3D Model Reconstruction Based on Process Information

The traditional strategy of 3D model reconstruction mainly concentrates on orthographic projections or engineering drawings. But there are some shortcomings. Such as, only few kinds of solids can be reconstructed, the high complexity of time and less information about the 3D model. The research is extended and process card is treated as part of the 3D reconstruction. A set of process data is a superset of 2D engineering drawings set. The set comprises process drawings and process steps, and shows a sequencing and asymptotic course that a part is made from roughcast blank to final product. According to these characteristics, the object to be reconstructed is translated from the complicated engineering drawings into a series of much simpler process drawings. With the plentiful process information added for reconstruction, the disturbances such as irrelevant graph, symbol and label, etc. can be avoided. And more, the form change of both neighbor process drawings is so little that the engineering drawings interpretation has no difficulty; in addition, the abnormal solution and multi-solution can be avoided during reconstruction, and the problems of being applicable to more objects is solved ultimately. Therefore, the utility method for 3D reconstruction model will be possible. On the other hand, the feature information in process cards is provided for reconstruction model. Focusing on process cards, the feasibility and requirements of Working Procedure Model reconstruction is analyzed, and the method to apply and implement the Natural Language Understanding into the 3D reconstruction is studied. The method of asymptotic approximation product was proposed, by which a 3D process model can be constructed automatically and intelligently. The process model not only includes the information about parts characters, but also can deliver the information of design, process and engineering to the downstream applications.

A 3D Model Reconstruction Method Using Slice Images

Abstract：reconstruction method using slice im-ages is proposed. Wanting to extract the outermost contours from slice images, the method of the improved GVF-Snake model with optimized force field and ray method is employed. And then, the 3D model is reconstructed by contour connection using the im-proved shortest diagonal method and judgment function of contour fracture. The results show that the accuracy of reconstruction 3D model is improved.

New Virtual Cutting Algorithms for 3D Surface Model Reconstructed from Medical Images

This paper proposes a practical algorithms of plane cutting, stereo clipping and arbitrary cutting for 3D surface model reconstructed from medical images. In plane cutting and stereo clipping algorithms, the 3D model is cut by plane or polyhedron. Lists of edge and vertex in every cut plane are established. From these lists the boundary contours are created and their relationship of embrace is ascertained. The region closed by the contours is triangulated using Delaunay triangulation algorithm. Arbitrary cutting operation creates cutting curve interactively. The cut model still maintains its correct topology structure. With these operations, tissues inside can be observed easily and it can aid doctors to diagnose. The methods can also be used in surgery planning of radiotherapy.

Preoperative 3D reconstruction and fluorescent indocyanine green for laparoscopic duodenum preserving pancreatic head resection:A case report

BACKGROUND Duodenum-preserving pancreatic head resection(DPPHR)is the choice of surgery for benign or low-grade malignant tumors of the pancreatic head.Laparoscopic DPPHR(LDPPHR)procedure can be improved by preoperative 3D model reconstruction and the use of intravenous indocyanine green fluorescent before surgery for real-time navigation with fluorescent display to guide the surgical dissection and prevention of from injury to vessels and biliary tract.CASE SUMMARY Here we report the successful short-and long-term outcomes after one year following LDPPHR for a 60-year lady who had an uneventful recovery and was discharged home one week after the surgery.CONCLUSION There was no bile leakage or pancreatic leakage or delayed gastric emptying.The histopathology report showed multiple cysts in the pancreatic head and localized pancreatic intraepithelial tumor lesions.The resected margin was free of tumor.

Image processing based three-dimensional model reconstruction for cross-platform numerical simulation

Numerical simulation is the most powerful computational and analysis tool for a large variety of engineering and physical problems.For a complex problem relating to multi-field,multi-process and multi-scale,different computing tools have to be developed so as to solve particular fields at different scales and for different processes.Therefore,the integration of different types of software is inevitable.However,it is difficult to perform the transfer of the meshes and simulated results among software packages because of the lack of shared data formats or encrypted data formats.An image processing based method for three-dimensional model reconstruction for numerical simulation was proposed,which presents a solution to the integration problem by a series of slice or projection images obtained by the post-processing modules of the numerical simulation software.By means of mapping image pixels to meshes of either finite difference or finite element models,the geometry contour can be extracted to export the stereolithography model.The values of results,represented by color,can be deduced and assigned to the meshes.All the models with data can be directly or indirectly integrated into other software as a continued or new numerical simulation.The three-dimensional reconstruction method has been validated in numerical simulation of castings and case studies were provided in this study.

