application of structure-from-motion photogrammetry for erosion processes monitoring
DESCRIPTION
High-resolution topographic surveying is traditionally associated with high capital and logistic costs. Low-cost photogrammetric method named “Structure-form-Motion” (SfM) is ideally suited for low-budget research and application in remote areas. The aim of this paper is to present abilities of SfM photogrammetry and its application in geomorphological terrain analysis. The focus is to show 3D point clouds and digital elevation model delivered from an image sets. Investigated sight is located in Mošćenička Draga torrential flow catchment, approx. 2km NE from Mošćenička Draga settlement, 15 km SW from Rijeka. Sight is app. 40 m wide and 40 m height. Slopes are very steep to vertical and formed in talus breccias. This sediment type has less resistance from erosion. The catchment area of Mošćenička Draga is one of research locations in Croatian-Japanese project “Risk identification and land-use planning for disaster mitigation of landslides and floods in Croatia”. Images for SfM reconstruction were taken on several occasions between 2011 and 2013. The presented 3D model delivered from an image set has adequate quality for valuable use in visualizing and quantifying slopes morphological change. Presented technique is convenient for frequent acquisition of high-resolution DEM at a fraction of the time and cost of alternative approaches.TRANSCRIPT
APPLICATION OF ‘STRUCTURE-FROM-MOTION’ PHOTOGRAMMETRY FOR EROSION PROCESSES MONITORING, MOŠĆENIČKA DRAGA EXAMPLE
Igor Ružić1, Ivan Marović1, Martina Vivoda1, Sanja Dugonjić Jovančević1, Duje Kalajžić2, Čedomir Benac1, Nevenka Ožanić1
1University of Rijeka, Faculty of Civil Engineering
2University of Rijeka, IT Services
4th Workshop of the Japanese-Croatian Project on‘Risk Identification and Land-Use Planning for Disaster Mitigation of Landslides and Floods in Croatia’
Split (Croatia), 12-14 December 2013
OU
TLINE
Structure-from-Motion photogrammetry and 3d point cloud
Digital Elevation Model
Research idea
Tools and resources
Examples
Conclusions
3
5
7
9
10
21
SFM PH
OTO
GRAM
METRY
What is Structure-from-Motion photogrammetry?
‘Structure-from-Motion’ (SfM) operates similarly as stereoscopic photogrammetry, 3-D structure can be resolved from a series of overlapping, offset images.
SfM photogrammetry:The scene geometry, camera positions and orientation are solved automatically Approach is most suited to sets of images with a high degree of overlap that capture full three dimensional structure of the scene viewed from a wide array of positions, or as the name suggests, images derived from a moving sensor
Developed in the 1990s, this technique has its origins in the computer vision community
Available various free SfM Softwares
3D PO
INT CLO
UD
3D point cloud
A point cloud is a set of data points in some coordinate system.
In a three-dimensional coordinate system, these points are usually defined by X, Y, and Z coordinates, and often are intended to represent the external surface of an object.
In geographic information system, point clouds are one of the sources to make digital elevation model of the terrain. The point clouds are also employed in order to generate 3D model of urban environment, e.g.
3D point cloud can be generated using: 3d scanners, laser scanning, terrestrial radar, photogrammetry, SfM photogrammetry etc.
DEM
HISTO
RYWhat is digital terrain model?
TERMINOLOGYDigital Elevation Model (DEM) – generic term for altitude grid
Digital Terrain Model (DTM) – ground elevation modelDigital Surface Model (DSM) – ground + cover elevation model
Digital Height Model (DHM) – cover elevation model
DTM
DSM
DHM
Robers (1957) first proposed the use of the digital computer with photogrammetry as a new tool for acquiring data for planning and design in highway engineering
Miller & LaFlamme (1958) described the development in detail and introduced the concept of the digital terrain model
“The digital terrain model (DTM) is simply a statistical representation of the continuous surface of the ground by a large number of selected points with known X, Y , Z coordinates in an arbitrary coordinate field.” – definition given by Miller & LaFlamme in 1958
DEM
DEVELO
PMEN
TDigital representation of terrain
How to produce DEM?• Existing Contour Map• Aerial Photograph• Satellite:
• Optical Remote Sensing• SAR – Synthetic Aperture Radar
• Laser Scanner• SfM Photogrammetry
RESEARCH ID
EA3D Scanner vs SfM; TLS vs SfM– James*
*James, M. R., & Robson, S., Straightforward reconstruction of 3D surfaces and topography with a camera: Accuracy and geoscience application, Journal of Geophysical Research, 117, 2012.
