RESUMO
The analysis of the stability of human gait may be effectively performed when estimates of the base of support are available. The base of support area is defined by the relative position of the feet when they are in contact with the ground and it is closely related to additional parameters such as step length and stride width. These parameters may be determined in the laboratory using either a stereophotogrammetric system or an instrumented mat. Unfortunately, their estimation in the real world is still an unaccomplished goal. This study aims at proposing a novel, compact wearable system, including a magneto-inertial measurement unit and two time-of-flight proximity sensors, suitable for the estimation of the base of support parameters. The wearable system was tested and validated on thirteen healthy adults walking at three self-selected speeds (slow, comfortable, and fast). Results were compared with the concurrent stereophotogrammetric data, used as the gold standard. The root mean square errors for the step length, stride width and base of support area varied from slow to high speed between 10-46 mm, 14-18 mm, and 39-52 cm2, respectively. The mean overlap of the base of support area as obtained with the wearable system and with the stereophotogrammetric system ranged between 70% and 89%. Thus, this study suggested that the proposed wearable solution is a valid tool for the estimation of the base of support parameters out of the laboratory.
Assuntos
Caminhada , Dispositivos Eletrônicos Vestíveis , Adulto , Humanos , Marcha , Pé , FotogrametriaRESUMO
PURPOSE: The purpose of this study was to perform an in vitro evaluation of digital impressions using a mobile device and monoscopic photogrammetry in cases of orbital defects with undercuts. METHODS: Three 10-mm-square cubes were attached to a diagnostic cast of a patient with a right orbital defect. Still images acquired with a mobile device were used to generate facial three-dimensional (3D) data. Two types of still images were used: one was a whole face image, and the other was a defect site-focused image. For comparison, an extraoral scanner was used to obtain facial 3D data. Five dental technicians fabricated 3D printed models using additive manufacturing and measured the distances between the measurement points using a digital caliper. The discrepancy between the distances measured on the diagnostic cast of the patient and the 3D printed model was calculated. Friedman test was used to analyze the discrepancy, and the Bonferroni test was used to verify the differences between the pairs. RESULTS: Statistical significance was found with respect to the type of 3D model fabrication method. CONCLUSION: Within the limitations of this in vitro study, the results suggested that the workflow can be applied to digital impressions of the maxillofacial region.
Assuntos
Computadores de Mão , Imageamento Tridimensional , Humanos , Imageamento Tridimensional/métodos , Fotogrametria/métodosRESUMO
BACKGROUND: Immersive anatomic environments offer an alternative when anatomic laboratory access is limited, but current three-dimensional (3D) renderings are not able to simulate the anatomic detail and surgical perspectives needed for microsurgical education. OBJECTIVE: To perform a proof-of-concept study of a novel photogrammetry 3D reconstruction technique, converting high-definition (monoscopic) microsurgical images into a navigable, interactive, immersive anatomy simulation. METHODS: Images were acquired from cadaveric dissections and from an open-access comprehensive online microsurgical anatomic image database. A pretrained neural network capable of depth estimation from a single image was used to create depth maps (pixelated images containing distance information that could be used for spatial reprojection and 3D rendering). Virtual reality (VR) experience was assessed using a VR headset, and augmented reality was assessed using a quick response code-based application and a tablet camera. RESULTS: Significant correlation was found between processed image depth estimations and neuronavigation-defined coordinates at different levels of magnification. Immersive anatomic models were created from dissection images captured in the authors' laboratory and from images retrieved from the Rhoton Collection. Interactive visualization and magnification allowed multiple perspectives for an enhanced experience in VR. The quick response code offered a convenient method for importing anatomic models into the real world for rehearsal and for comparing other anatomic preparations side by side. CONCLUSION: This proof-of-concept study validated the use of machine learning to render 3D reconstructions from 2-dimensional microsurgical images through depth estimation. This spatial information can be used to develop convenient, realistic, and immersive anatomy image models.