自适应组合滤波算法在3D假肢模型中的应用

针对经典统计滤波算法无法自适应选取参数以及传统双边滤波算法难以兼顾保特征和光顺性的问题,提出一种自适应组合滤波算法。首先引入基于局部点云体积的自适应标准差倍数以灵活滤除假肢点云大尺度噪声;在滤除大尺度噪声的基础上,引入一种新的协方差矩阵加权方式,提高估计点云法向的准确性,并通过法向夹角变化程度的均值对特征权重因子进行改进,增强双边滤波因子的保特征性,旨在光顺三维假肢模型小尺度噪声。与单独使用统计滤波、双边滤波相比,所提算法在3个假肢模型的最大误差E_(max)至少降低了5%;平均误差E_(ave)至少降低了6.9%。仿真结果表明,该改进算法在有效剔除假肢模型大尺度噪声的同时又避免了过光顺和去噪不彻底,可以较好地保持模型中的几何特征。

Three-Dimensional Model Reconstruction of Nonwovens from Multi-Focus Images

The three-dimensional(3D)model is of great significance to analyze the performance of nonwovens.However,the existing modelling methods could not reconstruct the 3D structure of nonwovens at low cost.A new method based on deep learning was proposed to reconstruct 3D models of nonwovens from multi-focus images.A convolutional neural network was trained to extract clear fibers from sequence images.Image processing algorithms were used to obtain the radius,the central axis,and depth information of fibers from the extraction results.Based on this information,3D models were built in 3D space.Furthermore,self-developed algorithms optimized the central axis and depth of fibers,which made fibers more realistic and continuous.The method with lower cost could reconstruct 3D models of nonwovens conveniently.

基于在机测量的曲面共形电路3D打印误差补偿方法

基于3D打印技术制备曲面共形电路具有广阔的应用前景,然而,由于曲面基材加工误差和导电线路定位误差的影响,导致曲面电路3D打印头高度难以精确控制,进而影响打印精度。为此,本文以气动式直写打印为研究对象,提出了一种“在机测量+线路模型重构”的打印头高度误差补偿方法。设计了一种曲率自适应测量点选取方法,利用NURBS曲线反算法对测量数据进行重构,还原真实线路模型。通过生成真实线路的打印轨迹,替换原始理论打印轨迹,补偿了打印头高度误差。自主搭建了一套集成了在机测量系统的曲面共形电路3D打印平台,设计了直线、圆弧与NURBS自由曲线3种形状的线路,进行补偿前后电路打印的对比实验。结果表明,未进行补偿前,在线路曲率较大的地方,线路在基板上的波峰处会产生拉丝现象,波谷处会产生堆叠现象,而补偿后的导线线宽比较均匀;进一步对每条导线的电阻进行测量,发现各条线路补偿前的电阻值波动较大,补偿后的电路的电阻值均匀,且相较补偿前平均降低65.99%,最大电阻降幅达85.75%。

3D数字化模型在法医人类学教学中的应用探讨

法医人类学是一门理论与实践紧密结合的法医专业学科,然而法医人类学传统教学存在明显的限制,主要有标本紧张、直观性差等,上述问题导致学生上课积极性不高,对重难点知识理解困难,理论实践相互脱节,无法完全达到课程培养目标。3D数字化模型立体感强,可随意旋转缩放,能够清晰展现骨结构形态与差异,为学生提供更直观、清晰的学习体验,帮助学生更好地理解和掌握法医人类学知识。文章探讨如何将3D数字化模型合理融入法医人类学教学,在教学场景、模型获取及课后反馈等方面进行设计,分析3D模型融入法医人类学教学的优势和应用挑战,以期提高教学质量,实现较为理想的教学效果。

3DMAX室内环境感官设计建模方法

提出基于3DMAX的室内环境感官设计建模方法。首先通过划分室内空间环境,分别采集每个子空间激光点云环境数据,提取室内空间特征量,基于特征分量完成数据融合处理;然后考虑室内环境感官设计要求,重构三维视觉空间点,将室内环境二维图像矢量数据和激光点云匹配信息同步导入3DMAX软件中,自动生成室内环境感官设计三维模型。实验结果表明:误差仅为0.014 m,与对比实验方法建模结果的中误差分别少0.018、0.01 m,说明新研究方法可以更好地辅助室内环境感官设计,实现室内场景虚拟模型的高质量创建。

基于实时视频流的3D人体姿势和形状估计

为满足元宇宙、游戏及虚拟现实等应用场景中对实时视频流3D人体姿势和形状估计准确性和真实性的要求,提出了一种基于时间注意力机制的3D人体姿势和形状估计方法。首先,提取图像特征,并将其输入运动连续注意力模块以更好地校准需要注意的时间序列范围;随后,使用实时特征注意力集成模块以有效地组合当前帧与过去帧的特征表示;最后,通过人体参数回归网络得到最终结果,并使用基于图卷积的生成对抗网络判断模型是否来自真实的人体运动数据。相较于之前基于实时视频流的方法,在主流数据集上加速度误差平均减少了30%的同时,网络参数与计算量减少了65%,在实际测试中实现了每秒55~60帧的3D人体姿态和形状估计速度,为元宇宙、游戏及虚拟现实等应用场景提供更好的用户体验和更高的应用价值。

