Direct Interaction with Large Displays Through Monocular Computer Vision

Total Page:16

File Type:pdf, Size:1020Kb

Direct Interaction with Large Displays Through Monocular Computer Vision DIRECT INTERACTION WITH LARGE DISPLAYS THROUGH MONOCULAR COMPUTER VISION A thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy in the School of Information Technologies at The University of Sydney Kelvin Cheng October 2008 © Copyright by Kelvin Cheng 2008 All Rights Reserved Abstract Large displays are everywhere, and have been shown to provide higher productivity gain and user satisfaction compared to traditional desktop monitors. The computer mouse remains the most common input tool for users to interact with these larger displays. Much effort has been made on making this interaction more natural and more intuitive for the user. The use of computer vision for this purpose has been well researched as it provides freedom and mobility to the user and allows them to interact at a distance. Interaction that relies on monocular computer vision, however, has not been well researched, particularly when used for depth information recovery. This thesis aims to investigate the feasibility of using monocular computer vision to allow bare-hand interaction with large display systems from a distance. By taking into account the location of the user and the interaction area available, a dynamic virtual touchscreen can be estimated between the display and the user. In the process, theories and techniques that make interaction with computer display as easy as pointing to real world objects is explored. Studies were conducted to investigate the way human point at objects naturally with their hand and to examine the inadequacy in existing pointing systems. Models that underpin the pointing strategy used in many of the previous interactive systems were formalized. A proof-of-concept prototype is built and evaluated from various user studies. Results from this thesis suggested that it is possible to allow natural user interaction with large displays using low-cost monocular computer vision. Furthermore, models developed and lessons learnt in this research can assist designers to develop more accurate and natural interactive systems that make use of human’s natural pointing behaviours. ii Acknowledgements I would like to thank my supervisor Masahiro Takatsuka for his continuing support and for being a fantastic supervisor throughout my degree. I would also like to thank Peter Eades for his guidance and advice over the years, and to David Vronay for his supervision and for making possible the internship at Microsoft Research Asia. I want to thank Frank Yu, Tony Huang, Adel Ahmed, Ben Yip, Calvin Cheung, Nelson Yim and Daniel Rachmat for their advice and discussions at various times during my PhD. Thanks to Shea Goyette, Henry Molina, Abhaya Parthy, Howard Lau, Jacob Munkberg, Zianlong Zhou, and Sheila Cheng for proof-reading my thesis as well as the mathematics. A big thank you to all the volunteers from my usability studies particularly the few who have participated in all of my experiments. Thank you to my family for their support and constant encouragement. My thanks to fellow students at ViSLAB and the Infovis/HUM group for providing laughter and entertainment, creating a relaxed and enjoyable working atmosphere. Thanks to the various people at workshop, dp, the administrative and academic staff at the School of IT for helping me throughout the years in various areas during my time at SIT and especially for their help with my broken laptop. Thanks for the weekly supply of milk, and in particular for providing a fantastic espresso machine to keep me going during the day. iii Finally, thank you to The University of Sydney, Faculty of Science, Capital Markets Cooperative Research Centre and Microsoft Research Asia for keeping me funded. iv Table of Contents Abstract ................................................................................................................................................. ii Acknowledgements .............................................................................................................................. iii Table of Contents .................................................................................................................................. v List of Tables ......................................................................................................................................... x List of Illustrations .............................................................................................................................. xi Chapter 1 Introduction ........................................................................................................................ 1 1.1 Human-Computer Interaction ..................................................................................................... 1 1.2 Interaction with Large Displays .................................................................................................. 2 1.2.1 Entertainment Systems ........................................................................................................ 4 1.2.2 Presentation Systems ........................................................................................................... 5 1.3 Alternate input techniques ........................................................................................................... 6 1.4 Pointing Strategies ...................................................................................................................... 9 1.5 Aim of this Thesis ......................................................................................................................... 9 1.6 Contribution of this Thesis ......................................................................................................... 11 1.7 Research Methodology .............................................................................................................. 12 1.8 Thesis Structure ......................................................................................................................... 13 Chapter 2 Background and Previous Work ..................................................................................... 15 2.1 Manipulation and Interaction .................................................................................................... 15 2.2 Graphical User Interface .......................................................................................................... 16 2.3 Handheld Intrusive Devices....................................................................................................... 18 2.4 Non-intrusive Techniques .......................................................................................................... 