ON MULTI-IMAGE RECONSTRUCTION FROM HISTORIC PHOTOGRAPHS 
I. Kalisperakis b , M. Rova a , E. Petsa 3 , G. E. Karras b 
a Department of Surveying, Technological Educational Institute of Athens, GR-12210 Athens, Greece (petsa@teiath.gr) 
a Department of Surveying, National Technical University of Athens, GR-15780 Athens, Greece (ilias_k, gkarras@central.ntua.gr 
KEY WORDS: Calibration, Orientation, Non-Metric, Bundle, Reconstruction, Visualization, Architectural Heritage Conservation 
ABSTRACT 
The ultimate purpose of this work is to reconstruct photogrammetrically a distinguished building in the centre of Athens, which has 
been tom down years ago. Five old photographs were available taken apparently with the same camera, the nominal calibration para 
meters of which could be somehow ‘guessed’. As a first step, it was decided to employ our own bundle-adjustment software, which 
works within a commercial CAD environment. Besides, unlike most commercially available 3D reconstruction software, it allows full 
control over the whole adjustment process (by presenting individual image point residuals, producing RMS errors for check points, 
accommodating additional calibration parameters etc.). A second task was to compare these results with PhotoModeler, in order to 
evaluate this widely used (but in certain aspects ‘obscure’) tool against a rigorous photogrammetric approach. Besides solutions with 
no control information, a few full and partial control points were established from existing architectural drawings, allowing self-cali 
bration procedures. The two software tools produced essentially equivalent results, thus validating the precision of the PhotoModeler 
approach. However, certain additional features of a proper bundle adjustment program (e.g. recovery of radial lens distortion, self-ca 
libration with minimal or unconventional control), discussed here, may allow a fuller exploitation of the powerful reconstruction and 
visualisation tools of the PhotoModeler type. It was confirmed that, using suitable software, rigorous approaches can be applied to 
historic images, and results of reasonable precision may be expected, limited only by possible inaccuracies in scale. 
1. INTRODUCTION 
Working with historic images (and regrettably this is not all that 
rare) represents one of the most challenging aspects of architec 
tural photogramme try. The facts that these mostly depict objects 
which no longer exist and, hence, cannot be surveyed or photo 
graphed anew; that very often no control information is at hand; 
that the cameras may be unknown; that these photographs have 
mostly been taken at random - these facts point to the difficulty 
facing the photogrammetrist. Single-image techniques, to which 
C1PA Task Group 2 is dedicated, is a topic most studied as re 
gards typically structured man-made objects (Brauer-Burchardt 
& Voss, 2001; Petsa et al., 2001; van den Heuvel, 2001). To a 
certain extent, one might say, the methods could be somewhat 
standardised in such cases. If overlapping images are available, 
more options are open, depending on the existing additional in 
formation. Double-image or multi-image solutions may be con 
sidered, either employing rigorous photogrammetric approaches 
or using the commercially available (essentially user-oriented) 
3D reconstruction tools. 
At the present example, both options were taken using the well- 
established PhotoModeler (3.1) tool and our own bundle adjust 
ment software. Commercial programs, like 3DBuilder or Photo 
Modeler, have two main aspects. On the one hand, they provide 
tools allowing fast production of results. Besides, although it is 
highly questionable whether non-expert users can in fact handle 
even mildly complicated cases, such programs have greatly con 
tributed to the acceptance of photogrammetry in architectural or 
archaeological documentation. On the other hand, however, as 
they do not address the photogrammetrist, they are in no need to 
offer a full documentation of the algorithms. As a consequence, 
certain aspects remain obscure, and at some points one may not 
be sure as to how results have been obtained, which is the actual 
accuracy, whether any assumptions have been made etc. In the 
framework of the 3D reconstruction of a demolished building in 
Athens, several of the above issues have also been investigated. 
Built in 1870 by an unknown architect, the ‘Tsopotos’ residence 
was, until its demolition, a characteristic Athenian house, partly 
imitating a particular ancient Greek monument (Fig. 1). 
Figure 1. The ‘Tsopotos’ residence painted by the distinguished 
poet and painter N. Egonopoulos (Egonopoulos, 2001). 
2. IMAGES AND SOFTWARE 
2.1 The historic photographs 
Five medium format historic photographs of this building were 
available (Fig. 2). Although it is was obvious that they had been 
acquired at different times, the photographer was known to the 
source (EA1A Archives), and it was assumed that in all probabi 
lity the same camera, with a normal 80 mm lens, had been used. 
This was confirmed by using two vanishing points on images, 
which (ignoring the principal point) are sufficient for an estima 
tion of the camera constant. 
2.2 The bundle adjustment program 
Besides PhotoModeler, as mentioned already, our own bundle 
adjustment software was used. This particular program, named