Investigating the Applicability of Standard Software Packages for Laser Scanner Based Deformation Analyses

Transcription

1 Investigating the Applicability of Standard Software Packages for Laser Scanner Based Deformation Analyses Presented at the FIG Working Week 2017, May 29 - June 2, 2017 in Helsinki, Finland FIG Working Week Christoph Holst, Berit Schmitz, Heiner Kuhlmann University of Bonn Institute of Geodesy and Geoinformation

2 Point based deformation analysis Congruency test T = dt Q dd 1 d/h s Differences between corresponding points 2. Stochastic model F h,f,1 α Heiner Kuhlmann, Laser Scanner Based Deformation Analysis Folie 2

3 TLS-based deformation analysis 1. Corresponding points? One possiblity: Point cloud comparison 2. Stochastic model? Difficult! Many influencing factors: misconstruction of laser scanner, incidence angle, reflectivity/material/color of surface => In practice: T = dt Q dd 1 d/h s 0 2 F h,f,1 α Heiner Kuhlmann, Laser Scanner Based Deformation Analysis Folie 3

4 Point cloud comparison Possibilities implemented in standard software (e.g. 3DReshaper, CloudCompare, Geomagic Studio/Control) Cloud to cloud comparison (C2C) Cloud to mesh comparison (C2M) Mesh to mesh comparsion (M2M) Multiscale model to model cloud comparison (M3C2) Reduction of random errors Heiner Kuhlmann, Laser Scanner Based Deformation Analysis Folie 4

5 Is these point cloud comparison applicable for geodetic deformation analysis? Heiner Kuhlmann, Laser Scanner Based Deformation Analysis Folie 5

6 Case 1: Out-of-plane shape deformation blue: epoch 1 green: epoch 2 Heiner Kuhlmann, Laser Scanner Based Deformation Analysis Folie 6

7 Case 1: Out-of-plane shape deformation Yes: Large differences where shape is deformed Heiner Kuhlmann, Laser Scanner Based Deformation Analysis Folie 7

8 Case 2: In-plane rigid body movement Heiner Kuhlmann, Laser Scanner Based Deformation Analysis Folie 8

9 Case 2: In-plane rigid body movement No: Large differences only at high surface curvature Heiner Kuhlmann, Laser Scanner Based Deformation Analysis Folie 9

10 Two examples in paper Wooden panel Water dam Heiner Kuhlmann, Laser Scanner Based Deformation Analysis Folie 10

11 M3C2 (CloudCompare) Leica P20, 2 epochs: march and june 2016 [m] Shape deformation of 6 mm to water side Heiner Kuhlmann, Laser Scanner Based Deformation Analysis Folie 11

12 Conclusion At TLS-based deformation analyses, no corresponding points between epochs Detection of deformations / differences by point cloud comparison is possible Usefulness of point cloud comparison depends on direction of deformation (in-plane or out-of-plane) No stochstic model, no significance range Heiner Kuhlmann, Laser Scanner Based Deformation Analysis Folie 12

13 Thanks for your attention! Heiner Kuhlmann, Laser Scanner Based Deformation Analysis Folie 13

14 Example 1: Deformation wooden panel Heiner Kuhlmann, Laser Scanner Based Deformation Analysis Folie 14

15 Out-of-plane shape deformation Deformation of 23 mm Heiner Kuhlmann, Laser Scanner Based Deformation Analysis Folie 15

16 C2M (Geomagic Control) [m] Deformation of about 23 mm visible! Heiner Kuhlmann, Laser Scanner Based Deformation Analysis Folie 16

17 In-plane rigid body movement Translation and rotation of about mm Heiner Kuhlmann, Laser Scanner Based Deformation Analysis Folie 17

18 Moved area M2M (Geomagic Control) [m] 15 mm = Distance to wall Rigid body movement of mm not visible in results Heiner Kuhlmann, Laser Scanner Based Deformation Analysis Folie 18

19 Example 2: Deformation water dam 3 stations 2 epochs Registration by targets Heiner Kuhlmann, Laser Scanner Based Deformation Analysis Folie 19

20 2 special issues in avn AVN 6/2016 Holst, Neuner, Wieser, Wunderlich, Kuhlmann: Calibration of Terrestrial Laser Scanners Kauker, Holst, Schwieger, Kuhlmann, Schön: Spatio-Temporal Correlations of Terrestrial Laser Scanning Wujanz, Holst, Neitzel, Kuhlmann, Niemeier, Schwieger: Survey Configuration for Terrestrial Laser Scanning AVN 11/2016 Neuner, Holst, Kuhlmann: Overview on Current Modelling Strategies of Point Clouds for Deformation Analysis Wunderlich, Niemeier, Wujanz, Holst, Neitzel, Kuhlmann: Areal Deformation Analysis from Point Clouds the Challenge Bureick, Neuner, Harmening, Neumann: Curve- and Surface- Approximation of 3D-point clouds Heiner Kuhlmann, Laser Scanner Based Deformation Analysis Folie 20