24 2.4.1 Sensitive Surfaces .............................................................................................................. 24 2.4.2 Computer Vision ................................................................................................................ 25 2.5 Selection Strategies ................................................................................................................... 38 v 2.5.1 Mouse click-less interfaces ................................................................................................ 38 2.5.2 Laser Pointer ...................................................................................................................... 39 2.5.3 Hand gesture ...................................................................................................................... 40 2.6 Summary .................................................................................................................................... 42 Chapter 3 Case Study – Current Interactive Methods ................................................................... 45 3.1 User Interface for the Media PC ............................................................................................... 45 3.2 Related Work ............................................................................................................................. 46 3.2.1 Input devices ...................................................................................................................... 46 3.2.2 User Interface and Interaction Design ............................................................................... 48 3.3 Hypotheses................................................................................................................................. 49 3.4 Usability Study .......................................................................................................................... 49 3.5 Apparatus .................................................................................................................................. 49 3.6 Participants ............................................................................................................................... 50 3.7 Procedure .................................................................................................................................. 51 3.8 Design ........................................................................................................................................ 51 3.9 Results ....................................................................................................................................... 52 3.10 Participants’ comments ........................................................................................................... 53 3.11 General Observations .............................................................................................................
Recommended publications
  • Depth Camera Technology Comparison and Performance Evaluation
    DEPTH CAMERA TECHNOLOGY COMPARISON AND PERFORMANCE EVALUATION Benjamin Langmann, Klaus Hartmann and Otmar Loffeld ZESS – Center for Sensor Systems, University of Siegen, Paul-Bonatz-Strasse 9-11, Siegen, Germany Keywords: Depth, Range camera, Time-of-Flight, ToF, Photonic Mixer Device, PMD, Comparison. Abstract: How good are cheap depth cameras, namely the Microsoft Kinect, compared to state of the art Time-of- Flight depth cameras? In this paper several depth cameras of different types were put to the test on a variety of tasks in order to judge their respective performance and to find out their weaknesses. We will concentrate on the common area of applications for which both types are specified, i.e. near field indoor scenes. The characteristics and limitations of the different technologies as well as the concrete hardware implementations are discussed and evaluated with a set of experimental setups. Especially, the noise level and the axial and angular resolutions are compared. Additionally, refined formulas to generate depth values based on the raw measurements of the Kinect are presented. 1 INTRODUCTION when used outdoors. Currently, ToF imaging chips reaching resolutions up to 200x200 pixels are on the Depth or range cameras have been developed for market and chips with 352x288 pixels are in several years and are available to researchers as well development and for a few years some ToF chips as on the market for certain applications for about a feature methods to suppress ambient light (e.g. decade. PMDTec, Mesa Imaging, 3DV Systems and Suppression of Background Illumination - SBI). Canesta were the companies driving the Other depth cameras or measuring devices, such development of Time-of-Flight (ToF) depth as laser scanners or structured light approaches, cameras.
    [Show full text]
  • WIMP Interfaces for Emerging Display Environments
    Graz University of Technology Institute for Computer Graphics and Vision Dissertation WIMP Interfaces for Emerging Display Environments Manuela Waldner Graz, Austria, June 2011 Thesis supervisor Prof. Dr. Dieter Schmalstieg Referee Prof. Dr. Andreas Butz To Martin Abstract With the availability of affordable large-scale monitors and powerful projector hardware, an increasing variety of display configurations can be found in our everyday environments, such as office spaces and meeting rooms. These emerging display environments combine conventional monitors and projected displays of different size, resolution, and orientation into a common interaction space. However, the commonly used WIMP (windows, icons, menus, and pointers) user interface metaphor is still based on a single pointer operating multiple overlapping windows on a single, rectangular screen. This simple concept cannot easily capture the complexity of heterogeneous display settings. As a result, the user cannot facilitate the full potential of emerging display environments using these interfaces. The focus of this thesis is to push the boundaries of conventional WIMP interfaces to enhance information management in emerging display environments. Existing and functional interfaces are extended to incorporate knowledge from two layers: the physical environment and the content of the individual windows. The thesis first addresses the tech- nical infrastructure to construct spatially aware multi-display environments and irregular displays. Based on this infrastructure, novel WIMP interaction and information presenta- tion techniques are demonstrated, exploiting the system's knowledge of the environment and the window content. These techniques cover two areas: spatially-aware cross-display navigation techniques for efficient information access on remote displays and window man- agement techniques incorporating knowledge of display form factors and window content to support information discovery, manipulation, and sharing.
