Generation of Three-Dimensional (3D) Surface Models of Baleen Whale Skulls (Cetacea: Mysticeti) for Morphometric Analyses: Possibilities and Limits of Photogrammetry

2014 ◽  
Vol 13 ◽  
pp. 171-171
Author(s):  
Julia M. Fahlke
Author(s):  
Mahbubur R. Meenar ◽  
John A. Sorrentino

Three-dimensional surface modeling has become an important element in the processing and visualization of geographic information. Models are created from a finite sample of data points over the relevant area. The techniques used for these activities can be broadly divided into raster-based interpolation methods and vector-based triangulation methods. This chapter contains a discussion of the benefits and costs of each set of methods. The functions available using 3D surface models include elevation, queries, contours, slope and aspect, hillshade, and viewshed. Applications include modeling elevation, pollution concentration and run-off and erosion potential. The chapter ends with a brief discussion of future trends, and concludes that the choice among the methods depends on the nature of the input data and the goals of the analyst.


2019 ◽  
Vol 3 (6) ◽  
Author(s):  
Francisco Hita-Garcia ◽  
Ziv Lieberman ◽  
Tracy L Audisio ◽  
Cong Liu ◽  
Evan P Economo

Abstract Discothyrea Roger, 1863 is a small genus of proceratiine ants with remarkable morphology and biology. However, due to cryptic lifestyle, Discothyrea are poorly represented in museum collections and their taxonomy has been severely neglected. We perform the first comprehensive revision of Discothyrea in the Afrotropical region through a combination of traditional and three-dimensional (3D) cybertaxonomy based on microtomography (micro-CT). Species diagnostics and morphological character evaluations are based on examinations of all physical specimens and virtual analyses of 3D surface models generated from micro-CT data. Additionally, we applied virtual dissections for detailed examinations of cephalic structures to establish terminology based on homology for the first time in Discothyrea. The complete datasets comprising micro-CT data, 3D surface models and videos, still images of volume renderings, and colored stacked images are available online as cybertype datasets (Hita Garcia et al. 2019, http://doi.org/10.5061/dryad.3qm4183). We define two species complexes (D. oculata and D. traegaordhi complexes) and revise the taxonomy of all species through detailed illustrated diagnostic character plates, a newly developed identification key, species descriptions, and distribution maps. In total, we recognize 20 species; of which, 15 are described as new. We also propose D. hewitti Arnold, 1916 as junior synonym of D. traegaordhi Santschi, 1914 and D. sculptior Santschi, 1913 as junior synonym of D. oculata Emery, 1901. Also, we designate a neotype for D. traegaordhi to stabilize its status and identity, and we designate a lectotype for D. oculata. The observed diversity and endemism are discussed within the context of Afrotropical biogeography and the oophagous lifestyle.


Author(s):  
David G. Alciatore

Abstract This paper describes a process which is used to generate three-dimensional computer graphics surface models of gross anatomical structures. Key steps in the generation of these models include acquiring 2D cross-sectional data from macrocryotome slicing, generating 2D cross section contours from edge detection and region segmentation, generating a polygonal mesh surface model by triangulating between the 2D contours, and interactive sculpting of the 3D surface for editing and changing the appearance of the model. The algorithms and development involved with these steps are briefly described here and several images resulting from the process are presented. The main purpose of the paper is not to present the details of implementation of the various algorithms, but rather to present the overall methodology and illustrate the results. Implementation details can be found in other papers referenced here. The most recent results of our efforts, which are presented here, are 3D surface models of the complete human thorax. These models have numerous applications in anatomy and biomechanics visualization and teaching.


2021 ◽  
Author(s):  
Ellen J Coombs ◽  
Ryan N Felice

Three-dimensional measurements of morphology are key to gaining an understanding of a species' biology and to answering subsequent questions regarding the processes of ecology (or palaeoecology), function, and evolution. However, the collection of morphometric data is often focused on methods designed to produce data on bilaterally symmetric morphologies which may mischaracterise asymmetric structures. Using 3D landmark and curve data on 3D surface meshes of specimens, we present a method for first quantifying the level of asymmetry in a specimen and second, accurately capturing the morphology of asymmetric specimens for further geometric analyses. We provide an example of the process from initial landmark placement, including details on how to place landmarks to quantify the level of asymmetry, and then on how to use this information to accurately capture the morphology of asymmetric morphologies or structures. We use toothed whales (odontocetes) as a case study and include examples of the consequences of mirroring landmarks and curves, a method commonly used in bilaterally symmetrical specimens, on asymmetric specimens. We conclude by presenting a step-by-step method to collecting 3D landmark data on asymmetric specimens. Additionally, we provide code for placing landmarks and curves on asymmetric specimens in a manner designed to both save time and ultimately accurately quantify morphology. This method can be used as a first crucial step in morphometric analyses of any biological specimens by assessing levels of asymmetry and then if required, accurately quantifying this asymmetry. The latter not only saves the researcher time, but also accurately represents the morphology of asymmetric structures.


