Three-dimensional Scanning Technology Research Articles

Evaluation of In-Brace Coronal and Sagittal Plane Measurements Between CAD/Chêneau-Style and Traditionally Fabricated Wilmington Braces in Adolescent Idiopathic Scoliosis

ABSTRACT Introduction Traditional thoracolumbosacral orthosis fabrication involves truncal casting (traditionally fabricated [TF] Wilmington brace [WB]), whereas the newer Chêneau-style brace (computer-aided design [CAD]) involves three-dimensional truncal scanning technology. We sought to evaluate how these two brace styles affect the position of the spine in the coronal and sagittal plane. Materials and Methods Inclusion criteria included adolescent idiopathic scoliosis treated with WB or CAD Chêneau-style brace, major curve Cobb angle 20°–45°, age 10–15 years, Risser 0–3, and radiographs (prebrace and in-brace posteroanterior and lateral). Analysis included 28 CAD Chêneau-style braces and 56 WB patients. Results There was no difference between groups regarding age, sex, body mass index, major curve location, major curve degree, sagittal plane curvature, and pelvic parameters. In-brace analysis demonstrated decreased sagittal plane curvatures and increased T1 pelvic angle in both groups; both had significantly reduced major curve correction. Coronal plane major curve correction ratio of the two groups was similar (P = 0.236). In the CAD Chêneau-style brace group, the thoracolumbar junction became more kyphotic (P = 0.03). In the WB group, both coronal balance and thoracic trunk shift were leftward (P = 0.001). Both groups had a significant increase in T1 pelvic angle, but this increase was higher in the CAD Chêneau-style brace group (P = 0.045). Conclusions Both braces exert a flattening effect on the spine and positive global sagittal balance. Coronal plane major curve correction was similar for both groups. Coronal plane trunk shift and C7 coronal balance were significantly changed leftward after WB application. Kyphotic thoracolumbar transition and forward tilt of the spine (T1 pelvic angle) were significantly greater in CAD Chêneau-style brace than WB. Clinical Relevance A Chêneau-style brace fabricated with CAD/computer-aided manufacturing technology can produce a brace comparable to one fabricated by traditional methods using cast molding.

Local–overall buckling behavior of corroded intermediate compression-bending H-section steel columns

The primary aim of this paper is to assess the impact of corrosion damage on intermediate H-section steel columns subjected to combined compression and bending about the strong axis. The study conducted a comprehensive investigation into the corrosion-induced transition in the buckling behavior of steel columns through experimental and numerical analyses. Six H-section Q355 steel intermediate columns were designed, with five undergoing an artificial spray-accelerated corrosion process. The three-dimensional scanning technology was employed to quantify the general corrosion and corrosion pits. Eccentric compression tests were carried out on intermediate H-section steel columns to investigate the effect of the different corrosion levels on the failure mode and load-displacement curves, as well as to determine local buckling load based on the load-strain curves. The test results showed that the corrosion characteristic parameters of each cross-section of the steel column exhibited irregularity and variation in all locations, reflecting the heterogeneity of corrosion. The density of corrosion pits exhibited a decreasing trend with increased corrosion duration. Corrosion remarkably reduced both the ultimate carrying capacity and local buckling capacity, with the most severely corroded specimen exhibiting an average cross-sectional area loss rate of 37 %, resulting in a 43 % and 51 % reduction in ultimate load and buckling load compared to the uncorroded specimen. Furthermore, the corrosion features substantially influenced the failure mode, resulting in a transition from overall buckling to local buckling or local-global interaction buckling. A numerical methodology was developed to incorporate the actual surface morphology of corrosion, and the reliability of the modeling method was validated through comparison with experimental results, further revealing the failure mechanism of corroded intermediate H-section steel columns under compression and bending about the strong axis.

3D Analysis of Breast Morphological Changes after Vertical-Scar Reduction Mammoplasty: A Prospective Study.