RESEARCH ID
EAApplications of SfM photogrammetry in geoscience – Westoby, 2012*
*Westoby, M. J., Brasington, J., Glasser, N. F., Hambrey, M. J., & Reynolds, J. M., “Structure-from-Motion” photogrammetry: A low-cost, effective tool for geoscience applications, Geomorphology, 179:, 300–314, 2012.
OFFICE WORK
FIELD WORK
TOO
LS AND
RESOU
RCESAvailable tools and resources
Photo equipment
RTK-GPS
123D Catch/ReCap (Autodesk)
CloudCompare
Matlab
3D SCANNING
3D MODELLING
DIGITAL ELEVATION MODEL (DEM)
MO
ŠĆENIČKA D
RAGA EXAM
PLEMošćenička Draga – example of monitoring area
One of research locations in Croatian-Japanese project „Risk identification and land-use planning for disaster mitigation of landslides and floods in Croatia”
LOCATIO
N O
F MO
NITO
RING
AREAMošćenička Draga – example of monitoring area
Investigation aims:• Monitoring of steep to vertical slopes formed in talus breccias• Application of SfM photogrammetry• Possible landslide• Possible landslide lake formation and debris flow• Implementation of Mošćenička Draga Early warning System
MO
NITO
RING
PROCESS
2012-11-05 2013-11-28
Mošćenička Draga – two SfM 3D Point Clouds were compared
SEDIM
ENT ACCU
MU
LATION
-15 -10 -5 0 5 10 15 20 25 30 350
5
10
15
20
25
30
35
profile 5
[m]
[m]
05-Nov-2012
28-Nov-2013
X profile 5Sediment accumulation between y axis 11m and 21m
3d Point Cloud and x profiles (-15:5:+15)
5 10 15 20 255
10
15
20
profile 5
[m]
[m]
05-Nov-2012
28-Nov-2013
SEDIM
ENT ERO
SION
-10 -5 0 5 10 15 20 25 30 350
5
10
15
20
25
30
35
profile 15
[m]
[m]
05-Nov-2012
28-Nov-2013
X profile 15Sediment erosion between y axis 11m and 21m
3d Point Cloud and x profiles (-15:5:+15)
4 6 8 10 12 14 16
3
4
5
6
7
8
9
10
11
12
profile 15
[m]
[m]
05-Nov-2012
28-Nov-2013
SEDIM
ENT ACCU
MU
LATION
3d Point Cloud and x profiles (-15:5:+15)
Y profile 20Sediment accumulation between x axis 6m and 14m
-30 -20 -10 0 10 20 30
10
15
20
25
30
35
40
45
50
55
60profil 17.5
[m]
[m]
05-Nov-2012
28-Nov-2013
2 4 6 8 10 12 14 16 18
12
14
16
18
20
22
24
profil 17.5
[m]
[m]
05-Nov-2012
28-Nov-2013
COM
PARISON
-25 -20 -15 -10 -5 0 5 10 15 20
15
20
25
30
35
40
45
50
profil 20
05-Nov-2012
28-Nov-2013
3d Point Cloud and x profiles (-15:5:+15)
Y profile 20Good profile matching
EXAMPLES
Havišće – example of field and office work
EXAMPLES
Point cloud and profiles
EXAMPLES
Visualization and results
EXAMPLES
Visualization and results
CON
CLUSIO
NS
Final remarks
Presented 3D point cloud derived from an image set has adequate quality for valuable use in
visualizing and quantifying slope morphological changes
• cloud density about 2000 points per square meter
• Standard ReCap 3D model mesh size is used (in order to get higher density it is possible to use even
higher mesh size)
• Ground Control Points – definition
This technique is convenient for frequent acquisition of high-resolution DEM at a fraction of the
time and cost of alternative approaches
One of the application of SfM photogrammetry method is monitoring of landslide movements
Possible as well in real-time landslide monitoring processes
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