that 
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the 
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from 
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ment 
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ngs, 
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Though roots of electric poles or manhole lids 
could be easily found everywhere, they were 
intentionally excluded, because the center of a 
root of an electric pole is difficult to find and 
manhole lids are not clearly imaged. In some 
places with no signs on roads or parks, however, 
those points were unavoidably included. 
Since, unlike with GOKUU, simultaneous observation 
is impossible with BC-1, the judgment on whether 
signs on roads had been redrawn or not was in some 
cases difficult. The operator excluded such points 
as have very different displacements from the 
trend of surrounding points. But we are stil] 
afraid of some points being mis- identified. Eig.7 
and 8 show a part of obtained horizontal and 
vertical displacement maps respectively. 
6.CONCLUSION 
This paper describes the constitution and func- 
tions of a digital-image-based plotter GOKUU with 
a special interest on the modified least squares 
correlation for matching orientation points. 
GOKUU's measurement performance was presented in 
the experimental application to the project of 
measurement of ground displacement in the Kobe 
earthquake. The measurement precision was compared 
with an analytical plotter, BC-1. According to an 
experiment, both the positional and densitometric 
resolutions were shown to be insufficient for 
precision measurement. But in turn GOKUU was 
proved far advantageous in simultaneous and 
comparative observation of images by operators to 
identify corresponding points in the photographs 
taken before and after the earthquake. 
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Ackermann,F.(1984), Digital Image Correlation in 
Photogrammetry,Photogrammetric Record, 11(64), 
pp.429-439 
Hattori,S., S.Murai and H.Ohtani (1989), A Semi- 
automatic Terrain Measurement System for Earthwork 
Control, PE&RS, 55(5),pp.573-579 
Hattori,S., S.Gyoji, A. Seki,et.al(1994), Develop- 
ment of a Fully Software-Oriented Digital Image- 
Based Plotter in ISPRS Proc. of the Com.V Symp. on 
Close Range Techniques and Machine Vision, 
Melbourne, Australia, Vol.XXX, Part5, pp.155-162 
Iannino,A. and Shapiro,S.D.(1979), An Iterative 
Generalization of the  Sobel Edge Detection 
Operator, proc. of IEEE on PR&IP, pp.130-137 
Nolette,C., P.-A Gagnon, and J.-P.Agnard(1992),The 
DVP: Design, Operation and Performance, PE&RS, 
58(1), pp.65-69 
151 
Okamoto, A.,et.al.(1996), Report on Damages in 
the Hanshin,Awaji Big Earthquake (In Japanese) 
W.H.Press, S.A.Teukolsky, W.T. Vetterling and 
B.P.Flannery (1992) ,Numerical Recipes in. C, 
pp.125-128, Cambridge 
  
  
  
Fig.1 Screen Design of COMPARATOR MODE 
  
fur. Detiee Scope y 
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Fig.2 Screen Design of RECTIFICATION 
  
Fig.3 Screen Design of PLOTTER MODE 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B2. Vienna 1996