scholarly journals Development and Validation of LiDAR Sensor Simulators Based on Parallel Raycasting

Sensors ◽  
2020 ◽  
Vol 20 (24) ◽  
pp. 7186
Author(s):  
Guilherme Ferreira Gusmão ◽  
Carlos Roberto Hall Barbosa ◽  
Alberto Barbosa Raposo
Keyword(s):  
Forest Canopy ◽  
Three Dimensional ◽  
Point Clouds ◽  
Industrial Sector ◽  
Imaging Systems ◽  
Digital World ◽  
Development And Validation ◽  
Metrological Parameters ◽  
Yielding Point

Three-dimensional (3D) imaging technologies have been increasingly explored in academia and the industrial sector, especially the ones yielding point clouds. However, obtaining these data can still be expensive and time-consuming, reducing the efficiency of procedures dependent on large datasets, such as the generation of data for machine learning training, forest canopy calculation, and subsea survey. A trending solution is developing simulators for imaging systems, performing the virtual scanning of the digital world, and generating synthetic point clouds from the targets. This work presents a guideline for the development of modular Light Detection and Ranging (LiDAR) system simulators based on parallel raycasting algorithms, with its sensor modeled by metrological parameters and error models. A procedure for calibrating the sensor is also presented, based on comparing with the measurements made by a commercial LiDAR sensor. The sensor simulator developed as a case study resulted in a robust generation of synthetic point clouds in different scenarios, enabling the creation of datasets for use in concept tests, combining real and virtual data, among other applications.

A Voxel-Based Numerical Method for Computing and Visualising the Workspace of Offshore Cranes

2015 ◽  
Author(s):  
Lars I. Hatledal ◽  
Filippo Sanfilippo ◽  
Yingguang Chu ◽  
Houxiang Zhang
Keyword(s):  
Numerical Method ◽  
Three Dimensional ◽  
Point Clouds ◽  
Third Party ◽  
Operational Performance ◽  
The Monte Carlo Method ◽  
Load Limit ◽  
Offshore Crane ◽  
Safe Working

Workspace computation and visualisation is one of the most important criteria in offshore crane design in terms of geometry dimensioning, installation feasibility and operational performance evaluation. This paper presents a numerical method for the computation and visualisation of the workspace of offshore cranes. The Working Load Limit (WLL) and the Safe Working Load (SWL) can be automatically determined. A three-dimensional (3D) rectangular grid of voxels is used to describe the properties of the workspace. Firstly, a number of joint configurations are generated by using the Monte Carlo method, which are then mapped from joint to Cartesian space using forward kinematics (FK). The bounding box of the workspace is then derived from these points, and the voxels are distributed on planes inside the box. The method distinguishes voxels by whether they are reachable and if they are on the workspace boundary. The output of the method is an approximation of the workspace volume and point clouds depicting both the reachable space and the boundary of the workspace. Using a third-party software that can work with point clouds, such like MeshLab, a 3D mesh of the workspace can be obtained. A more in-depth description and the pseudo-code of the presented method are presented. As a case study, the workspace of a common type of offshore crane, with three rotational joints, is computed with the proposed method.

Application of Conventional UAVs for the Identification and Classification of Dense Green Spaces

2021 ◽  
pp. 364-388
Author(s):  
Josep Roca ◽  
Blanca Arellano
Keyword(s):  
Plant Species ◽  
Low Cost ◽  
Three Dimensional ◽  
Point Clouds ◽  
Urban Spaces ◽  
Green Spaces ◽  
Spatial Density ◽  
Public Parks

The objective of this chapter is to show the usefulness of conventional UAVs for the identification, inventory, and classification of trees in the context of dense green spaces. The aim is to demonstrate the potential of low-cost drones (with traditional red, green, blue [RGB] sensors) to identify and classify trees in public parks. A case study is discussed on Turó Parc in Barcelona, in which a 3D model was developed and an exercise to identify and classify the vegetation was carried out using the information provided by a UAV. The example confirms that conventional drones could be useful for studying green urban spaces characterized by a high density of plant species. Non-professional UAVs have a potential that should not be undervalued, as they enable three-dimensional point clouds to be obtained of high spatial density.

scholarly journals EVALUATION OF HISTORICAL HERITAGE DOCUMENTATION: REALITY BASED SURVEY AND DERIVATIVE MODELS

2019 ◽  
Vol XLII-2/W17 ◽  
pp. 115-122
Author(s):  
A. di Luggo ◽  
M. Campi ◽  
L. Repola ◽  
V. Cera ◽  
S. Scandurra ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Point Clouds ◽  
Artistic Value ◽  
North East ◽  
The North ◽  
Accuracy And Precision ◽  
First Results ◽  
The Subject ◽  
Historical Heritage

