A. Georgopoulos, Ch. Ioannidis, S. Tapinaki, S. Ioakeim, I. Papageorgaki Laboratory of Photogrammetry School of Rural & Surveying Engineering National Technical University of Athens (NTUA) From Imagery to map: digital photogrammetric technologies – Attica October 2009

Overview Introduction The Photogrammetry Lab of NTUA Educational & Research activities Instrumentation (H/W – S/W) The contribution of Racurs PHOTOMOD ® Close Range application Aerial photogrammetric application Conclusions

The Laboratory of Photogrammetry Established in 1917 Education in Photogrammetry and Cadastre (and Remote Sensing until 1988) 3 Faculty members in Photogrammetry 3 Supporting staff (2 Surv. Eng – 1 technical) 10 PhD students

Educational Activities Photogrammetry courses (undergraduate) 2 compulsory (100 students per year) Photogrammetry I & II (5 th & 6 th sem.) 3 electives Photogrammetry III (7 th sem.) Photographic Data Acquisition (8 th sem.) Photogrammetry summer field course (9 th sem.) Contribution in Metrology (8 th sem.) Postgraduate courses

Research Activities Digital photogrammetric procedures Digital automation Exploitation of innovative acquisition systems (LiDAR, SAR etc.) Close Range Applications Geometric Documentation of Monuments

Instrumentation Data Acquisition Systems 2 Digital Cameras (8MP, 21MP) Photogrammetric scanner (Z/I PhotoScan ®) Terrestrial Laser Scanner (Leica ScanStation 2 ®) Structured Light Scanner (XYZRGB SL2) Digital Photogrammetric Workstations Z/I SSK ® Leica LPS ® Autometric Softplotter ® RACURS Photomod ®

RACURS PHOTOMOD ® full local suite PHOTOMOD Core PHOTOMOD AT PHOTOMOD SolverA PHOTOMOD SolverS PHOTOMOD DTM PHOTOMOD Mosaic PHOTOMODStereoDraw PHOTOMOD VectOr

Contribution Education Demo in class (Photogrammetry I) Laboratory exercise (Photogrammetry II) Extensive use in the practical courses Research Implementation in Diploma Theses Use in related research projects

Implementation Examples Close Range Geometric Documentation of a Church in Cyprus Aerial Phtoogrammetry Alternative method for measuring the Classical Marathon Course

Photogrammetric station PHOTOMOD ® Interior orientation Exterior orientation DEM collection Orthophoto Exterior orientation DTM Collection Orthophoto Archis ® Image rectification 10 Geometric Documentation of a Church in Cyprus

Products Façades Horizontal Section Cross-Sections

Alternative method for measuring the Classic Marathon Course

34 colour aerial photos, 2005 Z/I RMK Top (c = mm) Scale 1:15000 Colour diapositives scanned at 21μm 550 MB per frame

Alternative method for measuring the Classic Marathon Course Aerial images distribution

Alternative method for measuring the Classic Marathon Course Relative Orientation: 0,003 – 0,012 mm Absolute Orientation using bundle adjustment 17 GCPs 2 Iterations RMS 0.09m in X,Y and Z DTM Automatic ~ 25% erroneous (buildings or large homogenous areas) Orthophoto production

Orthophotography

Conclusions Advantages Easy to learn Accepts many image formats Flexible in pointing during RO and AO Disadvantages Slow in opening images Problematic in displaying stereo vision Suggestion Incorporation of rectification algorithm