On Line Model Accuracy Inspection of Model Maker Rapid Prototyping Using Vision Technology

The principle of rapid prototyping (RP, or layer manufacturing) is to fabricate a 3D object layer by layer. Vision technology has been employed and has demonstrated its ability to measure the single-layer profile dimensions of the Model Maker (MM) RP system model. The on-line profile dimensional inspection and accuracy analysis of multiple layers is presented in this paper. The image-processing algorithms, developed to measure the layer profile dimensions, were adapted to process the captured profiled image of multiple layers, layer by layer. Hence, the layer profile dimensions of multiple layers were inspected on-line and layer by layer. The problems of vision inspection associated with colour mixing of multiple layers are addressed. A colour CCD camera was employed to resolve the colour mixture problem, but it is too expensive and too much memory is required. A new image difference algorithm was proposed to solve the problem of colour reflected from adjacent layers. The results demonstrate the promise of on-line profile dimensions inspection and accuracy analysis using vision technology.     

实现精确种牙的现代设计与制造技术

针对国内种牙手术中普遍存在的依赖医生临床经验进行操作,手术的精确度和质量有待改善的问题,将图像处理、三维重建、快速成形制造等现代设计与制造技术与医学结合,构建精确种牙技术体系。对系统框架、口腔三维重建、手术导板设计、物理模型制造等关键问题进行了深入研究,实现了种牙导板的设计与制造,并在11例种牙手术中得到了应用。临床应用实例表明,应用精确种牙技术体系,种牙的效率和质量可以得到有效提高。     

An investigation of three-dimensional scanning of human body surfaces and its use in the design and manufacture of prostheses

The capture of highly accurate data describing the complex surfaces of the human body may prove extremely useful in many medical situations. The data provide a method of measuring and recording changes to the surface of a patient's soft tissue. The data may be applied to computer-controlled manufacturing techniques, such as rapid prototyping (RP). This enables accurate physical replicas of the patient topography to be produced. Such models may be used as an aid in the design and manufacture of prostheses. This paper describes an investigation aimed at identifying problems that may be encountered when scanning patients and describes the application of the resulting data in the design and manufacture of facial prostheses. The results of the experiment are presented together with a discussion of the accuracy and potential advantages afforded by this approach.     

Digital denture manufacturing-An integrated technologies of abrasive computer tomography, CNC machining and rapid prototyping

The orthodontic denture produced by the traditional method is heavily relied on the skill and experience of the technician. Its quality is depended on the accuracy of the technician’s subjective judgment. In addition, the manual process involves many steps that require a long time to complete. Most importantly, it does not preserve any quantitative information for future retrieval.In this paper, a novel device for scanning denture image and reconstructing 3D digital information of teeth models by abrasive computer tomography (ACT) is presented. The orthodontic denture is then to be produced by rapid prototyping (RP) or computer numerical control (CNC) machining methods based on the digital information. A force feedback sculptor (Freeform system, U.S.A.), using 3D touch technology, was applied to modify the teeth profile or features of the denture. It enables the dentist to perform digital manipulation of the denture profile with real-time and interactive operation. Due to its user-friendly human-computer interface, the dentist can directly access the 3-D model without relying on a CAD/CAM technician or denture technician. In this paper, the comparison between traditional manual operation and digital manufacture using RP and CNC machining technology for denture production is summarized.In this paper, a digital denture manufacturing protocol using an economic and harmless computer abrasive teeth profile scanning, computer-aided denture design, 3D touchable feature modification, and numerical denture manufacturing were proposed here. These proposed methods provide solid evidence that digital design and manufacturing technologies may become a new avenue for custom made denture design, analysis, and production in the 21th century.     

Three-dimensional object recognition system for enhancing the intelligence of a KUKA robot

Machine intelligence has been a research hotspot in mechatronics in recent years. This research presents a 2D/3D object recognition system for enhancing the intelligence of an industrial robot (KUKA robot). The image processing and object recognition algorithms were developed using software packages VisionPro and LabVIEW. Experiments were carried out to verify the performance of the system. It can be concluded that the system is able to recognise any general 2D object within a time of six seconds. The performance of the system in 3D object recognition is slower compared to 2D objects, which is largely affected by the number of trained images stored in the database, the complexity of the object, and the presence of similar objects in the database. Despite the complexity of the objects being recognised, both the overall accuracy and success rate of the system are close to 100%. The developed system proved to be robust and allows for automatic recognition of objects in the manufacturing environment described in this paper.     

