Three-dimensional Reconstruction Technique Research Articles

Lung Cancer Detection

Abstract: This paper presents a comprehensive approach to lung cancer detection utilizing state-of-the-art machine learning techniques, specifically Convolutional Neural Networks (CNNs). Using CNN[1] the model is trained and it can detect whether the given lung cancer cell image contains cancerous cells or not. The first component of the proposed approach involves high-resolution medical imaging, such as computed tomography (CT) scans, to capture detailed anatomical information about the lungs. Image processing algorithms are applied to enhance the quality of the images and extract relevant features. Additionally, innovative three-dimensional reconstruction techniques are employed to visualize the lung tissue at a microscopic level, facilitating the identification of subtle abnormalities.

A 3D Reconstruction Method Based on Homogeneous De Bruijn-Encoded Structured Light

Structured light three-dimensional reconstruction is one of the important methods for non-contact acquisition of sparse texture object surfaces. Variations in ambient illumination and disparities in object surface reflectance can significantly impact the fidelity of three-dimensional reconstruction, introducing considerable inaccuracies. We introduce a robust method for color speckle structured light encoding, which is based on a variant of the De Bruijn sequence, termed the Homogeneous De Bruijn Sequence. This innovative approach enhances the reliability and accuracy of structured light techniques for three-dimensional reconstruction by utilizing the distinctive characteristics of Homogeneous De Bruijn Sequences. Through a pruning process applied to the De Bruijn sequence, a structured light pattern with seven distinct color patches is generated. This approach ensures a more equitable distribution of speckle information.

Uniform boundary conditions on models of spherical particles through alpha shape surface tracking and Laguerre–Voronoi diagrams

This study describes the adaptation of the alpha-shape three-dimensional surface reconstruction technique to boundaries of spherical particle packings, such as those modeled using Discrete Elements. The alpha shape technique is employed to reconstruct a boundary surface for a packing as well as to assemble a Laguerre–Voronoi Diagram of the packing's boundary. The reconstructed surface can be used to track the evolution of the packing surface, while the surface diagram can be used to directly obtain the discrete force vectors that result from applying a uniform stress tensor (Static Uniform Boundary Condition), as well as the discrete velocity vectors that result from applying a uniform velocity gradient tensor (Kinematic Uniform Boundary Condition) to a model of spherical discrete particles. Doing so continuously throughout a simulation allows for the application of uniform boundary conditions on spherical discrete particles, whilst enabling precise tracking of stress and deformation tensors of the packing. An implementation of this novel approach in the Yade open-source DEM code is detailed here. The power and versatility of the real-time boundary tracking approach is demonstrated using some boundary value problem simulations on polydisperse spherical particle models.

Data-driven classification of left atrial morphology and its predictive impact on atrial fibrillation catheter ablation.

Various left atrial (LA) anatomical structures are correlated with postablative recurrence for atrial fibrillation (AF) patients. Comprehensively integrating anatomical structures, digitizing them, and implementing in-depth analysis, which may supply new insights, are needed. Thus, we aim to establish an interpretable model to identify AF patients' phenotypes according to LA anatomical morphology, using machine learning techniques. Five hundred and nine AF patients underwent first ablation treatment in three centers were included and were followed-up for postablative recurrent atrial arrhythmias. Data from 369 patients were regarded as training set, while data from another 140 patients, collected from different centers, were used as validation set. We manually measured 57 morphological parameters on enhanced computed tomography with three-dimensional reconstruction technique and implemented unsupervised learning accordingly. Three morphological groups were identified, with distinct prognosis according to Kaplan-Meier estimator (p < .001). Multivariable Cox model revealed that morphological grouping were independent predictors of 1-year recurrence (Group 1: HR = 3.00, 95% CI: 1.51-5.95, p = .002; Group 2: HR = 4.68, 95% CI: 2.40-9.11, p < .001; Group 3 as reference). Furthermore, external validation consistently demonstrated our findings. Our study illustrated the feasibility of employing unsupervised learning for the classification of LA morphology. By utilizing morphological grouping, we can effectively identify individuals at different risks of postablative recurrence and thereby assist in clinical decision-making.