In addition to symptom relief, the crucial objective of reduction mammoplasty is to achieve a stable and esthetically pleasing postoperative breast shape. However, the morphological changes in breasts following reduction mammoplasty have not been comprehensively understood. In this study, we applied three-dimensional (3D) scanning technology for long-term follow-up monitoring of breast morphological changes to discern their changing trends. Our goal was to provide a reliable basis for assessing postoperative effects and determining follow-up time points. This prospective study included patients undergoing vertical-scar reduction mammoplasty. We utilized a combination of linear measurements and 3D scanning to measure various parameters, including breast volume, breast volume distribution, nipple position, and scar length at various time points: pre-surgery, immediately post-surgery, 3-month postoperative, 6-month postoperative, and 1-year postoperative. A total of 115 patients were enrolled in this study. Throughout the initial 3 months of postoperative follow-up, there was a gradual reduction in breast volume, which tended to stabilize from 3 to 12months. The nipple position showed a gradual shift both laterally, inferiorly, and posteriorly. The volume of the lower and lateral part of the breast increased gradually. Notably, at 1year after surgery, the scar length was approximately 6.3% shorter compared to the immediate postoperative measurement. Our 3D analysis unveiled comprehensive changes in breast morphology: The overall breast volume shifted laterally and inferiorly, the nipple position moved laterally, inferiorly, and posteriorly, and there was a significant reduction in scar length. Concurrently, breast volume exhibited a gradual decrease and stabilization after 3months, establishing it as a suitable follow-up point for assessing postoperative results. Additionally, surgical plans can be formulated based on the overall trend of changes in breast volume and distribution, combined with methods such as three-dimensional scanning, to enhance surgical outcomes and patient satisfaction. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to authors www.springer.com/00266 .

Application and research of artificial intelligence in civil engineering intelligent construction

When artificial intelligence (AI) begins to intervene, the production and lifestyles of various industries have also undergone great changes. The civil engineering construction industry has taken this opportunity to carry out the industry transformation, from traditional civil engineering construction to the intelligent construction of civil engineering with the participation of AI. Through the dynamic tracking and data analysis of construction sites and buildings through AI, the life safety of construction workers can be ensured by improving efficiency and ensuring quality. This paper analyzes the feature of intelligent construction, and discusses the current situation of intelligent construction and the application progress of intelligent construction in civil engineering construction, including Building information modeling (BIM) technology, Internet of Things and big data technology, AI technology, virtual reality technology, three-dimensional scanning technology, intelligent equipment and construction robots. At the same time, the problems and disadvantages of AI in the construction field are analyzed, and the application prospect of intelligent construction technology in future engineering construction is forecasted.

Study on the Digital Reassembly of Yoni Monument Excavated from Cella of Hong Nang Sida, Lao PDR

During the dismantling of the cella of the Hong Nang Sida temple in Laos, 100 highly significant Yoni-monument members were recovered as fragmented individual stones. To restore the Hong Nang Sida temple to its former glory, it is necessary to restore the fragmented Yoni-monument members to their original positions. However, the high weight and low mobility of the stones make it difficult to physically reassemble the story members. Therefore, this study utilized three-dimensional (3D) scanning, modeling, and printing technologies to digitally reassemble the Yoni monument. To achieve this goal, optimization modeling was performed to connect the three-dimensional (3D) scanning data of individual fragmented stones, after which each story member was reduced to a 1/5 of its original size and printed by sand printing to evaluate the feasibility of physical assembly. Finally, 3D scans of the Yoni monument assembled using the sand-printing outputs were taken, and all the story members were virtually aligned based on the scan data to complete the digital reassembly. We believe that the results of this study will improve the feasibility and completeness of the physical reassembly by allowing for a full preliminary examination of stone blocks, which would otherwise be difficult to achieve because of the risk of secondary damage or weight limitation. In particular, it is possible to objectively and visually illustrate the geometric relationship between the members of each story, which can be extended to similar stone-based cultural heritage sites. To broaden the utility of the digital-reassembly model, it must be evolved into a historic building information model that links the unstructured data, including documents, photos, and images, obtained throughout the process life cycle.