Assuntos
Realidade Virtual , Humanos , Simulação por Computador , Dissecação , Fotogrametria , Aprendizado de MáquinaAssuntos
Fotogrametria , Smartphone , Humanos , Queixo , Tomografia Computadorizada por Raios X , TomografiaRESUMO
Advances in the scientific fields of photogrammetry and computer vision have led to the development of automated multi-image methods that solve the problem of 3D reconstruction. Simultaneously, 3D scanners have become a common source of data acquisition for 3D modeling of real objects/scenes/human bodies. This article presents a comprehensive overview of different 3D modeling technologies that may be used to generate 3D reconstructions of outer or inner surfaces of different kinds of targets. In this context, it covers the topics of 3D modeling using images via different methods, it provides a detailed classification of 3D scanners by additionally presenting the basic operating principles of each type of scanner, and it discusses the problem of generating 3D models from scans. Finally, it outlines some applications of 3D modeling, beyond well-established topographic ones.
Assuntos
Imageamento Tridimensional , Fotogrametria , Humanos , Imageamento Tridimensional/métodos , Fotogrametria/métodosRESUMO
Recently, the term smartphone photogrammetry gained popularity. This suggests that photogrammetry may become a simple measurement tool by virtually every smartphone user. The research was undertaken to clarify whether it is appropriate to use the Structure from Motion-Multi Stereo View (SfM-MVS) procedure with self-calibration as it is done in Uncrewed Aerial Vehicle photogrammetry. First, the geometric stability of smartphone cameras was tested. Fourteen smartphones were calibrated on the checkerboard test field. The process was repeated multiple times. These observations were found: (1) most smartphone cameras have lower stability of the internal orientation parameters than a Digital Single-Lens Reflex (DSLR) camera, and (2) the principal distance and position of the principal point are constantly changing. Then, based on images from two selected smartphones, 3D models of a small sculpture were developed. The SfM-MVS method was used, with self-calibration and pre-calibration variants. By comparing the resultant models with the reference DSLR-created model it was shown that introducing calibration obtained in the test field instead of self-calibration improves the geometry of 3D models. In particular, deformations of local concavities and convexities decreased. In conclusion, there is real potential in smartphone photogrammetry, but it also has its limits.
Assuntos
Fotogrametria , Smartphone , Fotogrametria/métodos , CalibragemRESUMO
This study aimed to determine the mean values of the nasal anthropometric measurements through 2-dimensional photogrammetry in for rhinoplasty patients. The study group included 72 healthy individuals, 36 men, and 36 women. The patients were aged 18 to 42 years. All patients had undergone primary rhinoplasty in our clinic between 2013 and 2020. Seven landmarks were identified from the preoperative photographs taken with the patient's head in neutral position in the frontal and lateral planes. Five distances (total nasal length, nasal bridge length, morphological nose width, alar length, and nasal tip protrusion) and 2 angles (nasofrontal and nasolabial) measurements were calculated. We noted a statistically significant difference between the male and female sexes in terms of total nasal length and morphological nose width (P<0.05). The results were compared with the nasal anthropometric measurements reported in the literature for the Turkish population as well as other ethnic groups. We believe results of this study may facilitate preoperative planning in Turkish patients who request rhinoplasty and improve the success rate of the surgery.
Assuntos
Rinoplastia , Humanos , Feminino , Masculino , Rinoplastia/métodos , Nariz/cirurgia , Nariz/anatomia & histologia , Antropometria/métodos , Fotogrametria , EtnicidadeRESUMO
BACKGROUND: The most accurate methods for assessing fat grafted volume, such as computed tomography (CT) scan and magnetic resonance imaging, use 3-dimensional (3D) evaluation of the recipient area. Currently, other measurement techniques such as photogrammetry (compilation of photos) are employed. OBJECTIVES: The aim of the present study was to compare 3D images obtained by CT scan with those obtained by photogrammetry in patients undergoing autogenous fat grafting to the chin. METHODS: A prospective longitudinal study was undertaken to assess patients undergoing autologous fat grafting to the chin, capturing preoperative and postoperative (6 months) images with CT scan and photogrammetry. Captured images were submitted to 3D reconstruction with Blender image software. RESULTS: A total of 40 patients were submitted to surgery. Seventy-five percent were female. Median age and BMI were 26.5 years and 23.6 kg/m2, respectively. Median volume of fat grafted was 10 mL (interquartile range 8-12.25 mL). Results showed that the median preoperative volume measured by CT scan was larger than the photogrammetry measurement (12.48 mL vs 12.01 mL, respectively, P < .001). Likewise, a larger volume was measured by CT scan than by photogrammetry (15.54 mL vs 14.94 mL respectively, P < .001) 6 months postoperatively. However, there was no difference between CT scan and photogrammetry measurements of the change in volume from preoperatively to postoperatively (P = .89). CONCLUSIONS: There was no agreement between fat graft volume measurements obtained by 3D photogrammetry and CT scan techniques with regard to absolute values of fat graft volume measurements, however no difference was found between the 2 methods when comparing preoperative with postoperative fat graft volume variation.
