Application of the curvature scale space transform to the representation of three-dimensional models

2013 ◽  
Vol 18 (1) ◽  
pp. 23-29
Author(s):  
Dariusz Frejlichowski
Keyword(s):  
Computer Aided Design ◽  
Shape Representation ◽  
Three Dimensional ◽  
Shape Descriptor ◽  
3D Models ◽  
Scale Space ◽  
3D Shape ◽  
Three Dimensional Objects ◽  
Curvature Scale Space ◽  
Planar Shapes

Abstract In this paper an algorithm for the representation of 3D models is described and experimentally evaluated. Three-dimensional objects are becoming very popular recently and they are processed in various ways - analysed, retrieved, recognised, and so on. Moreover, they are employed in various aplications, such as virtual reality, entertainment, Internet, Computer Aided Design, or even in biometrics or medical imaging. That is why the development of appropriate algorithms for the representation of 3D objects is so important recently. These algorithms - so called 3D shape descriptors - are assumed to be invariant to particular transformations and deformations. One of the possible approaches is based on the projections of a 3D object into planar shapes and representation of them using a 2D shape descriptor. An algorithm realising this idea is described in this paper. Its first stage is based on the rendering of 20 2D projections, from various points of view. Later, the obtained projections are stored in a form of bitmaps and the Curvature Scale Space algorithm is applied for the description of the planar shapes extracted from them. The proposed approach is experimentally compared with several other 3D shape representation methods.

THE NORMALIZED WAVELET DESCRIPTOR FOR SHAPE RETRIEVAL

2008 ◽  
Vol 06 (01) ◽  
pp. 25-36 ◽  
Author(s):  
KIMCHENG KITH ◽  
BAREND J. VAN WYK ◽  
MICHAËL A. VAN WYK
Keyword(s):  
Image Analysis ◽  
Image Retrieval ◽  
Shape Descriptor ◽  
Scale Space ◽  
Experimental Results ◽  
Shape Retrieval ◽  
Fourier Descriptor ◽  
Curvature Scale Space ◽  
Wavelet Descriptor

In many image analysis applications, such as image retrieval, the shape of an object is of primary importance. In this paper, a new shape descriptor, namely the Normalized Wavelet Descriptor (NWD), which is a generalization and extension of the Wavelet Descriptor (WD), is introduced. The NWD is compared to the Fourier Descriptor (FD), which in image retrieval experiments conducted by Zhang and Lu, outperformed even the Curvature Scale Space Descriptor (CSSD). Image retrieval experiments have been conducted using a dataset containing 2D-contours of 1400 objects extracted from the standard MPEG7 database. For the chosen dataset, our experimental results show that the NWD outperforms the FD.

Performance of 3D computers and 3D printed models as a fundamental means for spatial engineering information visualization

2014 ◽  
Vol 41 (10) ◽  
pp. 869-877 ◽  
Author(s):  
Gabriel B. Dadi ◽  
Timothy R.B. Taylor ◽  
Paul M. Goodrum ◽  
William F. Maloney
Keyword(s):  
Computer Aided Design ◽  
Three Dimensional ◽  
3D Models ◽  
The Body ◽  
Information Modeling ◽  
Simple Task ◽  
Great Opportunity ◽  
Cad Models ◽  
Engineering Information ◽  
3D Printed

Engineering information delivery can be a source of inefficient communication of design, leading to construction rework and lower worker morale. Due to errors, omissions, and misinterpretations, there remains a great opportunity to improve the traditional documentation of engineering information that craft professionals use to complete their work. Historically, physical three dimensional (3D) models built by hand provided 3D physical representations of the project to assist in sequencing, visualization, and planning of critical construction activities. This practice has greatly diminished since the adoption of 3D computer-aided design (CAD) and building information modeling technologies. Recently, additive manufacturing (a.k.a. 3D printing) technologies have allowed for three dimensional printing of 3D CAD models. A cognitive experiment was established to measure the effectiveness of 2D drawings, a 3D computer model, and a 3D printed model in delivering engineering information to an end-user are scientifically measured. The 3D printed model outperformed the 2D drawings and 3D computer interface in productivity measures. This paper’s primary contribution to the body of knowledge is identification of how different mediums of engineering information influence the performance of a simple task execution.

scholarly journals Simulation Informed CAD for 3D Nanoprinting

Micromachines ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 8 ◽  
Author(s):  
Jason D. Fowlkes ◽  
Robert Winkler ◽  
Eva Mutunga ◽  
Philip D. Rack ◽  
Harald Plank
Keyword(s):  
Analytical Model ◽  
Computer Aided Design ◽  
Critical Mass ◽  
Three Dimensional ◽  
Three Dimensional Objects ◽  
Non Linear ◽  
Out Of Plane ◽  
Digital Scanning ◽  
Definition Of ◽  
Bending Nanowires

