Research On Reconstruction Method For Unknown3-D Objects Based On The Visual Space Of The Line-laser Monocular Vision System

With the development of advanced measuring equipment and novel measuringtechnology, the reverse engineering has been of great importance applications inthe areas of aviation, space, shipbuilding, automobile, mould and so on. It hasattracted more and more attentions and researches. While in the reserveengineering, the automatic measurement and reconstruction for unknownthree-dimensional objects is a focusing topic. So this paper proposed a new viewplanning method based on the visual space of the monocular vision system. Thevision system can correctly and efficiently fulfill the automatic measurement andreconstruction of unknown3-D objects according to the partly knowninformation of the objects.Firstly, the visual space of the adopted line-laser monocular vision system isobtained. Then the limit visual space of the system is modeled.Secondly, a new view planning strategy that incorporates the visual space ofthe vision system with the limit visual surfaces is proposed. The maximal surfaceextension information of the unknown model is predicted by the limit visualsurface. And the position parameters (rotation angle and translation distance)that ensure the visibility of next view are obtained by acquiring the nextviewpoint visibility criterion. Then the candidate positions that could obtain themaximal projected area of the visual region at next view are determined. Thenext best view of the sensor is the position that can obtain the maximal projectedarea of the visual region among the candidate viewpoints.Thirdly, to terminate the planning process automatically, a two-step planningself-termination criterion is presented. Namely, angle termination criterion andsurface data integrity criterion are presented. The initial reconstruction is terminated by using the angle termination criterion. And the occlusion parts ofthe object are determined by the point pitch. Simultaneously, to obtain theocclusion information, the occlusion planning method is selected according tothe distance that from the point to the rotary-table center. Then thereconstruction process for unknown3-D object is completed automatically.Finally, the automatic reconstructions for the CAD testing model and theactual objects are experimented to validate the feasibility and efficiency of theproposed method in practical implementation.