingly attractive approach for in vivo 3D reconstruction of the soft-tissue surface geometry. This paper reviews the state-of-the-art methods for optical intra-operative 3D reconstruction in laparoscopic surgery and discusses the technical challenges and future perspectives towards clinical translation. With the recent paradigm shift of surgical practice towards MIS and new developments in 3D opti- cal imaging, this is a timely discussion about technologies that could facilitate complex CAS procedures in dynamic and deformable anatomical regions

Proceedings: Aeronautics and Space Science

VARIABILITY IN AGN ABSORPTION LINES BASED ON HUBBLE SPACE TELESCOPE/COS DATA BALQSO KINETIC LUMINOSITY DETERMINATION WITH C III* MEASUREMENTS BREWSTER ANGLE MICROSCOPY AND CHARACTERIZATIONS OF LANGMUIR FILMS SORTING LIGHT’S TOTAL ANGULAR MOMENTUM FOR COMMUNICATION SYSTEMS THE PHOSPHORYLATION PATTERN OF RPA2, IN RESPONSE TO DOUBLE-STRAND BREAKS, DIFFERS DEPENDING ON THE LOCATION IN THE CELL AND THE PHASE OF THE CELL CYCLE THE DIOPHANTINE EQUATION Ax^4+By^4=Cz^4 IN QUADRATIC FIELDS THE SBML STANDARD TO SHARE COMPUTATIONAL MODELS OF BIOLOGICAL SYSTEMS HIGH SPEED ELECTRO-DISCHARGE DRILLING AND WIRE ELECTRODE-DISCHARGE MACHINING OF TITANIUM ALLOYS FOR AEROSPACE APPLICATIONS ROUTING OVER THE INTERPLANETARY INTERNET WIRELESS INTEGRATED RELAY SYSTEM (WIRS) HUMAN REACTIONS TO FLUCTUATING NOISE CONDITIONS AS PRODUCED BY LOW-BOOM SUPERSONIC AIRCRAFT NONINVASIVE, AMBULATORY, LONG-TERM, DEEP GASTROINTESTINAL BIOSENSOR AND IMPLANTER RECONFIGURATION PLANNING OF MODULAR ROBOT UNDER UNCERTAINTY DYNAMIC GAIT ADAPTION IN FIXED CONFIGURATION FOR MODULAR SELF-RECONFIGURABLE ROBOTS USING FUZZY LOGIC CONTROL EARLY STAGE DEVELOPMENT OF A MEDICAL DEVICE FOR NON-INVASIVE MEASUREMENT OF INTRACRANIAL PRESSURE COMPLIANT LAPAROSCOPIC SURGICAL GRASPER MODULAR JOYSTICK FOR VIRTUAL REALITY SURGICAL SIMULATION NOVEL ASSISTIVE LOCOMOTOR TOOL FOR GAIT REHABILITATION IN THE ELDERLY GAIT VARIABILITY HAS NO RELATION TO COGNITIVE PERFORMANCE ON THE PHONETIC FLUENCY TEST EFFECT OF TACTILE STIMULI ON LOCOMOTOR RHYTHM UNDERGRADUATE RESEARCH PIPELINE IN MATHEMATICS COLLEGE OF SAINT MARY ELEMENTARY SCIENCE OUTREACH PROGRAM FOSTERING STUDENT AWARENESS ON GLOBAL CLIMATE CHANGE AND ENVIRONMENTAL STEWARDSHIP THROUGH CURRICULAR AND CO-CURRICULAR ACTIVITIES AUTONOMOUS RC CAR HIGH-ALTITUDE BALLOON SOLAR PANEL VOLTAGE VARIATION MICROBENTHIC ALGAE DENSITIES IN THE DUPLIN WATERSHED ESTIMATING UNCERTAINTY OF REFLECTANCE AND ERROR PROPAGATION IN