Zhaokun Zhu

Automatic Three-Dimensional Measurement of Large-Scale Structure Based on Vision Metrology

All relevant key techniques involved in photogrammetric vision metrology for fully automatic 3D measurement of large-scale structure are studied. A new kind of coded target consisting of circular retroreflective discs is designed, and corresponding detection and recognition algorithms based on blob detection and clustering are presented. Then a three-stage strategy starting with view clustering is proposed to achieve automatic network orientation. As for matching of noncoded targets, the concept of matching path is proposed, and matches for each noncoded target are found by determination of the optimal matching path, based on a novel voting strategy, among all possible ones. Experiments on a fixed keel of airship have been conducted to verify the effectiveness and measuring accuracy of the proposed methods.

Theodolite-camera videometrics system based on total station

A novel measuring system, named Theodolite-camera Videometrics System (TVS) based on total station, has been introduced in this paper, and the concept of theodolite-camera which is the key component of TVS has been proposed, it consists of non-metric camera and rotation platform generally, and can rotate horizontally and vertically. TVS based on total station is free of field control points, and the fields of view of its theodolite-cameras are nonfixed, thus TVS is qualified for targets with wide moving range or big structure. Theodolite-camera model has been analyzed and presented in detail in this paper. The calibration strategy adopted has been demonstrated to be accurate and feasible by both simulated and real data, and TVS has also been proved to be a valid, reliable, precise measuring system, and living up to expectations.