CAD/CAM/CAE representation of 3D objects measured by fringe projection

Author(s):  
Tomasz Pancewicz ◽  
Malgorzata Kujawinska
Keyword(s):  
Author(s):  
Hong-Seok Park ◽  
Chintal Shah ◽  
Rima Shah

3D shape recognization technique is rapidly advancing from last decade in the fields of manufacturing, computer science, entertainment and medical technology. Due to the restriction of size and area of cavity, it’s challenging to develop such non-contact optical technologies for scanning. 3D digitization technology plays a vital role in the field of dentistry benefiting dentists and patients by eliminating long time procedures for making the prosthesis/abutments and results into ultimate comfort. In this paper, we have recounted a design of a prototype for a three-dimensional intra-oral scanner using the principle of fringe projection and active triangulation method. LED as a light source passed through the liquid crystal on silicon (LCoS) which radiates the light into three colors and strikes onto the collimating lens assembly and then passed through the optical deflectors. Once the light strikes the object through scanning window it is guided back through the flat reflectors and the fringe pattern on the object is stored into the gray encoding plate. With the help of camera all these images are stored. After the acquisition of images, firstly it will calculate the phase distribution using four-step phase shifting algorithm and unwrap the wrap phase which helps us in getting accurate images. Later, we get display of scanned oral cavity onto the computer screen. Phase-height mapping algorithm has been realized for the reconstruction of the 3D real time reconstruction of the scanned oral cavity which helps us in fast scanning with accurate data. A novel approach of LED as a light source and LCoS display for scattering light fragments into three different colors helps us to scan more effectively for registration of dental surfaces from the patient’s mouth more accurately. Apart from that, its sleek design helps to scan with less pain to the patient’s having low mouth opening. Experiment was performed on the prototype of denture and using this proposed method we have achieved the accuracy of 25μm and it took around 180 sec for the full arc scan of the lower oral cavity. The result of scanned data was checked using the CAD/CAM software for dentistry and compared with the prototype data of denture. Further this image can be used for making prosthesis/abutment directly into production using 3D printing machine or the milling machine. Thus, an abutment or prosthesis obtained with this method is of high quality and eliminates conventional long procedures which helps in reducing pain of patient’s and helps dentists to attain more patients in less time.


2007 ◽  
Vol 127 ◽  
pp. 189-194 ◽  
Author(s):  
T. Horii ◽  
M. Ishikawa ◽  
Soshu Kirihara ◽  
Yoshinari Miyamoto ◽  
Nobu Yamanaka

A newly developed freeform fabrication process named 3D Micro-Welding, which is a combined system of a micro-TIG welding and a layered manufacturing method, is demonstrated. Various refractory alloys such as Inconel, stainless steel, and Invar can be freeformed besides elemental metals like titanium. Small metal beads of ~1mm in diameter are formed by emitting micro arc to the top of a thin metal wire of 0.2mm diameter. A fused bead is welded to a metal substrate or previously formed beads. By continuing this process and building up beads layer by layer under the control of CAD/CAM system, 3D objects were produced. In this study, optimization of micro-welding parameters such as the waveform of pulsed arc current and electrode materials were investigated and simple 3D objects of Inconel 600, SUS 304, Invar 42 were formed. The interfaces between adjacent beads were joined well and no crack or pore existed in the formed objects. The density and Vickers hardness of Inconel 600 objects showed comparable values to the commercial Inconel alloy, however the yield strength and Young’s modulus was about 80% and 70% of that alloy, respectively.


2012 ◽  
Vol 503-504 ◽  
pp. 1437-1440 ◽  
Author(s):  
Ming Rang Yu ◽  
Ying Jie Zhang ◽  
Ding Zhang

Optical measurement has been widely used in many fields of science and engineering, such as CAD/CAM, machine vision, quality inspection, reverse engineering, etc, due to its properties of non-contact and high speed. Fringe projection methods have caused much more attentions in full field measurement and insensitive to the change of the objects’ reflectivity. This paper reviews state-of-the art progresses in the 3D shape measuring methods using fringe projection techniques. A comparison of the existing methods is performed with their advantages and drawbacks also are pointed out.