基于流程的制造绩效评价体系研究

面向制造业企业,引入制造绩效指标评价体系和生产能力测量,并在此基础上提出了制造绩效测量系统的概念设计及基于流程分析的制造绩效评价系统模型,在系统的3个层次上分别设计了绩效指标群、网络层及协议层的指标,分析了网络层中评价指标间的交互关系,并提出协议层中各个绩效指标的测量和报告规范。     

3D light scanning macrography

The technique of 3D light scanning macrography permits the non-invasive surface scanning of small specimens at magnifications up to 200×. Obviating both the problem of limited depth of field inherent to conventional close-up macrophotography and the metallic coating required by scanning electron microscopy, 3D light scanning macrography provides three-dimensional digital images of intact specimens without the loss of colour, texture and transparency information. This newly developed technique offers a versatile, portable and cost-efficient method for the non-invasive digital and photographic documentation of small objects. Computer controlled device operation and digital image acquisition facilitate fast and accurate quantitative morphometric investigations, and the technique offers a broad field of research and educational applications in biological, medical and materials sciences.     

基于彩色条纹投影术的三维形貌测量

物体表面三维形貌数据的获取在智能制造、航空航天、文物保护、医疗卫生、远程教育等领域有着广泛的应用。三维形貌数据的获取受限于系统硬件的性能,特别是现有数字投影系统的投影速度,无法快速测得物体面形的三维形貌。彩色成像和投影系统的出现,为并行多颜色通道三维成像系统提供了新的研究方向。详细综述了基于彩色条纹投影术的三维形貌数据测量研究的现状。具体包括彩色条纹投影术的基本原理、彩色条纹调制和解调相关技术、三维成像系统的标定、以及未来的研究方向。接着给出几个利用彩色条纹投影术获取物体表面三维形貌和彩色纹理的实例。为彩色条纹投影术测量物体表面三维形貌数据提供了详尽的综述,并指明了未来潜在的研究新方向。     

Measurement of the geometric features of a cutting tool edge with the aid of a digital image processing technique

For the further development of new machining systems such as flexible manufacturing systems (FMS), this paper reports on a new measuring system developed for the multi-purpose understanding of the geometric features of cutting tool edges having serious influences on the machining outputs. In this system, to detect three-dimensional (3D) features of the toolface and tool flank only from the two-dimensional (2D) microscopic observation of the toolface and to describe an overall 3D geometric feature of the tooledge as a digital 2D image as well as to enable inexpensive system development, two convenient measuring principles are used. These are the scanning optical section method for the toolface contour mapping and the cutting edge profile comparison method for the flank wear landwidth estimation. Based on these, experimental hardware was arranged and various processing softwares were developed. They were applied to an observation of the cutting edge wear development in some cylindrical turning experiments, to show that various effective cutting edge parameters could be easily extracted from the integrated toolface image recorded, and that sufficient accuracy and resolution for practical use could be obtained.     

A fast full-field 3D measurement system for BGA coplanarity inspection

Ball-Grid-Array (BGA) has become one of the most popular packaging techniques in the electronics industry. Coplanarity inspection of BGA solder balls is critical for process and quality control in BGA manufacturing. Currently, the 3D measurement systems for BGA coplanarity inspection are mainly based on laser scanning techniques. However, they suffer from low inspection speed due to the physical line-scanning process. In this paper, a fast and cost-effective 3D measurement system for coplanarity inspection of BGA solder balls is proposed. The proposed system uses an LCD-based phase measuring technique to perform full-field 3D measurement of BGA solder balls with high accuracy. Experiments have shown that the coplanarity measurement of BGA solder balls is very efficient and effective with the proposed system. The measurement repeatability is in the micrometer range. The processing time of the proposed 3D measurement system for an image of 640×480 pixels is less than 2 s on a typical personal computer.     

