A STUDY ON REAL-TIME PHOTOGRAMMETRY FOR ARCHAEOLOGICAL SITES 
USING WIRELESS CCD CAMERA 
Hirofumi CHIKATSU, Kazuya NAKANO, Tetsuji ANAI 
Department of Civil Engineering, Tokyo Denki University 
Hatoyama, Saitama, 350-03, Japan 
Commission V,Working Group 4 
KEY WORDS :Wireless CCD camera,Calibration,Archaeology,Site recording,matching,Real-time 
photogrammetry 
ABSTRACT 
In general, recording for archaeological sites is performed by plane-table surveying, leveling or section drawing , 
expending a great deal of time and labor. Digital photogrammetry is expected to become a useful tool in this field. 
However, time consumed in geodetic surveying for camera calibration is still an issue which needs to be resolved. By 
using information such as distance which is included in the image as proposed in this paper, time consuming aspects of 
geodetic surveying can be improved. 
This paper describes a real-time photogrammetric system for site recording using a wireless CCD camera . 
1. INTRODUCTION 
Many archaeological sites are excavated yearly in Japan. 
The number of archaeological sites amounted to over 
8,000 in 1994 and the majority of these archaeological 
sites are found at the foundational stage of a 
construction.If ^ archaeological sites are found, 
construction should be stopped during the excavation for 
site recording. In general, site recording is a slow 
process since photogrammetric techniques are not yet 
widely used in archaeology. Even in the case of 
photogrammetric techniques for site recording, it takes 
much time to develop film and to enlarge photos since a 
still camera is widely used . Consequently, finding 
archaeological sites become a severe problem not only 
for requester but also contractor. 
For real-time photogrammetry, there are two complicated 
subjects which have to be resolved. One is real-time 
camera calibration without any geodetic surveying for 
control. The second is real-time image acquisition from 
tethered balloons, kites or model helicopter. Ideally, real- 
time camera calibration without control points can be 
performed by using GPS and an optical gyro. Such 
equipment, however, is not widely used due to 
unacceptable cost. Reducing control points by utilizing 
information such as distance which are included in the 
image are considered as a calibration method that does 
not depend on this equipment. 
2.CAMERA CALIBRATION COMBINED 
WITH DISTANCE 
With regard to film camera, simultaneous adjustment of 
photogrammetric and geodetic data such as distances , 
angles, or heights has been developed by the authors( 
Chikatsu et al,1988,1989). The basic idea for the camera 
calibration combined with the constraint condition of 
82 
distance is as follows: first, let the border point on the 
measured line be control point A and let another border 
point on the same line be control point B. Similarly, let the 
border points on another measured line be control points 
Cand D. Second, let the line from point A to point B be 
the X axis and the perpendicular line at point A be the Y 
axis. Finally, let the ground coordinate of control point A 
be (0,0,0) and assume that the distance between point A 
and Bis L .The initial ground coordinate of control point B 
becomes (L,0,0) and the ground coordinate for points C 
and D can be calculated from the relationship for the 
positions on the image between Ato C and A to D (Figure 
1). 
Q;(X6, Yo, Zc) 
aso L2 s 
— uli: 4, 
  
    
    
  
dw 
B(L1,0,0) 
Figure 1 Conception for camera 
calibration combined with distance 
In the case of the CCD camera, the unknown parameters 
are as follows: exterior orientation parameters (w, ¢, « 
Xo Yo, Zp), interior orientation parameters { f, x,, y, 
(principal points), a, ‚a, (scale factor), p, (lens 
distortion)} and ground coordinate for control Points { 
B(Xg, Yg,Zg), C(Xo, Yo, Ze), DUXp, Y p, Zp))- These unknowns 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B5. Vienna 1996 
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