Three-dimensional Reconstruction Research Articles

Poliface: A Multi-pose Synchronous Imaging System

To enhance the accuracy of face recognition technology in real-world scenarios, it is necessary to train deep learning models on datasets that contain a large number of labeled human face images under multiple poses, lighting, and accessory variations. In this paper, we introduce a novel acquisition system named the Poliface. This system can capture multiple high-resolution images simultaneously around the human head. We designed this system with a well-built aluminum structure, control electronic circuits, and high-performing in-house software. The results demonstrate the precise operation and exceptional stability of this system. Using this Poliface system, we have collected over 6 million photos, which can be used to train and evaluate facial recognition models, and exploited for three-dimensional (3D) virtual face reconstruction.

Comprehensive Management of Intracranial Aneurysms in Rare and Variant Arterial Locations: A Detailed Case Report

AbstractAneurysms on variant arteries, especially involving the persistent trigeminal artery (PTA), azygos artery, and lenticulostriate arteries (LSAs), are rare. This report presents a case and subsequent management of a patient with multiple unruptured aneurysms arising from variant anatomical structures. A 48-year-old patient with a history of worsening headaches presented with three unruptured aneurysms at the PTA, azygos artery, and left LSA, confirmed via catheter angiography with three-dimensional reconstruction. Given the potential effects on conventional cerebrovascular structures, managing multiple aneurysms in rare and variant locations requires a tailored strategy. This case was successfully treated with an endovascular approach and a period of observation, emphasizing the need for individualized treatment planning.

Automatic fovea detection and choroid segmentation for choroidal thickness assessment in optical coherence tomography.

To develop an automated model for subfoveal choroidal thickness (SFCT) detection in optical coherence tomography (OCT) images, addressing manual fovea location and choroidal contour challenges. Two procedures were proposed: defining the fovea and segmenting the choroid. Fovea localization from B-scan OCT image sequence with three-dimensional reconstruction (LocBscan-3D) predicted fovea location using central foveal depression features, and fovea localization from two-dimensional en-face OCT (LocEN-2D) used a mask region-based convolutional neural network (Mask R-CNN) model for optic disc detection, and determined the fovea location based on optic disc relative position. Choroid segmentation also employed Mask R-CNN. For 53 eyes in 28 healthy subjects, LocBscan-3D's mean difference between manual and predicted fovea locations was 170.0 µm, LocEN-2D yielded 675.9 µm. LocEN-2D performed better in non-high myopia group (P=0.02). SFCT measurements from Mask R-CNN aligned with manual values. Our models accurately predict SFCT in OCT images. LocBscan-3D excels in precise fovea localization even with high myopia. LocEN-2D shows high detection rates but lower accuracy especially in the high myopia group. Combining both models offers a robust SFCT assessment approach, promising efficiency and accuracy for large-scale studies and clinical use.

Three-dimensional Reconstruction of Grassland Landforms Based on Intelligent Robot Vision System and Numerical Simulation of Its Characteristics

Three-dimensional Reconstruction of Grassland Landforms Based on Intelligent Robot Vision System and Numerical Simulation of Its Characteristics

A clinical study on the effect of axillary approach in the treatment of Ideberg type II scapular glenoid fractures

BackgroundDue to its deep position and complex surrounding anatomy, the scapular glenoid fracture was relatively difficult to deal with especially in cases of severe fracture displacement. Improper treatment may lead to failure of internal fixation and poor fracture reduction, severely affecting the function of the shoulder joint. Inferior scapular glenoid fracture was Ideberg type II fracture, and posterior approach was commonly used to deal with inferior scapular glenoid fracture. However, there are shortcomings of above surgical approach for inferior scapular glenoid fracture, such as insufficient exposure of the operative field, significant trauma, and limited screw fixation direction. This study adopts the axillary approach for surgery, which has certain advantages.MethodsThe clinical data of 13 patients with Ideberg type II scapular glenoid fractures treated from December 2018 to January 2024 were retrospectively analyzed. There were 8 males and 5 females, with an age range of 19 to 58 years and an average age of 38 years. The causes of injury were falls from heights in 7 cases and car accidents in 6 cases. There were 5 cases on the left side and 8 cases on the right side. The time from injury to surgery was 2 to 11 days, with an average of 5.5 days. All cases underwent open reduction and internal fixation through the axillary approach. Postoperative X-ray and CT three-dimensional reconstruction were performed on the next day to evaluate the fracture reduction and the position of internal fixation. During the follow-up period, follow-up examinations were performed every two months in the first half of the year and every three months in the second half. CT scans were performed during the examinations to assess the glenohumeral joint congruence, fracture healing, and position of internal fixation. The shoulder joint function was evaluated at 6 months postoperatively according to the Constant-Murley value score.ResultsThe patients all achieved primary wound healing after surgery, without any complications such as infection or nerve injury. Re-examination on the second day after operation, all fractures obtained excellent reduction, and the internal fixation was in excellent position, and no screw was found to enter the joint cavity. All patients in this group were followed up for 6 to 25 months, with an average follow-up time of 11.7 months. All fractures were bony unioned, and the healing time ranged from 4 to 6 months, with an average healing time of 4.8 months. At 6-month follow-up, according to the Constant-Murley score, 11 cases were excellent and 2 case was good.ConclusionOpen reduction and internal fixation through the axillary approach is an feasible and safe surgical method for the treatment in scapular Ideberg type II glenoid fractures with less stripping of soft tissue, minimal surgical trauma, and the incision is concealed and beautiful. It can provide a strong internal fixation for fractures, so patients can perform functional exercise early after operation, and the clinical results is satisfactory.