    [Show full text]
  • Download Free Bumptop-3D Windows Desktop Organizer
    download free bumptop-3d windows desktop organizer Updated : Tuesday 08 June 2021 Maybe even better than free. Any file in any format can be uploaded and downloaded for free. If only we could, we surely would! On the other hand, using file can actually save you money. Why pay storage fees for a file that you just wanted to send to a friend or colleague? Also, many team chat apps have limits to the size of files that can be transferred within their apps. Files transferred the old-fashioned way tend to pile up and be forgotten about, eventually costing you money in data storage fees. Your wallet will be none-the-lighter! Just so we’re all 100% clear here: When you share a file, data is being transferred between your computer or phone andour servers, then from our servers to your friends device. Just upload the file you want to share with your friends and we send you a download link to your file.Files can be downloaded from any computer from our high speed servers. Unfortunately, we can’t make that part free. You decide who you want to share yourfiles with. Our service is completely free for everyone. filehosting provides an easy possibility for you to send large files to your friends. It is also allowed tolink to the download page from websites and communities. File is free to use with no gotchas and no hidden fees. Simply upload your file and share the link.You can give this download link to your friends by mail or instant messenger.
    [Show full text]
  • 3D Desktop Vdock Exodo Theme Free Download for Windows 7
    3d desktop vdock exodo theme free download for windows 7 click here to download 3D Abstract is a Window 7 Theme which includes 10 backgrounds of high resolution 3D shapes. This is a high resolution Windows 7. jab comics free galleries online, vengeance issential club sound vol2, look back in anger pdf torrent, 3d desktop dock exodo theme xp free download. Download Vista DreamScenes, Windows 7 Themes, Win 7 Themes, Win7 Themes, Vista Themes, XP Skins & Visual Styles and desktop themes for DesktopX, WindowBlinds, ObjectDock, Google and Vista Sidebar Gadgets, Virtual Dock 3D Exodo DesktopX Theme: vDock3D Exodo Link It's simple, and FREE! Login. 3d desktop vdock exodo theme for win7 free download the window xvid 3d desktop dock exodo theme indirPokemon FireRed LeafGreen Prima Official. Virtual Dock3D Exodo for DesktopX. (Running on Windows Vista, Intel Dual core, 2GB Ram). 3D Desktop. How to save a DesktopX theme? - Duration: Dario Arnaez 2, views · · how to download. 3d desktop free win 7 dock. Lala Karmela Satu Jam Saja (OST Satu Jam Saja). 3d desktop vdoc. 3d desktop dock exodo theme full download. 3d desktop ffor. real desktop free transforme l'écran de votre ordinateur en véritable bureau 3d, dans lequel vous Windows > 3d desktop vdock exodo theme free download. Desktop to Desktop exodo on free desktop vdock theme from 7 Pro On office 3d download Exodo 3d windows7 Para Senha vdock vdock 3g. 3D Desktop - VDock Exodo theme Опубликовано: 7 лет назад; Virtual Dock3D Exodo for DesktopX. who do things. Thain signatory overworking their pens download windows 8 paint for windows 7 64 bit edition and feeding long! corimbosa and covinous.
