Tridimensional Reconstruction Research Articles

Properties of charge recombination in liquid argon

Liquid argon is an excellent medium for detecting particles, given its yields and transport properties of light and charge. The technology of liquid argon time projection chambers has reached its full maturity after four decades of continuous developments and is, or will be, used in world class experiments for neutrino and dark matter searches. The collection of ionization charge in these detectors allows to perform a complete tridimensional reconstruction of the tracks of charged particles, calorimetric measurements, particle identification. This work proposes an innovative approach to the problem of charge recombination in liquid argon which moves from a microscopic model and is applied to the cases of low energy electrons, alpha particles, and nuclear recoils. It takes inspiration and expands the recombination models commonly used by the liquid argon community. The model is able to describe precisely several sets of experimental data available in the literature, over wide ranges of electric field strengths and kinetic energies and can be easily extended to other particles. Published by the American Physical Society 2024

Biomechanical gait analysis in sheep: kinematic parameters.

Animals have been used as models to help to better understand biological and anatomical systems, and pathologies in both humans and non-human species, and sheep are often used as an in vivo experimental model for orthopedic research. Gait analysis has been shown to be an important tool in biomechanics research with clinical applications. The purpose of this study was to perform a kinematic analysis using a tridimensional (3D) reconstruction of the sheep hindlimb. Seven healthy sheep were evaluated for natural overground walking, and motion capture of the right hindlimb was collected with an optoelectronic system while the animals walked in a track. The analysis addressed gait spatiotemporal variables, hip, knee and ankle angle and intralimb joint angle coordination measures during the entire walking cycle. This study is the first that describes the spatiotemporal parameters from the hip, knee and ankle joints in a tridimensional way: flexion/extension; abduction/adduction and inter/external rotation. The results of this assessment can be used as an outcome indicator to guide treatment and the efficacy of different therapies for orthopedic and neurological conditions involving the locomotor system of the sheep animal model.

C5aR1 signaling promotes region- and age-dependent synaptic pruning in models of Alzheimer's disease.

Synaptic loss is a hallmark of Alzheimer's disease (AD) that correlates with cognitive decline in AD patients. Complement-mediated synaptic pruning has been associated with this excessive loss of synapses in AD. Here, we investigated the effect of C5aR1 inhibition on microglial and astroglial synaptic pruning in two mouse models of AD. A combination of super-resolution and confocal and tridimensional image reconstruction was used to assess the effect of genetic ablation or pharmacological inhibition of C5aR1 on the Arctic48 and Tg2576 models of AD. Genetic ablation or pharmacological inhibition of C5aR1 partially rescues excessive pre-synaptic pruning and synaptic loss in an age and region-dependent fashion in two mouse models of AD, which correlates with improved long-term potentiation (LTP). Reduction of excessive synaptic pruning is an additional beneficial outcome of the suppression of C5a-C5aR1 signaling, further supporting its potential as an effective targeted therapy to treat AD. C5aR1 ablation restores long-term potentiation in the Arctic model of AD. C5aR1 ablation rescues region specific excessive pre-synaptic loss. C5aR1 antagonist, PMX205, rescues VGlut1 loss in the Tg2576 model of AD. C1q tagging is not sufficient to induce VGlut1 microglial ingestion. Astrocytes contribute to excessive pre-synaptic loss at late stages of the disease.