3D point cloud global denoising algorithm based on different noise characteristics

When acquiring object point cloud data by three-dimensional scanning technology, noise is generated due to instrument accuracy and external factors. Existing algorithms rarely consider the characteristics of different noises and different regional noises when solving the point cloud denoising problem, this results in a limited effect on denoising. This paper presents an algorithm for denoising based on the characteristics of different types of noise and different regions in the point cloud. The algorithm includes large-scale noise removal and small-scale noise smoothing. Remove large-scale noise points by the relationship between the local point cloud and the global point cloud. For small-scale noise, the feature regions and non-feature regions are extracted according to the normal cosine information entropy. According to the characteristics of the small-scale noise in two regions, the noise distance distribution and the optimized bilateral filtering are used to deal with the small-scale noise in two regions respectively. Comparison experiments show that our algorithm can effectively remove the noise points mixed in the normal point cloud. The accuracy of large-scale noise removal reaches 99.1%. The proposed algorithm can protect the feature areas from being over-smoothed while smoothing the small-scale noise in non-featured areas.

Shear behaviours and roughness degeneration based on a quantified rock joint surface description

The asperity wear of rock joints significantly affects their shear behaviour. This study discusses the wear damage of the asperities on the joint surface, highlighting the roughness degradation characteristics during the shear process. The direct shear experiment of artificial specimens containing rock joints was conducted under different normal stresses based on three-dimensional scanning technology. These experimental results showed the contribution of joint wear to roughness degeneration, such as the height, zone, and volume of asperity degeneration. The wear coefficient of the rock joint was obtained based on the volume wear of asperities in the laboratory experiment. The functional relationship between the friction coefficient and wear coefficient is subsequently determined. To quantitatively analyse the wear damage of a joint surface, a calculation method for determining the wear depth of the rock joint after shearing was proposed based on wear theory. The relationship between the ultimate dilation and wear depth was analysed. A coefficient m, which can describe the damage degree of the joint surface, and a prediction method of joint surface roughness after shearing are established. Good agreement between analytical predictions and measured values demonstrates the capability of the developed model. Lastly, the sensitivity factors on the wear depth are explored.

Recurrence Network-Based 3D Geometry Representation Learning for Quality Control in Additive Manufacturing of Metamaterials

Abstract Metamaterials are designed with intricate geometries to deliver unique properties, and recent years have witnessed an upsurge in leveraging additive manufacturing (AM) to produce metamaterials. However, the frequent occurrence of geometric defects in AM poses a critical obstacle to realizing the desired properties of fabricated metamaterials. Advances in three-dimensional (3D) scanning technologies enable the capture of fine-grained 3D geometric patterns, thereby providing a great opportunity for detecting geometric defects in fabricated metamaterials for property-oriented quality assurance. Realizing the full potential of 3D scanning-based quality control hinges largely on devising effective approaches to process scanned point clouds and extract geometric-pertinent information. In this study, a novel framework is developed to integrate recurrence network-based 3D geometry profiling with deep one-class learning for geometric defect detection in AM of metamaterials. First, we extend existing recurrence network models that focus on image data to represent 3D point clouds, by designing a new mechanism that characterizes points’ geometric pattern affinities and spatial proximities. Then, a one-class graph neural network (GNN) approach is tailored to uncover topological variations of the recurrence network and detect anomalies associated with geometric defects in the fabricated metamaterial. The developed methodology is evaluated through comprehensive simulated and real-world case studies. Experimental results have highlighted the efficacy of the developed methodology in identifying both global and local geometric defects in AM-fabricated metamaterials.

Divergence in the internal genital morphology of females and correlated divergence in male intromittent structures among populations of a millipede.

Our understanding of genital evolution comes largely from studies of male genitalia. Females have received far less attention because of the difficulties inherent in quantifying the shapes of their internal genital structures. Here we combine advances in micro-computed tomography with a new landmark free method of quantifying three-dimensional trait shape, to document patterns of divergence in female genital shape, and the correlated divergence of male genitalia among populations of the millipede Antichiropus variabilis. We used single-nucleotide polymorphisms to estimate levels of neutral genetic divergence among seven populations of millipede. Genetic divergence was high and correlated with geographic distance. Comparing phenotypic divergence in genital shape to neutral genetic divergence, we found that genital shape for both females and males has diverged more than would be expected from random drift, consistent with a pattern of directional selection. While there was significant covariation between female and male genital shape across populations, the magnitude of divergence in genital shape between the sexes was not correlated. Our results demonstrate the utility of using three-dimensional scanning technologies to examine female genital traits and add to a small but growing number of studies showing that like male genitalia, female genitalia can be under strong directional selection.