VEGETATION INDICES ESTIMATING SURFACE VISIBILITY ON THE U.S. EAST COAST: INCORPORATING THE AEROSOL VERTICAL PROFILE FROM GEOS-5 EFFECTS OF VOLCANIC EMISSIONS ON THE EARTH-ATMOSPHERE SYSTEM OBSERVING THE TRANSPORTATION OF DUST ON EARTH USING MISR ARGOS AND MICROGRAVITY FREE FLYER EVALUATION UNL LUNABOTICS TEAM: DESIGNING A ROBOT FOR THE NASA LUNABOTICS ROBOT COMPETITION DESIGN, BUILD, FLY UNIVERSITY STUDENT LAUNCH INITIATIVE EHD THIN FILM BOILING IN MICROGRAVITY ENVIRONMENTS COMBINING SATELLITE OBSERVATIONS OF FIRE ACTIVITY AND NUMERICAL WEATHER PREDICTION TO IMPROVE THE PREDICTION OF SMOKE EMISSIONS SEARCH FOR ASYMMETRIC INTERACTIONS BETWEEN CHIRAL MOLECULES AND SPIN-POLARIZED ELECTRONS AUTOIGNITION IN AN UNSTRAINED METHANOL/AIR MIXING LAYER ANALYSIS OF THE HST/COS SPECTRUM OF THE MASS OUTFLOW IN SEYFERT 1 GALAXY MRK 279 CHARACTERIZATION OF A 5.8KV SIC PIN DIODE FOR ELECTRIC SPACE PROPULSION APPLICATIONS WIRELESS POWER TRANSFER: DESIGN AND APPLICATION FORCE SENSING OF GRASPING EVENTS FOR MINIATURE SURGICAL ROBOTS UNDERSTANDING WALKING AND BREATHING COUPLING WHEN ABNORMAL BREATHING PATTERNS ARE PRESENT EXAMINING THE QUALITY OF MODIS REFLECTANCE PRODUCTS USING A FOUR-BAND SPECTRORADIOMETER INVESTIGATING LAND AND ATMOSPHERE CHARACTERISTICS DURING THE 2012 CENTRAL PLAINS DROUGHT USING MODIS AND TRMM PRODUCTS A MARXIST APPROACH TO US HISTORICAL ARCHAEOLOGY: A REVIEW AND SUMMARY OF THE HISTORY AND APPLICATION OF MARXISM ON THE FIELD OF HISTORICAL ARCHAEOLOGY IN THE US JOHN COLLIER, ANTHROPOLOGY, AND THE INDIAN NEW DEA

Proceedings: Aeronautics and Space Science

VARIABILITY IN AGN ABSORPTION LINES BASED ON HUBBLE SPACE TELESCOPE/COS DATA BALQSO KINETIC LUMINOSITY DETERMINATION WITH C III* MEASUREMENTS BREWSTER ANGLE MICROSCOPY AND CHARACTERIZATIONS OF LANGMUIR FILMS SORTING LIGHT’S TOTAL ANGULAR MOMENTUM FOR COMMUNICATION SYSTEMS THE PHOSPHORYLATION PATTERN OF RPA2, IN RESPONSE TO DOUBLE-STRAND BREAKS, DIFFERS DEPENDING ON THE LOCATION IN THE CELL AND THE PHASE OF THE CELL CYCLE THE DIOPHANTINE EQUATION Ax^4+By^4=Cz^4 IN QUADRATIC FIELDS THE SBML STANDARD TO SHARE COMPUTATIONAL MODELS OF BIOLOGICAL SYSTEMS HIGH SPEED ELECTRO-DISCHARGE DRILLING AND WIRE ELECTRODE-DISCHARGE MACHINING OF TITANIUM ALLOYS FOR AEROSPACE APPLICATIONS ROUTING OVER THE INTERPLANETARY INTERNET WIRELESS INTEGRATED RELAY SYSTEM (WIRS) HUMAN REACTIONS TO FLUCTUATING NOISE CONDITIONS AS PRODUCED BY LOW-BOOM SUPERSONIC AIRCRAFT NONINVASIVE, AMBULATORY, LONG-TERM, DEEP GASTROINTESTINAL BIOSENSOR AND IMPLANTER