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3d Identification of Face and Flank in Micro-mills for Automatic measurement of Rake Angle

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Nanomanufacturing and Metrology 2020年第2期3卷 151-163页

作者： Stefano Petro Giovanni Moroni department of Mechanical Engineering Politecnico di MilanoVia Giuseppe la Masa 120156 MilanItaly

In an Industry 4.0 context,to each object a"digital twin"is associated,which is a virtual counterpart of the object *** the case of a tool,this includes,together with its material and manufacturing information,its solid *** geometry knowledge is fundamental to enable effective tool management,manufacturing verification,and tooling *** for tool management the conventional 2d presetting is sufficient,tooling simulation and tool manufacturing verification require a complete 3d *** is particularly true in the case of the microtools:the process of micro-chip formation is still a research *** the 3d geometry of a tool is well established in the ISO 3002 series of standard,only recently 3d measurement of tools has been made possible by new measuring ***,tool geometry verification requires a lot of human *** paper aims at setting the base for the automatic analysis of point meshes scanned on the whole surface of tools,and in particular *** first step for doing this is the identification of the active surfaces of the tool,that is the face and the flank plus the cutting *** identification of these geometric features is in general possible thanks to their specific characteristics:in particular,the cutting edge is characterized by a high curvature,and it separates the face from the *** paper considers cylindrical micro end-mills as a first example of an approach that can be extended to in principle any kind of *** cylindrical helix characterizing the cutting edge is the key geometry to be considered in the development of the specific *** the tool features(face,flank,and cutting edge)have been separated,of the tool angles,for instance,can be *** first angle to study,the rake angle has been *** approach will be validated on simulated data and on real scans of micro-tools.

关键词： Tool metrology 3d measurement Partitioning Tool angles

Recent Progress of Full‑Field Three‑dimensional Shape measurement Based on Phase Information

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Nanomanufacturing and Metrology 2024年第2期7卷 26-41页

作者： Yajing Bai Zonghua Zhang Shuai Fu Hongwei Zhao Yubo Ni Nan Gao Zhaozong Meng Zeqing Yang Guofeng Zhang Wei Yin School of Mechanical Engineering Hebei University of TechnologyTianjin 300401China School of Mechanical Engineering Xi’an Jiaotong UniversityXi’an 710049ShaanxiChina National Key Laboratory of Strength and Structural Integrity Aircraft Strength Research Institute of ChinaXi’an 710065ShaanxiChina

Full-field three-dimensional(3d)measurement technology based on phase information has become an indispensable part of geometric dimension measurement in modern scientific research and engineering *** field has been developing and evolving for the study of highly reflective phenomena,diffuse reflections,and specular surfaces,and many novel methods have emerged to increase the speed of measurements,enhance data accuracy,and broaden the robustness of the ***,we will discuss the latest research progress in full-field 3d shape measurement based on phase information systematically and ***,the fundamentals of 3d shape measurement based on phase information are introduced,namely,phase-shifting and transform-based ***,recent technological innovations are highlighted,including increases in measurement speed and automation and improvements in robustness in complex *** particular,the challenges faced by these technological advances in solving highly dynamic,composite surface measurement problems are presented,i.e.,with multiexposure techniques proposed for high dynamics that extend the dynamic range of the camera to reduce the effects of overexposure but increase the cost of time and have high hardware requirements,fringe adaptive techniques that overcome light variations but are computationally complex,and multipolarized camera techniques that reduce the effects of light variations but are sensitive to the light ***,the phase-shifting method combined with coding is proposed to improve the measurement speed,but the accuracy is slightly *** learning techniques are proposed to cope with measurements in complex environments,but the dataset computation process is ***,future research directions are suggested,and the challenges are ***,this work provides a reference for researchers and engineers.

关键词： 3d measurement Phase information Fringe projection Phase measuring deflectometry

3d Concave defect measurement System of the Cryogenic Insulated Cylinder Based on Linear Structured Light

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3D Concave Defect Measurement System of the Cryogenic Insula...

A 3d GIS spatial data model based on conformal geometric algebra

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作者： Yongsheng Zhao Jian Liu Guofeng Wang Yusheng Fan Houde Wu College of Information Science and Technology Dalian Maritime University

Cryogenic insulated cylinders’ features of the large size and reflecting make the geometric size measurement a challenge work. A new system for 3 d visualization measurement of cryogenic insulated cylinders is designed in this paper. The system consists of three CCd cameras and three laser projectors. The measurement method is mainly based on monocular vision, linear structured light extraction and 3 d reconstruction. Cylinder fitting and connected component labeling methods are adopted to process the point cloud data after 3 d reconstruction. At the same time, approximate voxel grid filter based on Point Cloud Library（PCL） is applied to simplify the processing. Accordingly, the concave depth and position of the cylinder can be obtained. Through the experimental verification, the system can achieve the actual measurement demands of the measurement standard and the error of the depth measurement is lower than 1 mm.