Estimation of the Skeletal Muscle Cross-Sectional Area of the Lower Extremity Using Structured Light Three-Dimensional Scanning Technology

Estimation of the Skeletal Muscle Cross-Sectional Area of the Lower Extremity Using Structured Light Three-Dimensional Scanning Technology

A STUDY ON CONVERGENCE MODELING OF CULTURAL ARTIFACT USING X-RAY COMPUTED TOMOGRAPHY AND THREE-DIMENSIONAL SCANNING TECHNOLOGIES

Abstract. Optical three-dimensional (3D) scanning technology is extensively used for digital recording and shape analysis of cultural heritage because it is simple to obtain precise surface shape and color information. In addition, X-ray computed tomography (X-ray CT) is used to record and analyze the internal shape of cultural heritage. However, while the 3D shape acquired by X-ray CT technology is excellent for visualizing the internal shape, expressing the high resolution of the surface shape is difficult. If the benefits of each technology are used to digitize the inside and outside of cultural heritage, the results of surface shape recording based on 3D scanning can be advanced, and various stereoscopic analysis can be performed. Therefore, an optimization modeling process that combines X-ray CT and optical surface scanning is required to record both internal and external shapes of cultural heritage. In this study, optimization modeling methodology was applied to cultural heritage by combining X-ray CT technology and optical 3D scanning technology. Based on the models obtained through both technologies, a mesh-based optimization convergence modeling methodology considering internal and external surface shapes and color is organized. Furthermore, because the X-ray CT data has a characteristic of a voxel base, it is determined that additional convergence methods, including internal voxel data, are required, and a voxel-based optimization model process is established concurrently. Following that, two convergence modeling methods were applied to each of the deer-shaped horn cup artifacts that had an interior shape. As a result, the 3D convergence model creation and mapping optimization process, which can reveal important internal and external information about artifacts such as surface color, fine shape, and internal structure, can be improved. This 3D convergence modeling methodology was able to supplement the two technologies while preserving the benefits of optical 3D scanning and X-ray CT technology. This is thought to contribute to the expansion of the digital recording process from a single technology to multiple technologies. The X-ray CT-based convergence modeling pipeline is expected to be an opportunity in promoting the revitalization of X-ray CT technology in the cultural heritage field because it can be used for a wide range of purposes such as shape analysis, preservation status evaluation, monitoring, restoration, and reproduction.

Underwater explosion resistance of air-backed plate with steel and polyurea: Effect of polyurea spraying position

Improving hull-structure resistance against underwater explosion (UNDEX) is an important problem for designers. It has been proved that polyurea coating on steel can reduce the deformation of a plate subjected to UNDEX. In this study, the effect of the polyurea position was explored by performing a series of UNDEX tests on air-backed plates. They had polyurea sprayed on the front side (PS type), back side (SP type), and both sides (PSP type). The deformation result was obtained using three-dimensional (3D) scanning technology, and the bubble movement was observed by a high-speed camera. The experimental results proved that the polyurea spraying position had no significant effect on the formation and movement of bubble or water jet. More importantly, the PS-type plate exhibited the best explosion resistance when standoff distance was less than 3Rexplosive (radius of charge), whereas the SP-type plate did so when standoff distance exceeded Rbubble (maximum bubble radius). Numerical models for these UNDEX tests were established and verified by experimental results. The numerical results demonstrated that the PS-type plate could reflect part of the energy back into the water by compression, thus reducing the energy absorbed by steel. The SP-type plate could disperse impact stress in the steel, but the protective effect was poor within close standoff distance. This was attributed to spallation under reflected tensile wave.

Three-Dimensional Volumetric Analysis of the Effect of Interval Time in Autologous Fat Graft Breast Augmentation.