Spatio-temporal reconstruction of droplet impingement dynamics by means of color-coded glare points and deep learning

Abstract The present work introduces a deep learning approach for the three-dimensional reconstruction of the spatio-temporal dynamics of the gas-liquid interface on the basis of monocular images obtained via optical measurement techniques.
The method is tested an evaluated at the example of liquid droplets impacting on structured solid substrates.
The droplet dynamics are captured through high-speed imaging in an extended shadowgraphy setup with additional glare points from lateral light sources that encode further three-dimensional information of the gas-liquid interface in the images.
A neural network is trained for the physically correct reconstruction of the droplet dynamics on a labelled dataset generated by synthetic image rendering on the basis of gas-liquid interface shapes obtained from direct numerical simulation.
The employment of synthetic image rendering allows for the efficient generation of training data and circumvents the introduction of errors resulting from the inherent discrepancy of the droplet shapes between experiment and simulation. 
The accurate reconstruction of the three-dimensional shape of the gas-liquid interface during droplet impingement on the basis of images obtained in the experiment demonstrates the practicality of the presented approach.
The introduction of glare points from lateral light sources in the experiments is shown to improve the reconstruction accuracy, which indicates that the neural network learns to leverage the additional three-dimensional information encoded in the images for a more accurate depth estimation.
By the successful reconstruction of obscured areas in the input images, it is demonstrated that the neural network has the capability to learn a physically correct interpolation of missing data from the numerical simulation.
Furthermore, the physically reasonable reconstruction of unknown gas-liquid interface shapes for drop impact regimes that were not contained in the training dataset indicates that the neural network learned a versatile model of the involved two-phase flow phenomena during droplet impingement.

A preliminary investigation of the left atrial suspended cord and its significance as revealed by coronary CT angiography: an observational study with a systematic literature review

BackgroundThe occurrence of suspended cords of the left atrium (SCLA) is rare and has seldom been described. The purpose of this study was to summarize the cases of SCLA accidentally detected by coronary CT angiography (CCTA), describe their imaging features, conduct a preliminary analysis of their clinical significance, and review relevant literature.MethodsA total of 10,796 patients who underwent CCTA examinations from July 2020 to November 2021 were consecutively selected. The original and three-dimensional reconstruction images were reviewed to identify patients with SCLA. A control group was selected in a 1:2 ratio based on age, BMI, sex, and education level. The imaging characteristics and clinical data of the two groups were collected and compared. The case group was divided into two subgroups based on the starting and ending positions of the SCLA: Group 1 with the SCLA between the free wall and free wall, and Group 2 with the SCLA between the septum wall and free wall. The clinical features of these subgroups were compared. Furthermore, a review of literature on SCLA published in the past fifteen years that includes its clinical and imaging features was conducted.ResultsIn this study, a total of 35 patients were found to have SCLA, resulting in an incidence rate of approximately 0.32%. After excluding 1 patient for whom clinical features could not be obtained, the case group included a total of 18 males and 16 females, with a male-to-female ratio of 1:1 and a median age of 57.00 (52.00–64.00) years. It was found that 19 (55.88%) cases of SCLA were located near the right superior pulmonary vein ostia, while no SCLA was found near the left lower pulmonary vein orifice. A significant difference in the incidence of atrial arrhythmia between the two groups was observed (p = 0.009). Additionally, 3 patients (8.82%) in the SCLA group had a history of transient cerebral ischemic attack (TIA), which was significantly different from that in the control group (p = 0.035). The anteroposterior and transverse diameters of the left atrium were longer in the case group than in the control group (p < 0.05), but there was no significant change in left atrial volume. Subgroup analyses found no significant difference in the incidence of cerebral infarction, atrial arrhythmia, or other intracardiac structural malformations, although there was a significant difference in cord length (p = 0.013), with the length of SCLA in Group 1 and Group 2 being 2.64 ± 0.99 cm and 3.39 ± 0.68 cm, respectively. Notably, only 1 of these 34 patients was diagnosed based on echocardiography, whereas all cases were perfectly visualized using CCTA.ConclusionSCLA is rare. CCTA can accurately detect and depict this abnormal structure as compared to echocardiography. SCLA may be linked to a higher incidence of atrial arrhythmias or transient ischemic attacks. It is important for radiologists and cardiovascular experts to recognize this structure, and further investigation is necessary to determine its clinical significance.