关键词： 3d measurement Cryogenic insulated cylinders Linear structured light 3d reconstruction Concave depth

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Science China Earth Sciences 2011年第1期54卷 101-112页

作者： YUAN LinWang YU ZhaoYuan LUO Wen ZHOU LiangChen LU GuoNia Key Laboratory of VGE Ministry of Education Nanjing Normal University Nanjing 210046 China

We propose a new Geographic Information System (GIS) three-dimensional (3d) data model based on conformal geometric algebra (CGA). In this approach, geographic objects of different dimensions are mapped to the corresponding basic elements (blades) in Clifford algebra, and the expressions of multi-dimensional objects are unified without losing their geometric meaning. Geometric and topologic computations are also processed in a clear and coordinates-free way. Under the CGA framework, basic geometrics are constructed and expressed by the inner and outer operators. This expression combined geometrics of different dimensions and metric relations. We present the structure of the framework, data structure design, and the data storage, editing and updating mechanisms of the proposed 3d GIS data model. 3d GIS geometric and topological analyses are performed by CGA metric, geometric and topological operators using an object-oriented approach. demonstrations with 3d residence district data suggest that our 3d data model expresses effectively geometric objects in different dimensions, which supports computation of both geometric and topological relations. The clear and effective expression and computation structure has the potential to support complex 3d GIS analysis, and spatio-temporal analysis.

关键词： conformal geometric algebra 3d data model 3d measurement 3d spatial relation

Research and development of fringe projection-based methods in 3d shape reconstruction

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第6期7卷 1026-1036页

作者： WU Lu-shen PENG Qing-jin department of Mechanical and Electronic Engineering Nanchang University Nanchang 330029 China department of Mechanical and Industrial Engineering University of Manitoba R3T 5V6 Canada

This paper discusses current research and development of fringe projection-based techniques. A system based on Fourier transform profilometry (FTP) is proposed for three-dimensional (3d) shape recovery. The system improves the method of phase unwrapping to gain accurate 3d shapes of objects. The method uses a region-growing algorithm for the path prediction guided by the quality map to increase the recovering accuracy and provides a fast and simple tool for 3d shape recovery. The shape measurement and data recovery are integrated to offer a new method of 3d modelling. Examples are presented to verify the feasibility of the proposed method.

关键词： 3d modelling Fringe projection Quality map 3d measurement Reverse engineering

Viewpoint Planning for Freeform Surface Inspection Using Plane Structured Light Scanners

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International Journal of Automation and computing 2016年第1期13卷 42-52页

作者： Qian Wu Wei Zou de Xu Research Center of Precision Sensing and Control Institute of Automation Chinese Academy of Sciences

This paper proposes an automatic model-based viewpoint planning method, which can achieve high precision and high efficiency for freeform surfaces inspection using plane structured light scanners. The surface model is utilized in stereolithography format, which is widely used as an industrial standard. The proposed method consists of 4 steps： topology reconstruction, mesh refinement, scan direction determination and viewpoint generation. In the first step, the topology structure of the surface model is reconstructed according to a designed data structure, based on which a neighborhood search algorithm is developed. In the second step, big facets in the surface model are segmented into several small ones, which are suitable for viewpoint planning. In the third step, an initial scan region of a viewpoint is grouped by the neighborhood search algorithm combining with total area and normal vector restrictions. Accordingly, the scan direction is determined by the normal vectors of facets in the initial scan region. In the fourth step, the position, the orientation, and the final scan region of the viewpoint are determined by 4 scan constraints, i.e., field of view, working distance range, view angle and overlap. Experimental results verify the effectiveness and advantages of the proposed method.

关键词： Freeform surface 3d measurement structured light scanner stereolithography (STL) viewpoint planning.