New media art design based on fast visual segmentation and 3D image processing

Acquiring innovative styles and compositions from intricate and heterogeneous artistic imagery has emerged as a pivotal research quandry within contemporary new media art image conception. In a concerted effort to adeptly distill the quintessence of artistic styles and elements embedded within these visuals, an innovative methodology is posited herein, underpinned by an enhanced U-net segmentation framework and harmoniously fused with the surface extraction image reconstruction algorithm. This meticulous amalgamation endeavors to attain accurate segmentation and tridimensional reconstruction of the artistry encapsulated in these images. Primarily, the imagery is meticulously partitioned, culminating in an output that artfully encapsulates the inherent artistic attributes. Subsequently, this segmentation outcome is adeptly reconstituted, bestowing form to a three-dimensional artistry model. Empirical validation substantiates the efficacy of this approach, with the method’s Mean Intersection over the Union (MIoU) parameter yielding an impressive score of 0.939 in segmentation performance. Moreover, the peak signal-to-noise ratio and structural similarity attain commendable zeniths of 38.16 and 0.9808, respectively, underscoring the excellence of the reconstruction process. The proposed methodology demonstrates its prowess in exacting segmentation and comprehensive reconstruction of semantic intricacies and nuanced features pervading the realm of artistic imagery. Consequently, this novel methodology augments artists’ capacity to discern diverse artistic paradigms and fabricate superlative new media art compositions of heightened caliber.

Regularization techniques for 3D surface reconstruction from four quadrant backscattered electron detector images

In scanning electron microscopy (SEM), a four quadrants backscattered electron detector (FQBSD) provides signals that can be combined to obtain a tridimensional reconstruction of the surface. The main challenge of the reconstruction operation consists of integrating the gradient field obtained as the normalized signal difference from each pair of opposite quadrants. Owing to the presence of electronic noise that eventually turns into image noise, a least square integration approach has been widely adopted for surface reconstruction. In the present work, we demonstrate the possibility of adopting regularization techniques (Tichonov’s and Dirichlet’s) to the surface reconstruction from FQBSD images to reduce the distortions due to sensitivity variations amongst the detector quadrants or an imprecise alignment of the FQBSD with the gun axis. This allows for a substantial improvement in the 3D surface reconstruction quality in terms of resolution and reduction of artifacts. These procedures have been experimentally validated on AISI 316L stainless steel polished surfaces with hardness indentation and on laser-patterned aluminum and silicon samples showing promising results.

3D Curvature-Based Tip Load Estimation for Continuum Robots

This letter presents a method intended for the estimation of external force and moment applied at the tip of thin rods using vision-based shape measurements, with a view to be applied on continuum robots. A versatile vision process is developed that does not require any additional markers nor sensors to provide an accurate tri-dimensional reconstruction of the deformable rod shape. Then, the tip loads (i.e., forces and moments) are directly deduced from the curvature along this curve formed by deformed rod thanks to the resolution of a linear system without requiring any iterative optimization. The curvature is determined with a robust method that allows filtering out measurement noise and artifacts. Simulations show that this approach gives fast and precise results in both 2D (planar forces estimation without torsion) and 3D (spatial forces estimation). Experimental results on cantilever rods demonstrate an accuracy of 2.2% and 2.7% of the applied forces and moments, respectively.

Madelung Deformity: Diagnosis and Treatment Options

AbstractMadelung deformity (MD) comprises an increased volar and ulnar tilt of the joint facet of the distal radius, secondary to an idiopathic physeal dysplasia. Such change causes radial shortening and consequent distal ulnar prominence, along with wrist pain and loss of motion. Surgery becomes an option in patients with severe deformity that do not respond to conservative treatment.The classic surgical techniques are problematic for adults, as they are specific for children and adolescents, whose radial physis is still open. Very few papers discuss the treatment of adult patients; furthermore, most are focused on the distal radioulnar joint, and thus do not approach the origin of the pathology.When analyzing computed tomography scans with tridimensional reconstruction, a feature of MD, growth arrest of the volar and ulnar portions of the distal radius, is noted, causing the typical distal radius deformity that leads to lack of coverage of the lunate bone. That leads to palmar subluxation of the lunate bone and consequent radiocarpal instability.We herein describe the possibilities of treatment in different stages of evolution, summarizing the authors' view on MD.

Skull osteology of the holotype of the rhynchosaur Hyperodapedon sanjuanensis (Sill, 1970) from the Upper Triassic Ischigualasto Formation of Argentina.