3D-Aligner: advanced computational tool for correcting image distortion in expansion microscopy

Expansion Microscopy (ExM) is an innovative and cost-effective super-resolution microscopy technique that has become popular in cell biology research. It achieves super-resolution by physically expanding specimens. Since its introduction, ExM has undergone continuous methodological developments to enhance its resolution and labeling capabilities. However, ExM imaging often encounters sample drift during image acquisition due to the physical movement of the expanded hydrogel, posing a significant challenge for accurate image reconstruction. Despite many proposed experimental solutions to mitigate sample drift, a universal solution has yet to be established. In response to this challenge, we developed 3D-Aligner, an advanced and user-friendly image analysis tool designed to computationally correct drift in ExM images for precise three-dimensional image reconstruction and downstream quantification. We demonstrate that 3D-Aligner effectively determines and corrects drift in ExM images with different expansion rates and various fluorescently labeled biological targets, showcasing its capabilities and robustness in drift correction. Additionally, we validate the precision of 3D-Aligner by comparing drift values across different labeled targets and highlight the importance of drift correction in quantification of biological structures.

Single-centre retrospective analysis: 16 cases of percutaneous nephrolithotripsy complicating hepatic puncture injury in a 7-year experience.

The aim of this retrospective analytical study was to investigate the diagnosis and management of liver puncture injuries caused by percutaneous nephrolithotripsy (PCNL). The clinical data of 1069 patients who underwent PCNL between Oct. 2017 and Apr. 2024 were analyzed. The diagnosis of liver puncture injury was confirmed by postoperative examination of three-dimensional reconstruction computed tomography (3D-CT) findings, and the data from these patients were statistically and retrospectively analyzed. A total of 16 cases were collected, including 9 males and 7 females, with an average age of 58.31 ± 14.30years, a mean body mass index (BMI) of 23.54 ± 3.88kg/m2. Liver puncture injury was identified and classified as tangential or penetrating according to the anatomy of the nephrostomy tube and liver. The average decrease in hemoglobin level after operation was 14.25 ± 11.97g/L. One patients received blood transfusions for preoperative anemia and postoperative blood loss, and all patients were cured and discharged after delaying the removal of nephrostomy tube under conservative treatment, the time of nephrostomy tube removal after a single PCNL procedure was 6.44 ± 1.26days. This article proposes a grading system for PCNL-complicated liver puncture injuries that will help physicians to better understand their characteristics and guide the development of management. In the absence of obvious signs of peritonitis and hemodynamic stability, conservative treatment of the liver puncture injury caused by PCNL is safe and effective.

A pituitary gland squeezed upward by intrasellar kissing carotid arteries: Mimicking a pituitary microadenoma

Background: Intrasellar kissing carotid arteries are a rare variant in which bilateral internal carotid arteries run very near each other at their cavernous sinus portion. We encountered a woman with the pituitary gland mimicking a pituitary microadenoma because the pituitary gland was compressed bilaterally by intrasellar kissing carotid arteries. Case Description: A 61-year-old woman with a chronic headache underwent magnetic resonance imaging, which revealed a sellar mass measuring 10.2 mm in height, 8.2 mm in length, and 4.0 mm in width at the midintercarotid level. Blood levels of all pituitary and target-organ hormones were within normal range. The height and superior convex shape of the sellar mass suggested that it was a nonfunctioning microadenoma, which was monitored over the past 16 years. A recent three-dimensional reconstruction of magnetic resonance angiography clearly showed that the pituitary gland was squeezed upward, compressed bilaterally, and extended superiorly by intrasellar kissing carotid arteries. Conclusion: The pituitary gland can be squeezed upward by intrasellar kissing carotid arteries and mimic pituitary tumor.

