A NEW SYSTEM OF SURFACE MEASUREMENT 
N.Kochi,H.Ohtani,S.Nakamura, T. Utiyama,M. Yamada,M.Chida, T. Noma, T.Ito,H.Aokı 
Topcon Corporation 
75-1,Hasunuma-Cho,Itabashi-ku, Tokyo,174 Japan 
Commission V /3 
KEYWORDS: surface measurement, CCD camera, digital plotter, correlation, CAD, close-range photogrammetry 
ABSTRACT: 
The objective of our research is to create a practical "new system of surface measurement". It is the 
system to measure the body surface irregularity and curve by means of highly accurate 3D measurement 
through photogrammetry. 
Lately, the exterior characteristics of a train body, for example, are increasingly diversified in its form, 
color, length etc. For example, often times, its surface is plain without design, or sandy with 
sandblasting or simply lustrous, or three dimensionally deep with curve, all of which characteristics 
make it so much more difficult to measure by automatic stereo-matching. Besides, when an object to be 
measured is large, not only more accurate but also faster measurement will be necessary. 
The system we have developed consists of an image acquiring part of two high-resolution CCD cameras 
(16.77 million pixels) and an image analyzing part of stereo-image-workstation PI-1000. And its 
measurement is done with the automatic stereo-matching mode based on "the coarse-to-fine correlation". 
Through the analysis of our PI-1000 we can obtain the image with stereo-contour-lines, the perspective 
view as well as the cross section of an object. Besides, the data obtained by our PI-1000 can be output in 
multi-applicable format (DXF) of CAD, and thus can be used for many purposes. 
Therefore, as a preliminary experiment we executed the stereo-matching on various simulated surfaces 
and measured the accuracy of our system. And then we proceeded to test it actually on the flat surface of 
a real train of stainless steel as well as on the nose (length 1m, width 3m, depth 1m) of a bullet train of 
Japan Railway for 3D measurement. 
This paper will explain the general outline of our system, the data of the above tests and their inputting 
into CAD systems as an example of the CAD application. 
the focal length is changeable, its principal point 
does not fluctuate. And for camera lens, we have 
1.INTRODUCTION developed a special and low-cost lens whose 
distortion curve does not change even with the 
Since weight alleviation is now sought as far as change of focal length. Our high resolution CCD 
possible in the construction of all vehicles (in our camera, therefore, requires the calibration only 
case we test on the railroad vehicle), their exterior once. 
surface board tends to be thinner and interior For camera-calibration we use "the 
frame, to be more slender. Therefore, it is Self-calibrating bundle adjustment software", 
becoming increasingly difficult to maintain the which we developed. We have also developed, 
surface flatness. Especially in the stainless steel however, a new software to detect automatically 
body, it is almost impossible to take out the targets placed on 3D testified designed for 
welding distortion. At present the measurement of calibration. 
the flatness of body surface and the measurement In order, therefore, to confirm and verify the 
of the nose curve are done by a steel tape hand high accuracy of our measurement devices we 
work, which, of course, is not so accurate and can made the following two kinds of experiment. First, 
not any way be called modern as it is not able to for exterior surface flatness measurement we 
assure the same exact result in repeated tested on the simulated sandy and lustrous 
measurement and effective data controlling. surfaces and then applied it on the actual surface 
It is, therefore, imperative to develop a new of a stainless train body. Second, for curve 
device which allows us to measure the flatness of surface measurement we tested on the simulated 
body surface highly accurately to facilitate the curve surfaces and then applied our method on the 
quality control and the examination of the aging. actual nose of a bullet train. 
The system we have developed consists of the Thus, in this presentation we will first present 
image-acquiring part and analyzing part. the general outline of our system, and then its 
Our high resolution CCD camera has 16.77 experimental results, followed by the examples of 
million pixels and is made such a way that while the data-inputting into CAD systems. 
76 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B5. Vienna 1996 
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