Three-dimensional periorbital asymmetry assessment of congenital microphthalmia children with a structured light 3D scanning system

2021 ◽  
Author(s):  
Bowei Yuan ◽  
Xue Jiang ◽  
Yan Liu ◽  
Jie Dong ◽  
Dongmei Li
Keyword(s):  
Structured Light ◽  
Three Dimensional ◽  
3D Scanning ◽  
Scanning System

scholarly journals Structured-light 3D scanning of exhibited historical clothing—a first-ever methodical trial and its results

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Jerzy Montusiewicz ◽  
Marek Miłosz ◽  
Jacek Kęsik ◽  
Kamil Żyła
Keyword(s):  
Cultural Heritage ◽  
Information Technologies ◽  
Structured Light ◽  
Three Dimensional ◽  
3D Models ◽  
3D Scanning ◽  
Dimensional Representation ◽  
3D Scanner ◽  
Three Dimensional Representation ◽  
3D Scanners

AbstractHistorical costumes are part of cultural heritage. Unlike architectural monuments, they are very fragile, which exacerbates the problems of their protection and popularisation. A big help in this can be the digitisation of their appearance, preferably using modern techniques of three-dimensional representation (3D). The article presents the results of the search for examples and methodologies of implementing 3D scanning of exhibited historical clothes as well as the attendant problems. From a review of scientific literature it turns out that so far practically no one in the world has made any methodical attempts at scanning historical clothes using structured-light 3D scanners (SLS) and developing an appropriate methodology. The vast majority of methods for creating 3D models of clothes used photogrammetry and 3D modelling software. Therefore, an innovative approach was proposed to the problem of creating 3D models of exhibited historical clothes through their digitalisation by means of a 3D scanner using structural light technology. A proposal for the methodology of this process and concrete examples of its implementation and results are presented. The problems related to the scanning of 3D historical clothes are also described, as well as a proposal how to solve them or minimise their impact. The implementation of the methodology is presented on the example of scanning elements of the Emir of Bukhara's costume (Uzbekistan) from the end of the nineteenth century, consisting of the gown, turban and shoes. Moreover, the way of using 3D models and information technologies to popularise cultural heritage in the space of digital resources is also discussed.

Complex 3D Measuring by Multiple Laser Scanning of Automotive Parts

2013 ◽  
Vol 837 ◽  
pp. 511-516
Author(s):  
Adrian Catalin Voicu ◽  
Gheorghe I. Gheorghe
Keyword(s):  
Reverse Engineering ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Correct Choice ◽  
3D Scanning ◽  
Single Step ◽  
Graph Representation ◽  
Scanning System ◽  
Production Environment ◽  
Virtual Design

For over 20 years the term"three-dimensional scan"(3D) showed the world the possibilities of virtual design, simulation, or reverse engineering. 3D scanning is also known as 3D digitizing, the name coming from the fact that this is a process that uses a contact or non-contact digitizing probe to capture the objects form and recreate them in a virtual workspace through a very dense network of points (xyz) as a 3D graph representation. Until recently, digitization was limited by the speed of the scan head and the correct choice of the probing system, type of scanned piece and budget for the purchase or develops the scanning system. With the evolution of technology appeared a number of new techniques that tend to improve the properties of classical methods. Even if intended for copying or geometrical control, or rather virtual geometric modelling or product realization, there are two groups of technologies: with contact (classical methods with probes) or without contact (laser, optical or combination). Most automotive manufacturers currently use 3D scan metrology based on optical or laser systems to validate products quality. The pieces are initially measured by 3D scanning then they are compared with the designed model (CAD file) using a specialized software. By this comparison producer can interfere very quickly in the manufacturing process to remove the cause of defects, this technique being called Reverse Engineering (RE). There are many variables that affect accuracy of laser scanning and therefore the quality of information: reflectance of surface, colour object, recesses, openings narrow and sharp edges can be difficult to scan. This accuracy may vary from micron to millimetre and the acquisitions size from a few points to several thousand points per second. The overall accuracy of a 3D acquisition system depends above all on the sensors precision and on the acquisition device (acquisition with contact) or acquisition structure (acquisition without contact). In a perfect world or in an integrated production environment, 3D measuring systems should be able to measure all the necessary parameters in a single step without errors, and to render the results in the same way to the manufacturing networks equipped with computers, in formats useful for machines control and processes management.

