%0 Journal Article
%A YU Yongsheng
%A BI Weitao
%T A Calibration Method for Far-Field Photogrammetry and Its Application
%D 2006
%R
%J Acta Scientiarum Naturalium Universitatis Pekinensis
%P 628-631
%V 42
%N 5
%X In displacement measurements by far-field photography, the scale between object and image has to be calibrated. The calibration can be carried out by placing a rule at the position of the object. In practice, however, this is usually not possible. Especially the orientation of the rule is difficult to set precisely. In this research, a calibration method is proposed by use of equilateral polygon, which can be the hat of a bolt. The authors prove the equilateral polygons that have the same front projection are congruent. Therefore, the size of the equilateral polygon can be uniquely extracted by its front-projection image and the photogrammetric calibration can be done accordingly. This calibration method is successfully implemented in a field measurement of the wind-induced vibration of a structure.
%U https://xbna.pku.edu.cn/EN/abstract/article_1034.shtml