基于单幅图像形状特征的三维漫画人脸重建

针对单幅图像的三维漫画人脸重建存在地标检测准确性差和生成模型还原高频细节能力低的问题,提出了一种多尺度特征融合与高频信息映射的两阶段方法。在第一阶段中,多尺度通道融合地标检测器用于提高检测的准确性。其中多尺度特征由HRNet产生;由通道注意力和Swin Transformer构成的注意力层用于多尺度通道融合特征提取;为了提高生成地标的精度,损失函数由地标损失和热图损失两部分构成。在第二阶段中,傅里叶特征共享层变形网络使生成的三维漫画人脸具有更丰富的高频形状细节。其中傅里叶特征映射提取高维特征,使网络学习更多形状的高频信息;共享层超网络加快了网络的收敛和重建速度。该方法应用于CaricatureFace和3DCaricShop数据集。实验结果表明,该方法中的地标检测器的平均检测误差减少了4.4%;变形网络在形状重建上的均方误差减少了26%,并且平均重建时间减少了18%;最终重建出的三维漫画人脸具有夸张的形状和自然的细节。

3D Vector Reconstruction of the Typical Cervical Vertebra from Anatomical Sections of Korean Visible Human at the Laboratory of Clinical and Digital Anatomy of Paris Descartes University

Aim: To carry out a 3D vector reconstruction of the typical cervical vertebra from anatomical sections of the “Korean Visible Human” for educational purposes. Material and Methods: The anatomical subject was a 33-year-old Korean man who died of leukemia. He was 164 cm tall and weighed 55 kg. This man donated his body to science. Her body was frozen and cut into several anatomical sections after an MRI and CT scan. These anatomical sections were made using a special saw called a 0.2 mm thick cryomacrotome. Thus 8100 cuts were obtained. Only the sections numbered 940 to 1200 were used for our study. A segmentation by manual contouring of the different parts of the typical cervical vertebra was made using the software Winsurf version 3.5 on a laptop PC running Windows 7 equipped with a Ram of 8 gigas. Results: Our 3D vector model of the typical cervical vertebra is easily manipulated using the Acrobat 3DPDF interface. Each part of the vertebra accessible in a menu can be displayed, hidden or made transparent, and 3D labels are available as well as educational menus for learning anatomy. Conclusion: This original work constitutes a remarkable educational tool for the anatomical study of the typical cervical vertebra and can also be used as a 3D atlas for simulation purposes for training in therapeutic gestures.

3.0T磁共振三种序列在3D半月板模型重建中的对比分析

目的:比较磁共振自旋回波(SE)T1WI、快速自旋回波(TSE)T2WI和质子压脂成像(FS-PDWI)三种序列在重建3D半月板模型中的价值。方法:采用超导3.0T MR对30例正常膝关节半月板进行扫描,所有病例扫描参数保持一致,获得T1WI(A组)、T2WI(B组)和FS-PDWI(C组)三组序列DICOM 3.0格式的影像数据,利用Mimics 16.0软件重建3D半月板模型。采用SPSS19.0软件统计分析,比较三组图像质量的主观评分,比较3D模型与原始二维图像半月板前角、后角及体部的高度和宽度。结果:三组图像质量评分分别为A组4.52±0.31,B组3.98±0.24,C组4.10±0.46;A组vs.B组q值=7.32(P<0.05),B组vs.C组q值=2.38(P>0.05),A组vs.C组q值=5.04(P<0.05)。3D模型与原始二维图像半月板测量值之间差异无统计学意义(P>0.05)。结论:MRI T1WI序列为半月板3D重建优势序列,3D模型能清晰精确地模拟半月板的三维几何形态,为半月板生物打印技术提供模型。

基于3D建模的海底管道在位稳定分析

由于海流潮冲刷等影响,软土海床上的海底管道存在大量裸露甚至悬空,易导致海底管道存在安全稳定风险。基于传统的海底管道检测方法不能全面、精细地反映海底管道的状态信息,无法准确判断海底管道的安全状态。因此,提出一种基于多源数据融合的在役海底管道3D建模方法。该方法通过声波探测技术获取海底管道数据信息,融合含有海底管道状态的多源数据信息,提取识别海底管道及其空间坐标信息,以胜利油田海底输油管道为研究对象,建立海底管道3D模型,实现海底管道3D可视化精细表达,确定海底管道空间位置状态;并对海床上处于不同位置状态下非掩埋管道的安全裸露长度的进行分析计算,结合3D精细模型分析得到在役海底管道的实时安全稳定状态。