A promising 3D nanoprinting method, used to deposit nanoscale mesh style objects, is prone to non-linear distortions which limits the complexity and variety of deposit geometries. The method, focused electron beam-induced deposition (FEBID), uses a nanoscale electron probe for continuous dissociation of surface adsorbed precursor molecules which drives highly localized deposition. Three dimensional objects are deposited using a 2D digital scanning pattern—the digital beam speed controls deposition into the third, or out-of-plane dimension. Multiple computer-aided design (CAD) programs exist for FEBID mesh object definition but rely on the definition of nodes and interconnecting linear nanowires. Thus, a method is needed to prevent non-linear/bending nanowires for accurate geometric synthesis. An analytical model is derived based on simulation results, calibrated using real experiments, to ensure linear nanowire deposition to compensate for implicit beam heating that takes place during FEBID. The model subsequently compensates and informs the exposure file containing the pixel-by-pixel scanning instructions, ensuring nanowire linearity by appropriately adjusting the patterning beam speeds. The derivation of the model is presented, based on a critical mass balance revealed by simulations and the strategy used to integrate the physics-based analytical model into an existing 3D nanoprinting CAD program is overviewed.

scholarly journals 3D Compression: from A to Zip a first complete example

2008 ◽  
Vol 15 (1) ◽  
pp. 9-38
Author(s):  
Thomas Lewiner
Keyword(s):  
Computer Aided Design ◽  
Three Dimensional ◽  
3D Models ◽  
Data Representation ◽  
Specific Class ◽  
Physical Simulations ◽  
Image Creation ◽  
Multidimensional Objects ◽  
Aided Design ◽  
Fast Access

Images invaded most of contemporary publications and communications. This expansion has accelerated with the development of efficient schemes dedicated to image compression. Nowadays, the image creation process relies on multidimensional objects generated from computer aided design, physical simulations, data representation or optimisation problem solutions. This variety of sources motivates the design of compression schemes adapted to specific class of models. The recent launch of Google Sketch’up and its 3D models warehouse has accelerated the shift from two-dimensional images to three-dimensional ones. However, these kind of systems require fast access to eventually huge models, which is possible only through the use of efficient compression schemes. This work is part of a tutorial given at the XXth Brazilian Symposium on Computer Graphics and Image Processing (Sibgrapi 2007).

scholarly journals Modelling and Visualization of Three Dimensional Objects Using Inexpensive Digital Cameras

2018 ◽  
Author(s):  
Ismail Elkhrachy
Keyword(s):  
Low Cost ◽  
Three Dimensional ◽  
Point Clouds ◽  
3D Models ◽  
Bundle Adjustment ◽  
Control Points ◽  
Digital Cameras ◽  
Three Dimensional Objects ◽  
Spatial Positioning ◽  
And Control

This paper analyses and evaluate the precision and the accuracy the capability of low-cost terrestrial photogrammetry by using many digital cameras to construct a 3D model of an object. To obtain the goal, a building façade has imaged by two inexpensive digital cameras such as Canon and Pentax camera. Bundle adjustment and image processing calculated by using Agisoft PhotScan software. Several factors will be included during this study, different cameras, and control points. Many photogrammetric point clouds will be generated. Their accuracy will be compared with some natural control points which collected by the laser total station of the same building. The cloud to cloud distance will be computed for different comparison 3D models to investigate different variables. The practical field experiment showed a spatial positioning reported by the investigated technique was between 2-4cm in the 3D coordinates of a façade. This accuracy is optimistic since the captured images were processed without any control points.

scholarly journals Geometric modeling and development of custom libraries in the design of engineering facilities

2020 ◽  
pp. 1-7
Author(s):  
Elena Sergeevna Reshetnikova ◽  
Irina Aleksandrovna Savelyeva ◽  
Ekaterina Anatolyevna Svistunova
Keyword(s):  
Design Process ◽  
Computer Aided Design ◽  
Geometric Modeling ◽  
Three Dimensional ◽  
3D Models ◽  
Conveyor Belt ◽  
General Idea ◽  
Design Stage ◽  
Preliminary Design ◽  
Design Documentation

