Penrose_presentation_no_animation.ppt

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					The use of a laser rangefinder attached to
 a pocket PC to capture and analyze 3D
 digital geologic data in the field– a case
  study – Preston Railroad Cut, Texas

                Mohammed Alfarhan
               msfarhan@yahoo.com
                    Carlos Aiken
                aiken@utdallas.edu
                    Xueming Xu
           xuemingx@realearthmodels.com
                  John Thurmond
                Objectives
• Initial proof of concept of digital mapping.
  – Integration of GPS, lasers and portable
    computers.
  – Integration of laser gun data and fast scanner
    data
• Digital terrain by GPS and lasers.
• Real time strike and dip determination.
• Initial test of oblique photography.
Study Area Location

             Preston Canyon
Preston Canyon, Austin Chalk,
           Plano
              Laser Mapping System
Laser gun using                   Laser gun          Laser gun
memory cards                      attached to        attached to
                                     laptop           pocket pc




                   Laser
                   rangefinder

                     Encoder
                                 Portable computer
        Customization of ArcPad
• The Geological Survey of Canada was a pioneer
  in developing data logging geology with their
  GanField program using ArcPad installed in
  pocket pc with an interface to capture the data
  using GPS
• In cooperation with the GSC we are modifying
  that software using ArcPad 7 attached to a laser
  rangefinder to capture the data in real time
  digitally and display it in the field such as used in
  UTD’s Cybermap.
   Comparison between Laser Mapping System
Laser gun using memory      Laser gun using laptop      Laser gun using pocket pc
   card                                                    (ArcPad & Terrasync
                            1. Need holder to help
1. Can’t display the data      carrying the laptop      1. Light and easy to carry
   captured.                2. Can display the data     2. Can display 2D data
2. Need post process the       captured                    captured in the field
   data.                    3. Can shoot continuous     3. Can shoot single shot
3. Can shoot single or         (only laser atlanta or      only
   continuous (only laser      MDL) and single shot     4. Can save the data as
   atlanta or MDL)          4. Save the data as GIS        GIS format
                               format or text format    5. Can’t process the data
                               no need for post            in the field.
                               processing
                            5. Can display the data
                               as 2D or 3D in the
                               field.
                            6. Can process the data
                               and drape digital
                               photographs on the
                               3D model in the field
             New generation of laptop

$1700.00 - $1900.00
specifications
1GHz Transmeta Crusoe
30GB hard drive (shock-mounted)
512MB DDR RAM
Dimensions: 4.9" x 3.4" x 0.9"
Weight: 14 ounces
800 x 480 W-VGA 5" transflective display
(indoor/outdoor readable)
3D accelerated graphics with 8MB of
video RAM
QWERTY thumb keyboard with mouse
buttons and TrackStik
802.11b wireless
Bluetooth wireless
Example OCP, Sony
CyberMapping Design Flowchart




                 Laser
                 rangefinder

                    Encoder
                               Portable computer
Main Window Interface of
 CyberMapping Software
3D perspective view using
     CyberMapping
3D perspective view using ArcScene
Map view of the mapping of layer and faults
Continuously shooting Topcon total station
North side of cut, vertical section mapped by GPS
 controlled Topcon reflectorless laser mapping.
LPM and Riegl Z360 Scanner



     Riegl Z360


                    LPM
Point cloud taken by fast scanner
Triangulated Mesh
    Surface cleaning (in Polyworks)


• In draping photo the
  single most time
  consuming part of
  entire process (90%
  of time).
  – Filling the holes
    (because of scan
    shadow)
  – Correct triangles
Digital photographs draped on
       triangulated mesh
Failed attempt to drape oblique photo onto terrain by
         rubbersheeting with ESRI software

          Orthophoto draped onto terrain
The integration between laser gun data capture
  and fast scanner photorealistic 3D model
The integration between laser gun data capture
  and fast scanner photorealistic 3D model
The integration between laser gun data capture
  and fast scanner photorealistic 3D model
The integration between the data taken by
     laser gun and draped orthoquad
Converting the points to lines and surfaces
Converting the points to lines and surfaces
Converting the points to lines and surfaces
Converting the points to lines and surfaces
   3D Digitization of zoom of mesh model
     texture mapped with photography


                             Digitized layer




Surface fit to
digitized interface
to define 3D
feature
Digitizing the features using open
            scene graph
                  Conclusion
The integration between laser gun and fast scanner is
very useful.
ArcPad has limited features and the new generation of
the handheld laptop and CyberMapping and ArcGIS
installed in it will replace the pocket pc and ArcPad.
Customization is the key to make capturing the data
easier and faster. Douglas Walker in University of Kansas
was pioneer in customizing ArcView and ArcGIS
software.
In the future work we will cooperate with Walker in UK to
build an extension that will allow ArcGIS capture the data
using a laser gun and add more customization to ArcGIS.

				
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