EVALUATION OF NERF 3D RECONSTRUCTION FOR ROCK ART DOCUMENTATION

Abstract. Digital documentation of rock art traditionally relies on a point cloud captured by a terrestrial laser scanner (TLS) or derived from an oriented image obtained using photogrammetry. In modern photogrammetry, the dense point cloud is generated using multi-view stereo (MVS) and subsequently used to generate a photorealistic 3D model. A recent method to reconstruct 3D models from images is Neural Radiance Fields (NeRF), which uses volume density to render the scenes through neural networks. The advantage of NeRF is that it can construct 3D models faster without using high computer processors and memory. NeRF has been studied in various applications, including cultural heritage, but not specifically for rock art documentation. Therefore, this paper evaluates three-dimensional (3D) reconstruction techniques using NeRF on Nerfstudio platform on two rock art datasets and compares them with the point cloud and 3D mesh models obtained from TLS and photogrammetry/MVS. The results have shown that NeRF does not match MVS in achieving geometric precision and texture quality. However, its learning-based approach accelerates reconstruction and offers potential enhancements to complement photogrammetric workflow.

The Atlas of the Inferior Mesenteric Artery and Vein under Maximum-Intensity Projection and Three-Dimensional Reconstruction View

(1) Background: Understanding vascular patterns is crucial for minimizing bleeding and operating time in colorectal surgeries. This study aimed to develop an anatomical atlas of the inferior mesenteric artery (IMA) and vein (IMV). (2) Methods: A total of 521 patients with left-sided colorectal cancer were included. IMA and IMV patterns were identified using maximum-intensity projection (MIP) and three-dimensional (3D) reconstruction techniques. The accuracy of these techniques was assessed by comparing them with surgical videos. We compared the amount of bleeding and operating time for IMA ligation across different IMA types. (3) Results: Most patients (45.7%) were classified as type I IMA, followed by type II (20.7%), type III (22.6%), and type IV (3.5%). Newly identified type V and type VI patterns were found in 6.5% and 1% of patients, respectively. Of the IMVs, 49.9% drained into the superior mesenteric vein (SMV), 38.4% drained into the splenic vein (SPV), 9.4% drained into the SMV–SPV junction, and only 2.3% drained into the first jejunal vein (J1V). Above the root of the left colic artery (LCA), 13.1% of IMVs had no branches, 50.1% had one, 30.1% had two, and 6.7% had three or more branches. Two patients had two main IMV branches, and ten had IMVs at the edge of the mesocolon with small branches. At the IMA root, 37.2% of LCAs overlapped with the IMV, with 34.0% being lateral, 16.9% distal, 8.7% medial, and both the marginal type of IMV and the persistent descending mesocolon (PDM) type represented 1.4%. MIP had an accuracy of 98.43%, and 3D reconstruction had an accuracy of 100%. Blood loss and operating time were significantly higher in the complex group compared to the simple group for IMA ligation (p &lt; 0.001). (4) Conclusions: A comprehensive anatomical atlas of the IMA and IMV was provided. Complex IMA patterns were associated with increased bleeding and operating time.

Study on the Effect of Three-dimensional Reconstruction Technique Based on Human Gait Plantar Transient Data on Rehabilitation of Patients with Abnormal Foot Arch

This research employs non-contact plantar 3D data scanning and gait analysis methodologies to establish a rehabilitation assistance system tailored for foot arch anomalies. The system utilizes a non-contact plantar 3D data model to mitigate dysfunctions within the plantar skeletal-muscular system. Its objectives include facilitating personalized remote diagnosis of foot arch anomalies, enabling patients to monitor their rehabilitation progress, and supporting at-home rehabilitation efforts. A dataset comprising 124 cases of physiological foot arch anomalies in adults aged 18 and above was collected and analyzed. The findings demonstrate the system’s flexibility, high spatial resolution, personalization, and innovation. Notably, the system achieves real-time measurement of positive pressure and shear force distribution at the plantar interface, facilitates the construction of accurate geometric models, and yields high-quality plantar three-dimensional coordinate data. This research contributes theoretical and technical underpinnings for the application of footwork anomaly diagnosis and correction.