Assuntos
Fotogrametria , Smartphone , Humanos , Feminino , Masculino , Queixo , Estudos Prospectivos , Estudos Longitudinais , Fotogrametria/métodos , Tomografia Computadorizada por Raios X , Imageamento TridimensionalRESUMO
BACKGROUND: The development of intraoral scanning technology has effectively enhanced the digital documentation of orthodontic dental casts. Albeit, the expense of this technology is the main limitation. The purpose of the present study was to assess the validity and reliability of virtual three-dimensional (3D) models of orthodontic dental casts, which were constructed using smartphone-based 3D photogrammetry. METHODS: A smartphone was used to capture a set of two-dimensional images for 30 orthodontic dental casts. The captured images were processed to construct 3D virtual images using Agisoft and 3DF Zephyr software programs. To evaluate the accuracy of the virtual 3D models obtained by the two software programs, the virtual 3D models were compared with cone-beam computed tomography scans of the 30 dental casts. Colored maps were used to express the absolute distances between the points of each compared two surfaces; then, the means of the 100%, 95th, and 90th of the absolute distances were calculated. A Wilcoxon signed-rank test was applied to detect any significant differences. RESULTS: The differences between the constructed 3D images and the cone-beam computed tomography scans were not statistically significant and were accepted clinically. The deviations were mostly in the interproximal areas and in the occlusal details (sharp cusps and deep pits and fissures). CONCLUSIONS: This study found that smartphone-based stereophotogrammetry is an accurate and reliable method for 3D modeling of orthodontic dental casts, with errors less than the accepted clinically detectable error of 0.5 mm. Smartphone photogrammetry succeeded in presenting occlusal details, but it was difficult to accurately reproduce interproximal areas.
Assuntos
Modelos Dentários , Smartphone , Reprodutibilidade dos Testes , Tecnologia , Fotogrametria/métodosRESUMO
Positional plagiocephaly (PP) is the most common skull deformity in infants. Different classification systems exist for graduating the degree of PP, but all of these systems are based on two-dimensional (2D) parameters. This limitation leads to several problems stemming from the fact that 2D parameters are used to classify the three-dimensional (3D) shape of the head. We therefore evaluate existing measurement parameters and validate a newly developed 3D parameter for quantifying PP. Additionally, we present a new classification of PP based on a 3D parameter. 210 patients with PP and 50 patients without PP were included in this study. Existing parameters (2D and 3D) and newly developed volume parameters based on a 3D stereophotogrammetry scan were validated using ROC curves. Additionally, thresholds for the new 3D parameter of a 3D asymmetry index were assessed. The volume parameter 3D asymmetry index quantifies PP equally as well as the gold standard of 30° diagonal difference. Moreover, a 3D asymmetry index allows for a 3D-based classification of PP. The 3D asymmetry index can be used to define the degree of PP. It is easily applicable in stereophotogrammetric datasets and allows for comparability both intra- and inter-individually as well as for scientific analysis.