Rhynchosaurs are bulky quadrupedal herbivores that achieved a cosmopolitan distribution during the Middle and Late Triassic. Rhynchosaurids are characterized by a pair of premaxillae modified into an edentulous beak that had a bone-to-bone occlusion with the tips of the dentaries, and a specialized masticatory apparatus composed of groove(s) on the maxilla and ridges(s) on the dentary. The Argentinian fossil record of rhynchosaurs is abundant, but only two nominal species have been named so far. One of them, the hyperodapedontine Hyperodapedon sanjuanensis, is the most abundant tetrapod of the Ischigualasto Formation of northwestern Argentina. However, the anatomy of H. sanjuanensis remains poorly studied. The repreparation and computed tomographic (CT) scanning of its holotypic skull (MACN-Pv 18185) allowed a detailed description of its anatomy. Among the novel anatomical data presented here, we provide the first tridimensional complete reconstruction of a rhynchosaurid palate. This structure is extremely complex in comparison to the plesiomorphic archosauromorph condition, and more data on other rhynchosaurid palates are needed to shed light on the sequence of character states acquisition that resulted in this peculiar anatomy. The presence of a pair of septomaxillae in H. sanjuanensis is the first report of these bones in a rhynchosaurid, and this new information allowed to identify septomaxillae also in the hyperodapedontines Teyumbaita sulcognathus and Hyperodapedon mariensis. The better understanding of the skull anatomy of the holotype of H. sanjuanensis is a first step towards an improved knowledge of the morphology and taxonomy of the South American rhynchosaurs.

3D skull modelling and description of a new baurusuchid (Crocodyliformes, Mesoeucrocodylia) from the Late Cretaceous (Bauru Basin) of Brazil.

Baurusuchidae is one of the most diverse groups of South American notosuchians, unambiguously recorded in Late Cretaceous deposits of Brazil and Argentina. The group is characterized by a reduced tooth formula, a lateromedially compressed rostrum, and a verticalized quadrate, representing one of the top predators of their faunas. Historically, skull morphology is the most employed tool to investigate the relationships of baurusuchids, as most of the species have been primarily based on cranial remains. The present study describes a new baurusuchid species from the Bauru Basin of Brazil, based on the first tridimensional digital reconstruction of individualized skull bones for Notosuchia, and discusses its phylogenetic position within the group. The new species differs from all the other known baurusuchids by a depression on the posterior portion of the nasal bearing a crest, an infraorbital crest of the jugal that extends until the anterior margin of the lacrimal, the dorsal surface of the frontal lacking a longitudinal crest or depression, and the lateral convexity of the squamosal prongs participating in the occipital wall. The new taxon is consistently positioned as sister to the remaining baurusuchines, with Aplestosuchus sordidus and Stratiotosuchus maxhechti, as successive sister-taxa to a monophyletic Baurusuchus (Ba. albertoi, Ba. Salgadoensis, and Ba. pachecoi). Our updated phylogenetic analysis helps to differentiate the two major Baurusuchidae lineages, Baurusuchinae and Pissarrachampsinae. Yet, the new species shares morphological features with both groups, suggesting the occurrence of "Zones of Variability" in the radiation of Baurusuchidae.

Seizure-Induced Acute Glial Activation in the in vitro Isolated Guinea Pig Brain.