Finite element analysis of female pelvic organ prolapse mechanism: current landscape and future opportunities.

The prevalence of pelvic organ prolapse (POP) has been steadily increasing over the years, rendering it a pressing global health concern that significantly impacts women's physical and mental wellbeing as well as their overall quality of life. With the advancement of three-dimensional reconstruction and computer simulation techniques for pelvic floor structures, research on POP has progressively shifted toward a biomechanical focus. Finite element (FE) analysis is an established tool to analyze the biomechanics of complex systems. With the advancement of computer technology, an increasing number of researchers are now employing FE analysis to investigate the pathogenesis of POP in women. There is a considerable number of research on the female pelvic FE analysis and to date there has been less review of this technique. In this review article, we summarized the current research status of FE analysis in various types of POP diseases and provided a detailed explanation of the issues and future development in pelvic floor disorders. Currently, the application of FE analysis in POP is still in its exploratory stage and has inherent limitations. Through continuous development and optimization of various technologies, this technique can be employed with greater accuracy to depict the true functional state of the pelvic floor, thereby enhancing the supplementation of the POP mechanism from the perspective of computer biomechanics.

Three-dimensional reconstruction based on micro-imaging under wavelength-tunable illumination.

The three-dimensional reconstruction technique has been widely applied across various fields, with imaging serving as a fundamental approach to achieve this reconstruction. In the present study, we employed micro-imaging to realize 3D reconstruction based on the "shape from focus" and the chromatic aberration effect. This approach eliminates the need for sample or imaging lens movement to locate the focal plane for obtaining clear images. Instead, by utilizing tunable illuminance, we can adjust the imaging distance through the chromatic aberration, thereby achieving accurate reconstructions. As a means of verification, a simple system was accordingly constructed with an adjustable illuminance range (500-750nm) at a magnification of 10× for imaging purposes. The fine reconstruction achieved high precision in micrometers; however, the depth of field emerged as an issue during the reconstruction process. To assess this method, a coin was employed, and the resulting reconstruction bias was determined to be as low as 0.01mm. These findings indicate that the proposed method is practical for surface reconstruction and its capabilities will be further enhanced through optical design improvements.

Five-view three-dimensional reconstruction for ultrafast dynamic imaging of pulsed radiation sources

Multiaxial neutron/x-ray imaging and three-dimensional (3D) reconstruction techniques play a crucial role in gaining valuable insights into the generation and evolution mechanisms of pulsed radiation sources. Owing to the short emission time (∼200 ns) and drastic changes of the pulsed radiation source, it is necessary to acquire projection data within a few nanoseconds in order to achieve clear computed tomography 3D imaging. As a consequence, projection data that can be used for computed tomography image reconstruction at a certain moment are often available for only a few angles. Traditional algorithms employed in the process of reconstructing 3D images with extremely incomplete data may introduce significant distortions and artifacts into the final image. In this paper, we propose an iterative image reconstruction method using cylindrical harmonic decomposition and a self-supervised denoising network algorithm based on the deep image prior method. We augment the prior information with a 2D total variation prior and a 3D deep image prior. Single-wire Z-pinch imaging experiments have been carried out at Qin-1 facility in five views and four frames, with a time resolution of 3 ns for each frame and a time interval of 40 ns between adjacent frames. Both numerical simulations and experiments verify that our proposed algorithm can achieve high-quality reconstruction results and obtain the 3D intensity distribution and evolution of extreme ultraviolet and soft x-ray emission from plasma.

The fertility tracks of pollen tube in the ovary of Solanum nigrum by three-dimensional reconstruction.