Assuntos
Plagiocefalia não Sinostótica , Lactente , Humanos , Plagiocefalia não Sinostótica/diagnóstico por imagem , Fotogrametria , Pâncreas , Curva ROCRESUMO
The precision modelling of intrinsic camera geometry is a common issue in the fields of photogrammetry (PH) and computer vision (CV). However, in both fields, intrinsic camera geometry has been modelled differently, which has led researchers to adopt different definitions of intrinsic camera parameters (ICPs), including focal length, principal point, radial distortion, decentring distortion, affinity and shear. These ICPs are indispensable for vision-based measurements. These differences can confuse researchers from one field when using ICPs obtained from a camera calibration software package developed in another field. This paper clarifies the ICP definitions used in each field and proposes an ICP transformation algorithm. The originality of this study lies in its use of least-squares adjustment, applying the image points involving ICPs defined in PH and CV image frames to convert a complete set of ICPs. This ICP transformation method is more rigorous than the simplified formulas used in conventional methods. Selecting suitable image points can increase the accuracy of the generated adjustment model. In addition, the proposed ICP transformation method enables users to apply mixed software in the fields of PH and CV. To validate the transformation algorithm, two cameras with different view angles were calibrated using typical camera calibration software packages applied in each field to obtain ICPs. Experimental results demonstrate that our proposed transformation algorithm can be used to convert ICPs derived from different software packages. Both the PH-to-CV and CV-to-PH transformation processes were executed using complete mathematical camera models. We also compared the rectified images and distortion plots generated using different ICPs. Furthermore, by comparing our method with the state of art method, we confirm the performance improvement of ICP conversions between PH and CV models.
Assuntos
Algoritmos , Software , Computadores , Simulação por Computador , Fotogrametria/métodosRESUMO
This article concerns the research of the HUBO full-body scanner, which includes the analysis and selection of the scanner's geometrical parameters in order to obtain the highest possible accuracy of the reconstruction of a human figure. In the scanner version analyzed in this paper, smartphone cameras are used as sensors. In order to process the collected photos into a 3D model, the photogrammetry technique is applied. As part of the work, dependencies between the geometrical parameters of the scanner are derived, which allows to significantly reduce the number of degrees of freedom in the selection of its geometrical parameters. Based on these dependencies, a numerical analysis is carried out, as a result of which the initial values of the geometrical parameters are pre-selected and distribution of scanner cameras is visualized. As part of the experimental research, the influence of selected scanner parameters on the scanning accuracy is analyzed. For the experimental research, a specially prepared dummy was used instead of the participation of a real human, which allowed to ensure the constancy of the scanned object. The accuracy of the object reconstruction was assessed in relation to the reference 3D model obtained with a scanner of superior measurement uncertainty. On the basis of the conducted research, a method for the selection of the scanner's geometrical parameters was finally verified, leading to the arrangement of cameras around a human, which guarantees high accuracy of the reconstruction. Additionally, to quantify the results, the quality rates were used, taking into account not only the obtained measurement uncertainty of the scanner, but also the processing time and the resulting efficiency.
Assuntos
Corpo Humano , Imageamento Tridimensional , Humanos , Imageamento Tridimensional/métodos , Fotogrametria/métodosRESUMO
Volume estimation of specific objects via close-range remote sensing is a complex task requiring expensive hardware and/or significant computational burden, often discouraging users potentially interested in the technology. This paper presents an innovative system for cost-effective near real-time volume estimation based on a custom platform equipped with depth and tracking cameras. Its performance has been tested in different application-oriented scenarios and compared against measurements and state-of-the-art photogrammetry. The comparison showed that the developed architecture is able to provide estimates fully comparable with the benchmark, resulting in a quick, reliable and cost-effective solution to the problem of volumetric estimates within the functioning range of the exploited sensors.