Autologous adipose tissue has become increasingly popular in cosmetic and plastic reconstructive surgery, especially breast augmentation surgery. However, the volume retention rate after transplantation significantly varies and may be unsatisfactory. Many patients need two or more autologous fat graft breast augmentations to achieve the expected effect. There are currently no studies on optimal timing between fat injections. We identified target patients with secondary or multiple autologous fat transplantations by inclusion and exclusion criteria and used three-dimensional scanning technology to calculate the volume retention. Patients were divided into two groups according to the dates of the first and second operations (group A: interoperative time < 120 days, group B: interoperative time ≥ 120 days). We used SPSS 26 for statistical calculations. We included 161 patients in this retrospective study, with an average volume retention rate of 36.56% in group A (n = 85) and 27.45% in group B (n = 76). The independent sample t test showed that the volume retention rate in group A was higher than that in group B (P < 0.001). And the paired t test showed there is a significant improvement of volume retention rate after the second fat graft session (P < 0.001). Multivariate regression analysis showed that the interval time was an independent factor affecting the postoperative volume retention rate. The interval time between autologous fat transplantation for augmentation mammaplasty was an independent factor affecting the postoperative volume retention rate. The postoperative volume retention rate of the < 120 days group was higher than that of the ≥ 120 days group. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Three-Dimensional Immersion Scanning Technique: A Scalable Low-Cost Solution for 3D Scanning Using Water-Based Fluid

Three-dimensional scanning technology has been traditionally used in the medical and engineering industries, but these scanners can be expensive or limited in their capabilities. This research aimed to develop low-cost 3D scanning using rotation and immersion in a water-based fluid. This technique uses a reconstruction approach similar to CT scanners but with significantly less instrumentation and cost than traditional CT scanners or other optical scanning techniques. The setup consisted of a container filled with a mixture of water and Xanthan gum. The object to be scanned was submerged at various rotation angles. A stepper motor slide with a needle was used to measure the fluid level increment as the object being scanned was submerged into the container. The results showed that the 3D scanning using immersion in a water-based fluid was feasible and could be adapted to a wide range of object sizes. The technique produced reconstructed images of objects with gaps or irregularly shaped openings in a low-cost fashion. A 3D printed model with a width of 30.7200 ± 0.2388 mm and height of 31.6800 ± 0.3445 mm was compared to its scan to evaluate the precision of the technique. Its width/height ratio (0.9697 ± 0.0084) overlaps the margin of error of the width/height ratio of the reconstructed image (0.9649 ± 0.0191), showing statistical similarities. The signal-to-noise ratio was calculated at around 6 dB. Suggestions for future work are made to improve the parameters of this promising, low-cost technique.

Displacement response characteristics of different sand tunnel excavation faces under true triaxial loading

During the construction of subway tunnels, the geotechnical body is affected by excavation to produce three-dimensional spatial deformation. The deformation of geotechnical bodies is an important safety hazard for project advancement, so it is important to understand the excavation disturbance range and deformation mechanism. The current related research is mainly about the theory of land subsidence and the two-dimensional plane displacement of the stratum, and there are few studies on the specific three-dimensional disturbance mode and its mechanism. In order to better understand the three-dimensional displacement characteristics of the tunnel excavation soil, a tunnel excavation model test was established based on a true triaxial stress loading system combined with three-dimensional scanning technology for a superimposed sandy soil. Based on the established model, the vector displacement response range and three-dimensional deformation characteristics of the excavation face were studied in the main displacement affected area around the excavation face. Meanwhile, the deformation characteristics, such as vertical settlement and horizontal displacement of the stratum in the main influence area were analyzed. The results show that the main influence area of tunnel excavation is elliptical and distributed within a range of twice the diameter of the tunnel axis. The main influence range is bell-shaped in the vertical direction and inverted wedge-shaped in the horizontal direction. The three-dimensional space presents a “W” deformation distribution. The three-dimensional deformation theoretical model of the excavation face established in this paper can provide some references for the excavation engineering of superimposed sand-soil tunnels.

Analyzing the changes in anthropometric measurements with various postures using three-dimensional scanning technology

In this study, the dynamic changes in human body shape according to movement have been analyzed using three-dimensional scanning system. For this, 12 male subjects were scanned in six postures and the amount of changes in 32 anthropometric measurement items were examined. As for the height items, all items changed in walking pose, and for the length items, the shoulder and chest lengths were affected by arm movement. For circumference items, considerable changes were observed in the chest and waist region according to the movement. A body cross section analysis software has been developed to analyze the change in body shape according to movement in various perspectives. As a result, the chest region was found to be affected by the movement of the arms, the waist region by the movement of the trunk, and hip region was by the movement of the leg.

