基于光切法的全三维量脚制鞋系统的设计和实现

介绍了基于光切法的全三维量脚制鞋系统。利用基于光切法的三维形貌扫描仪对足型进行测量,得到精度为±0.4mm的足型数据。根据足部关键参数,选择标准鞋楦。将脚型划分为多个特征段,足型数据和标准鞋楦的规则化点云拟合为NURBS曲线,各段内根据脚型的特点对标准鞋楦进行整体缩放以局部修改,利用能量优化原则同时修改控制点和权因子,对标准鞋楦进行修改,使其符合脚型的整体三维特点。定制鞋楦建模后,利用等距面法得到鞋楦的刀具加工轨迹并转化为通用格式的NC代码送入数据刻楦机进行加工,定制的鞋楦用于生产适合脚型的鞋子。该系统打破了根据有限的足部参数来选鞋的传统,真正实现了基于全三维足型数据的量脚制鞋。     

基于被动立体视觉的脚型建模与比对方法

为了解决个性化鞋楦开发中三维脚型获取与检索困难的问题,提出一种三维脚型精确建模与比对方法.运用已标定的双目照相机拍摄立体图像对,进行足部整体视差估计;在对立体图像对进行自动预处理后,采用非接触式的信息采集技术,运用基于复小波的相位相关技术对足部表面进行亚像素级小区域频域匹配,考虑顺序匹配约束、连续性约束和相关性约束条件,重建足部密集三维点云信息,并自动拼接不同角度点云生成相应的足部三维模型;对其归一化后,提取其高阶矩向量进行比对,为后续的三维鞋楦设计提供必要信息.实验结果表明,该方法使足部信息采集过程快捷可靠,重建过程不需要人工干预.     

鞋楦的数字化设计与软件开发

以逆向工程技术和软件开发为基础,对鞋楦的数字化设计进行研究：结合传统鞋楦制作技术,采用基于点云的散乱结构的均匀网格方法,对扫描获取的鞋楦点云数据进行精简;采用最小二乘逼近的方法,将处理后的点云数据拟合成NURBS曲线,进而采用蒙皮算法得到鞋楦曲面。开发了鞋楦数字化设计专用模块,为以后根据脚型对标准鞋楦进行个性化修改的开发奠定了基础。     

基于标记点图案的三维脚型建模与测量方法

面向个性化制鞋,提出并实现了一种新颖的基于立体视觉原理的三维脚型建模与测量方法.该方法把标记点图案设置在袜子上,通过10台普通摄像机来采集用户穿着这种袜子的脚型图像;然后从脚型图像中提取出标记点并进行匹配,根据立体视觉原理重建出袜子上各个标记点的三维几何位置,并利用三角化处理以及曲面细分等手段获取用户的三维脚型;最后根据制鞋工艺要求测量出制鞋相关的参数.实验结果表明,该方法可瞬间完成无盲区图像的采集,有效地减少了生物体抖动所带来的误差,使误差在±1mm之内,可应用于个性化制鞋服务.     

基于立体视觉的鞋楦数字化研究

针对鞋楦图像在三维重建中的匹配问题,提出一种改进的鞋楦数字化方法。对鞋楦表面做纹理网格化处理,利用Harris与Laplace算子相结合的方法提取特征点,采用改进的去除误匹配方法进行精匹配,通过双目视觉三角测量法求出匹配点的三维坐标。使用迭代近邻点算法实现不同方向点集的坐标融合和三维拼接,对全部三维点云数据进行三角网格化和曲面拟合,完成鞋楦三维重建。实验结果表明,该方法能便捷、高效地实现鞋楦数字化重建,可满足个性化制鞋需求。     

基于粒子系统和形状匹配的实时无网格变形仿真

介绍了一种基于粒子系统和形状匹配的无网格变形算法。该算法将模型的每个顶点当成一个粒子,一个模型对应一个粒子系统,通过粒子系统控制物体外形。同时,每个粒子都对应一个目标位置,粒子与其目标位置之间存在弹力,能将粒子拉向目标位置,使得变形后的物体能够恢复原来的形状。目标位置可以通过粒子系统未变形时的静止状态与当前变形状态之间的形状匹配来计算。该算法简单,易于实现,且不需要复杂的数据结构。实验结果表明该算法稳定,具有实时性,可以有效地应用于三维游戏中。     

三维鞋样交互设计方法研究

提出了一种在三角网格鞋楦模型上生成三维帮样曲线的离散表示及其交互编辑修改方法。基于改进的能量模型对鞋楦曲面的选择区域进行展平,利用展平过程建立的三维帮面与展平后二维帮面间的拓扑对应关系,实现鞋样曲线在三维空间与二维展平空间的实时关联;所生成的二维帮样曲线以3次非均匀B-spline表示,并以DXF格式输出,便于其他程序调用。算例结果显示,本文方法具有交互性好、实时直观的优点,能够满足基于楦型的帮样交互设计要求。     