Assuntos
Fotogrametria , Tecnologia de Sensoriamento Remoto , Tecnologia de Sensoriamento Remoto/métodosRESUMO
BACKGROUND: Facial mutilation and deformities can be caused by cancer, tumours, injuries, infections, and inherited or acquired deformities and has the potential to degrade one's quality of life by interfering with fundamental tasks like communication, breathing, feeding, and aesthetics. Depending on the type of defect, producing maxillofacial prostheses for the rehabilitation of patients with various defects can be challenging and complex. The prosthesis is used to replace missing or damaged parts of the cranium and face, like the nose, auricle, orbit, and surrounding tissues, as well as missing areas of soft and hard tissue, with the primary goal of increasing the patient's quality of life by rehabilitating oral functions such as speech, swallowing, and mastication. Traditional maxillofacial prosthesis impression and fabrication processes include a number of complicated steps that are costly, time-consuming, and uncomfortable for the patient. These rely on the knowledge of the maxillofacial team, dental clinicians, and maxillofacial technician. The foundation of the impression is the keystone for creating a prosthesis. However, this is the most time-consuming and difficult chair-side operation in maxillofacial prosthesis manufacturing since it requires prolonged interaction with the patient. The field of prosthesis fabrication is being transformed by the digital revolution. Digital technology allows for more accurate impression data to be gathered in less time (3 to 5 min) than traditional methods, lowering patient anxiety. Digital impressions eliminate the need for messy impression materials and provide patients with a more pleasant experience. This method bypasses the procedure of traditional gypsum model fabrication. This eliminates the disparity caused by a dimensional distortion of the impression material and gypsum setting expansion. Traditional dental impression processes leave enough room for errors, such as voids or flaws, air bubbles, or deformities, while current technology for prosthesis planning has emerged as an alternative means to improve patient acceptability and pleasure, not only because the end result is a precisely fitted restoration but also because the chair-side adjustments required are reduced. The most frequent approaches for creating 3D virtual models are the following. To begin, 3D scanning is employed, in which the subjects are scanned in three dimensions, and the point cloud data is used to create a virtual digital model. METHODS: It will be a hospital-based randomised control trial, carried out at the Department of Prosthodontics, Sharad Pawar Dental College, Sawangi (Meghe), Wardha, a part of Datta Meghe Institute of Medical Sciences (Deemed University). A total of 45 patients will be selected from the outpatient department (OPD) of the Department of Prosthodontics. All the patients will be provided written consent before their participation in the study. METHODOLOGY: 1. Patient screening will be done, and the patient will be allocated to three techniques that are the conventional manual method, photogrammetry method, and 3D scanning in a randomised manner 2. The impression of the defect will be recorded by conventional manual method, photogrammetry method, and 3D scanning 3. The defect will be modelled in three ways: first is as per the manual dimension taken on the patient, second is the organisation of photographic image taken with lab standards and third is plotting of point cloud data to generate the virtual 3D model 4. For photogrammetric prosthesis design, finite photos/images will be taken at multiple angles to model the 3D virtual design. With the use of minimum photographs, the 3D modelling can be performed by using freeware, and a mould is obtained 5. The CAD software was used to design the prosthesis, and the final negative mould can be printed using additive manufacturing 6. The mould fabricated by all three methods will be analysed by a software using reverse engineering technology Study design: Randomised control trial Duration: 2 years Sample size: 45 patients DISCUSSION: Rodrigo Salazar-Gamarra1, Rosemary Seelaus, and Jorge Vicente Lopes da Silva et al., in the year 2016, discussed, as part of a method for manufacturing face prostheses utilising a mobile device, free software, and a photo capture protocol, that 2D captures of the anatomy of a patient with a facial defect were converted into a 3D model using monoscopic photogrammetry and a mobile device. The visual and technical integrity of the resulting digital models was assessed. The technological approach and models that resulted were thoroughly explained and evaluated for technical and clinical value. Marta Revilla-León, Wael Att, and Dr Med Dent et al. (2020) used a coordinate measuring equipment which was used to assess the accuracy of complete arch implant impression processes utilising conventional, photogrammetry, and intraoral scanning. Corina Marilena Cristache and Ioana Tudor Liliana Moraru et al. in the year 2021 provided an update on defect data acquisition, editing, and design using open-source and commercially available software in digital workflow in maxillofacial prosthodontics. This research looked at randomised clinical trials, case reports, case series, technical comments, letters to the editor, and reviews involving humans that were written in English and included detailed information on data acquisition, data processing software, and maxillofacial prosthetic part design. TRIAL REGISTRATION: CTRI/2022/08/044524. Registered on September 16, 2022.