    [Show full text]
  • Per-Pixel Calibration for RGB-Depth Natural 3D Reconstruction on GPU
    University of Kentucky UKnowledge Theses and Dissertations--Electrical and Computer Engineering Electrical and Computer Engineering 2016 Per-Pixel Calibration for RGB-Depth Natural 3D Reconstruction on GPU Sen Li University of Kentucky, [email protected] Author ORCID Identifier: http://orcid.org/0000-0001-9906-0481 Digital Object Identifier: https://doi.org/10.13023/ETD.2016.416 Right click to open a feedback form in a new tab to let us know how this document benefits ou.y Recommended Citation Li, Sen, "Per-Pixel Calibration for RGB-Depth Natural 3D Reconstruction on GPU" (2016). Theses and Dissertations--Electrical and Computer Engineering. 93. https://uknowledge.uky.edu/ece_etds/93 This Master's Thesis is brought to you for free and open access by the Electrical and Computer Engineering at UKnowledge. It has been accepted for inclusion in Theses and Dissertations--Electrical and Computer Engineering by an authorized administrator of UKnowledge. For more information, please contact [email protected]. STUDENT AGREEMENT: I represent that my thesis or dissertation and abstract are my original work. Proper attribution has been given to all outside sources. I understand that I am solely responsible for obtaining any needed copyright permissions. I have obtained needed written permission statement(s) from the owner(s) of each third-party copyrighted matter to be included in my work, allowing electronic distribution (if such use is not permitted by the fair use doctrine) which will be submitted to UKnowledge as Additional File. I hereby grant to The University of Kentucky and its agents the irrevocable, non-exclusive, and royalty-free license to archive and make accessible my work in whole or in part in all forms of media, now or hereafter known.
    [Show full text]
  • Motion Capture Technologies 24
    MOTION CAPTURE TECHNOLOGIES 24. 3. 2015 DISA Seminar Jakub Valcik Outline Human Motion and Digitalization Motion Capture Devices Optical Ranging Sensor Inertial and Magnetic Comparison Human Motion Brain + Skeleton + Muscles Internal factors External Factors Musculature Shoes Skeleton Clothes Weight Type of surface Injuries Slope of surface Movement habits Wind Pregnancy Gravity State of mind Environment Motion Capture 푛 Sequence of individual frames 푚 = (푓푘)푘=1 Captured information Static body configuration Position in space Orientation of body Silhouette vs. Skeleton Appearance Based Approaches Eadweard Muybridge, 1878 Boys Playing Leapfrog, printed 1887 Appearance Base Approaches Originally only regular video cameras, CCTV Silhouette oriented 푓푘 ≔ 퐵푘 푥, 푦 ∈ {0, 1} Silhouette extraction is a common bottleneck Model Based Approaches Additional abstraction – 2D, 3D Stick figure, volumetric model, … Skeleton Joint (or end-effector), Bone Undirected acyclic graph 퐽 – tree Joint ~ Vertex, Bone ~ Edge 3×|푉 퐽 | Static configuration ~ Pose 푝 ∈ ℝ 푛 푛 푚 = (푓푘)푘=1= (푝푘)푘=1 Motion Capture Devices Optical Both, appearance and Markerless model based approaches Invasive Inertial Magnetic Only model based Mechanical approaches Radio frequency Optical Markerless MoCap Devices 3D scene reconstruction Multiple views Depth sensors RGB stereoscopic cameras Multiple synchronized cameras Additional sensors Silhouette extraction Depth sensing IR camera, ranging sensor Ranging Sensor - Triangulation Laser
    [Show full text]
  • Enriching the Desktop Metaphor with Physics, Piles and the Pen
    Enriching the Desktop Metaphor with Physics, Piles and the Pen by Anand Agarawala A thesis submitted in conformity with the requirements for the degree of Master of Science Graduate Department of Computer Science University of Toronto © Copyright by Anand Agarawala 2006 Abstract Enriching the Desktop Metaphor with Physics, Piles and the Pen Anand Agarawala Master of Science Graduate Department of Computer Science University of Toronto 2006 We explore making virtual desktops behave in a more physically realistic manner by adding physics simulation and using piling instead of filing as the fundamental organizational structure. Objects can be casually dragged and tossed around, influenced by physical characteristics such as friction and mass, much like we would manipulate objects in the real world. In addition we explore giving icons the affordances of paper supporting crumpling, creasing and pinning up to the walls for annotation. To manipulate and browse piles we integrate advances in techniques and propose our own novel set. We present a prototype, called BumpTop, that coherently integrates a variety of interaction and visualization techniques optimized for pen input we have developed to support this new style of desktop organization. Encouraging results of a user evaluation are also presented in which participants were able to complete 88% of tasks and find the interface enjoyable and satisfying. i Acknowledgements During my time at the University of Toronto, I developed in a few ways. I moved away from home, matured and grew up a little, gained some intellectual capacity, gained some pounds and my first grey hairs, gained the affectionate nickname “crispy”, gained several friends through a multitude of good times, infamously embarrassed myself, got to meet some interesting people like Master T and be in the proximity of others (Rick Mercer, Naomi Klein, JRS-One), and had my ego destroyed and rebuilt numerous times.