基于Kinect人体脚型三维构建

针对传统测量方法成本高、操作复杂、图像特征匹配率准确度不高等问题,提出了一种将Kinect传感器与计算机视觉技术相结合的构建人体三维脚型的方法。利用Kinect传感器搭建测量系统,获取不同角度的深度信息图像,通过改进的Harris-SIFT算法对特征点进行提取与匹配,并通过迭代最近点(ICP)算法完成对点云数据的拼接。结果表明:所提方法能够便捷、准确地实现人体三维脚型的构建。     

空间机械臂运动过程中的碰撞检测方法

针对一种六关节机械臂,导出了各关节和末端的坐标,对可能与舱体碰撞的机械臂的几个连杆,将其上面的各点表示成两端关节坐标的函数,并由此给出了该点与舱体碰撞的检查方法;该方法不仅能检查机械臂关节与舱体的碰撞,而且能够检查机械臂连杆上任何位置与舱体的碰撞;对可能发生相互碰撞的机械臂的每对连杆,将其上面的各点表示成两端关节坐标的函数,并由此给出了每对连杆相互碰撞的检查方法;该方法不仅能检查机械臂两连杆两端关节的相互碰撞,而且能够检查机械臂两连杆上任何位置之间的相互碰撞;仿真结果证实了两种碰撞检查方法可行性和有效性。     

随机并行梯度下降图像匹配方法性能研究及优化

随机并行梯度下降图像匹配方法是一种全新的图像匹配方法,该方法同时对所有的变形参数施加相互统计独立的随机扰动,并以相关系数随机梯度分量代替真实的梯度分量进行迭代运算,使之能够快速地得到最优参数估计。在编程实现该技术方案的过程中,匹配坐标系选取、双边或单边扰动方式等因素对匹配效果影响明显。本文主要从这两个方面对匹配性能的影响进行分析研究并采取优化措施,使该方法得到进一步完善。     

Footwear bio-modelling: An industrial approach

There is a growing need within the footwear sector to customise the design of the last from which a specific footwear style is to be produced. This customisation is necessary for user comfort and health reasons, as the user needs to wear a suitable shoe. For this purpose, a relationship must be established between the user foot and the last with which the style will be made; up until now, no model has existed that integrates both elements. On the one hand, traditional customised footwear manufacturing techniques are based on purely artisanal procedures which make the process arduous and complex; on the other hand, geometric models proposed by different authors present the impossibility of implementing them in an industrial environment with limited resources for the acquisition of morphometric and structural data for the foot, apart from the fact that they do not prove to be sufficiently accurate given the non-similarity of the foot and last. In this paper, two interrelated geometric models are defined, the first, a bio-deformable foot model and the second, a deformable last model. The experiments completed show the goodness of the model, with it obtaining satisfactory results in terms of comfort, efficiency and precision, which make it viable for use in the sector.     

鞋楦CAD中的鞋楦建模与局部修改技术

讨论了CAD中的鞋楦建模方法，针对鞋楦曲面的不规则性，提出一种离散造型方法并给出一种计算鞋楦围度的逼近算法，同时，提出一个斜率定义，进而给出一个比较实用的基于斜率变化的自适应楦面局部修改算法（简称SAD算法），最后给出一个实例。     

基于跖跗围参数的鞋楦曲面重构

针对面向合脚性、舒适性的鞋楦个性化设计中的曲面重构问题,提出并实 现了一种基于鞋楦跖跗围截面变换技术的鞋楦曲面参数化重构方法。通过对鞋楦跖跗截面围 长和高度的控制,将跖、跗围的截面曲线变换到个性化设计所需求效果;基于三次样条插值 函数构造局部、整体两类扩散函数,实现两种将两围截面变换效果扩散到整个鞋楦曲面的方 式。此算法不仅可以准确地满足鞋楦围长约束要求,且保持了曲面光顺性。所提出的重构过 程在Matlab 平台上可以实现可视化交互设计,界面具有操作简单方便的特点。     

Classification and mass production technique for three-quarter shoe insoles using non-weight-bearing plantar shapes

We have developed a technique for the mass production and classification of three-quarter shoe insoles via a 3D anthropometric measurement of full-size non-weight-bearing plantar shapes. The plantar shapes of fifty 40-60-year-old adults from Taiwan were categorized and, in conjunction with commercially available flat or leisure shoe models, three-quarter shoe-insole models were generated using a CAD system. Applying a rapid prototype system, these models were then used to provide the parameters for manufacturing the shoe insoles. The insoles developed in this study have been classified into S, M and L types that offer user-friendly options for foot-care providers. We concluded that these insoles can mate tightly with the foot arch and disperse the pressure in the heel and forefoot over the foot arch. Thus, practically, the pressure difference over the plantar region can be minimised, and the user can experience comfort when wearing flat or leisure shoes.     

