Study On Low-cost 3D Foot Measurement Based On Multiview Stereo Vision

With the development of society,the improvement of living standard makes people pay more attention to the experience of the necessities of life,and not only the basic function of the necessities.The comfort of shoes has always been an important issue,affecting the growth of the human foot and the health of the human body.In the past,the mass unification of the shoes has been unable to meet the needs of people,the amount of personalized foot shoe has become an inevitable trend.Laser foot scanner on the market has been a good application.However,the high cost of laser,poor jitter resistance,making this product is not conducive to large-scale promotion.Structured light based method is also used to obtain the shape of 3D objects.Since it needs to gain the three-dimensional shape of the target according to the grating transmitted on the target surface,it will be affected by the ambient light,which is not conducive to the application in the product.Under the premise of ensuring the accuracy,the requirement of reducing the cost is more and more intense.The decline of hardware cost and the development of stereo vision technology provide the possibility for the development of low-cost 3D foot measurement.In this dissertation,a kind of active marking method is used to mark the points on the white thin socks.With a strong robustness to the change of view,the centroid of the mark points is used as the feature point,and the blob detection algorithm is used to extract it.Our method only needs pairs of cameras and socks,which greatly reduces the cost of the foot acquisition,and has a good balance between the precision and the cost of the foot.This dissertation adopts a method of two level matching,first using the epipolar constraint and SAD algorithm to match the seed point,then the seed points implement Delaunay triangulation.So each marking point falls on each triangle area.Then use the method of triangle constraint to match the feature points,which has better effect on the basis of the triangle as the actual location close to flat surface.Get the views of the point cloud after the patches,then get full foot by Poisson Reconstruction.The foot parameters in this measurement include the length of feet,the width of feet wide,plantar circumference,tarsal circumference and Dou Wei,the first metatarsophalangeal joint height,anterior tarsal height,bending height of the boat,these parameters have important reference value for the production of shoes.The foot point cloud can be projected onto the plane of the sole of the foot,and the foot contour lines can be obtained according to a certain step size.Locate the 2D position of several feature points on the contour line,and get the actual position back to the 3D.Generate the auxiliary planes using these feature points,and the foot curve length is the intersection of the length of auxiliary planes and the foot model.The method is realized using Studio Visual 2008 and Open CV on Windows platform.In this dissertation,we use this method to measure the parameters of several feet.The results show that the method is feasible and accurate.