    [Show full text]
  • Lecture 1: Course Introduction and Overview
    MIT Media Lab MAS 131/ 531 Computational Camera & Photography: Camera Culture Ramesh Raskar MIT Media Lab http://cameraculture.media.mit.edu/ MIT Media Lab Image removed due to copyright restrictions. Photo of airplane propeller, taken with iPhone and showing aliasing effect: http://scalarmotion.wordpress.com/2009/03/15/propeller-image-aliasing/ Shower Curtain: Diffuser Courtesy of Shree Nayar. Used with permission. Source: http://www1.cs.columbia.edu/CAVE/projects/ separation/occluders_gallery.php Direct Global A Teaser: Dual Photography Projector Photocell Figure by MIT OpenCourseWare. Images: Projector by MIT OpenCourseWare. Scene Photocell courtesy of afternoon_sunlight on Flickr. Scene courtesy of sbpoet on Flickr. A Teaser: Dual Photography Projector Photocell Figure by MIT OpenCourseWare. Images: Projector by MIT OpenCourseWare. Scene Photocell courtesy of afternoon_sunlight on Flickr. Scene courtesy of sbpoet on Flickr. A Teaser: Dual Photography Projector Camera Figure by MIT OpenCourseWare. Scene Images: Projector and camera by MIT OpenCourseWare. Scene courtesy of sbpoet on Flickr. The 4D transport matrix: Contribution of each projector pixel to each camera pixel projector camera Figure by MIT OpenCourseWare. Photo courtesy of sbpoet on Flickr. Scene Images: Projector and camera by MIT OpenCourseWare. Scene courtesy of sbpoet on Flickr. The 4D transport matrix: Contribution of each projector pixel to each camera pixel projector camera Figure by MIT OpenCourseWare. Scene Images: Projector and camera by MIT OpenCourseWare. Sen et al, Siggraph 2005 Scene courtesy of sbpoet on Flickr. The 4D transport matrix: Which projector pixel contributes to each camera pixel projector camera Figure by MIT OpenCourseWare. ? Scene Images: Projector and camera by MIT OpenCourseWare. Sen et al, Siggraph 2005 Scene courtesy of sbpoet on Flickr.
    [Show full text]
  • Research Article Human Depth Sensors-Based Activity Recognition Using Spatiotemporal Features and Hidden Markov Model for Smart Environments
    Hindawi Publishing Corporation Journal of Computer Networks and Communications Volume 2016, Article ID 8087545, 11 pages http://dx.doi.org/10.1155/2016/8087545 Research Article Human Depth Sensors-Based Activity Recognition Using Spatiotemporal Features and Hidden Markov Model for Smart Environments Ahmad Jalal,1 Shaharyar Kamal,2 and Daijin Kim1 1 Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea 2KyungHee University, Suwon, Republic of Korea Correspondence should be addressed to Ahmad Jalal; [email protected] Received 30 June 2016; Accepted 15 September 2016 Academic Editor: Liangtian Wan Copyright © 2016 Ahmad Jalal et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Nowadays, advancements in depth imaging technologies have made human activity recognition (HAR) reliable without attaching optical markers or any other motion sensors to human body parts. This study presents a depth imaging-based HAR system to monitor and recognize human activities. In this work, we proposed spatiotemporal features approach to detect, track, and recognize human silhouettes using a sequence of RGB-D images. Under our proposed HAR framework, the required procedure includes detection of human depth silhouettes from the raw depth image sequence, removing background noise, and tracking of human silhouettes using frame differentiation constraints of human motion information. These depth silhouettes extract the spatiotemporal features based on depth sequential history, motion identification, optical flow, and joints information. Then, these features are processed by principal component analysis for dimension reduction and better feature representation.