Assuntos
Sulfato de Cálcio , Imageamento Tridimensional , Humanos , Imageamento Tridimensional/métodos , Qualidade de Vida , Software , Desenho de Prótese , Fotogrametria/métodosRESUMO
Photogrammetric techniques for weakly-textured surfaces without sufficient information about the R (red), G (green) and B (blue) primary colors of light are challenging. Considering that most urban or indoor object surfaces follow simple geometric shapes, a novel method for reconstructing smooth homogeneous planar surfaces based on MVS (Multi-View Stereo) is proposed. The idea behind it is to extract enough features for the image description, and to refine the dense points generated by the depth values of pixels with plane fitting, to favor the alignment of the surface to the detected planes. The SIFT (Scale Invariant Feature Transform) and AKAZE (Accelerated-KAZE) feature extraction algorithms are combined to ensure robustness and help retrieve connections in small samples. The smoothness of the enclosed watertight Poisson surface can be enhanced by enforcing the 3D points to be projected onto the absolute planes detected by a RANSAC (Random Sample Consensus)-based approach. Experimental evaluations of both cloud-to-mesh comparisons in the per-vertex distances with the ground truth models and visual comparisons with a popular mesh filtering based post-processing method indicate that the proposed method can considerably retain the integrity and smoothness of the reconstruction results. Combined with other primitive fittings, the reconstruction extent of homogeneous surfaces can be further extended, serving as primitive models for 3D building reconstruction, and providing guidance for future works in photogrammetry and 3D surface reconstruction.
Assuntos
Algoritmos , Imageamento Tridimensional , Imageamento Tridimensional/métodos , FotogrametriaRESUMO
Biological and forensic anthropologists face limitations while studying skeletal remains altered by taphonomic alterations and perimortem trauma, such as in remains from the Spanish Civil War. However, virtual anthropology techniques can optimize the information inferred from fragmented and deformed remains by generating and restoring three-dimensional bone models. We applied a low-cost 3D modelling methodology based on photogrammetry to develop novel forensic applications of virtual 3D skull reconstruction, assembly, restoration and ancestry estimation. Crania and mandible fragments from five Spanish Civil War victims were reconstructed with high accuracy, and only one cranium could not be assembled due to extensive bone loss. Virtual mirroring successfully restored reconstructed crania, producing 3D models with reduced deformation and perimortem trauma. High correlation between traditional and virtual craniofacial measurements confirmed that 3D models are suitable for forensic applications. Craniometric databases of world-wide and Spanish populations were used to assess the potential of discriminant analysis to estimate population ancestry. Our protocol correctly estimated the continental origin of 86.7 % of 15 crania of known origin, and despite low morphological differentiation within European populations, correctly identified 54.5 % as Spanish and 27.3 % of them with high posterior probabilities. Two restored crania from the Civil War were estimated as Spanish, and one as a non-Spanish European. Results were not conclusive for one cranium and did not confirm previous archeological hypotheses. Overall, our research shows the potential to assess the presence of foreign volunteers in the Spanish Civil War and highlights the added value of 3D-virtual techniques in forensic anthropology.
Assuntos
Restos Mortais , Antropologia Forense , Humanos , Antropologia Forense/métodos , Crânio/diagnóstico por imagem , Crânio/anatomia & histologia , Cefalometria , FotogrametriaRESUMO
Automated inspection technology based on computer vision is now widely used in the manufacturing industry with high speed and accuracy. However, metal parts always appear in high gloss or shadow on the surface, resulting in the overexposure of the captured images. It is necessary to adjust the light direction and view to keep defects out of overexposure and shadow areas. However, it is too tedious to adjust the position of the light direction and view the variety of parts' geometries. To address this problem, we design a photometric-stereo-based defect detection system (PSBDDS), which combines the photometric stereo with defect detection to eliminate the interference of highlights and shadows. Based on the PSBDDS, we introduce a photometric-stereo-based defect detection framework, which takes images captured in multiple directional lights as input and obtains the normal map through the photometric stereo model. Then, the detection model uses the normal map as input to locate and classify defects. Existing learning-based photometric stereo methods and defect detection methods have achieved good performance in their respective fields. However, photometric stereo datasets and defect detection datasets are not sufficient for training and testing photometric-stereo-based defect detection methods, thus we create a photometric stereo defect detection (PSDD) dataset using our PSBDDS to eliminate gaps between learning-based photometric stereo and defect detection methods. Furthermore, experimental results prove the effectiveness of the proposed PSBBD and PSDD dataset.