In this paper, we present an enhanced method for automatically capturing a large number of consecutive paraffin sections using a microscope. Leveraging these microstructural images, we employed three-dimensional visualisation and reconstruction techniques to investigate the dispersal growth process of pollen tube bundles upon entering the ovary of Solanum nigrum. Additionally, we explored their behaviour within different ovules and examined the relationship between the germination rate of seeds and the fertilisation process. Our findings reveal that despite the abundance of Solanum nigrum seeds, only a fraction of them is capable of successful germination. The germination rate of seeds is closely related to whether fertilisation of the ovules and pollen tubes is completed. Due to the limited number of pollen tubes entering the ovary, only a portion of the ovules can be fertilised. The proportion of fertilised ovules positively correlates with the germination rate of the seeds. Through three-dimensional reconstruction, we observed a phenomenon of proximity during the pollination process, wherein ovules closer to the pollen tube bundles are more likely to be fertilised. Furthermore, fertilised ovules exhibited significant changes in morphology and embryo sac structure. The number of fertilised ovules directly impacts the germination rate of wild Solanum nigrum seeds. Although all Solanum nigrum ovules have the potential to develop into seeds, most seeds originating from unfertilised ovules are unable to germinate normally, resulting in an incomplete germination rate of seeds and preventing it from reaching 100%.

Numerical simulation on gas behavior inside pellet based on X-ray micro-computed tomography

The objective of this work is to investigate gas behavior inside a realistic pellet model while varying inlet velocities and comparing it against published studies. A CT three-dimensional (3D) reconstruction technique was performed to construct a realistic pellet model from the two-dimensional (2D) tomographic images. The distribution of gas velocity, pressure, and species inside the pellet was investigated with computational fluid dynamics (CFD) and microfluidic boundary layer theory. The results indicated that pellet morphology, pore size, and position were responsible for the variability in velocity anisotropy inside the pellet. The pressure gradient between the windward and leeward sides of the pellet tended to rise as the inlet velocity increased, up to a maximum value of 4.2 Pa. Moreover, the pressure gradient resulted in a higher species concentration on the windward side, particularly at lower flow velocities. Finally, the potential effect of the pellet structure on the reduction process is proposed.

Study on sound absorption characteristic of porous asphalt mixture based on macroscale and mesoscale analysis

To explore the sound absorption characteristics of porous asphalt mixture, the effects of macroscopic parameters of asphalt mixture on sound absorption coefficient (SAC) were studied by the sound absorption coefficient test, and the mesoscopic void structure was investigated by industrial computed tomography (CT) and three-dimensional (3D) reconstruction techniques. The results show that the SAC can be increased by increasing the porosity or thickness and reducing the NMAS. The increase of porosity and the decrease of pavement thickness can better absorb high frequency noise (above 1000 Hz). Through the grey correlation analysis, it can be seen that the SAC of porous asphalt mixture is most affected by the porosity. There is a strong linear relationship between the microscopic void characteristic of porous asphalt mixture and the peak and mean value of SAC.

A study on alveolar ridge augmentation guided by orthodontic forced eruption in patients with severe periodontitis

Objective: To evaluate the clinical effect of alveolar bone augmentation in teeth with severe periodontitis using orthodontic forced eruption. Methods: Twelve patients (5 males and 7 females) with severe periodontitis and malocclusion who visited the Department of Orthodontics and Department of Periodontology, Peking University School and Hospital of Stomatology from October 2018 to May 2022 were included in this retrospective study. The age was (38.8±6.6) years (24-49 years). A total of 16 maxillary incisors that could not be retained due to severe periodontitis were included. The orthodontic fixed appliance was used to extrude the teeth. Cone-beam CT (CBCT) images of the patients before and after orthodontic forced eruption were collected. The voxel-based registration was used to superpose the images before and after orthodontic forced eruption. The height, thickness, and apical alveolar bone area were measured on the sagittal plane. The alveolar bone volume before and after orthodontic forced eruption was measured using three-dimensional reconstruction technique, and the influencing factors related to the alveolar volume change were analyzed. Results: The results of this study showed that the eruption distance of the teeth was (2.37±0.82) mm, and the alveolar bone height increased by (1.11±0.79) and (0.98±0.79) mm (t=3.73, P=0.010; t=4.85, P<0.001). The proximal and distal alveolar bone height increased by (1.10±0.78) and (0.86±1.08) mm, respectively (t=5.59, P<0.001; t=3.18, P=0.006). The alveolar bone thickness decreased (0.30±0.31) mm (t=-3.75, P=0.002) and alveolar bone area increased (6.84±5.86) mm2 (t=3.71, P<0.001). The alveolar bone volume increased (53±49) mm3 (t=4.38, P<0.001). The alveolar bone volume was moderately positively correlated with eruption distance, apical and mesial alveolar bone thickness (r=0.55, P=0.028; r=0.63, P=0.008; r=0.67, P=0.005). Conclusions: Orthodontic forced eruption results in a favorable increase of the alveolar bone in the upper incisor that cannot be retained due to severe periodontitis, which provides better periodontal hard tissue conditions for subsequent dental implant.