scholarly journals STRUCTURED LIGHT BASED 3D SCANNING FOR SPECULAR SURFACE BY THE COMBINATION OF GRAY CODE AND PHASE SHIFTING

2016 ◽  
Vol XLI-B3 ◽  
pp. 137-142
Author(s):  
Yujia Zhang ◽  
Alper Yilmaz
Keyword(s):  
High Frequency ◽  
Structured Light ◽  
Gray Code ◽  
3D Scanning ◽  
Phase Shifting ◽  
Scanning System ◽  
High Quality ◽  
Specular Surface ◽  
Combination Technique ◽  
Indirect Illumination

Surface reconstruction using coded structured light is considered one of the most reliable techniques for high-quality 3D scanning. With a calibrated projector-camera stereo system, a light pattern is projected onto the scene and imaged by the camera. Correspondences between projected and recovered patterns are computed in the decoding process, which is used to generate 3D point cloud of the surface. However, the indirect illumination effects on the surface, such as subsurface scattering and interreflections, will raise the difficulties in reconstruction. In this paper, we apply maximum min-SW gray code to reduce the indirect illumination effects of the specular surface. We also analysis the errors when comparing the maximum min-SW gray code and the conventional gray code, which justifies that the maximum min-SW gray code has significant superiority to reduce the indirect illumination effects. To achieve sub-pixel accuracy, we project high frequency sinusoidal patterns onto the scene simultaneously. But for specular surface, the high frequency patterns are susceptible to decoding errors. Incorrect decoding of high frequency patterns will result in a loss of depth resolution. Our method to resolve this problem is combining the low frequency maximum min-SW gray code and the high frequency phase shifting code, which achieves dense 3D reconstruction for specular surface. Our contributions include: (i) A complete setup of the structured light based 3D scanning system; (ii) A novel combination technique of the maximum min-SW gray code and phase shifting code. First, phase shifting decoding with sub-pixel accuracy. Then, the maximum min-SW gray code is used to resolve the ambiguity resolution. According to the experimental results and data analysis, our structured light based 3D scanning system enables high quality dense reconstruction of scenes with a small number of images. Qualitative and quantitative comparisons are performed to extract the advantages of our new combined coding method.

scholarly journals A Portable Electromagnetic System Based on mm-Wave Radars and GNSS-RTK Solutions for 3D Scanning of Large Material Piles

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 757
Author(s):  
Humberto Fernández Álvarez ◽  
Guillermo Álvarez-Narciandi ◽  
María García-Fernández ◽  
Jaime Laviada ◽  
Yuri Álvarez López ◽  
...  
Keyword(s):  
High Resolution ◽  
Raw Materials ◽  
Three Dimensional ◽  
Control Unit ◽  
3D Scanning ◽  
Raw Material ◽  
Scanning System ◽  
Electromagnetic System ◽  
Cereal Grain ◽  
Large Material

In this paper, a portable three-dimensional (3D) scanning system for the accurate characterization of large raw material (e.g., cereal grain, coal, etc.) stockpiles is presented. The system comprises an array of high resolution millimeter-wave radars and a cm-level accuracy positioning system to accurately characterize large stockpiles by means of a high-resolution 3D map, making it suitable for automation purposes. A control unit manages the data received by the sensors, which are sent to a computer system for processing. As a proof of concept, the entire sensor system is evaluated in a real environment for electromagnetically scan a scaled stockpile of coal, used in the industry for handling raw materials. In addition, a highly efficient processing adaptive algorithm that may reconstruct the scanned structure in real-time has been introduced, enabling continuous dynamic updating of the information. Results are compared with those from a photogrammetry-like technique, revealing an excellent agreement.