Introduction: It has been proposed that seizures induce IL-1β biosynthesis in astrocytes and increase blood brain barrier (BBB) permeability, even without the presence of blood borne inflammatory molecules and leukocytes. In the present study we investigate if seizures induce morphological changes typically observed in activated glial cells. Moreover, we will test if serum albumin extravasation into the brain parenchyma exacerbates neuronal hyperexcitability by inducing astrocytic and microglial activation.Methods: Epileptiform seizure-like events (SLEs) were induced in limbic regions by arterial perfusion of bicuculline methiodide (BMI; 50 μM) in the in vitro isolated guinea pig brain preparation. Field potentials were recorded in both the hippocampal CA1 region and the medial entorhinal cortex. BBB permeability changes were assessed by analyzing extravasation of arterially perfused fluorescein isothiocyanate (FITC)–albumin. Morphological changes in astrocytes and microglia were evaluated with tridimensional reconstruction and Sholl analysis in the ventral CA1 area of the hippocampus following application of BMI with or without co-perfusion of human serum albumin.Results: BMI-induced SLE promoted morphological changes of both astrocytes and microglia cells into an activated phenotype, confirmed by the quantification of the number and length of their processes. Human-recombinant albumin extravasation, due to SLE-induced BBB impairment, worsened both SLE duration and the activated glia phenotype.Discussion: Our study provides the first direct evidence that SLE activity per se is able to promote the activation of astro- and microglial cells, as observed by their changes in phenotype, in brain regions involved in seizure generation; we also hypothesize that gliosis, significantly intensified by h-recombinant albumin extravasation from the bloodstream to the brain parenchyma due to SLE-induced BBB disruption, is responsible for seizure activity reinforcement.

A Rare Case of a Radicular Dens Invaginatus Associated with an Inflammatory Periapical Cyst

Radicular Dens Invaginatus (RDI) represent a rare form of dens invaginatus which develops in the root of the tooth after the crown development is completed that can sometimes cause complex pathological conditions that are difficult to diagnose. This case report describes a case of a RDI associated with an inflammatory periapical cyst. A 17-year-old female complained of mobility in tooth 22. The tooth showed gyroversion and colour change and no evidence of caries or root fracture. Axial slices and tridimensional reconstruction of the cone-beam computed tomography revealed the presence of a RDI on the distal surface of the root that extended from cervical to the apical third. The diagnostic hypothesis was symptomatic infectious apical periodontitis, and conventional root canal treatment was performed. Subsequently, it was opted for a complementary surgical approach, which involved an aspiration puncture bulletin with a collection of yellow-citrus liquid, periapical curettage, apicectomy, retro-preparation and retrofilling with Mineral Trioxide Aggregate (MTA). Histopathological examination revealed was inflammatory periapical cyst. After 3-years, repair of the area was evident. Surgical management of this rare condition can be favourable for resolving endodontic infection related to this dental anomoly.

Comparison of diagnostic accuracy of computed tomography virtual endoscopy and flexible fibre-optic laryngoscopy in the evaluation of neck anatomic structures and neoplasms

Computed tomography virtual endoscopy (CT-VE) is a non-invasive technique which allows visualisation of intraluminal surfaces by tridimensional reconstruction of air/soft tissues. The aim of this study was to compare the diagnostic accuracy of CT-VE and flexible fibre-optic laryngoscopy (FFL) in identifying normal neck anatomic structures and pharyngeal and laryngeal lesions. Forty-two patients with a history of neck cancer were assessed by two ENT surgeons using FFL and by one neuroradiologist using CT-VE in order to evaluate the visualisation of the epiglottis, vallecula, glossoepiglottic folds, pyriform sinuses, vocal cords and mass pathology. The visualisation of the structures in both modalities was assessed according to the following score: 0 = not visualised, 1 = partial visualisation, 2 = complete and clear visualisation. A weighted kappa coefficient was used to evaluate the inter-observer agreement. McNemar's test was performed to compare the two diagnostic tests. The inter-observer agreement between FFL and CT-VE was fair in the assessment of the vocal cords (k = 0.341); moderate in the assessment of the glossoepiglottic folds (k = 0.418), epiglottis (k = 0.513) and pyriform sinuses (k = 0.477); and substantial in the assessment of the vallecula (k = 0.618) and the tumour (0.740). McNemar's test showed no significant difference between the two tests (p<0.05). CT-VE is a non-invasive technique with a diagnostic accuracy comparable to FFL in terms of visualisation of anatomical structures and pharyngeal and laryngeal lesions.