Research on a three-dimensional radiation field reconstruction algorithm based on an improved 3D CNN

This article investigates the application of an improved three-dimensional convolutional neural network (3D CNN) for sparse data-based reconstruction of radiation fields. Sparse radiation data points are consolidated into structured three-dimensional matrices and fed into a self-attention integrated CNN, enabling the network to interpolate and produce complete radiation distribution grids. The model’s validity is assessed through experiments with randomly sourced radiation in scenarios both with and without shielding, as well as in refined grid configurations. Results indicate that in unshielded environments, a mere 5%(15 points) sampling yields an average relative error of 4%, while in shielded settings, a 7% (21 points) sampling maintains the error around 11%. In refined grid contexts, a 2% sampling rate suffices to limit the error to 6.58%. Thus, the improved 3D CNN is demonstrated to be highly effective for precise three-dimensional radiation field reconstruction in sparse data scenarios.

Indocyanine green fluorescence identification of the intersegmental plane by the target segmental vein-first single-blocking during thoracoscopic segmentectomy

BackgroundInnovative attempt to explore the feasibility and accuracy of using indocyanine green fluorescence (ICGF) to identify the intersegmental plane by the target segmental veins preferential ligation during thoracoscopic segmentectomy.MethodsA retrospective analysis was conducted on clinical data of 32 consecutive patients who underwent thoracoscopic segmentectomy with intersegmental plane identification using both ICGF and inflation-deflation method after target segmental veins prioritized blocking at Nanjing Chest Hospital from December 2022 to June 2023. Preoperative three-dimensional reconstruction was used to identify the target segment and the anatomical structure of the arteries, veins, and bronchi. After ligating the target segmental veins during surgery, the first intersegmental plane was immediately identified and marked with an electrocoagulation device using an inflation-deflation method. Subsequently, the second intersegmental plane was determined using the ICGF method. Finally, the consistency of the two intersegmental planes was evaluated.ResultsAll the 32 patients successfully completed thoracoscopic segmentectomy without ICG-related complications and perioperative death. The average operation time was (98.59 ± 20.72) min, the average intraoperative blood loss was (45.31 ± 35.65) ml, and the average postoperative chest tube removal time was (3.5 ± 1.16) days. The average postoperative hospital stay was (4.66 ± 1.29) days, and the average tumor margin width was (26.96 ± 5.86) mm. The intersegmental plane determined by ICGF method was basically consistent with inflation-deflation method in all patients.ConclusionThe ICGF can safely and accurately identify the intersegmental plane by target segmental veins preferential ligation during thoracoscopic segmentectomy, which is a beneficial exploration and important supplement to the simplified thoracoscopic anatomical segmentectomy.

Anatomical and Computed Tomography Study of the Mandible of the Patagonian Huemul (Hippocamelus bisulcus): Ecological and Clinical Insights.

Given the high prevalence of skeletal and mandibular diseases in the Patagonian Huemul, comprehensive anatomical studies are essential to understand the impact of nutritional deficiencies and support conservation efforts. The aim of this study is to provide a detailed anatomical characterisation of three exhumed mandibles of Patagonian huemul (Hippocamelus bisulcus) through three-dimensional reconstructions obtained from computed tomography data and semi-automatic segmentation, documenting their distinctive features. The findings revealed distinctive features in the mandible, consistent with the browsing habits of herbivores, such as a robust coronoid process, a wide and deep pterygoid fossa, a significantly lower mandibular condyle compared to other deer species and a unique configuration of the mandibular canal with a curved caudal portion and a straight rostral portion. These anatomical adaptations are likely related to the species' feeding habits and behaviour. The study also addressed the challenges of researching an endangered species, given that access to biological material is restricted by strict regulations in Chile and Argentina. These restrictions limited the available sample size and hindered the acquisition of additional specimens, which could affect the generalisation of the results. Despite these limitations, the research provides valuable anatomical insights that are fundamental for the biology, clinical practice and management of specimens. In conclusion, the mandibles of both juvenile and adult Patagonian huemul demonstrate distinctive features characteristic of browsing herbivores. The findings can serve as a basis for future comparative studies on mandibular anatomy and function in this endangered deer species as well as in other herbivorous deer.