An Improved Calibration Method of Grating Projection measurement System

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Computers, Materials & Continua 2023年第5期75卷 3957-3970页

作者： Qiucheng Sun Weiyu dai Mingyu Sun Zeming Ren Mingze Wang College of Computer Science and Technology Changchun Normal University130000ChangchunChina

In the traditional fringe projection profilometry system,the projector and the camera light center are both spatially virtual *** spatial position relationships specified in the model are not easy to obtain,leading to inaccurate system parameters and affectingmeasurement *** paper proposes a method for solving the system parameters of the fringe projection profilometry system,and the spatial position of the camera and projector can be adjusted in accordance with the obtained calibration *** steps are as follows:First,in accordance with the conversion relationship of the coordinate system in the calibration process,the calculation formula of the vertical distance from the camera light center to the reference plane and the calculation formula of the distance between the projector and the camera light center are given ***,according to the projector calibration principle,the position of the projector light axis perpendicular to the reference plane is gained by comparing the parallel relationship between the reference plane coordinate system and the projector coordinate system’s ***,in order to fulfill the position restriction that the line between the projector light center and the camera light center must be parallel to the reference plane,the camera’s spatial location is adjusted so that the vertical distance between it and the reference plane tends to that between the projector light center and the reference *** finally,the three-dimensional(3d)reconstruction of the target object can be finished using the phase height model’s system parameters once the aforementioned position limitations are put into *** results demonstrate that the method improves the measurement accuracy,and verifies that it is effective and available in 3d shape measurement.

关键词： 3d measurement calibration phase shift phase height model

A light field measurement system through PSF estimation by a morphology-based method

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International Journal of Extreme Manufacturing 2021年第4期3卷 113-124页

作者： Lingbao Kong Panyu Zhou Shanghai Engineering Research Center of Ultra-precision Optical Manufacturing Fudan UniversityShanghai 200433People’s Republic of China

Light field imaging technology can obtain three-dimensional(3d)information of a test surface in a single *** light field reconstruction algorithms not only take a long time to trace back to the original image,but also require the exact parameters of the light field system,such as the position and posture of a microlens array(MLA),which will cause errors in the reconstructed image if these parameters cannot be precisely *** paper proposes a reconstruction algorithm for light field imaging based on the point spread function(PSF),which does not require prior knowledge of the *** accurate PSF derivation process of a light field system is presented,and modeling and simulation were conducted to obtain the relationship between the spatial distribution characteristics and the PSF of the light field system.A morphology-based method is proposed to analyze the overlapping area of the subimages of light field images to identify the accurate spatial location of the MLA used in the system,which is thereafter used to accurately refocus light field imaging.A light field system is built to verify the algorithm’s *** results show that the measurement accuracy is increased over 41.0%compared with the traditional method by measuring a step *** accuracy of parameters is also improved through a microstructure measurement with a peak-to-valley value of 25.4%and root mean square value of 23.5%*** further validates that the algorithm can effectively improve the refocusing efficiency and the accuracy of the light field imaging results with the superiority of refocusing light field imaging without prior knowledge of the *** proposed method provides a new solution for fast and accurate 3d measurement based on a light field.

关键词： light field deconvolution 3d measurement PSF estimation measurement accuracy MLA

Laboratory Simulation of the Formation Process of Surface Geochemical Anomalies Applied to Hydrocarbon Exploration

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Acta Geologica Sinica(English Edition) 2016年第6期90卷 2149-2162页

作者： WANG Guojian TANG Yuping CHENG Tongjin TANG Junhong FAN Ming LU Li Wuxi Research Institute of Petroleum Geology Research Institute of Petroleum Exploration and ProductionSINOPEC College of Material & Environmental Engineering Hangzhou Dianzi University

The formation mechanisms and processes of geochemical anomalies used as proxies in surface geochemistry exploration （SGE） have not been well understood. Previous studies cannot realize 3d measurement of microseeping hydrocarbons from reservoirs to the surface, which made it difficult to understand the features and pathways of deep hydrocarbon microseepages. Understanding the processes of hydrocarbon microseepages will contribute to the acceptance and effectiveness of surface geochemistry. Based on a simplified geological model of hydrocarbon microseepages, including hydrocarbon reservoir, direct caprock, overlying strata and Quaternary sediments, this work established a 3d experimental system to simulate the mechanisms and processes of deep hydrocarbon microseepes extending to the surface. The dispersive halos of microseeping hydrocarbons in the subsurface were adequately described by using this 3d experimental system. Results indicate that different migration patterns of hydrocarbons above the point gas source within the simulated caprock and overlying strata can be reflected by the ratio of i-butane to n-butane （i-C4/n-C4）, which follow diffusion and infiltration （buoyancy） mechanisms. This is not the case for vertical measurement lines far from the point gas source. A vertical gas flow in the form of a plume was found during hydrocarbon microseepage. For sampling methods, the high-density grid sampling is favorable for delineating prospecting targets. Hydrocarbon infiltration or buoyancy flow occurs in the zones of infiltration clusters, coupling with a diffusion mechanism at the top of the water table and forming surface geochemical anomalies. These results are significant in understanding hydrocarbon microseepage and interpreting SGE data.

关键词： hydrocarbon microseepage surface geochemical anomaly 3d measurement laboratory simulation migration mechanisms and processes