Shoji Ogawa

Geometrical accuracy measurement for large-scale steel bridge members

This paper presents a practical 3-dimensional measurement system which is applied to geometrical accuracy measurenient for large-scale steel bridge members. The measuring niethod is based on stereo vision using precision CCD-cameras linked with a personal computer. The developed system can automatically recognize every target point in its view field and determine theX Y and Z coordinates within a remarkable short time and the measurement accuracy of the system is better than 0. 5 mm for a view field of about 3 m(H) by 2. 3 m(v). This system is applied to an inspection station for the measurement of steel bridge members. The inspection station can measure the geometrical and dimensional accuracy of a steel bridge member of about 3 m x 4 m x 20 in in maximum size with an acceptable measurement accuracy and the results obtained from practical runs for the last three years verify the feasibility of the developed system.