The effect of tendons on foot skin deformation

Anatomical human models are usually divided into layers including skin, muscle and skeleton. In spite of the realistic animation of the models that can be achieved, and the realistic appearance of the model determined by the underlying muscles and skeleton, the role of tendons in determining the deformation of skin surface has not been well addressed.This paper presents an approach for modeling human foot tendons and determines their influence on the skin layer deformation. Our goal is to model deformation of the tendons such that a realistic foot simulation can be obtained. An anatomical foot model including skin, muscle, tendon and skeleton layers is adopted. The appearance of the skin layer is determined based on the underlying layers. To allow interactive deformation of the tendon models, the axial deformation technique is adopted. Given the position of the foot and the basis function, the position of the data points that control the axial curve is updated. To allow more accurate computation of the data point positions, a method that estimates the basis function based on real data obtained from foot images is also presented. Experimental results showed that the axial deformation technique can model deformation of the foot tendons with satisfactory visual realism. With the tendon deformation, the visual realism on the skin deformation is also enhanced.     

Human foot modeling towards footwear design

Comfort test of footwear is mainly based on subjective perception of the wearer and a large number of subjects are required to obtain a reliable result. Therefore, the subjective comfort test is expensive and time consuming. Although the foot size and shape of a subject can be obtained by using a three-dimensional (3D) foot scanner, it is still difficult to create foot motion animations of each subject suitable for computer simulation.In this paper, we propose a fast approach to model foot deformation and present its application in simulating interaction with footwear towards footwear design. The simulation determines deformation of foot and footwear models. It can also determine stress distribution in the footwear. Given an initial foot model and a captured foot motion, human foot animation is created first. Then, the footwear model is fitted to the foot to compute the deformation and stress in the footwear. In this article, the boundary element method (BEM) is adopted. We demonstrate the results by conducting simulation of a captured gait motion. Experimental results showed that the method can be used to simulate human gait motion, and can determine deformation of footwear.     

Ethnic differences in forefoot shape and the determination of shoe comfort

The kinanthropometric aspects of comfort of fit of sport shoes has not been subjected to any great scrutiny. It is suggested that comfort of fit is largely determined by the match of foot shape to shoe shape and consequently there is a need for normative data that describe foot shape, dimension and proportion for discrete populations. A study of 708 second generation Caucasian N. American (NA) and 513 Japanese and Korean (JK) male subjects was conducted to determine normative data with respect to forefoot shape and dimension. A series of 2 height, 7 length, 1 breadth and 1 girth measures of the right foot bearing full body weight was recorded using a modified Mitutoyo digital caliper interfaced with a micro-processor. Substantial differences were noted in the incidence of digital patterning. The relative proportion of digital patterns I(l>2>3>4>5) and II (2 > 1 > 3 > 4 > 5) were NA 76.09%, 23.91%; JK 50.80% and 49.20% respectively. The distance between the pternion and the distal extremity of the second digit expressed as a percentage of die maximum foot lengdi (MFL) was found to be 98.60% (NA) and 99.60% (JK). In addition, the distance between the pternion and the distal extremity of the fifth digit relative to MFL was 82-60% (NA) and 85.00% (JK). The implication of these data is that the anterior margin of the JK foot makes a less acute angle with the long axis of the foot than the NA population. Additional information with respect to foot breadth leads to the conclusion that the shape of the JK forefoot differs from that of the NA, with the implication that unique shoe lasts for both populations are required for optimal shoe comfort.     

Analysis of foot shape variation based on the medial axis of foot outline

The variations in foot outline forms are analyzed by using flexion angles of the medial axis of foot outline. Foot outline and 12 conventional measurements taken on the right foot of 443 male and 297 female subjects with no visible pathological deformation of the foot were used for analyses. The results indicate that the foot is outflared in most of the subjects. Medial bulge and lateral concavity of foot outline are responsible for the foot outflare, and they are not correlated with each other. Medial bulge is due to the overhang of navicular bone that is caused by the pronation of the foot. Its intensity is negatively correlated with dorsal arch height. Lateral concavity is partly due to the abduction of talus and calcaneus relative to the tarsometatarsal bones anterior to them. These three-dimensional morphological characteristics of outflared feet intimately relate to the fit and comfort of the shoe. The flexion angles of medial axis of foot outline provide a useful tool in morphological analysis of the foot for the following reasons; (1) they carry the information on the three-dimensional foot shape that cannot be represented by conventional measurements; and (2) the data is easily obtained and calculations are easily made with minimum expense.     

An analysis and evaluation of fitness for shoe lasts and human feet

The main purpose of this research is to develop a process for identifying the most suitable shoe last for human feet. A fitness function was defined to determine the most suitable shoe last among several alternatives. Based on reverse engineering (RE) technology, this research included scanning the surface of human feet and shoe lasts in STL (Stereo Lithography) format. An STL slicing algorithm constructed the three most important measurements for human feet and shoe last, i.e., ball girth, waist girth, and instep girth. Fuzzy theory was used to analyze and build the membership functions of these three girths between the shoe last and human feet. The analytical hierarchy process (AHP) was applied to decide the weighting functions for each girth to determine the fitness function in all shoe last databases for the feet. Three case studies were implemented to find the ranking of 10 shoe lasts in the database. This research, which defined as the relationships between shoe last and human feet, can be used as a good reference for design in the shoe-making process.