scholarly journals A COMPARISON OF LASER AND STRUCTURED LIGHT SCANNING TECHNOLOGIES FOR ARCHAEOLOGICAL APPLICATIONS

2021 ◽  
Vol 13 (3) ◽  
pp. 111-116
Author(s):  
Nikolaos Papas ◽  
◽  
Konstantinos Tsongas ◽  
Dimitrios Karolidis ◽  
Dimitrios Tzetzis ◽  
...  
Keyword(s):  
Structured Light ◽  
Three Dimensional ◽  
3D Models ◽  
3D Scanning ◽  
Acquisition Time ◽  
Digital Reference ◽  
Scanning Time ◽  
Actual Equipment ◽  
Scan Data

Reverse engineering and in particular three-dimensional digitization have become an essential part of the documentation of archaeological findings. 3D scanning produces a high-precision digital reference document. The factors that influence the quality of the 3D scanned data are the scanned object’s surface colour, its glossiness and geometry, and the ambient light during the scanning process. However, the actual equipment and scanning technologies are of primary importance. The current paper presents a qualitative and quantitative comparison between two 3D scanning devices of different technologies; structured light 3D scanning and laser 3D scanning. The benchmark for this comparison is an ancient Roman vase from the city of Thessaloniki, Greece. The object was scanned with every possible setting on each scanner, but only one configuration of settings on each device was selected for the final comparison. The main criterion for the final selection of the two 3D models acquired with the use of the two technologies was the proximity in the number of points and polygons produced for digitally restoring the ancient vase in the best possible way. The results indicate important differences regarding the accuracy of the final digital model. The laser technology produced better accuracy but with a significant cost in scanning time and model data size. On the other hand, the structured light technology achieved the optimal combination of scanning quality and accuracy, along with reduced acquisition time of scan data.

scholarly journals Metrological evaluation of Structured Light 3D scanning system with an optical feature-based gauge

2017 ◽  
Vol 13 ◽  
pp. 526-533 ◽  
Author(s):  
E. Cuesta ◽  
J.M. Suarez-Mendez ◽  
S. Martinez-Pellitero ◽  
J. Barreiro ◽  
B.J. Alvarez ◽  
...  
Keyword(s):  
Structured Light ◽  
3D Scanning ◽  
Scanning System ◽  
Optical Feature ◽  
Feature Based ◽  
Metrological Evaluation

scholarly journals A Structured-Light Approach for the Reconstruction of Complex Objects

2011 ◽  
Vol 6 ◽  
pp. 259-266
Author(s):  
Ilias Kalisperakis ◽  
Lazaros Grammatikopoulos ◽  
Elli Petsa ◽  
George Karras
Keyword(s):  
Low Cost ◽  
Structured Light ◽  
Digital Camera ◽  
3D Scanning ◽  
Scanning System ◽  
Complex Objects ◽  
Ongoing Research ◽  
Video Projector ◽  
3D Objects ◽  
Novel Algorithms

Recently, one of the central issues in the fields of Photogrammetry, Computer Vision, Computer Graphics and Image Processing is the development of tools for the automatic reconstruction of complex 3D objects. Among various approaches, one of the most promising is Structured Light 3D scanning (SL) which combines automation and high accuracy with low cost, given the steady decrease in price of cameras and projectors. SL relies on the projection of different light patterns, by means of a video projector, on 3D object sur faces, which are recorded by one or more digital cameras. Automatic pattern identification on images allows reconstructing the shape of recorded 3D objects via triangulation of the optical rays corresponding to projector and camera pixels. Models draped with realistic phototexture may be thus also generated, reproducing both geometry and appearance of the 3D world. In this context, subject of our research is a synthesis of state-of-the-art as well as the development of novel algorithms, in order to implement a 3D scanning system consisting, at this stage, of one consumer digital camera (DSLR) and a video projector. In the following, the main principles of structured light scanning and the algorithms implemented in our system are presented, and results are given to demonstrate the potential of such a system. Since this work is part of an ongoing research project, future tasks are also discussed.

scholarly journals Accurate three dimensional body scanning system based on structured light

2018 ◽  
Vol 26 (22) ◽  
pp. 28544 ◽  
Author(s):  
Haosong Yue ◽  
Yue Yu ◽  
Weihai Chen ◽  
Xingming Wu
Keyword(s):  
Structured Light ◽  
Three Dimensional ◽  
Scanning System ◽  
Body Scanning
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