The subject of research is the process of designing a conveyor belt. The authors consider parameterization in geometric modeling of parts and components of equipment and the creation of custom libraries in Compass 3D as a means of reducing the complexity and improving the quality of the design process. The preliminary design is the design stage of the development of design documentation and aims to determine the fundamental design solutions for a general idea of the device, operating principles and dimensions of the product. It is advisable to develop a preliminary design before the stage of developing a technical project and creating design documentation. Today, at all stages of work on the project, modern computer-aided design (CAD) systems are used, which not only accelerate the design process, but also make it possible to demonstrate to the customer the finished project at the stage of making technical decisions. This allows making timely changes in accordance with the requirements of the customer and to carry out high-quality preparation of the project for its implementation. The volume and time for further stages of work depend on the timing of the presentation of the preliminary design, therefore, the use of three-dimensional modeling parametrization in CAD is an effective way for designing engineering objects. Parameterization when working with 3D models allows you to get a set of typical product designs based on a once-created model by changing the set values of the variables, which significantly reduces the time spent on the project.

scholarly journals Three-dimensional dental topography and feeding ecology in the extinct cave bear

2020 ◽  
Vol 16 (12) ◽  
pp. 20200792
Author(s):  
Alejandro Pérez-Ramos ◽  
Alejandro Romero ◽  
Ernesto Rodriguez ◽  
Borja Figueirido
Keyword(s):  
Feeding Behaviour ◽  
Giant Panda ◽  
Ursus Arctos ◽  
High Efficiency ◽  
Three Dimensional ◽  
Shape Descriptor ◽  
3D Models ◽  
Ailuropoda Melanoleuca ◽  
Feeding Preferences ◽  
Cave Bear

The cave bear ( Ursus spelaeus s.l .) was an iconic extinct bear that inhabited the Pleistocene of Eurasia. The cause of extinction of this species is unclear and to identify the actual factors, it is crucial to understand its feeding preferences. Here, we quantified the shape descriptor metrics in three-dimensional (3D) models of the upper teeth (P 4 –M 2 ) of the cave bear to make inferences about its controversial feeding behaviour. We used comparative samples, including representatives of all living bear species with known diets, as a template. Our topographic analyses show that the complexity of upper tooth rows in living bears is more clearly associated with the mechanical properties of the items consumed than with the type of food. Cave bears exhibit intermediate values on topographic metrics compared with the bamboo-feeder giant panda ( Ailuropoda melanoleuca ) and specialists in hard mast consumption ( Ursus arctos and Ursus thibetanus ). The crown topography of cave bear upper teeth suggests that they could chew on tough vegetal resources of low quality with high efficiency, a characteristic that no living bear currently displays. Our results align with a climate-driven hypothesis to explain the extinction of cave bear populations during the Late Pleistocene.

scholarly journals Tangible interface for shape modeling by block assembly of wirelessly connected blocks

2019 ◽  
Vol 6 (4) ◽  
pp. 542-550 ◽  
Author(s):  
Jinwon Son ◽  
Hoik Jang ◽  
Young Choi
Keyword(s):  
Wireless Communication ◽  
Computer Aided Design ◽  
3D Models ◽  
Shape Modeling ◽  
Sensor Data ◽  
3D Shape ◽  
Cad System ◽  
Visual Occlusion ◽  
The Status ◽  
Efficient Data

Abstract Tangible computer-aided design (CAD) that can generate and manipulate 3D models more efficiently than conventional modeling interfaces is a new interface technology between users and computers through tangible physical devices. Because the majority of tangible CAD systems use cameras or projectors, 3D models of complex structures with visual occlusion cannot be generated. In this work, we propose and develop a system that allows users to create complex shapes by assembling wireless blocks. By allowing more freedom in the orientations of blocks, models created by the assembly operation can be used to generate true 3D shapes compared to the 2.5D shapes resulting from previous research. The physical blocks of the proposed system include infrared proximity sensors, inertial magnetic units, Zigbee modules, and Arduino microcontrollers. The status of the block assembly is transmitted to the workstation wirelessly by the Zigbee. The workstation collects the sensor data of the blocks and generates and renders 3D models of the physically assembled blocks. The concept of the proposed tangible CAD system can be used in various application areas where simple, easy-to-use shape modeling interfaces for creating models by assembling small blocks are sufficient. The education and gaming industries are good examples of where this concept can be applied easily. Highlights A 3D shape modeling system through physical block assembly with sensors is developed. Using wireless communication, a degree of freedom of block assembly is increased. The rotation of the block was calculated through the 9-axis sensor and applied to the rendered 3D model. Through efficient data processing, the problems of real-time wireless communication environment are overcome. Users who are not trained in CAD tools can easily create 3D shape models.

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