基于3D人脸重建的光照、姿态不变人脸识别

待匹配人脸图像与库存原型图像之间姿态和光照的差异是自动人脸识别的两个主要瓶颈问题,已有的解决方法往往只能单独处理二者之一,而不能同时处理光照和姿态问题.提出了一种对人脸图像中的姿态和光照变化同时进行校正处理的方法,即通过光照不变的3D人脸重建过程,将姿态和光照都校正到预先定义的标准条件下.首先,利用先验的统计变形模型,结合人脸图像上的一些关键点来恢复较为精细的人脸3D形状.基于此重建的3D形状,进而通过球面谐波商图像的方法估计输入图像的光照属性并提取输入图像的光照无关的纹理信息,从而将光照无关的3D人脸完全重构出来,生成输入人脸图像在标准姿态和光照条件下的虚拟视图,用于最终的分类识别,实现了对光照和姿态问题的同时处理.在CMUPIE数据库上的实验结果表明,此方法可以在很大程度上提高现有人脸识别方法对于原型集合(gallery)和测试集合中图像在姿态和光照不一致情况下识别结果的正确性.

3D打印体外建模辅助微创治疗复杂骨盆骨折

目的探讨3D打印体外建模辅助微创治疗复杂骨盆骨折的临床疗效。方法选择2016年4月至2017年6月采用3D打印体外建模辅助治疗的18例复杂骨盆骨折病例,记录手术时间及术中出血量,术后通过X射线片、CT及Matta评分标准评估骨折复位情况,通过Majeed功能评分评估功能恢复情况。结果手术时间80～160 min,平均(120±23.1) min;术中出血量75～160 m L,平均(113.6±29.1) m L;切口长度7～14 cm,平均(9.3±1.8) cm。18例患者均获随访12～24个月,平均15.8个月。根据Matta评分标准,骨折复位:优12例,良4例,可2例,优良率88.9%。术后6个月使用Majeed评分标准评定功能恢复情况,结果显示:优13例,良4例,可1例,优良率94.4%。所有患者随访期间无内固定松动、断裂等并发症发生。结论采用3D打印体外建模辅助治疗复杂骨盆骨折可使手术操作更加精准及微创,减少并发症的发生,有利于患者术后康复。

基于裸眼3D视觉效果的脑血管CT图像快速三维重建方法研究

目的:针对传统脑血管CT图像三维重建过程的复杂性与不便捷性,探究一种基于裸眼3D视觉效果的脑血管CT图像三维重建方法,使重建过程更加快速。方法:在智能化神经网络融合模型的基础上,对脑血管CT图像病灶部分进行分割,建立3D人体模型数据库,从数据库选取相应部分对病灶进行替换,快速地完成脑血管CT三维重建过程。结果:通过3D人体模型数据库,节省了重建过程的时间,大大提高了脑血管CT图像三维重建的效率,从而有助于快速完成诊断。结论:该方法有利于更快速、便捷地实现脑血管CT的逼真展示,方便医生与病患的交流与沟通。

模型驱动的激光点云输电线路杆塔高效3D建模方法

为了提升输电杆塔三维建模的效率和质量,提出了一种模型驱动的激光点云输电线路杆塔建模方法,以解决实际生产应用中大范围输电杆塔的快速、高精度三维模型建立问题。本方法先建立不同类型的杆塔模型,然后利用获取的输电网点云数据计算点云分布的方向特征,确定输电杆塔的主方向,为每个杆塔确定局部坐标系。进而通过半自动化方式从杆塔点云中捕捉杆塔关键点,通过模型匹配算法,确定与点云数据最佳匹配的杆塔模型。相较于现有的人工编辑方式和组件式建模方法,以模型驱动的方法可以保证所建立的杆塔模型的完整性以及准确性,需要较少人工编辑的同时提升了效率和质量。经过真实数据测试表明,本文方法具有可行性和实用性。

计算机影像数据心脏三维重建及3D打印技术研究

目的通过心脏实体三维模型，观察心脏内部病变结构及病变组织关系，直观设计术前预案和术后效果评估。方法采用256增强CT扫描心脏区域获得连续断层数据，导入Mimics软件，经过人工分割数据进行心脏三维实体重建形成STL文件，设计编排图像被3D打印机识别，打印出1：1心脏模型。结果成功重建心脏三维实体模型并完成激光3D打印机完成模型制作，重建的模型能以多结构显示心脏各结构的空间位置及毗邻关系。结论CT医学数据图像完全可以转换成计算机心脏三维实体模型，通过激光3D打印机可以打出完整的心脏三维模型。