Preliminary digital data for part of a regional, three-dimensional map of Quaternary sediments; southern Lake Michigan area

1991 ◽  
Author(s):  
David R. Soller
Author(s):  
Susanne Charlotta Åberg ◽  
Annika Katarina Åberg ◽  
Kirsti Korkka-Niemi

AbstractGreater complexity in three-dimensional (3D) model structures yields more plausible groundwater recharge/discharge patterns, especially in groundwater/surface-water interactions. The construction of a 3D hydrostratigraphic model prior to flow modelling is beneficial when the hydraulic conductivity of geological units varies considerably. A workflow for 3D hydrostratigraphic modelling with Leapfrog Geo and flow modelling with MODFLOW-NWT was developed. It was used to evaluate how the modelling results for groundwater flow and recharge/discharge patterns differ when using simple or more complex hydrostratigraphic models. The workflow was applied to a study site consisting of complex Quaternary sediments underlain by fractured and weathered crystalline bedrock. Increasing the hydrostratigraphic detail appeared to improve the fit between the observed and simulated water table, and created more plausible groundwater flow patterns. Interlayered zones of low and high conductivity disperse the recharge/discharge patterns, increasing the vertical flow component. Groundwater flow was predominantly horizontal in models in which Quaternary sediments and bedrock were simplified as one layer per unit. It appears to be important to define the interlayered low-conductivity units, which can limit groundwater infiltration and also affect groundwater discharge patterns. Explicit modelling with Leapfrog Geo was found to be effective but time-consuming in the generation of scattered and thin-layered strata.


2007 ◽  
Vol 44 (3) ◽  
pp. 278-285 ◽  
Author(s):  
Virgilio F. Ferrario ◽  
Fabrizio Mian ◽  
Redento Peretta ◽  
Riccardo Rosati ◽  
Chiarella Sforza

Objective: To compare three-dimensional nasal measurements directly made on subjects to those made on plaster casts, and nasal dimensions obtained with a surface-based approach to values obtained with a landmark representation. Methods: Soft-tissue nasal landmarks were directly digitized on 20 healthy adults. Stone casts of their noses were digitized and mathematically reconstructed using nonuniform rational B-splines (NURBS) curves. Linear distances, angles, volumes and surface areas were computed using facial landmarks and NURBS-reconstructed models (surface-based approach). Results: Measurements on the stone casts were somewhat smaller than values obtained directly from subjects (differences between −0.05 and −1.58 mm). Dahlberg's statistic ranged between 0.73 and 1.47 mm. Significant (p < .05) t values were found for 4 of 15 measurements. The surface-based approach gave values 3.5 (volumes) and 2.1 (surface area) times larger than those computed with the landmark-based method. The two values were significantly related (volume, r = 0.881; surface, r = 0.924; p < .001), the resulting equations estimated actual values well (mean difference, volume −0.01 mm3, SD 1.47, area 0.05 cm2, SD 1.44); limits of agreement between −2.89 and 2.87 mm3 (volume); −2.88 and 2.78 cm2 (area). Conclusions: Considering the characteristics of the two methods, and for practical purposes, nasal distances and angles obtained on plaster models were comparable to digital data obtained directly from subjects. Surface areas and volumes were best obtained using a surface-based approach, but could be estimated using data provided by the landmark representation.


Author(s):  
Federico Cesarani ◽  
Maria Cristina Martina ◽  
Valter Capussotto ◽  
Andrea Giuliano ◽  
Renato Grilletto ◽  
...  

Facial reconstruction of mummies and corpses is important in anthropological, medical and forensic studies. The purpose of our study was to evaluate the role of three- Dimensional Multidetector CT examination for 3D facial reconstruction. We present a multidisciplinary work performed by radiologists, anthropologists and forensic police in reconstructing the possible physiognomy of an ancient Egyptian mummy. Three-Dimensional data were obtained from a well-preserved completely wrapped Egyptian mummy from the collection of the Egyptian Museum in Torino, Italy, dated from XXII or XXIII dynasty (945-715 BC). Data were used as a model for the rapid prototyping stereolithographic technique, a method which allows the creation of 3D model with digital data using synthetic materials such as resin or nylon.


2019 ◽  
Vol 8 (6) ◽  
pp. 285 ◽  
Author(s):  
Balletti ◽  
Ballarin

In recent decades, 3D acquisition by laser scanning or digital photogrammetry has become one of the standard methods of documenting cultural heritage, because it permits one to analyze the shape, geometry, and location of any artefact without necessarily coming into contact with it. The recording of three-dimensional metrical data of an asset allows one to preserve and monitor, but also to understand and explain the history and cultural heritage shared. In essence, it constitutes a digital archive of the state of an artefact, which can be used for various purposes, be remodeled, or kept safely stored. With the introduction of 3D printing, digital data can once again take on material form and become physical objects from the corresponding mathematical models in a relatively short time and often at low cost. This possibility has led to a different consideration of the concept of virtual data, no longer necessarily linked to simple visual fruition. The importance of creating high-resolution physical copies has been reassessed in light of different types of events that increasingly threaten the protection of cultural heritage. The aim of this research is to analyze the critical issues in the production process of the replicas, focusing on potential problems in data acquisition and processing and on the accuracy of the resulting 3D printing. The metric precision of the printed model with 3D technology are fundamental for everything concerning geomatics and must be related to the same characteristics of the digital model obtained through the survey analysis.


2011 ◽  
Vol 19 (3) ◽  
pp. 189
Author(s):  
Karsten Rodenacker ◽  
Klaus Hahn ◽  
Gerhard Winkler ◽  
Dorothea P Auer

Spatio-temporal digital data from fMRI (functional Magnetic Resonance Imaging) are used to analyse and to model brain activation. To map brain functions, a well-defined sensory activation is offered to a test person and the hemodynamic response to neuronal activity is studied. This so-called BOLD effect in fMRI is typically small and characterised by a very low signal to noise ratio. Hence the activation is repeated and the three dimensional signal (multi-slice 2D) is gathered during relatively long time ranges (3-5 min). From the noisy and distorted spatio-temporal signal the expected response has to be filtered out. Presented methods of spatio-temporal signal processing base on non-linear concepts of data reconstruction and filters of mathematical morphology (e.g. alternating sequential morphological filters). Filters applied are compared by classifications of activations.


2019 ◽  
Vol 2 (2) ◽  
pp. 150-165
Author(s):  
Damien Vurpillot ◽  
Quentin Verriez ◽  
Matthieu Thivet

High density remote survey technologies have become widespread practices. In recent years, we have seen a tenfold increase in volume of digital data acquired. Beyond this sheer amount of data, multimodal three-dimensional data exploitation has become another common challenge for specialists. The Aspectus project aims to ease the access to complex three-dimensional data and to promote collaborative work and remote expert assessment. Thus, we can get past the problem of distance and availability of the “object of expertise”, ranging from cultural heritage sites to artefacts. By extension, it enables us to circumvent the ever-present problem of destruction. Aspectus takes advantage of available open source solutions to produce a flexible web-based visualization and collaboration tool. After an overview of the theoretical framework and its technical implementation, we will discuss a practical application as part of the “Bibracte Numérique” project.


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