Assuntos
Algoritmos , Fotogrametria , Fotogrametria/métodos , FotometriaRESUMO
The creation of accurate three-dimensional models has been radically simplified in recent years by developing photogrammetric methods. However, the photogrammetric procedure requires complex data processing and does not provide an immediate 3D model, so its use during field (in situ) surveys is infeasible. This paper presents the mapping of fragments of built structures at different scales (finest detail, garden sculpture, architectural interior, building facade) by using a LiDAR sensor from the Apple iPad Pro mobile device. The resulting iPad LiDAR and photogrammetric models were compared with reference models derived from laser scanning and point measurements. For small objects with complex geometries acquired by iPad LiDAR, up to 50% of points were unaligned with the reference models, which is much more than for photogrammetric models. This was primarily due to much less frequent sampling and, consequently, a sparser grid. This simplification of object surfaces is highly beneficial in the case of walls and building facades as it smooths out their surfaces. The application potential of the IPad LiDAR Pro is severely constrained by its range cap being 5 m, which greatly limits the size of objects that can be recorded, and excludes most buildings.
Assuntos
Lasers , FotogrametriaRESUMO
Coral growth is an important metric of coral health and underpins reef-scale functional attributes such as structural complexity and calcium carbonate production. There persists, however, a paucity of growth data for most reef-building regions, especially for coral species whose skeletal architecture prevents the use of traditional methods such as coring and Alizarin staining. We used structure-from-motion photogrammetry to quantify a range of colony-scale growth metrics for six coral species in the Mexican Caribbean and present a newly developed workflow to measure colony volume change over time. Our results provide the first growth metrics for two species that are now major space occupiers on Caribbean reefs, Agaricia agaricites and Agaricia tenuifolia. We also document higher linear extension, volume increase and calcification rates within back reef compared to fore reef environments for four other common species: Orbicella faveolata, Porites astreoides, Siderastrea siderea and Pseudodiploria strigosa. Linear extension rates in our study were lower than those obtained via computed tomography (CT) scans of coral cores from the same sites, as the photogrammetry method averages growth in all dimensions, while the CT method depicts growth only along the main growth axis (upwards). The comparison of direct volume change versus potential volume increase calculated from linear extension emphasizes the importance of assessing whole colony growth to improve calcification estimates. The method presented here provides an approach that can generate accurate calcification estimates alongside a range of other whole-colony growth metrics in a non-invasive way.
Assuntos
Antozoários , Animais , Recifes de Corais , Ecossistema , Calcificação Fisiológica , FotogrametriaRESUMO
The aim of the study was to determine the relationship between idiopathic asymmetry in infants and body posture in children at an early school age. The study included 45 girls aged nine. The Diers Formetric III 4D device was used to assess body posture, which allows photogrammetric registration of the back surface using the raster stereography process. For the purposes of the re-search project, the examination was performed via DiCAM using the "Average measurement" mode. Despite physiotherapy, these children had more postural defects later on compared to the control group due to asymmetry. They mainly concerned pelvic skewness, scoliosis angle, deviation from the vertical line and lateral deviation, as well as surface rotation. Positive correlations were observed between direction of asymmetry and pelvic skewness (r = 0.40), and between the location of asymmetry and the location of curvature (r = 0.39). Significant negative correlations were also found between the age of treatment initiation and trunk length (r = -0.42). There was also a negative correlation between the number of physiotherapeutic appointments and deviation from the vertical line, which means that along with an increase in the number of physiotherapeutic visits, the value of deviation from the vertical line decreased (p = -0.40). For scoliosis angle, the most important predictor was the direction of asymmetry (p = 0.05). For the location of the curvature, the most important predictor was the direction of asymmetry (p = 0.04), as well as the number of physiotherapeutic appointments (p = 0.04). Additionally, regression analysis allowed us to show that the number of physiotherapeutic visits (p = 0.03) was the most important predictor of curvature direction. The applied physiotherapy probably contributed to the occurrence of a smaller number of postural defects in these children at a later age. Physiotherapy as a specific and targeted form of physical activity among infants with idiopathic asymmetry should play a very important role in the prevention of body posture defects.