Corresponding measurement-based patternmaking method for leggings using three-dimensional body scanning technology

Based on 3D body scanning, this study developed the corresponding measurement-based patternmaking (CMP) method for leggings that could systematically provide an excellent fit and control tightness for different body parts. The CMP method for leggings was qualitatively validated by comparing the fit suitability of the produced leggings prototypes through a wear test. The results suggest that the CMP method is an option to design leggings with outstanding suitability in terms of appearance satisfaction, size satisfaction, compression satisfaction, usefulness in movement, ease of movement, ease in donning and doffing for different body parts. In particular, the graduated application percentage (GAP) provided an advantage in usefulness in movement, while the fixed application percentage (FAP) showed an advantage in ease in donning and doffing. As such, this study suggests selecting the CMP method of the application percentage (AP) depending on the purpose of use. This study demonstrated that the proposed method ensured validity in directly implementing a leggings pattern with 3D body scanning and body measurement alone.

Numerical Simulation Analysis on Surface Quality of Aluminum Foam Sandwich Panel in Plastic Forming

The surface quality of an aluminum foam sandwich panel (AFSP) is very important for its appearance and application. This paper mainly studies the surface quality of AFSP after plastic forming. Combined with three-dimensional (3D) scanning technology, the normal deviation between the experimental AFSP and the target surface was obtained, and the surface quality parameters Sq, Sz and dmax were calculated to evaluate surface quality. The AFSP models with cubic-spherical (CS) and tetrakaidecahedral (TKD) as foam structures were established respectively. A series of numerical simulations of multi-point forming (MPF) were then carried out. Equivalent strain and deformation characteristics of spherical and saddle-shaped AFSP were discussed. The main surface defects produced by AFSP in plastic forming, such as surface wrinkle, the local straight face effect and surface dimpling were analyzed. Finally, MPF experiments were carried out, and it was found that the numerical simulation results were significantly corresponded to the experimental AFSP in terms of the degree and distribution of normal deviation and surface quality evaluation parameters. The TKD model was more consistent with the experimental results than the CS model. Moreover, the results show that the surface quality can be improved by thicker face sheets and smaller core cell sizes.

3D Numerical Investigation of Heat Transfer of Infants in the Indoor Environment

This study aimed to investigate the heat transfer around the infant surface in the indoor environment based on computational fluid dynamics analysis. A three-dimensional numerical model containing a virtual infant manikin was developed in COMSOL software. The high-quality geometry model of the infant was obtained using three-dimensional body scanning technology. Governing fluid flow and energy equations were solved along with the low Re k–ε turbulence model. Real-scale measurements were carried out to determine the accuracy of the developed numerical model. Good agreement was found between the simulation results and the experimental data. The results showed that, at room temperature of 21oC, the convective heat transfer coefficient was 64.2% greater than the radiative heat transfer coefficient, which demonstrated that the convective heat transfer was the main approach for heat exchange between the infant and its surrounding environment. Moreover, the largest convective heat transfer coefficients were observed at the forearm and calf, indicating the importance of the additional thermal protection at these regions. The findings will be beneficial to provide some instructions on infant thermal care for caregivers.

AN GROUND AND UNDER-GROUND URBAN ROADS SURVEYING APPROACH USING INTEGRATED 3D LIDAR AND 3D GPR TECHNOLOGY

Abstract. Digitalization of urban roads is an important part of smart city construction. In addition to having a basic understanding of the structure of the transportation network, we need to have a preliminary understanding of the information around the road, the current status of the road, and the impact that municipal projects may have on the road. At present, the three-dimensional information of the ground parts of roads can be obtained efficiently and accurately on a large scale by using three-dimensional scanning technology. However, there is a lack of comprehensive and intuitive understanding of the under-ground information and a lack of synergistic consideration of the ground and under-ground information. In this paper, a ground and under-ground urban road surveying system based on 3D LiDAR and 3D ground penetrating radar (GPR) is presented. The system covers multi-sensor coordinated control, time-space datum setup, and post-processing data. Experiments show that the system can realize the integrated ground and under-ground 3D surveying for urban roads, generate intuitive three-dimensional point cloud map model of ground and under-ground of urban roads, and provide effective technical support for smart city construction.