Automatic Modelling Method for Steel Structures Using Photogrammetry

Industrial Photogrammetry which has advantages of high accuracy and fast measurement time is widely used in the manufacture measurement application. Especially, industrial photogrammetry has more powerful capability of quickness in the 3 dimensional coordinate measurement then comparing with optical measurement system like total station, laser tracker and laser scanner. The purpose of this paper is to improve product quality and shorten working term by 3D precise measurement of steel box girder shape using industrial photogrammetry method. This method is expected replacement to the pre-assemble step which is test fabrication with each box girder before shipment. In addition, the proposed target calibration technique use template data which has correction data of each coded target thickness and relationship between coded target and hole adapter. Moreover, length and corner point of members and bolt hole position are defined using corrected coded targets. In the result, this research technique expects that calibrated target can be used to decrease the number of target, auto-modelling procedure can decrease the overall processing time, and the automatic procedure time is approximately 50% decreased than normal manual procedure in the steel box girder measurement.