Study Of 3D Portrait Printing Based On Structured Lignt Technologie

3D portrait printing is currently a popular and stylish doll production method that incorporates 3D measurement and 3D printing technologies and that is being commercialized into a new business: 3D portrait printing shop.Given the expensiveness of importing machines from abroad and the underdevelopment of domestic technology,3D portrait printing service in China costs a lot at present,which leads to an arrested development in this field.Therefore,it is necessary and worthwhile to conduct further study on 3D portrait printing.This study focuses on 3D technology in virtue of structured light measurement and Fused Deposition Modeling(FDM)printing.Targeting at the problem that dark,fine and loose hairs can’t be modeled via the method of structured light measurement,this thesis proposed a new method,namely hairstyle matching,to prepare for the following FDM printing.The study includes:(1)Analysis on the process of structured light measurement system.In light of a binocular structured light measurement that grating encoded through phase measuring profilometry,discussions on the key technologies of structured light measurement,such as camera calibration,image capturing,phase calculation,stereo matching and 3-dimensional reconstruction,are made.Furthermore,the point cloud match data of different doll bodies are obtained via 3D measurement.(2)Processing on the data obtained in(1),including point cloud matching,triangular meshing,Non-Uniform Rational B-Splines(NURBS)surface reconstruction and mesh simplification,etc.Through which a hairless doll CAD models is worked out: triangular mesh model and NURBS curved surface model.On the basis of comparison of accuracy,a conclusion is reached: the triangular mesh model is more precise than the NURBS model in terms of 3D doll imaging.(3)With respect to the problem that dark hair can not be captured through structured light,it is suggested in the thesis to establish a hairstyle template base for matching the doll image gained in(2)with hairstyle data so as to secure a completed 3D doll photo.This method is called as "Capping Method".On the MATLAB platform,the binary STL doll image display and the automatic matching of image and hairstyle are realized.(4)The feasibility of "Capping Method" is tested through FDM printing technology.Based on illustration on the principles and process of FDM printing,a 3D printing of a model with zoom factors 0.15(62.76×77.34 ×73.74mm)and 0.2(83.97×56.34×103.12mm)is conducted using FDM printer.The completed and vivid doll product proves that the method proposed in this thesis is feasible.(5)Further study on doll’s surface texture.The author holds that it is the so-called "step effect" caused by FDM slicing that leads to the rough surface of doll.After measurement,the maximum(2.155mm~-2.311mm),mean errors(-0.360mm)and standard dimension errors(0.232mm),of 3D doll are obtained.On a comprehensive analysis basis,it is proposed that technologies of FDM slicing and nozzle extrusion,as well as elements such as final treatment method,solidification characters of ABS plastic wire and FDM shaping machine are all influencing factors to topography of doll products.