Machines ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 13
Author(s):  
Yuhang Yang ◽  
Zhiqiao Dong ◽  
Yuquan Meng ◽  
Chenhui Shao

High-fidelity characterization and effective monitoring of spatial and spatiotemporal processes are crucial for high-performance quality control of many manufacturing processes and systems in the era of smart manufacturing. Although the recent development in measurement technologies has made it possible to acquire high-resolution three-dimensional (3D) surface measurement data, it is generally expensive and time-consuming to use such technologies in real-world production settings. Data-driven approaches that stem from statistics and machine learning can potentially enable intelligent, cost-effective surface measurement and thus allow manufacturers to use high-resolution surface data for better decision-making without introducing substantial production cost induced by data acquisition. Among these methods, spatial and spatiotemporal interpolation techniques can draw inferences about unmeasured locations on a surface using the measurement of other locations, thus decreasing the measurement cost and time. However, interpolation methods are very sensitive to the availability of measurement data, and their performances largely depend on the measurement scheme or the sampling design, i.e., how to allocate measurement efforts. As such, sampling design is considered to be another important field that enables intelligent surface measurement. This paper reviews and summarizes the state-of-the-art research in interpolation and sampling design for surface measurement in varied manufacturing applications. Research gaps and future research directions are also identified and can serve as a fundamental guideline to industrial practitioners and researchers for future studies in these areas.


2021 ◽  
Vol 9 (4) ◽  
pp. 325-337
Author(s):  
Robert Z. Selden ◽  
Lauren N. Butaric ◽  
Kersten Bergstrom ◽  
Dennis Van Gerven

ABSTRACTThe production of three-dimensional (3D) digital meshes of surface and computed tomographic (CT) data has become widespread in morphometric analyses of anthropological and archaeological data. Given that processing methods are not standardized, this leaves questions regarding the comparability of processed and digitally curated 3D datasets. The goal of this study was to identify those processing parameters that result in the most consistent fit between CT-derived meshes and a 3D surface model of the same human mandible. Eight meshes, each using unique thresholding and smoothing parameters, were compared to assess whole-object deviations, deviations along curves, and deviations between specific anatomical features on the surface model when compared with the CT scans using a suite of comparison points. Based on calculated gap distances, the mesh that thresholded at “0” with an applied smoothing technique was found to deviate least from the surface model, although it is not the most biologically accurate. Results have implications for aggregated studies that employ multimodal 3D datasets, and caution is recommended for studies that enlist 3D data from websites and digital repositories, particularly if processing parameters are unknown or derived for studies with different research foci.


2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
F. G. Mangano ◽  
F. Luongo ◽  
G. Picciocchi ◽  
C. Mortellaro ◽  
K. B. Park ◽  
...  

Purpose. To evaluate the soft tissue stability around single implants inserted to replace maxillary lateral incisors, using an innovative 3D method.Methods. We have used reverse-engineering software for the superimposition of 3D surface models of the dentogingival structures, obtained from intraoral scans of the same patients taken at the delivery of the final crown (S1) and 2 years later (S2). The assessment of soft tissues changes was performed via calculation of the Euclidean surface distances between the 3D models, after the superimposition of S2 on S1; colour maps were used for quantification of changes.Results. Twenty patients (8 males, 12 females) were selected, 10 with a failing/nonrestorable lateral incisor (testgroup: immediate placement in postextraction socket) and 10 with a missing lateral incisor (controlgroup: conventional placement in healed ridge). Each patient received one immediately loaded implant (Anyridge®, Megagen, Gyeongbuk, South Korea). The superimposition of the 3D surface models taken at different times (S2 over S1) revealed a mean (±SD) reduction of 0.057 mm (±0.025) and 0.037 mm (±0.020) fortestandcontrolpatients, respectively. This difference was not statistically significant (p= 0.069).Conclusions. The superimposition of the 3D surface models revealed an excellent peri-implant soft tissue stability in both groups of patients, with minimal changes registered along time.


Author(s):  
K. Davydova ◽  
G. Kuschk ◽  
L. Hoegner ◽  
P. Reinartz ◽  
U. Stilla

Texture mapping techniques are used to achieve a high degree of realism for computer generated large-scale and detailed 3D surface models by extracting the texture information from photographic images and applying it to the object surfaces. Due to the fact that a single image cannot capture all parts of the scene, a number of images should be taken. However, texturing the object surfaces from several images can lead to lighting variations between the neighboring texture fragments. In this paper we describe the creation of a textured 3D scene from overlapping aerial images using a Markov Random Field energy minimization framework. We aim to maximize the quality of the generated texture mosaic, preserving the resolution from the original images, and at the same time to minimize the seam visibilities between adjacent fragments. As input data we use a triangulated mesh of the city center of Munich and multiple camera views of the scene from different directions.


Author(s):  
Michael Alfertshofer ◽  
Konstantin Frank ◽  
Dmitry V. Melnikov ◽  
Nicholas Möllhoff ◽  
Robert H. Gotkin ◽  
...  

AbstractFacial flap surgery depends strongly on thorough preoperative planning and precise surgical performance. To increase the dimensional accuracy of transferred facial flaps, the methods of ultrasound and three-dimensional (3D) surface scanning offer great possibilities. This study aimed to compare different methods of measuring distances in the facial region and where they can be used reliably. The study population consisted of 20 volunteers (10 males and 10 females) with a mean age of 26.7 ± 7.2 years and a mean body mass index of 22.6 ± 2.2 kg/m2. Adhesives with a standardized length of 20 mm were measured in various facial regions through ultrasound and 3D surface scans, and the results were compared. Regardless of the facial region, the mean length measured through ultrasound was 18.83 mm, whereas it was 19.89 mm for 3D surface scans, with both p < 0.0001. Thus, the mean difference was 1.17 mm for ultrasound measurements and 0.11 mm for 3D surface scans. Curved facial regions show a great complexity when it comes to measuring distances due to the concavity and convexity of the face. Distance measurements through 3D surface scanning showed more accurate distances than the ultrasound measurement. Especially in “complex” facial regions (e.g., glabella region and labiomental sulcus), the 3D surface scanning showed clear advantages.


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