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PRODID:-//Memento EPFL//
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SUMMARY:Recent Advances in Range Imaging Metrology
DTSTART:20110527T110000
DTSTAMP:20260509T074051Z
UID:0c942e46d35c1fab93a4b84753d9a77e5d31bb492679a4aed8918402
CATEGORIES:Conferences - Seminars
DESCRIPTION:Prof. Derek Lichti\, Department of Geomatics Engineering\, The
  University of Calgary\, Canada\nTime-of-flight range cameras using photon
 ic mixer device technology offer great potential for close range metrology
  as there are many perceived advantages over other optical imaging methods
  such as photogrammetry and laser scanning. Unlike passive-image photogram
 metry\, a range camera can capture 3D data from a single sensor so there i
 s no correspondence problem to solve and targeting is not required. Unlike
  a laser scanner that captures 3D point measurements in a sequential manne
 r\, a range camera features simultaneous 3D data capture of all points wit
 hin its field view. In addition\, the cost of a range camera is much lower
  than that of a laser scanner. The drawbacks of a range camera for metrolo
 gy include low sensor resolution\, low ranging accuracy and the data are c
 ontaminated by many errors that include both random sources (e.g. shot noi
 se) and systematic sources. The latter can be categorised as either scene-
 dependent errors (e.g. the internal scattering artefact) or scene-independ
 ent\, instrumental errors (e.g. lens distortion\, periodic errors).  Solut
 ions to these problems that allow the use of a range camera for precise st
 ructural deformation measurements with millimetre-level accuracy will be d
 escribed in this three-part presentation. First\, experiments to character
 ise the internal scattering artefact and proposed correction models will b
 e presented. Second\, the scene-independent errors models will be reviewed
  and a performance comparison of three self-calibration techniques for the
  model coefficient estimation will be presented and analysed. Finally\, th
 e application of range cameras to structural deformation measurement will 
 be described. Laboratory testing of reinforced concrete beams has been per
 formed to quantify the efficacy of reinforcement with steel-reinforced pol
 ymer sheets. Techniques to reduce the impact of both the scene-dependent a
 nd the random errors on deflection measurements made with a range camera w
 ill be detailed. Results obtained with a SwissRanger SR4000 range camera w
 ill be presented and compared with those from a terrestrial laser scanner 
 for accuracy assessment.
LOCATION:GC C2 413
STATUS:CONFIRMED
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