Local classification of crystalline structures in complex plasmas using a PointNet

Abstract In complex plasmas, microparticles can form ordered crystalline structures under specific conditions. Accurately identifying these structures, such as face-centered cubic, hexagonal close-packed, and body-centered cubic, is a common task in physics. Previous methods rely on detecting symmetries in the spatial arrangement of particles, often requiring extensive calculations. This study presents a novel approach by utilizing a PointNet-based deep learning algorithm, called WignerNet, to classify these structures directly from three-dimensional reconstructions of their Voronoi cells. The model was trained exclusively on artificial and labeled data, incorporating various noise levels, and subsequently tested on real experimental data. The results demonstrate that our method effectively classifies structures, reducing computational complexity and improving accuracy compared to conventional techniques. This advancement opens up new possibilities for real-time analysis of complex plasma systems in various research.

Temporal Augmentation Effect of Reduction Malarplasty: Application of our Bracing Technique with Zygomatic Arch Elevation.

A broad midface is usually accompanied by temporal depression. Traditional reduction malarplasty may visually improve the temporal depression by the inward reduction of zygomatic arch, but also has a high risk of soft tissue sagging. Our bracing technique has been reported to have an anti-sagging effect and may have a temporal augmentation effect as observed during our long-term clinical practice. Data of patients who received reduction malarplasty with our bracing technique from September 2015 to July 2023 were retrospectively collected. The pre-op and post-op CT images of those who met the inclusion criteria were used for three-dimensional reconstruction and measurements of the thickness and volume of the temporal soft tissue as well as the elevation distance of zygomatic arch. Fifty-eight patients with an average follow-up of 18.4 ± 9.1months were included. Despite mild thinning of the temporalis muscle after reduction malarplasty, the overall thickness of the temporal soft tissue significantly increased due to the significant thickening of the temporal adipose-fascial layer. There was a 0.5ml-increase in the temporal volume although without statistical difference. No significant correlation was detected between the elevation distance of zygomatic arch and the temporal thickness or volume change. The bracing technique of reduction malarplasty not only plays an anti-sagging role, but also has a temporal augmentation effect through the superior bracing by the elevation and rigid fixation of the zygomatic arch. It adds brilliance to the traditional technique and can be suggested especially when the patients are disturbed by temporal depression. 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 .

Soft Tissue Facial Morphology in Growing Patients with Different Occlusal Classes.

The study of facial profiles in the dental field is very important for the diagnosis and the dental and orthodontic treatment plan. The aim of this study is to analyze the three-dimensional morphology of the faces of 269 growing patients with Class I and II occlusions, focusing on children aged between 6 and 9 years old. The analysis was conducted using a non-invasive computerized system, which allowed for the automatic collection of facial landmarks and the subsequent reconstruction of three-dimensional coordinates. The sample comprised 269 children within the specified age range. Each child's facial features were captured using the non-invasive computerized system, which utilized two infrared CCD cameras, real-time hardware for label recognition, and software for three-dimensional landmark reconstruction. Sixteen cutaneous facial landmarks were automatically collected for each participant. From these landmarks, 10 angular and 15 linear measurements, as well as five direct distance rates, were derived. The mean values for each age class were calculated separately for children with bilateral Angle Class I occlusion and compared with those for children with bilateral Class II occlusion. In all children, the left and right occlusal classes were measured as suggested by Katz. The analysis revealed notable differences, primarily in the three-dimensional angular measurements between children with Class I and II occlusions. Specifically, Class II children exhibited more convex faces in the sagittal plane and a less prominent lower jaw compared to Class I children. However, no significant differences were observed in linear measurements, except for the lower facial height rate, which varied inconsistently across age groups between the two occlusion types. the findings of this research highlight distinct three-dimensional facial morphological differences between children with Class I and II occlusions. While Class II children tended to have more convex facial profiles and less prominent lower jaws, linear measurements showed minimal variation between the two occlusion types. These results underscore the importance of three-dimensional analysis in understanding facial morphology in growing patients with different occlusal patterns.