Temperature-dependent voids and their impact on SMA surface course permeability

This study investigates the water permeability characteristics of newly constructed Stone Mastic Asphalt (SMA) surface course, with a specific focus on the influence of connected voids arising from the compaction temperature during pavement construction. On-site evaluation of the permeability coefficient was performed, followed by core sample extraction from the same locations to investigate the correlation between the permeability coefficient and porosity. Industrial CT scanning was used to identify and separate void regions in the core samples. Three-dimensional digital reconstruction techniques were employed to analyze the morphology and spatial distribution of voids within the core. The connectivity of voids was assessed, providing insights into water infiltration pathways within the SMA course. Additionally, finite element simulation of the pavement temperature field was conducted to investigate the spatially differentiated distribution of voids within the SMA course.The findings reveal that approximately 38.3% of the voids are concentrated within a 1 cm depth below the top surface of the 4 cm-thick SMA course. The aggregation of voids enhances the likelihood of interconnection, facilitating water seepage. Water infiltrates through the open voids on the top surface and flows vertically and horizontally along the interconnected pathways. Notably, at a depth of approximately 2.5 cm, the flow transitions to horizontal spreading, aligning with the primary distribution interval of interconnected voids. The non-uniform distribution of voids is primarily influenced by the compaction temperature. The top and bottom portions exhibit higher void percentages, while the middle portion shows relatively fewer voids, consistent with the observed compaction temperature pattern.

Current techniques of 3D reconstruction in computed tomography and magnetic resonance in diagnostic imaging of the spine

This review article presents an analysis of 36 scientific papers focusing on modern three-dimensional (3D) reconstruction techniques in computed tomography (CT ) and magnetic resonance imaging (MRI) for their applications in medical diagnostics. The objective of this review is to present the current state of knowledge regarding the development and utilization of 3D reconstruction techniques, as well as to identify key trends and challenges in this field. The first part of the study focuses on the advancements in MRI and CT . The analysis reveals the major trends in the evolution of these diagnostic methods, such as increased accessibility of CT and MRI examinations for patients, reduced scan duration, greater utilization of artificial intelligence, and expanded applications in interventional radiology.The second part of the article highlights the potential and effectiveness of 3D modelling in diagnostic imaging. Creating 3D models of anatomical structures is a complex and multi-step process. Through the review, it was determined that 3D models derived from MRI can be equally accurate and diagnostically valuable compared to the more commonly used CT -based reconstructions. In the future, fusion imaging of MRI/CT is expected to play an increasingly significant role in orthopaedic imaging. The review demonstrates the significant potential of 3D modelling in diagnostic imaging. However, further research is still required to better understand the capabilities of 3D modelling in diagnosing complex anatomical structures. The integration of information technology in medicine will be crucial in advancing this field.

COMPARATIVE ANALYSIS OF THE THREEDIMENSIONAL RECONSTRUCTION OF FACIAL CT SCANS AND THEIR RESPECTIVE STEREOPHOTOGRAMMETRY

The use of 3D technology has become important in the practice of surgeons, due to the limitations of 2D photographs. This is a prospective, analytical, and comparative study, which aims to analyze in a comparative way the three-dimensional reconstruction of two different systems, through computed tomography of the face and the respective stereophotogrammetry acquired from the same face. It was possible to reconstruct a total of 25 meshes from participants who underwent facial tomography and photogrammetry at the IPO Hospital. The study aims to describe the computerized technique of three-dimensional reconstruction of the face and mainly to evaluate the equivalence of the surface of the face obtained by two different techniques that propose the analysis of the anatomy. The first mesh was obtained by computed tomography. The second by the stereophotogrammetry technique, with capture performed by the clOner scanner and with the reconstruction of the mesh in the Reality Capture application. In addition, to demonstrate a three-dimensional facial evaluation system without ionizing radiation, low cost, and high availability. The results obtained were sufficient to demonstrate the equivalence between the meshes. Thus, stereophotogrammetry of the face is a new option for anatomical analysis of the face. It does not cause discomfort or risks to the patient and increases the possibilities of analysis.

