Line Drawing Based 3D Printing For Images

3D printing is an additive manufacturing technology for the purpose of easy and fast manufacturing of 3D objects of almost any shape.The essence of 3D printing technology is layered manufacturing.A complete 3D model is obtained via layer-by-layer material accumulation achieved by scanning two-dimensional polygons.But the FDM 3D printer prints on a linear printout based on a single color,it is not possible to print pixel by pixel which makes it difficult for 3D printing of an image.This thesis is inspired by halftone expressions,exoressing the image as line drawing that can reflect the variation of the tone,and then use the FDM 3D printer to print the line drawing so that the image can be physically output.The algorithm of this thesis is mainly divided into two steps:initialization and op-timization.Initialization is divided into three steps:first of all,image segmentation is performed by a marked watershed algorithm,segmenting the whole image into several sub-regions,and extracting the outline of each sub-region as image's feature line.Then sample each sub-regions and apply the Lloyd algorithm to distribute the sample points according to darkness within each sub-region.Finally solve the travel salesman prob-lem for sampling points within each sub-region,then use the Lin-Kernighan method to get a closed and continuous line,and get the initial line drawing through these three steps.Next,optimize the resulting line drawing.Correcting the position of the line drawing points by geometric optimization,smoothing the lines and reducing the num-ber of sharp-turns.Then change the connection relationship of points in the local area through topology optimization,eliminating the self-intersection problem caused by ge-ometric optimization and connecting the boundary with the inner lines at the same time,enhancing the stability of the structure.Finally,the connection sequence of the points is manufactured as a 3D printing path through a 3D printer.The final experimental results show that from the point of view,the local TSP algorithm after image segmentation has a significant reduction in the calculation time.From an effect point of view,the generated line drawing not only maintains the contour features of the image,but also has smooth lines and reduced sharp-turns.At the same time,the printed line drawing can keep its own structure firmly on the hand.