RECONFIGURATION PLANNING OF MODULAR ROBOT UNDER UNCERTAINTY DYNAMIC GAIT ADAPTION IN FIXED CONFIGURATION FOR MODULAR SELF-RECONFIGURABLE ROBOTS USING FUZZY LOGIC CONTROL EARLY STAGE DEVELOPMENT OF A MEDICAL DEVICE FOR NON-INVASIVE MEASUREMENT OF INTRACRANIAL PRESSURE COMPLIANT LAPAROSCOPIC SURGICAL GRASPER MODULAR JOYSTICK FOR VIRTUAL REALITY SURGICAL SIMULATION NOVEL ASSISTIVE LOCOMOTOR TOOL FOR GAIT REHABILITATION IN THE ELDERLY GAIT VARIABILITY HAS NO RELATION TO COGNITIVE PERFORMANCE ON THE PHONETIC FLUENCY TEST EFFECT OF TACTILE STIMULI ON LOCOMOTOR RHYTHM UNDERGRADUATE RESEARCH PIPELINE IN MATHEMATICS COLLEGE OF SAINT MARY ELEMENTARY SCIENCE OUTREACH PROGRAM FOSTERING STUDENT AWARENESS ON GLOBAL CLIMATE CHANGE AND ENVIRONMENTAL STEWARDSHIP THROUGH CURRICULAR AND CO-CURRICULAR ACTIVITIES AUTONOMOUS RC CAR HIGH-ALTITUDE BALLOON SOLAR PANEL VOLTAGE VARIATION MICROBENTHIC ALGAE DENSITIES IN THE DUPLIN WATERSHED ESTIMATING UNCERTAINTY OF REFLECTANCE AND ERROR PROPAGATION IN VEGETATION INDICES ESTIMATING SURFACE VISIBILITY ON THE U.S. EAST COAST: INCORPORATING THE AEROSOL VERTICAL PROFILE FROM GEOS-5 EFFECTS OF VOLCANIC EMISSIONS ON THE EARTH-ATMOSPHERE SYSTEM OBSERVING THE TRANSPORTATION OF DUST ON EARTH USING MISR ARGOS AND MICROGRAVITY FREE FLYER EVALUATION UNL LUNABOTICS TEAM: DESIGNING A ROBOT FOR THE NASA LUNABOTICS ROBOT COMPETITION DESIGN, BUILD, FLY UNIVERSITY STUDENT LAUNCH INITIATIVE EHD THIN FILM BOILING IN MICROGRAVITY ENVIRONMENTS COMBINING SATELLITE OBSERVATIONS OF FIRE ACTIVITY AND NUMERICAL WEATHER PREDICTION TO IMPROVE THE PREDICTION OF SMOKE EMISSIONS SEARCH FOR ASYMMETRIC INTERACTIONS BETWEEN CHIRAL MOLECULES AND SPIN-POLARIZED ELECTRONS AUTOIGNITION IN AN UNSTRAINED METHANOL/AIR MIXING LAYER ANALYSIS OF THE HST/COS SPECTRUM OF THE MASS OUTFLOW IN SEYFERT 1 GALAXY MRK 279 CHARACTERIZATION OF A 5.8KV SIC PIN DIODE FOR ELECTRIC SPACE PROPULSION APPLICATIONS WIRELESS POWER TRANSFER: DESIGN AND APPLICATION FORCE SENSING OF GRASPING EVENTS FOR MINIATURE SURGICAL ROBOTS UNDERSTANDING WALKING AND BREATHING COUPLING WHEN ABNORMAL BREATHING PATTERNS ARE PRESENT EXAMINING THE QUALITY OF MODIS REFLECTANCE PRODUCTS USING A FOUR-BAND SPECTRORADIOMETER INVESTIGATING LAND AND ATMOSPHERE CHARACTERISTICS DURING THE 2012 CENTRAL PLAINS DROUGHT USING MODIS AND TRMM PRODUCTS A MARXIST APPROACH TO US HISTORICAL ARCHAEOLOGY: A REVIEW AND SUMMARY OF THE HISTORY AND APPLICATION OF MARXISM ON THE FIELD OF HISTORICAL ARCHAEOLOGY IN THE US JOHN COLLIER, ANTHROPOLOGY, AND THE INDIAN NEW DEA