REPEATED OBJECT RECONSTRUCTION OF THE BREMEN HANSE COG 
M. Wiggenhagen, A. Elmhorst, U.WiBmann 
Institute of Photogrammetry and GeoInformation (IPI), University of Hannover 
Nienburger Str. 1, D-30167 Hannover, Germany 
(wigge,elmhorst,wissmann)@ipi.uni-hannover.de 
Commision V, WG 1 
KEY WORDS: Photogrammetry, Archeology, Reconstruction, Visualization 
ABSTRACT: 
Today the Bremen Hanse Cog is on display in the German Maritime Museum (Deutsches Schifffahrtsmuseum) in Bremerhaven. The 
cog was found in October 1962 in the river Weser and was prepared in conservation liquid between 1982 and 1999 (DSM, 2003b; 
Hoffmann, 1981). 
In 1982 the Institute of Photogrammetry and GeoInformation (IPI) used a metric camera SMK 120 to take about 80 analogue images 
of the cog from several directions. With additional geodetic measurements, signalised vertical lines and tie points the three- 
dimensional point cloud was calculated and line drawings from three directions of the cog were plotted. 
After 17 years of conservation distortions in the range of +/-10 - 25 cm of several parts of the wooden cog were detected. In 2003 
over 100 images were taken with digital cameras to carry out the photogrammetric object reconstruction and calculation of a point 
cloud of the cog again. To reconstruct the profiles measured in 1982 the profile lines have been visualized with white tape 
comparing the historic analogue drawings with the current surface of the ship. In 1982 the three dimensional data was calculated 
from overlapping stereo image pairs. Today the point cloud has been calculated by image coordinate measurements in convergent 
digital images and the application of the adjustment software PhotoModeler 5.0 Pro from Eos Systems Inc. This paper deals with the 
documentation of the photogrammetric measurement and adjustment process, the visualisation of results and the comparison of the 
measured profiles of the cog after 21 years. 
KURZFASSUNG: 
Heute wird die Bremer Hanse Kogge im Deutschen Schifffahrtsmuseum in Bremerhaven ausgestellt. Die Kogge wurde im Oktober 
1962 in der Weser gefunden und zwischen 1982 und 1999 in Konservierungsflüssigkeit prüpariert. 1982 nutzte das IPI die 
Messkamera SMK 120 um etwa 80 Messbilder der Kogge aus unterschiedlichen Richtungen anzufertigen. Mit zusätzlichen 
geodätischen Messungen, signalisierten vertikalen Profilen und Verknüpfungspunkten wurde die dreidimensionale Punktwolke 
berechnet und Strichzeichnungen der Kogge angefertigt. Nach 17 Jahren in der Konservierungsflüssigkeit wurde festgestellt, dass 
sich mehrere Bereiche der hólzernen Kogge um -/- 10 bis 25 cm verformt hatten. 2003 wurden über 100 Photos mit digitalen 
Kameras aufgenommen, um die photogrammetrische Objektrekonstruktion erneut durchzuführen. Um die im Jahre 1982 gemessenen 
Profile rekonstruieren zu können, wurden diese mit weißem Band auf der Schiffsoberfläche markiert. 1982 wurde das 
dreidimensionale Objektmodell aus überlappenden Stereoaufnahmen berechnet. 2003 wurde die Punktwolke durch 
Bildkoordinatenmessung in konvergenten digitalen Bildern unter der Anwendung der Software PhotoModeler 5.0 Pro. der Firma 
Eos Sytems Inc. berechnet. Dieser Beitrag beschreibt die photogrammetrische Messung und Ausgleichung, die Darstellung der 
Ergebnisse und den Vergleich der gemessenen Profile nach 21 Jahren. 
1. INTRODUCTION 
1.2 Current requirements 
1.1 Historical background 
In the year 2003 several deformations of the cog have been 
The three dimensional object reconstruction with photo- detected in the range of 10 to 25 cm. To ensure a flexible and 
grammetric methods was based in the past on the application of 
the analogue metric camera SMK 120 and the stereo image 
measurement with the Stereoplanigraph C8. In 1982 the 
documentation of the complete Bremen Hanse Cog consisted of 
line drawings of the wooden surface and plotted profiles in ten 
locations perpendicular to the main axis of the ship. The line 
drawings have been used by the museum specialists to 
reconstruct the wooden body of the cog the profiles were 
required to control the deformation of the cog while fixing it in 
the exhibition hall (Weski, 1999; DSM, 2003a; GNT, 2003). 
cost saving solution for the object reconstruction and 
deformation measurement digital cameras, a free convergent 
image bundle, and PC-based photogrammetric image 
measurement and triangulation methods have been used. 
Depending on local conditions and the applied cameras the 
image scale was calculated between 1: 929 up to 1 : 114. 
The customer again was interested in line drawings of the ten 
profiles which have been processed and exported in 
AUTOCAD DXF-format. 
    
   
    
    
    
  
  
  
  
   
   
    
  
   
   
   
   
    
  
    
  
   
   
  
  
    
   
     
  
   
  
  
    
   
    
   
   
    
   
   
   
   
    
  
  
  
   
  
Internatioi 
2.1 Obje 
The Brem 
exhibition 
diagonals 
fixing it * 
dimension: 
museum a 
first floor, 
restrictd tc 
walls and 
been used 
necessary | 
2.2 Histo 
The histor 
the woode 
measured | 
photogram 
have been 
deformatio 
points havi 
with white 
2.3 Digit: 
For the phe 
used. The 
Megapixel 
before wi 
calibration 
signalisatic 
Most of t 
signalisatio 
and image 
the PC. 
Due to the 
conditions 
With the I 
Nikon D: 
photogrami 
24.4 Coorc 
Prior to th 
was calcula 
Camer: 
ROLLE 
Sensor wi 
Focal lens 
NIKON 
Sensor wi 
Focal lens 
  
The calcula 
mm fulfille