The Research On Virtual Human Body Size Information Extraction

Design is people-oriented, so in order to design beautiful and comfortable clothing, it is important to understand the human body structure, function, size and shape, especially in the pattern design process, the human body size and shape quantification is particularly important. Furthermore, size designation of garment standard needed in industrial volume production also must be based on a lot of body measurement. Complied with the rapid development of diverse clothing business models, for example, MTM, network custom-made, virtual fitting form and so on,3d garment CAD system research is popular. Using 3d garment CAD system can realize personalized virtual human modeling, rapid human body size extraction, virtual clothing design&fitting and automatic conversion from 3d surface to 2d plane. Among them, the rapid body size information extraction is the key technology for 3d garment CAD.This thesis will ultimately develop a size extraction system, first of all, give a demand analysis, then design the system user interface and functional modules according to the application requirements. as professional background knowledge, the second chapter explains in detail the application of human measurement in garment industry. Donghua university now owns two kinds of non-contact 3d measuring equipments:[TC]2 and handheld laser scanning system EXAscan. EXAscan software subsystem lacks basic size extraction function, the function of [TC]2 software subsystem is not complete, lack of two-dimensional size extraction. this thesis is aimed at making use of the data files generated from [TC]2 and EXAscan to extract body size.As manual measurement, virtual human body is the reference to size extraction. That is the primary function of the size extraction system to make use of WRL and STL files (WRL file, generated form [TC]2, and STL files, generated from EXAscan system), to realize the virtual human modeling. The third chapter analysed the structure of STL and WRL file, based on this, put forward the algorithm and programming in MATLAB language to extract the valid data.After extracting valid data, make use of three-dimensional graphics functions in MATLAB, which can realize the reconstruction of the virtual human body. The fourth chapter discussed the three times spline curve interpolation theory and scattered data point triangulation theory used for modeling virtual human in the third chapter. The author builds four models:the point cloud, line box, triangle patch and authenticity strengthened model. Apply three times spline curve interpolation to points of the same coordinate height, and the point cloud model could transform to line box model, the interpolation curve can simulate body cross profile shape and extract the girth. with light function processing, the triangle patch model can transform to authenticity strengthened model, enhancing the reference effects of virtual human body in size extraction.The author developed a size information extraction system in MATLAB language in the fifth chapter. the system can be extract body one-dimensional, two-dimensional size in interactive way, including the body height, cross profile shape and girth, virtical section shape, and intersection angle etc. this chapter made detailed introduction of the system structure, functions and size extraction algorithm, and illustrated the system function with some examples.The important point and difficult point lies in the valid data automatic extraction from WRL and STL files. The valid data extraction is the base of virtual human modeling and size extraction, and the extraction accuracy and efficiency directly influence the personalized virtual human precision and modeling speed, thus weaken the reference role of the virtual human. Because some size information stored in the valid data directly, it will also affect the accuracy of size extraction.The innovation lies in the extraction of two-dimensional size. It has import meaning for body type classification and pattern theory research to extract two-dimensional size. The extracted two-dimensional sizes include the cross profile shape and girth, virtical section shape, and intersection angle etc., offsetting the [TC]2 drawback.