Low Cost Aerial Mapping with Consumer-Grade Drones

107 Pages·2017·10.91 MB·English

Introduction to
Photogrammetry
Presented By:
Sasanka Madawalagama
Geoinformatics Center
Asian Institute of Technology
Thailand www.geoinfo.ait.asia
Content
• Introduction to photogrammetry
• 2D to 3D
• Drones for mapping how it works
• Cameras
• Cameras for drones
• Image formation
• Elements of camera
• Lens distortions
• Illuminance, Aperture and Depth of field
• Images
• Photogrammetric processing
• Flight planning
• Photogrammetric GCPs
2
Photogrammetry
Photo - light
gramma - something drawn
metrein - measure
Photogrammetry = measuring with photographs
Objective is…
Inverse the process of photography (i.e. reconstruction of the object space
from image space).
Results can be,
• Topographical/Planimetric/Thematic maps
• Coordinates of the required object points
• Rectified Photos
3
From Object to Image
4
Inverted Mapping
5
2D  3D Why?
Can you used aerial photograph as a map directly?
Single Point
Perspective
The photo scale is different at the tops of the buildings than at
the street level. The tops of the building are displaced radially
outward relative to their location at the center.
6
2D  3D Why?
Can you used aerial photograph as a map directly?
7
2D  3D Why?
Can you used aerial photograph as a map directly?
Relief Displacement 8
How to prepare maps from Aerial Photographs?
Central
3D Aerial Photo -2D
Projection
Real World
Orthogonal
Map -2D Ground Model -3D
Projection
9
2D  3D
10