scholarly journals METHODS FOR MODELS PARAMETERS ESTIMATE TO SOLVE PROBLEMS ON 3D RECONSTRUCTION OF REAL OBJECTS COMPLEX MODELS

2016 ◽  
Vol 2016 (3) ◽  
pp. 233-242 ◽  
Author(s):  
Владислав Колякин ◽  
Vladislav Kolyakin ◽  
Владимир Аверченков ◽  
Vladimir Averchenkov ◽  
Максим Терехов ◽  
...  

Virtual threedimensional (3 D) models of complex objects are used in many fields of science and engineering, such as architecture, industry, medicine, robotics. Besides, 3D models are used in geoinformation systems, computer games, virtual and supplemented reality and so on. Three dimensional models can be formed in dif-ferent ways, one of which consists in 3 D reconstruc-tion. One of the stages of the 3 D reconstruction of complex models of real objects is a definition of the mathematical models of geometric primitives emphasized on the image. One of the ways for the estimate of model parameters is a method of Hough vote and its modifications – Hough probabilistic transformation, Hough random transformation, Hough hierarchical transformation, phase space blurriness, use of a gra-dient of image brightness and so on. As an alternative way for models selection is a choice of suitable points from a set of data.

Author(s):  
Vladimír Modrák ◽  
Jozef Novák Marcincin

After applications of virtual reality (VR) in the realm of flight simulators and computer games a need to exercise these technologies in industry is rising significantly. Nowadays one of the typical domains of using a virtual reality is designing and prototyping in automotive and air industry. A practical solution for a virtual model is using a virtual reality modeling language (VRML) that supports the distribution of three-dimensional models over the Internet. Web based virtual reality technology offers possibilities for sharing virtual models for supporting collaborative work and concurrent engineering. There are more standardized tools for virtual reality technology distributing 3D models by VRML. Another possible solution for exploiting an Internet environment through VRML is using a non-standard software package on PC basis created for 3D simulation and programming of automated workplaces, robots and other peripheral devices. The article is describing procedures for implementation of VRML 2.0 into software ROANS, which has been created in another programming language than VRML versions.


2021 ◽  
Vol 11 (12) ◽  
pp. 5321
Author(s):  
Marcin Barszcz ◽  
Jerzy Montusiewicz ◽  
Magdalena Paśnikowska-Łukaszuk ◽  
Anna Sałamacha

In the era of the global pandemic caused by the COVID-19 virus, 3D digitisation of selected museum artefacts is becoming more and more frequent practice, but the vast majority is performed by specialised teams. The paper presents the results of comparative studies of 3D digital models of the same museum artefacts from the Silk Road area generated by two completely different technologies: Structure from Motion (SfM)—a method belonging to the so-called low-cost technologies—and by Structured-light 3D Scanning (3D SLS). Moreover, procedural differences in data acquisition and their processing to generate three-dimensional models are presented. Models built using a point cloud were created from data collected in the Afrasiyab museum in Samarkand (Uzbekistan) during “The 1st Scientific Expedition of the Lublin University of Technology to Central Asia” in 2017. Photos for creating 3D models in SfM technology were taken during a virtual expedition carried out under the “3D Digital Silk Road” program in 2021. The obtained results show that the quality of the 3D models generated with SfM differs from the models from the technology (3D SLS), but they may be placed in the galleries of the vitrual museum. The obtained models from SfM do not have information about their size, which means that they are not fully suitable for archiving purposes of cultural heritage, unlike the models from SLS.


Author(s):  
Daniele Gibelli ◽  
Andrea Palamenghi ◽  
Pasquale Poppa ◽  
Chiarella Sforza ◽  
Cristina Cattaneo ◽  
...  

