Camera Planning Based On Director Knowledge Base In Mobile 3D Animation

In the 1990 s,Lu RuQian,the academician of Chinese Academy of Sciences,proposed the entire process of computer-assisted animation automatic generation technology,which is a creative fusion of artificial intelligence and computer animation technology,and taking computer graphics as a technical support achieving the 3D animation of the automatic creation process.With the promotion and popularization of mobile communication tools,Zhang SongMao,a researcher of the Chinese Academy of Sciences,proposed in 2008 that the whole process of computer-assisted animation automatic generation technology could be applied to the carrier of mobile phone short message,and led the members of the laboratory task to design and implement the mobile phone 3D animation automatic generation system.After receiving the sender's short message,the system successively processes the subject information of the short message,the qualitative plot plan,the quantitative animation calculation,and the animation rendering.Finally,the 3D animation corresponding to the content of the short message is generated and sent to the short message receiver.The virtual camera motion planning is an indispensable and important function in mobile 3D animation systems,including qualitative planning and quantitative computing.The camera qualitative planning module completes the selection of the shooting target and the planning of the lens shooting properties on the basis of the qualitative plot planning;the camera quantitative calculation module designs the a obstacle-free shooting path based on the animated data of figures,layouts,movements,lights,etc.calculated by the quantitative animation,which presents the audience with the main content of the scene to achieve the purpose of displaying the subject of the SMS.Research on camera motion planning is a difficult and important point in the automatic generation of mobile 3D animation.In the original camera planning of the mobile phone 3D animation automatic generation system,the randomly generated shooting technique is not closely related to the subject of the short message.To solve this problem,this paper first proposes a camera qualitative hierarchical planning based on the director's knowledge base: the first level based on the system's qualitative plot planning output obtains the shooting tactics corresponding to the theme of the animation scene according to the rules of the primitives;the second level completes the selection task of the lens combination based on the shooting tactics by the upper level.Taking the mature theoretical research in the field of photography as the background and constructing based on semantic network technology,the camera director knowledge base is divided into two parts: the ontology base and the rule base.The ontology base defines the classification of camera shooting tactics and its various attributes.The rule base represents the photography field shooting rules used in different scenarios.In the part of quantitative calculation of camera motion planning,this paper designs and implements octree-based camera global path planning.The octree structure is used to divide the scene,and a scene spanning tree algorithm is presented to automatically annotate the obstacles of the scene and the free space,and establish the surface adjacency graph of the free node in the scene.The path search algorithm based on adjacency graph is given,and the optimal path is selected according to the qualitative planning parameters of the camera.Finally,a smooth,continuous and barrier-free camera shooting path is generated.At present,the system has designed 13 high level photographic primitives with satisfactory results,and implemented 27 kinds of lens attribute rule specific schemes corresponding to high level photographic primitives.618 short messages received from December 2017 to April 2018 in the mobile 3D animation automatic generation system are selected to conduct performance evaluation experiments.Among them,66.18% of all short messages were successfully executed based on the camera plan of the director's knowledge base.This shows that the built-up director's ontology base and rule base can achieve more than half of the SMS data coverage in qualitative planning of the camera,thereby effectively improving the expression of the SMS subject ability.In the 618 messages,there were 326 executing camera global path planning messages,which accounted for 52.75% of all short messages,indicating the effectiveness of the camera's global path planning.The overall evaluation of the viewer's animation indicators ?The overall animation effect is satisfactory?,?The shooting target is clear?,?The shooting target is unobstructed? and ?The shooting path is smooth"? in audience viewing test of the camera's motion planning achieved 3.88 points(five points system),indicating that the camera's global path planning is conducive to the resolution of the camera's obstacle avoidance problem in the motion path and the generation of a smooth and stable camera shooting path.