Design And Implementation Of 3-D Modeling Of Trees From A Single Image Based On Mobile Device

Tree 3D model technology is widely used in 3D movies,animation production,virtual reality,agricultural science popularization and education.At present,the methods of generating realistic tree model are mainly divided into laser-scanning point cloud modeling and imagebased modeling.The point-cloud modeling method is not suitable for small-scale noncommercial tree modeling because it requires a high cost to obtain the equipment needed for modeling.Image-based modeling methods can be divided into single-image modeling methods and multi-image modeling methods.Generally,the modeling method based on multiple images requires multiple sequence pictures that can cover the tree uniformly,which can make up for the lack of object depth information provided by the pictures,but there are problems such as long data acquisition time and complex operation.The modeling method based on a single image only needs to input a single tree image and can complete complex 3d tree modeling through a few interactive operations by users.Under the premise that mobile devices have become a necessity for People's Daily travel,it has important research value to realize the rapid modeling method based on a single image in mobile devices.This paper will study the tree modeling method based on single image in mobile devices,and the main research contents are as follows:(1)This paper presents a shading restoration algorithm based on variational method for single image tree reconstruction.Firstly,the pixel area of the tree in the image is extracted through interactive image segmentation.Since the image is usually taken under outdoor natural light conditions,the spherical harmonic light model that can simulate natural light is selected in this paper.Secondly,variational shading restoration algorithm is used to recover the 3d surface information of the tree in the image.Thirdly,in order to generate three-dimensional point cloud in tree canopy space,this paper designed a method to simulate tree canopy shape based on the obtained three-dimensional tree surface information,and generated threedimensional point cloud in tree canopy space.Finally,based on the generated point cloud information,the spatial colonization algorithm is used to generate the skeleton structure of the tree.Experimental results show that the proposed method can recover the 3d information of the tree from single image and generate the geometric model of the given tree.(2)The tree modeling system based on single image is designed and implemented in Android platform.Based on the proposed single image tree modeling method,this paper designs an implementation scheme of tree model generation system based on Android platform from the perspective of software design.This paper analyzes the design structure of the system from the aspects of feasibility analysis,demand analysis,system architecture design,etc.,realizes the various functions of the modeling system by adopting the modular method,and tests the user interface,parameter range,system fluency and user satisfaction of the modeling system in the final test stage.The test results show that the tree 3d modeling system based on single image in the mobile platform proposed in this paper has the characteristics of high realism,user friendliness and good performance,which can meet the requirements of tree modeling for single image.