Genetic algorithms and bundle adjustment for the enhancement of 3D reconstruction

In this paper, we present a new technique of tridimensional reconstruction from a sequence of uncalibrated stereo images taken with cameras having varying parameters. At first, our system allows to recover initial coordinates of a set of 3D points. In this context, we have used our method of self-calibration based on the use of unknown 3D scene with its image projections and genetic algorithms to estimate all intrinsic parameters. After that extrinsic parameters are estimated based on classical pose estimation algorithms. Matching points and estimated value of intrinsic and extrinsic parameters are used to estimate initial 3D model that helps us in the initialization step. In order to have a reliable and relevant 3D reconstruction the proposed method is based on good and new exploitation of bundle adjustment (without camera poses initialization) technique based on Levenberg-Marquardt optimization with the aim to estimate our optimal 3D model that has special features compared to the classical case because it masks the pose parameters estimation in the optimization process. Finally, 3D mesh of the 3D scene is constructed with Delaunay algorithm and the 2D image is projected on the 3D model to generate the texture mapping. Experiments is conducted on real data to achieve demonstrate the validity and the performance of the proposed approach in terms of convergence, simplicity, stability and reconstruction quality.

Development and Evaluation of Pediatric Mixed-Reality Model for Neuroendoscopic Surgical Training

Neurosurgical training requires several years of supervised procedures and represents a long and challenging process. The development of surgical simulation platforms is essential to reducing the risk of potentially intraoperative severe errors arising from inexperience. To present and perform a phase I validation process of a mixed reality simulation (realistic and virtual simulators combined) for neuroendoscopic surgical training. Tridimensional videos were developed by the 3DS Max program. Physical simulators were made with a synthetic thermoretractile and thermosensible rubber, which, when combined with different polymers, produces >30 different textures that simulate consistencies and mechanical resistance of human tissues. Questionnaires regarding the role of virtual and realistic simulators were applied to experienced neurosurgeons to assess the applicability of the mixed-reality simulation for neuroendoscopic surgical training. The model was considered as a potential tool for training new residents in neuroendoscopic surgery. It was also adequate for practical application with inexperienced surgeons. According to the overall score, 83% of the surgeons believed that the realistic physical simulator presents distortions when compared with the real anatomic structure, afterwards the model improved 66% tridimensional reconstruction and 66% reported that the virtual simulator allowed a multiangular perspective ability. This model provides a highly effective way of working with 3-dimensional data and significantly enhances the learning of surgical anatomy and operative strategies. The combination of virtual and realistic tools may safely improve and abbreviate the surgical learning curve.

Le Terme di Nerone a Pisa : un grande complesso pubblico al confine tra città e suburbio

The archaeological investigations conducted by the Dipartimento di Civilta e Forme del Sapere (Universty of Pisa) during 2017 at the so-called ‘Baths of Nero’ in Pisa have provided a great opportunity to draw the attention of the scientific community to one of the most relevant ancient monuments of the city. This building complex, already known from Medieval times, raises several questions for investigation, which the new study has partly contributed to resolve. These large public baths, which during the Roman period overlooked the later disappeared river Auser, stand between the dense urban tissue and the suburban area which hosted many production activities; the thermae answered to the needs of both areas, which were highly populated. The tridimensional reconstruction of the structures and landscape and the use of the most modern technologies for a virtual tour (immersive VR) now offer the return to the public of a building of crucial importance in Roman Pisa.

Applications Of The Methods Of Image Diagnosis In Obstructive Sleepapnea

Modern methods of imaging diagnosis play more and more important role in severe sleep breathing disorders and of obstructive sleep apnea (OSA) itself. They could be classified in three main groups: x-ray, computed tomography (CT) and magnetic resonance imaging (MRI) diagnosis. In dental medicine, the following x-ray methods are most commonly used: intraoral x-ray examinations of the teeth, jaws and temporomandibular joints as well as cephalometry. Tri-dimensional and conventional panoramic tomography, dynamic tridimensional CT, multislice CT, cone-beam CT, volumetric tridimensional CT reconstruction and electric impendance tomography are more and more widely applied. The MRI is accomplished by a variety of refinements such as cine magnetic, dynamic, diffusion torsional, functional, etc. as well as in combination with CT and positron emission tomography.