Three-Dimensional Reconstruction of Zebra Crossings in Vehicle-Mounted LiDAR Point Clouds

In the production of high-definition maps, it is necessary to achieve the three-dimensional instantiation of road furniture that is difficult to depict on traditional maps. The development of mobile laser measurement technology provides a new means for acquiring road furniture data. To address the issue of traffic marking extraction accuracy in practical production, which is affected by degradation, occlusion, and non-standard variations, this paper proposes a 3D reconstruction method based on energy functions and template matching, using zebra crossings in vehicle-mounted LiDAR point clouds as an example. First, regions of interest (RoIs) containing zebra crossings are obtained through manual selection. Candidate point sets are then obtained at fixed distances, and their neighborhood intensity features are calculated to determine the number of zebra stripes using non-maximum suppression. Next, the slice intensity feature of each zebra stripe is calculated, followed by outlier filtering to determine the optimized length. Finally, a matching template is selected, and an energy function composed of the average intensity of the point cloud within the template, the intensity information entropy, and the intensity gradient at the template boundary is constructed. The 3D reconstruction result is obtained by solving the energy function, performing mode statistics, and normalization. This method enables the complete 3D reconstruction of zebra stripes within the RoI, maintaining an average planar corner accuracy within 0.05 m and an elevation accuracy within 0.02 m. The matching and reconstruction time does not exceed 1 s, and it has been applied in practical production.

A three-dimensional curve interface reconstruction algorithm for two-phase fluid flow

The curve interface reconstruction algorithm has received significant attention in the context of two-dimensional two-phase flow. However, it remains absent in the three-dimensional scenario. This paper proposes a novel three-dimensional curve interface reconstruction (CIR) algorithm to address this challenge within structured meshes for the first time. Specifically, a portion of the spherical surface is employed to reconstruct the three-dimensional curve interface segment, with the radius and center coordinates determined by curvature and mass conservation constraints, respectively. To enhance curvature accuracy, a sphere-based iterative reconstruction (SIR) algorithm is proposed to calculate the reconstructed distance function (RDF) for the three-dimensional curve interface. Various tests involving the interface reconstruction of spherical, ellipsoidal, and cubic objects demonstrate that the coupled SIR and CIR (SIR-CIR, simplified by SCIR) method achieves higher accuracy than many popular methods, particularly with coarse mesh resolutions. Additionally, the SCIR method offers the advantages of straightforward implementation and coding for interface reconstruction in two-phase flow research. This advantage results in reduced computational costs compared to the coupled volume-of-fluid and level set (VOSET) method, which also utilizes an iterative method to solve RDF.

Three-dimensional spatiotemporal wind field reconstruction based on LiDAR and multi-scale PINN

In this numerical study, we use a multi-scale version of physics-informed neural network (PINN) for wind field reconstruction from LiDAR measurements. The reference velocity field is obtained from high-fidelity large-eddy simulation of neutral atmospheric boundary layer, and the LiDAR measurement strategy is restricted to that of a real LiDAR. The multi-scale PINN reconstructs the velocity field by minimizing a combination of the L2-error with respect to the LiDAR measurements and residuals of the governing equations. Our most significant finding is that adding a multi-scale layer to PINN enables us to: (i) capture wider range of scales, (ii) reconstruct the flow field outside the LiDAR scanning area, and (iii) reach faster convergence. We also find that for volumetric flow reconstruction and to deal with uncertainty in the wind direction, the reconstruction accuracy can be greatly improved by employing multiple LiDAR devices. Overall, our results show that the normalized errors in the reconstructed wind field are lower than 5% for all the experiments conducted in this study and that the errors do not increase even in the presence of measurement noise levels of typical LiDAR. These findings show the feasibility of three-dimensional dynamic wind field reconstruction across large wind farms using LiDAR devices.

Analysis of microstructure of prefabricated fractured granite under thermal effects based on CT technology

In this study, Computed Tomography (CT) technology was employed to visually analyze the influence of thermal effects on the microstructure of prefabricated fractured granite. The porosity and heterogeneity of the samples were calculated using three-dimensional reconstruction techniques, and two parameters, crack length and orientation, were introduced to quantitatively evaluate the impact of prefabricated fractures on subsequent crack propagation. The results indicated that at 400 °C–500 °C, numerous microcracks were generated within the samples, but they did not interconnect. Above 600 °C, microcracks gradually propagated, forming well-connected crack networks. Due to the uneven thermal stress distribution caused by the prefabricated fractures, samples subjected to temperatures above 600 °C exhibited higher heterogeneity in the vertical direction. While in other directions, the samples gradually tended to homogenize as the temperature rose. Below 500 °C, crack length was significantly affected by the prefabricated fractures, although this influence diminished with increasing distance from the fractures. When the temperature was below 400 °C, microcracks mainly propagated along the direction of the prefabricated fractures. However, when the temperature exceeded 500 °C, microcracks began to initiate and propagate in the opposite direction of the prefabricated fractures, and anti-wing cracks started to emerge.