Study On The Key Techniques For3D Plant Scanner System

The research of morphology of plants has important theoretical significance in the research of study of plant growth pattern. The research plays an important role in guiding agricultural production, seed selection, breeding, intercropping, and increasing agricultural production. With the rapid development of computer technology, three-dimensional information acquisition technology can reconstruct three-dimensional digital model for plant morphology. The three-dimensional information acquisition technology provides a very useful visual analysis tools for studying plant physiological form, structure and function.A 3D scanning system for the plant morphology based on the non-contact surveying is introduced. It acquires 3D geometric information of the plant morphology surface through software processing with the body shape captured by visual equipments. The system is a high-tech product of abroad application. It can acquire automatically the coordinate information of the object surface points in 3D space, build 3D models of plant morphology surface, and save the acquired data as corresponding standard interface files. Several key problems of the 3D scanning system for the plant are emphasized:overall technical scheme of the system, software analysis of the system, spatial information acquisition from the scanned plant morphology, and so on.A systematical overview for the current status, technique points and future development trend of the art of 3D information acquisition technology at home and abroad is introduced. Hardware system and software modules of the system are summarized and detailed analysis on collection, pre-processing and acquisition of the 3D spatial information are deeply discussed, too.The method of the system is based on the idea of Image Based Modeling and Visual Hull which could satisfy all the practical working requirements with a low cost. The methods computing visual hulls are mainly classified into two categories:surface-based approaches and volume-based approaches. Surface-based approaches are precise and lack robustness while volume-based approaches are robust but inaccurate and work slowly. The paper proposes a novel method to compute visual hull rapidly. To this aim, the method is based on viewing edges. First, the viewing lines are computed from all the contours of the object from different viewpoints. Viewing edges are computed by simplifying the 3D intersection onto 2D image plane. Finally, a water-tight surface is extracted from the surface points on the visual hull. Experiments with real data are conducted to test the rapidity of the proposed method.A novel method is proposed to compute exact visual hull by taking advantage of surface-based approaches while retaining the simplicity and robustness of volume-based approaches. To this aim, a line-based model is built for each cube on the edge of octree volume structure of object. Convex surface points of visual hull in line-based model are searched by the idea of surface-based approaches. Experiments with real data are conducted to test the efficiency and exactness of our method.Modeling the 3D shape of plant stems is very important for the study of plant growth in precision agriculture. To construct 3D model of real plant stems from images fast, a novel volumetric method based on line-based models is proposed in this paper. The line-based models are constructed on the coarse 3D skeleton of the plant stems. Then the line-based models are carved with respect to silhouette consistency. The surface points on the plant stems are calculated from line-based models. Finally, a mesh surface model can be extracted from the surface points. The proposed method can give precise results together with low time complexity and space complexity. Experiments based on both synthetic data and real data are presented to evaluate the preciseness and spcediness of the proposed method.