Tutorial: Dealing with rotation matrices and translation vectors in image-based applications: A common reference system for cameras

This tutorial follows and completes a previous work concerning how to solve the factors of ambiguity intrinsic in the definition of rotation matrices, to describe the relative orientation of one or more cameras acquiring images from different points of view. The two works, jointly, aim to provide an error-avoiding methodology to describe the whole relative acquisition geometry (pose). This is a crucial task for those aerospace applications based on the use of imaging devices, like flying objects detection and tracking, automatic guidance, tridimensional reconstruction, images georegistration, and change detection. To describe the pose, not only the orientation but also the relative shift should be taken into account. This can be conveniently modeled through a translation vector. Using it together with a rotation matrix it is possible to achieve the goal, but it is also prone to ambiguity. In this contribution, the main factors that result in such ambiguity are addressed. Through a detailed analysis, it is shown how to solve them, in order to manage the interaction between translation vectors and rotation matrices properly. This avoids the errors that frequently occur in practical applications, whenever it is required to find the transformation that makes the reference system of a camera coincident with the reference system of another, or to switch from the expression of the coordinates of a point of the scene in the reference system of a camera to its expression in the reference system of another. One of the reasons why errors are likely to be made in describing the pose is the lack of a commonly adopted choice for the camera reference system. To obviate this lack, the manuscript also presents a recommended definition for it. For the sake of completeness, the definition includes a second reference system for identifying points on the camera sensor plane, in order to permit describing also the projective transformation operated by the camera during the image formation process.

Tutorial: Dealing with rotation matrices and translation vectors in image-based applications: A tutorial

Rotation matrices are a convenient and intuitive way to describe algebraically the relative orientation of multiple cameras or of the same camera shooting from different points of view. However, the definition of a rotation matrix is prone to intrinsic ambiguity, which often leads to a mismatch with the physical rotation one wants to describe, even if the definition is mathematically correct. This is a common source of errors whenever it is required to compute a rotation matrix from camera orientation data, or vice versa, to recover such data from a given rotation matrix. This tutorial aims to describe and solve the main factors that generate the ambiguity in using rotation matrices and to permit dealing with them properly both in theory and in practice. Through a detailed analysis of these factors, which ranges from basic mathematical aspects to the notation used to refer to them, it is shown how to avoid errors in the algebraic description of the relative orientation of different cameras by means of rotation matrices. This work is followed by another contribution, in which the interaction between rotation matrices and translation vectors (used to describe the shifts between pairs of cameras) is also analyzed, and a recommendation on how to define a common reference system coherent with a camera (a crucial aspect to model the camera acquisition geometry) is given. The two contributions jointly embrace the entire description of the relative acquisition geometry of images taken from different points of view and provide a complete and error-free methodology to recover it or to extract useful data from it. This topic is particularly important in a wide variety of aerospace applications, which often rely on multiple imaging sensors whose information should be merged, or on imaging devices carried by manned or unmanned vehicles. Such applications range from flying object detection to tridimensional reconstruction by using aerial or satellite images to drone automatic navigation, to change detection for area monitoring to georegistration by ground-to-aerial image matching.

REVERSE ENGINEERING USING PHOTOGRAMMETRY AND SEGMENTATION FOR INDUSTRIAL STRUCTURES

This paper presents an interdisciplinary approach to achieve a new working method for the three-dimensional modeling of buildings and structures. Using conventional digital cameras, the main achievement is the reduction of costs and time involved in the process of gathering information, keeping the dimensional accuracy. The results of this methodology are precise 3D models that are valid for reverse drawing documentation, structural assessment and retrofitting of existing buildings. Keywords: photogrammetry, tridimensional reconstruction, 3d modeling, structures, segmentation

PC378: Tridimensional reconstruction of the bone and soft tissue in challenging cases of the esthetic zone

PC378: Tridimensional reconstruction of the bone and soft tissue in challenging cases of the esthetic zone