CAD Model Generation Using 3D Scanning

2007 ◽  
Vol 23 ◽  
pp. 169-172
Author(s):  
Khalil Khalili ◽  
Seyed Yousef Ahmadi-Brooghani ◽  
M. Rakhshkhorshid
Keyword(s):  
Programming Languages ◽  
Point Clouds ◽  
3D Scanning ◽  
Industrial Applications ◽  
Free Form ◽  
Depth Information ◽  
Fuzzy Logic Algorithm ◽  
3D Scanners ◽  
Processing Techniques ◽  
Free Form Surfaces

3D Scanners are used in industrial applications such as reverse engineering and inspection. Customization of existing CAD systems is one of rapid ways to supplying a 3D Scanning software. In this paper, using AutoLisp and Visual Basic programming languages, AutoCAD has been customized. Also facilities of automatic scanning of physical parts, in the domain of free form surfaces, have been provided. Furthermore, possibilities such as, control of scanner automotive system, representation of registered point clouds, generation of polygon and /or NURBS model from primary or modified point clouds, have been prepared. Triangulation and image processing techniques along with a new fuzzy logic algorithm have been used to extract the depth information more accurate. These, accompanying with AutoCAD capabilities have provided acceptable facilities for 3D scanning.

Lyapunov Control Strategy for Thermoelectric Cooler Activating an Ice-Clamping System

2018 ◽  
Vol 10 (4) ◽  
Author(s):  
Alexandra Mironova ◽  
Paolo Mercorelli ◽  
Andreas Zedler
Keyword(s):  
Manufacturing Systems ◽  
Control Strategies ◽  
Industrial Applications ◽  
Machining Process ◽  
Free Form ◽  
Cooling Power ◽  
Machining Processes ◽  
Clamping System ◽  
Ice Strength ◽  
Free Form Surfaces

Deformation-free clamping plays an important role in manufacturing systems helping to ensure zero-defect production. The fixture of workpieces during machining processes poses challenges not only for microparts but also for thin-walled pieces or free-form surfaces in macromanufacturing. To address this challenge, a nontraditional adhesive technique, using frozen water to clamp, is introduced in this paper. By increasing the cooling power and thus reducing the temperature of the clamping plate, higher adhesive ice strength and, therefore, a safer clamping system during machining process, can be achieved. The objective of this investigation is to ensure a stable low temperature and to compensate for thermal disturbances. Thanks to their structural robustness, Lyapunov-based control strategies demonstrate an appropriate capability to achieve these results in real industrial applications. Model design of the clamping system as well as simulation and experimental results are shown and discussed.

scholarly journals Congruence analysis of point clouds from unstable stereo image sequences

2014 ◽  
Vol XL-5 ◽  
pp. 301-306 ◽  
Author(s):  
C. Jepping ◽  
F. Bethmann ◽  
T. Luhmann
Keyword(s):  
High Speed ◽  
Image Data ◽  
Point Clouds ◽  
Image Sequences ◽  
Stereo Image ◽  
Free Form ◽  
Crash Test ◽  
3D Point Clouds ◽  
Congruence Analysis ◽  
Free Form Surfaces

This paper deals with the correction of exterior orientation parameters of stereo image sequences over deformed free-form surfaces without control points. Such imaging situation can occur, for example, during photogrammetric car crash test recordings where onboard high-speed stereo cameras are used to measure 3D surfaces. As a result of such measurements 3D point clouds of deformed surfaces are generated for a complete stereo sequence. The first objective of this research focusses on the development and investigation of methods for the detection of corresponding spatial and temporal tie points within the stereo image sequences (by stereo image matching and 3D point tracking) that are robust enough for a reliable handling of occlusions and other disturbances that may occur. The second objective of this research is the analysis of object deformations in order to detect stable areas (congruence analysis). For this purpose a RANSAC-based method for congruence analysis has been developed. This process is based on the sequential transformation of randomly selected point groups from one epoch to another by using a 3D similarity transformation. The paper gives a detailed description of the congruence analysis. The approach has been tested successfully on synthetic and real image data.