2007 ◽  
Vol 07 (02) ◽  
pp. 321-351
Author(s):  
M. DJEBALI ◽  
M. MELKEMI ◽  
K. MELKEMI ◽  
N. SAPIDIS

In industry applications, the range images are generally huge points arrays and are additively noised. They usually represent surfaces of 3D objects and are used for reverse engineering process in CAD/CAM domains. To compute the geometrical model of each surface present in the range image, we denoise and sub-sample the raw range data. Denoising allows us to avoid the adverse effects of the noise on the obtained result. Sub-sampling the raw range data leads to a low image processing overheads like those of segmentation process. Based on interpolation properties of particular wavelets named coiflets, we propose a method for smoothing noisy range images. The smoothed image keeps invariant the "topological characteristics" of the represented surfaces. Thereafter, we propose a method for sub-sampling dense range images which leads to the reduction of the amount of raw data by a factor of four. This method eliminates the "redundant" information, thus the obtained result describes the essential details (as the shape of the physical surface) of the initial range image. The smoothing and sub-sampling methods are designed to be easily integrated in any reconstruction algorithm to improve its result and reduce its overhead in spite of its high complexity.


Author(s):  
Zhuojun Bao

Abstract Extended bintree as a new class of approximation models for solid modeling is presented in this paper. Based on the bintree data structure, it allows face, edge and vertex node types as well as the classical black, white and grey nodes. Using extended bintrees, Boolean operations can be carried out and are used to generate a new object representation. The required memory is less than that in term of bintree, that is a generalization of the quadtree and octree. This gives a new efficient way to represent polygonal and polyhedral objects exactly. The extended bintree is a general method of binary cellular models. From that, the corresponding other binary models can be easily deduced. The extended bintree representation can be used in image processing and model converting in CAD/CAM systems.


Author(s):  
Chaman L. Sabharwal ◽  
Jennifer L. Leopold

The intersection between 3D objects plays a prominent role in spatial reasoning, and computer vision. Detection of intersection between objects can be based on the triangulated boundaries of the objects, leading to computing triangle-triangle intersection. Traditionally there are separate algorithms for cross and coplanar intersection. For qualitative reasoning, intersection detection is sufficient, actual intersection is not necessary; in contrast, the precise intersection is required for geometric modeling. Herein we present a complete design and implementation of a single integrated algorithm independent of the type of intersection. Additionally, this algorithm first detects, then intersects and classifies the intersections using barycentric coordinates. This work is directly applicable to: (1) VRCC-3D+, which uses intersection detection between 3D objects as well as their 2D projections essential for occlusion detection; and (2) CAD/CAM geometric modeling where curves of intersection between a pair of surfaces are required for numerical control machines. Experimental results are provided.


Prospectiva ◽  
2018 ◽  
Vol 16 (1) ◽  
pp. 60-66
Author(s):  
Mario Mercado Coronado ◽  
Pablo Maestre ◽  
Esmeide Alberto Leal Narváez ◽  
Nallig Eduardo Leal Narváez
Keyword(s):  

El propósito de la reconstrucción tridimensional es convertir una gran cantidad de datos o puntos, en un modelo en la memoria del computador, manteniendo sus características físicas de volumen y forma, para llevarlo posteriormente a una figura real por medio de alguna de las diferentes técnicas de impresión 3D. La reconstrucción 3D tiene un amplio rango de aplicaciones entre las cuales se encuentran, el diseño asistido por computador CAD/CAM, la computación gráfica, el entretenimiento, los procesos de manufactura en la industria, la robótica, la visualización científica, la medicina, la cultura, entre otras.En esta Artículo se propone un método que, tomando como base la nube de puntos de un objeto previamente escaneado, calcula una serie de cortes a lo largo del eje principal del objeto, el cual es estimado usando Análisis de Componentes Principales (PCA). Estos cortes, pueden ser impresos en diferentes tipos de materiales (Poliestireno, MDF, Espuma, Cartón, Madera etc.) para luego obtener una reproducción a mayor escala del objeto escaneado. Por tratarse de puntos, se facilita el trabajo para ampliar el tamaño del objeto usando interpolación u otro método equivalente.


1997 ◽  
Vol 24 (7) ◽  
pp. 540-548 ◽  
Author(s):  
N. KAWAHATA ◽  
H. ONO ◽  
Y. NISHI ◽  
T. HAMANO ◽  
E. NAGAOKA
Keyword(s):  

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