A protocol for registration and correction of multicolour STED superresolution images

Multicolour fluorescence imaging by STimulated Emission Depletion (STED) superresolution microscopy with doughnut‐shaped STED laser beams based on different wavelengths for each colour channel requires precise image registration. This is especially important when STED imaging is used for co‐localisation studies of two or more native proteins in biological specimens to analyse nanometric subcellular spatial arrangements. We developed a robust postprocessing image registration protocol, with the aim to verify and ultimately optimise multicolour STED image quality. Importantly, this protocol will support any subsequent quantitative localisation analysis at nanometric scales. Henceforth, using an approach that registers each colour channel present during STED imaging individually, this protocol reliably corrects for optical aberrations and inadvertent sample drift. To achieve the latter goal, the protocol combines the experimental sample information, from corresponding STED and confocal images using the same optical beam path and setup, with that of an independent calibration sample. As a result, image registration is based on a strategy that maximises the cross‐correlation between sequentially acquired images of the experimental sample, which are strategically combined by the protocol. We demonstrate the general applicability of the image registration protocol by co‐staining of the ryanodine receptor calcium release channel in primary mouse cardiomyocytes. To validate this new approach, we identify user‐friendly criteria, which – if fulfilled – support optimal image registration. In summary, we introduce a new method for image registration and rationally based postprocessing steps through a highly standardised protocol for multicolour STED imaging, which directly supports the reproducibility of protein co‐localisation analyses. Although the reference protocol is discussed exemplarily for two‐colour STED imaging, it can be readily expanded to three or more colours and STED channels.     

3D打印再制造目前存在问题与应对措施

3D打印技术是一种节材、节能且经济效益突出的绿色先进制造技术,已在金属零件直接成形、生物医疗等行业得到了广泛应用,但其在装备零部件再制造领域的应用目前还处于初级阶段。介绍了3D打印再制造的内涵,并通过对3D打印再制造技术流程的分析指出：相比3D打印直接制造,3D打印再制造涉及技术领域更广,过程更复杂;3D打印再制造目前还存在技术相对单一、设备便携性差、效率低下等问题。最后,针对这些问题,提出了构建一体化再制造软件系统、开发桌面化3D打印系统以及大力开展远程3D打印再制造等相应的应对措施。     

A combined additive manufacturing and micro-syringe deposition technique for realization of bio-ceramic structures with micro-scale channels

This article presents a novel rapid layered manufacturing approach based on a combined additive manufacturing (AM) process and a UV-based micro-syringe deposition (μSD) technique to be used in the fabrication of bio-ceramic structures with controlled micro-sized channels for bone and osteochondral tissue regeneration. In the proposed rapid manufacturing method, micro-scale sacrificial photopolymer networks are integrated within the manufactured part by depositing the photopolymer on selected bio-ceramic powder layers using an injection system. This AM–μSD method along with a post-processing protocol can potentially overcome current limitations of traditional powder-based AM approaches that are restricted in terms of complexity of internal architecture and feature size. For bone or osteochondral repair applications, the material system composed of the bio-ceramic and sacrificial photopolymer, along with the post-processing protocol, must ensure that the final implants are free from manufacturing residuals that could trigger an immune response post-implantation. In this study, calcium polyphosphate bio-ceramic was used as the substrate material based on prior art, polyvinyl alcohol solution was used as the powder binding agent, and ethoxylated (10 bisphenol A diacrylate) photopolymer solution was used as the sacrificial photopolymer element. Material characterization suggests that the proposed material system along with heat treatment protocol is suitable for the targeted applications where micro-scale channels within the implant are produced by AM–μSD.     

Efficient soft tissue characterization under large deformations in medical simulations

The modeling of soft tissue behavior is essential for virtual reality (VR)-based medical simulation, providing a safe and objective medium for training of the medical personnel. This paper presents a soft tissue modeling framework including instrumentation design, in vitro organ experiments and material property characterization. As observed from the force responses measured by a force transducer, the tissue was assumed as a nonlinear, continuous, incompressible, homogeneous and isotropic material for modeling. An electromechanical indentation system to measure the mechanical behavior of soft tissues was designed, and a series harvested organ in vitro experiments were performed. The non-linear soft tissue model parameters were then extracted by matching finite element model predictions with the empirical data. The soft tissue characterization algorithm could become computationally efficient by reducing the number of parameters. The developed tissue models are suitable for computing accurate reaction forces on surgical instruments and for computing deformations of organ surfaces for the VR based medical simulation.     