Digital Measurement and its Error Analysis for the Machining Free-Form Surface

2014 ◽  
Vol 664 ◽  
pp. 263-267
Author(s):  
Feng Lu ◽  
Ning Li ◽  
Xiao Fei Zhang
Keyword(s):  
Laser Scanning ◽  
Optical Measurement ◽  
Three Dimensional ◽  
Point Clouds ◽  
Free Form ◽  
Digital Measurement ◽  
Machining Errors ◽  
Three Dimensional Measurement ◽  
Free Form Surface ◽  
Free Form Surfaces

To deal with the lack of accurate and efficient inspection methods in complex free-form surfaces, three-dimensional measurement method based on the optical measurement and computer image processing technology was proposed. It adopted laser scanning technology to get point clouds of free-form surface. Used rapid measurement software to inspect precision of point cloud& CAD model. What could be the cause of machining errors was analyzed. 3D deviation inspection of complex surfaces was applied by an artifact. Detected the machining error of an important section, and outputted test report. This research provides a convenient and swift method for the inspection of free-form surface and processing quality control.

Investigating the Segmentation of Freeform Triangulated Surfaces Using a Self-Organizing Map

2006 ◽  
Author(s):  
Alexander D. MacLennan ◽  
Geoff West ◽  
Michael Cardew-Hall
Keyword(s):  
Point Clouds ◽  
Free Form ◽  
Complex Object ◽  
Self Organizing Map ◽  
Discrete Curvature ◽  
Planar Surfaces ◽  
Object Based ◽  
Triangulated Surfaces ◽  
Free Form Surfaces ◽  
Self Organizing

Freeform surfaces can be used to describe manufactured objects. These surfaces can be represented as point clouds, triangulated surfaces and range images. Before these objects can be analysed in any way they need to be broken down into their constituent parts. Using this description stamped parts can be indexed and retrieved to assist in determining how to manufacture a part that has similar properties. One means of performing this task is to segment the object based upon its surface properties. Curvature can be used to describe the behaviour of a surface. In order to use these metrics a single Self-Organizing Map is used to automatically categorise surface into regions of similar curvature. The SOM is first trained using a small number of simple shapes and curvature metrics. It is then used to segment an object that is a mixture of free form surfaces and planes. The combination of these metrics, shapes and the use of a SOM allows for the representation of many types of surfaces. The shapes and curvature metrics used to train the model determine how sensitive it is to different surface descriptions. This technique is successfully applied to a complex object that combines free form surfaces and planar surfaces using robust discrete curvature metrics.

On the Classification of Fitting Problems for Single Patch Free-Form Surfaces in Reverse Engineering

2001 ◽  
Author(s):  
Mohammed M. Shalaby ◽  
Ashraf O. Nassef ◽  
Sayed M. Metwalli
Keyword(s):  
Reverse Engineering ◽  
Geometric Modeling ◽  
Linear Optimization ◽  
Optimization Methods ◽  
Industrial Applications ◽  
Spare Parts ◽  
Free Form ◽  
Modeling Techniques ◽  
Free Form Surfaces ◽  
Die And Mold

Abstract The design and manufacture of free-form surfaces increased in industrial applications, especially for the re-manufacture of spare parts, or in the die and mold industry. Reverse engineering has become the status quo technique in reproducing parts whose original designs are no longer existing or for parts, which assume slightly different shapes after manufacturing as in the case of die and mold industry. Laser scanners have been used extensively in sampling points from parts surfaces. The sampled points are then fitted with a free-form surface using one of the geometric modeling techniques such as Bezier or B-Spline surfaces. Since Non-Uniform Rational B-Splines (NURBS) is the most general form of geometric modeling techniques, this paper presents the possible formulations of the fitting problem optimization and presents some guidelines of the choice of the independent NURBS parameters, once the control points are evaluated using least squares fitting. The work shows that the use of NURBS weights can provide better improvements for the significant reduction of the fitting error, rather than the widely used knot values. In addition the work shows that parts with semi planar surfaces do not need further refinement using non-linear optimization methods.

scholarly journals Worm Selector: Volume Selection in a 3D Point Cloud Through Adaptive Modelling