AbstractPersonal identification of the living from video surveillance systems usually involves 2D images. However, the potentiality of three-dimensional facial models in gaining personal identification through 3D-3D comparison still needs to be verified. This study aims at testing the reliability of a protocol for 3D-3D registration of facial models, potentially useful for personal identification. Fifty male subjects aged between 18 and 45 years were randomly chosen from a database of 3D facial models acquired through stereophotogrammetry. For each subject, two acquisitions were available; the 3D models of faces were then registered onto other models belonging to the same and different individuals according to the least point-to-point distance on the entire facial surface, for a total of 50 matches and 50 mismatches. RMS value (root mean square) of point-to-point distance between the two models was then calculated through the VAM® software. Intra- and inter-observer errors were assessed through calculation of relative technical error of measurement (rTEM). Possible statistically significant differences between matches and mismatches were assessed through Mann–Whitney test (p < 0.05). Both for intra- and inter-observer repeatability rTEM was between 2.2 and 5.2%. Average RMS point-to-point distance was 0.50 ± 0.28 mm in matches, 2.62 ± 0.56 mm in mismatches (p < 0.01). An RMS threshold of 1.50 mm could distinguish matches and mismatches in 100% of cases. This study provides an improvement to existing 3D-3D superimposition methods and confirms the great advantages which may derive to personal identification of the living from 3D facial analysis.


Spatium ◽  
2016 ◽  
pp. 30-36 ◽  
Author(s):  
Petar Pejic ◽  
Sonja Krasic

Digital three-dimensional models of the existing architectonic structures are created for the purpose of digitalization of the archive documents, presentation of buildings or an urban entity or for conducting various analyses and tests. Traditional methods for the creation of 3D models of the existing buildings assume manual measuring of their dimensions, using the photogrammetry method or laser scanning. Such approaches require considerable time spent in data acquisition or application of specific instruments and equipment. The goal of this paper is presentation of the procedure for the creation of 3D models of the existing structures using the globally available web resources and free software packages on standard PCs. This shortens the time of the production of a digital three-dimensional model of the structure considerably and excludes the physical presence at the location. In addition, precision of this method was tested and compared with the results acquired in a previous research.


2021 ◽  
Vol 20 (7) ◽  
pp. 48-61
Author(s):  
Pavel V. Chistyakov ◽  
Ekaterina N. Bocharova ◽  
Ksenia A. Kolobova

This article provides a detailed account of the process of scanning, post-processing and further manipulation of three-dimensional models obtained with structured light scanners. Purpose. The purpose of the study is determined by the need for national archaeologists to learn the methods of three-dimensional modeling for the implementation of scientific research corresponding to international standards. Unfortunately, this direction in national archaeology began to develop in a relatively recent time and there is a lag in the application of three-dimensional modeling of national archaeology compared to the world level. Results. Any archaeological, experimental or ethnographic artifact can be used for three-dimensional scanning. To perform post-processing of three-dimensional models it is necessary to carry out primary scanning of an artifact by one of the existing algorithms. The algorithm for creating models, their positioning, simplification, saving in various formats and export is described. The main sequence of 3D models post-processing includes: processing of groups of scanned projections (their cleaning and alignment), creation of artifact model and processing/rectification of the resulting model using special software. Conclusion. As a result of correct implementation of the algorithm, the researcher receives a scaled model completely corresponding to the original artifact. Obtaining a scalable, texture-free three-dimensional model of the artifact, which fully corresponds to the original and exceeds a photograph in the quality of detail transfer, allows a scientist to conduct precise metric measurements and any procedures of non-invasive manipulation of the models. The ability to access a database of three-dimensional models of archaeological collections greatly simplifies the work of archaeologists, especially in situations when country borders are closed.


2004 ◽  
Vol 13 (6) ◽  
pp. 692-707 ◽  
Author(s):  
Sara Keren ◽  
Ilan Shimshoni ◽  
Ayellet Tal

This paper discusses the problem of inserting 3D models into a single image. The main focus of the paper is on the accurate recovery of the camera's parameters, so that 3D models can be inserted in the “correct” position and orientation. The paper addresses two issues. The first is an automatic extraction of the principal vanishing points from an image. The second is a theoretical and an experimental analysis of the errors. To test the concept, a system that “plants” virtual 3D objects in the image was implemented. It was tested on many indoor augmented-reality scenes. Our analysis and experiments have shown that errors in the placement of the objects are unnoticeable.