3D additive manufacture of oral and maxillofacial surgical models for preoperative planning

This paper investigates the errors generated during the fabrication stage for producing complex anatomical replicas derived from computed tomography coupled with the 3D additive manufacturing methods. Based on this research work, it is shown that patient-specific model based on computed tomography data can be converted into computer numerically controlled G-code. It is shown that 3D extrusion-based additive manufacturing technology is accurate to ±3 % equating to ±200 μm surface deviations due to plastic shrinkage and distortion formed during the process. Polylactic acid plastic extrusion through a 200-μm bore nozzle has resulted in a model being produced with an R_a roughness of 35.5 μm. An evaluation on the errors generated during the fabrication process has been used to accurately produce an adult female mandible. Internal nerve channels and complex external bone geometry has been produced within the model. It is shown that using this process results in bone complexity and accuracy required for producing low-cost surgical grades models which is in comparison with traditional selective laser sintering manufacturing techniques. The surface accuracies suggest that the reproduction of anatomically complex representative structures by 3D plastic extrusion additive manufacturing which can be used for pre-surgical planning.     

[学科发展]5D打印——生物功能组织的制造

生物制造是制造技术与生命科学技术交叉融合产生的新兴学科方向,这一学科方向的发展将为巨大的人体组织与器官市场提供新技术,同时也给制造技术变革带来新机遇。面向生物制造未来发展,提出5D打印制造概念,论述了5D打印的内涵,分析了其关键技术。结合生物制造技术的现有进展,介绍了研究团队在心肌组织支架的制造、类脑神经组织制造、爬行生命机械混合机器人方面取得的初步研究进展,为生物制造技术拓展新方向提供新思路。     

Development of a layered manufacturing system using sheet metal-polymer lamination for mechanical parts

Layered manufacturing enables us to make 3D objects rapidly and directly from 3D-CAD data and enables us to handle any design changes. But materials such as light cured polymers, paper, or wax don’t have enough strength to be used directly as mechanical parts. In order to solve such problems, layered manufacturing using both sheet metal and polymers is proposed in this paper. By using sheet metal and polymers, high strength parts with high dumping functions, suitable for use as mechanical parts can be manufactured. Also, a special unit for layered manufacturing is developed, which is designed to be coupled with a desktop NC milling machine, and can make 3D objects easily.     

成像光线追踪的舌面彩色三维成像方法研究

在中医舌诊的客观化研究中,舌面的彩色三维数据能为医生提供更全面的信息,提高诊断的准确性。提出了一种基于成像光线追踪的舌面彩色三维成像方法。在成像光线追踪模型的基础上,引入光平面约束,以准确确定成像点到空间测量点的映射,结合2个线结构光传感器的扫描测量,分别获取舌头上表面及下表面完整的三维信息,并根据空间测量点到成像点的映射,完成颜色渲染,获取对应测量空间点的颜色信息。设计并研制了舌面彩色三维成像系统,进行了测量及精度验证实验,实验结果表明该方法可以准确获取舌面的彩色三维信息。     

Shape from focus based on 3D structure tensor using optical microscopy

Shape from focus (SFF) is a widely used passive optical method for 3D shape reconstruction. In SFF, a focus measure, which is used to estimate the relative focus level, plays a critical role in depth estimation. In this article, we present a new focus measure for accurate 3D shape estimation in optical microscopy based on the analysis of 3D structure tensor. First, the 3D tensors are computed from the input image sequence for each pixel. Then, each tensor is decomposed into point, curve, and surface tensors by decomposing tensors into eigenvalues and eigenvectors. Finally, the surfaceness is used to measure the quality of sharpness. The proposed focus measure provides accurate focus values and better resistance against noise. The proposed measure is evaluated by conducting experiments using image sequences of simulated and microscopic real objects. The comparative analysis demonstrates the effectiveness of the proposed focus measure in recovering 3D shape.