    [Show full text]
  • Multiple View Geometry for Video Analysis and Post-Production
    University of Central Florida STARS Electronic Theses and Dissertations, 2004-2019 2006 Multiple View Geometry For Video Analysis And Post-production Xiaochun Cao University of Central Florida Part of the Computer Sciences Commons, and the Engineering Commons Find similar works at: https://stars.library.ucf.edu/etd University of Central Florida Libraries http://library.ucf.edu This Doctoral Dissertation (Open Access) is brought to you for free and open access by STARS. It has been accepted for inclusion in Electronic Theses and Dissertations, 2004-2019 by an authorized administrator of STARS. For more information, please contact [email protected]. STARS Citation Cao, Xiaochun, "Multiple View Geometry For Video Analysis And Post-production" (2006). Electronic Theses and Dissertations, 2004-2019. 815. https://stars.library.ucf.edu/etd/815 MULTIPLE VIEW GEOMETRY FOR VIDEO ANALYSIS AND POST-PRODUCTION by XIAOCHUN CAO B.E. Beijing University of Aeronautics and Astronautics, 1999 M.E. Beijing University of Aeronautics and Astronautics, 2002 A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the School of Electrical Engineering and Computer Science in the College of Engineering and Computer Science at the University of Central Florida Orlando, Florida Spring Term 2006 Major Professor: Dr. Hassan Foroosh °c 2006 by Xiaochun Cao ABSTRACT 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.
    [Show full text]
  • Evaluation of Microsoft Kinect 360 and Microsoft Kinect One for Robotics and Computer Vision Applications
    UNIVERSITÀ DEGLI STUDI DI PADOVA DIPARTIMENTO DI INGEGNERIA DELL’INFORMAZIONE Corso di Laurea Magistrale in Ingegneria Informatica Tesi di Laurea Evaluation of Microsoft Kinect 360 and Microsoft Kinect One for robotics and computer vision applications Student: Simone Zennaro Advisor: Prof. Emanuele Menegatti Co-Advisor: Dott. Ing. Matteo Munaro 9 Dicembre 2014 Anno Accademico 2014/2015 Dedico questa tesi ai miei genitori che in questi duri anni di studio mi hanno sempre sostenuto e supportato nelle mie decisioni. 2 Gli scienziati sognano di fare grandi cose. Gli ingegneri le realizzano. James A. Michener 3 TABLE OF CONTENTS Abstract ......................................................................................................................................................... 6 1 Introduction .......................................................................................................................................... 7 1.1 Kinect XBOX 360 ............................................................................................................................ 7 1.1.1 Principle of depth measurement by triangulation ................................................................ 7 1.2 Kinect XBOX ONE ........................................................................................................................ 10 1.2.1 Principle of depth measurement by time of flight .............................................................. 13 1.2.2 Driver and SDK ...................................................................................................................
    [Show full text]
  • THE Tof CAMERAS
    NEW SENSORS FOR CULTURAL HERITAGE METRIC SURVEY: THE ToF CAMERAS Filiberto CHIABRANDO1, Dario PIATTI2, Fulvio RINAUDO2 1Politecnico di Torino, DINSE Viale Mattioli 39, 10125 Torino, Italy, [email protected] 2 Politecnico di Torino, DITAG Corso Duca Degli Abruzzi 24 , 10129 Torino, Italy, [email protected], [email protected] Keywords: Time-of-Flight, RIM, calibration, metric survey, 3D modeling Abstract: ToF cameras are new instruments based on CCD/CMOS sensors which measure distances instead of radiometry. The resulting point clouds show the same properties (both in terms of accuracy and resolution) of the point clouds acquired by means of traditional LiDAR devices. ToF cameras are cheap instruments (less than 10.000 €) based on video real time distance measurements and can represent an interesting alternative to the more expensive LiDAR instruments. In addition, the limited weight and dimensions of ToF cameras allow a reduction of some practical problems such as transportation and on-site management. Most of the commercial ToF cameras use the phase-shift method to measure distances. Due to the use of only one wavelength, most of them have limited range of application (usually about 5 or 10 m). After a brief description of the main characteristics of these instruments, this paper explains and comments the results of the first experimental applications of ToF cameras in Cultural Heritage 3D metric survey. The possibility to acquire more than 30 frames/s and future developments of these devices in terms of use of more than one wavelength to overcome the ambiguity problem allow to foresee new interesting applications. 1.
    [Show full text]