2017 ◽  
Vol 17 (1) ◽  
pp. 1-20 ◽  
Author(s):  
Emmanuel Dubois ◽  
Adrien Hamelin
Keyword(s):  
Point Cloud ◽  
User Study ◽  
Point Clouds ◽  
Ease Of Use ◽  
Free Form ◽  
3D Point Cloud ◽  
3D Point Clouds ◽  
3D Scanners ◽  
Definition Of ◽  
Straight Lines

3D point clouds are more and more widely used, especially because of the proliferation of manual and cheap 3D scanners and 3D printers. Due to the large size of the 3D point clouds, selecting part of them is very often required. Existing interaction techniques include ray/cone casting and predefined or free-form selection volume. In order to cope with the traditional trade-off between accuracy, ease of use and flexibility of these different forms of selection techniques in a 3D point cloud, we present the Worm Selector. It allows to select complex shapes while remaining simple to use and accurate. Using the Worm Selector relies on three principles: 1) points are selected by progressively constructing a cylinder-like shape (the adaptative worm) through the sequential definition of several sections; 2) a section is defined as a set of two contours linked together with straight lines; 3) each contour is a freely drawn closed shape. A user study reveals that the Worm Selector is significantly faster than a classical selection mechanism based on predefined volumes such as spheres or cuboids, while maintaining a comparable level of precision and recall.

scholarly journals Design and Construction of a Device for Free Form Surfaces 3D Reconstruction Using Microsoft Kinect

2019 ◽  
pp. 82-86
Author(s):  
Tahseen F. Abbas ◽  
Ali Abbar. Khleif ◽  
Hameed S. Ismael
Keyword(s):  
3D Reconstruction ◽  
Processing Technique ◽  
Microsoft Kinect ◽  
Image Processing Technique ◽  
Free Form ◽  
Digital Cameras ◽  
Coordinate Measurement ◽  
3D Scanners ◽  
Free Form Surfaces

There is an increasing need for geometric 3D reconstruction models in the Reverse engineering which is ones of computer Vision applications, reconstruction from a sequence of 2D images is much cheaper than 3D scanners and coordinate measurement machine and also been able to take advantage of the developments in digital cameras and the increasing resolution and quality of images. This work aims to develop a concept of 3D free form surface reconstruction rig and generate the dimension of the surface depending on proposed image processing technique. Through the results obtained is observed that. The overall of calibration accuracy the Root mean square (RMS) value of the point was produced the residuals value in the image space was (0.2830 mm) in the IR images.

Reverse Engineering of Geometric Surfaces Using Tabu Search Optimization Technique

2007 ◽  
Author(s):  
Ayman M. A. Youssef ◽  
Ashraf O. Nassef ◽  
Sayed M. Metwalli
Keyword(s):  
Tabu Search ◽  
Reverse Engineering ◽  
Optimization Technique ◽  
Point Clouds ◽  
Local Minimizer ◽  
Free Form ◽  
Time Saving ◽  
Reactive Tabu Search ◽  
Search Optimization ◽  
Free Form Surfaces

Creating unavailable geometric models from existing parts plays an important role in the process of reverse engineering, for which the accuracy and fitting time of the created models are important factors. This paper proposes the use of Tabu Search (TS) technique in the optimal fitting of NURBS (Non Uniform Rational B-Spline) surfaces to laser-scanned point clouds of free-form surfaces for existing parts. The fitting process involves the initial estimation of the NURBS surface control points using least-squares approximation, followed by optimization of NURBS weights to minimize fitting error. Optimization is performed using a hybrid coding scheme, namely; Modified Continuous Reactive Tabu Search (M-C-RTS), in which a combinatorial optimization component, based on Reactive Tabu Search (RTS), co-operates with Sequential Quadratic Programming (SQP), as a local minimizer. The developed fitting algorithm was applied to a number of simulated free-form surfaces in addition to a laser-scanned PC mouse. Implementation was carried out using MATLAB software and the results were compared to those obtained using Genetic Algorithms (GAs) in an earlier publication. The results show the superiority of the proposed algorithm to the GA-based method with respect to the number of objective function evaluations (about 50% reduction). In addition to this time saving achievement, and surprisingly, M-C-RTS proved to be capable of finding better solutions than GAs.

Sign in / Sign up

Export Citation Format

Share Document