Root canal morphology and bifurcating/merging sites of permanent mandibular incisors in 9- to 12-year-old children: An in-vivo 3D visualization analysis in China

ObjectiveThis retrospective study aims to analyze the root canal morphology of permanent mandibular incisors and the bifurcating/merging sites of root canal systems in children aged 9–12 in a Chinese subpopulation.DesignCone-beam computed tomography scans of 976 healthy, untreated and fully developed mandibular incisors were collected. Root canal morphology was identified by Vertucci's classification. Combined three-dimensional reconstruction and visualization techniques were used to locate bifurcating/merging sites in root canals. ResultsVertucci I was the most common classification of mandibular central incisors (42.3%) while Vertucci III was most common in mandibular lateral incisors (37.9%). Females more frequently showed Vertucci I classification (49.5% central incisors and 36.7% lateral incisors) while Vertucci III was most common among males (44.5% central incisors and 41.0% lateral incisors). The difference in canal classification by sex was statistically significant (p < 0.05). 58.7% of Vertucci V canals bifurcated in the apical third (AT) in central incisors, while 69.5% bifurcated in the middle third (MT) in lateral incisors. Bifurcating and merging in AT (44.3%) was the most common style of Vertucci III canals in central incisors, while bifurcating in MT and merging in AT (53.8%) was the most common in lateral incisors. ConclusionThe root canal morphology of mandibular incisors in children aged 9–12 was different from that reported in previous studies on adults, and closely related to sex. Males had significantly greater canal variability than females. Lateral incisors had greater canal variability than central incisors. The bifurcating/merging sites were closely related to tooth type.

Three-dimensional morphology and crystallographic characteristics of the low-temperature bainitic microstructure in high-carbon steel

The three-dimensional morphology of low-temperature bainite in high-carbon steel was reconstructed by serial sectioning and computer-aided three-dimensional reconstruction techniques. Combined with laser scanning confocal microscope and electron backscatter diffraction analysis, the microstructural evolution and crystallographic orientation of low-temperature bainite were studied. The results show that the three-dimensional morphology of the low-temperature bainite sheaves is a plate-like structure. During the isothermal transformation, some new bainite plates stop growing after impinging on preformed bainite plates. However, some new bainite plates resume growth on the opposite surface of the impingement zone after briefly stopping. This is attributed to the accumulation of strain energy in the collision zone caused by impingement between bainite plates, which provides the driving force for new nucleation, thus stimulating new nucleation on the opposite surface of the collision zone. The bainite formed on the opposite surface maintains the same crystallographic orientation as the “twinned bainite”. Finally, the bainite plates form interlocked microstructures in the prior austenite grains via impingement, nucleation, and intersection.

Anal and Perianal Reconstruction using a Bilateral Angel Wing Flap without Temporary Colostomy: A Case Report

Anal and perianal defects after tumor resection often result in complicated circular defects, requiring three-dimensional reconstruction techniques to avoid scar contracture and ensure normal anal function. However, skin grafts are unsuitable in this region due to risk of contracture, and flaps such as the V-Y advancement flap, which have been commonly used, are too thick to create a natural structure for the anal sphincter. In this report, we present a case in which a 44-year-old woman underwent a bilateral angel wing flap operation to reconstruct an anal defect after tumor resection without the need for temporary colostomy. This flap formed a natural conduit and a much thinner and more suitable option for the physiologic and natural reconstruction of the anal and perianal region. During long-term follow-up, the patient experienced no complications such as flap necrosis or infection and neither did she have problems with anal function, including incontinence or obstruction of the anal passage. We propose the “angel wing” flap as a probable option for improving the quality of life of patients with anal and perianal defects.