2020 ◽  
Vol 75 ◽  
pp. 04016 ◽  
Author(s):  
Ihor Hevko ◽  
Olha Potapchuk ◽  
Iryna Lutsyk ◽  
Viktorya Yavorska ◽  
Viktoriia Tkachuk

The authors present methods building and printing three-dimensional models for graphical reconstruction of historical architectural objects. Procedure sequence of the methods is exemplified through building the model of the Parochial Cathedral of St. Mary of the Perpetual Assistance of the 1950s. After analyzing and assessing the most popular specialized software means, the 3DS Max environment is chosen to build a three-dimensional model. Suggested software tools enable increased accuracy, speed and granularity of fixation of complex systems and expanded databases, providing efficient instruments to deal with bulk data and being relevant to new IT achievements. Sequence and content of operations for analytical and modeling cycles are substantiated. The cathedral model is built on the basis of archive photographs and drafts. The authors describe methods and the algorithm of procedures, principles of architectural and spacious modeling to recreate the architectural object. The three-dimensional model is built by applying a stereogram miniature of the destroyed Cathedral. Reconstruction of spacious configuration of the objects is based on parallax assessment of images. Stages of project implementation are determined. There are described methods of implementing modeling by 3DS Max tools and preparing the model for 3D printing in Cura.


Heritage ◽  
2019 ◽  
Vol 2 (1) ◽  
pp. 306-314
Author(s):  
Monica Bercigli

This paper reports the research carried out using Structure from Motion survey techniques, which were developed on the basis of previous surveys and their subsequent representation through two-dimensional (2D) and three-dimensional (3D) drawings of the tomb, comparing them with drawings and watercolors by several painters of the past. This survey technique enables the reconstruction of three-dimensional models through photographs. The aim of this work is to define a procedural process which allows accurate and reliable three-dimensional reconstructions to be performed for the acquisition of knowledge and the dissemination of cultural heritage, taking advantage of representation and visualization techniques that have been developed in the last decade and that are based on historical references. The variety of digital products which can be produced (video games, 3D models, prints, websites, and augmented reality applications) allows a different approach to the representation to be taken, thereby re-evaluating limits, aims, and expressive potential. The virtual representative systems, enriched with cultural content, scientific information, and data, enhance the participation and awareness of knowledge of the final users of the products and are able to increase the interaction between the user and the information.


Author(s):  
Thomas D. Hedberg ◽  
Sylvere Krima ◽  
Jaime A. Camelio

Exchange and reuse of three-dimensional (3D) product models are hampered by the absence of trust in product-lifecycle data quality. The root cause of the missing trust is years of “silo” functions (e.g., engineering, manufacturing, and quality assurance) using independent and disconnected processes. Those disconnected processes result in data exchanges that do not contain all of the required information for each downstream lifecycle process, which inhibits the reuse of product data and results in duplicate data. The X.509 standard, maintained by the Telecommunication Standardization Sector of the International Telecommunication Union (ITU-T), was first issued in 1988. Although originally intended as the authentication framework for the X.500 series for electronic directory services, the X.509 framework is used in a wide range of implementations outside the originally intended paradigm. These implementations range from encrypting websites to software-code signing, yet X.509 certificate use has not widely penetrated engineering and product realms. Our approach is not trying to provide security mechanisms, but equally as important, our method aims to provide insight into what is happening with product data to support trusting the data. This paper provides a review of the use of X.509 certificates and proposes a solution for embedding X.509 digital certificates in 3D models for authentication, authorization, and traceability of product data. This paper also describes an application within the aerospace domain. Finally, the paper draws conclusions and provides recommendations for further research into using X.509 certificates in product lifecycle management (PLM) workflows to enable a product lifecycle of trust.


Author(s):  
E. A. Petrakova

It is known that the development of a three-dimensional parametric model is a creative process, since the same 3D-model can be built in various ways. In the article the methods for effective design of parametric 3D-models with the help of internal capabilities of CAD-program without the use of programming languages (macros) is developed. Using the methods and recommendations discussed in the article on the example of Autodesk Inventor functionality will allow the engineer to design parametric three-dimensional products in CAD-programs in the most rational way, reducing the number of errors. Recommendations for effective control of 3D-model parameters during creating of Assembly parts and 2D-drawings are given. Using the functionality discussed in the article will be useful for engineers using parametric modeling methods to create typical products, optimization and analysis of structures, development of their own database of standard products that are not in the library of CAD-program components.


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