Abstract. Three-dimensional acquisition systems for architecture have significantly evolved over just a few decades, with them allowing point clouds to be generated through active and passive optical sensor equipment.Accuracy levels vary considerably in relation to both the equipment and techniques used, with the data obtained acting as a scaffolding for the creation of derived models that allow specific analyses to be carried out.Ongoing research on Palazzo Donn’Anna, a Neapolitan sixteenth-century building of particular historical and artistic value, is being carried out in this context and the first results are presented in this paper.The entire building has been the subject of an instrumental survey. The north-east façade was proposed as a case-study for the experimentation of diversified reality-based sensors so as to compare the accuracy and precision of the data. The comparison was also aimed at evaluating the performance of some processing softwares. Finally, in order to obtain an estimate of the data in the transcription from the point cloud to a derived 3D model, the reproduction of the same portion of the prospectus in a derivative model of both object-oriented and NURBS types was experimented.

Construction of plastic contact deformation maps on ceramics: a case study on aluminum nitride

1996 ◽  
Vol 54 ◽  
pp. 636-637
Author(s):  
D. L. Callahan
Keyword(s):  
Plastic Deformation ◽  
Aluminum Nitride ◽  
Mechanical Response ◽  
Three Dimensional ◽  
Bright Field Image ◽  
Perfectly Plastic ◽  
Contrast Analysis ◽  
Deformation Patterns

Modern polishing, precision machining and microindentation techniques allow the processing and mechanical characterization of ceramics at nanometric scales and within entirely plastic deformation regimes. The mechanical response of most ceramics to such highly constrained contact is not predictable from macroscopic properties and the microstructural deformation patterns have proven difficult to characterize by the application of any individual technique. In this study, TEM techniques of contrast analysis and CBED are combined with stereographic analysis to construct a three-dimensional microstructure deformation map of the surface of a perfectly plastic microindentation on macroscopically brittle aluminum nitride.The bright field image in Figure 1 shows a lg Vickers microindentation contained within a single AlN grain far from any boundaries. High densities of dislocations are evident, particularly near facet edges but are not individually resolvable. The prominent bend contours also indicate the severity of plastic deformation. Figure 2 is a selected area diffraction pattern covering the entire indentation area.

scholarly journals Generative Models for Relief Perspective Architectures

2021 ◽  
Author(s):  
Leonardo Baglioni ◽  
Federico Fallavollita
Keyword(s):  
Research Methodology ◽  
Affine Space ◽  
Three Dimensional ◽  
Generative Models ◽  
Linear Perspective ◽  
Dimensional Structure ◽  
Three Dimensional Structure ◽  
Present Essay ◽  
Santa Maria

AbstractThe present essay investigates the potential of generative representation applied to the study of relief perspective architectures realized in Italy between the sixteenth and seventeenth centuries. In arts, and architecture in particular, relief perspective is a three-dimensional structure able to create the illusion of great depths in small spaces. A method of investigation applied to the case study of the Avila Chapel in Santa Maria in Trastevere in Rome (Antonio Gherardi 1678) is proposed. The research methodology can be extended to other cases and is based on the use of a Relief Perspective Camera, which can create both a linear perspective and a relief perspective. Experimenting mechanically and automatically the perspective transformations from the affine space to the illusory space and vice versa has allowed us to see the case study in a different light.

Decolonising a landscape architecture studio: Spatial modelling of student narratives

2021 ◽  
Vol 1 (1) ◽  
pp. 39-47
Author(s):  
Christine Price
Keyword(s):  
Spatial Model ◽  
Meaning Making ◽  
Three Dimensional ◽  
Spatial Modelling ◽  
First Year ◽  
Spatial Form ◽  
Public Park ◽  
New Meanings ◽  
Global North

This paper problematises the dominance of global north perspectives in landscape architectural education, in South Africa where there are urgent calls to decolonise education and make visible indigenous and vernacular meaning-making practices. In grappling with these concerns, this research finds resonance with a multimodal social semiotic approach that acknowledges the interest, agency and resourcefulness of students as meaning-makers in both accessing and challenging dominant educational discourses. This research involves a case study of a design project in a first-year landscape architectural studio. The project requires students to choose a narrative and to represent it as a spatial model: a scaled, 3D maquette of a spatial experience that could be installed in a public park. This practitioner reflection closely analyses the spatial model of one student, Malibongwe, focusing on his interest in meaning-making; the innovative meaning-making practices and diverse resources he draws on; and his expression of spatial signifiers of the Black experiences portrayed in his narrative. This reflection shows how Malibongwe’s narrative is not only reproduced in the spatial model, it is remade: the transformation of resources into three-dimensional spatial form results in new understandings and the production of new meanings.

scholarly journals Protocol for preparation of heterogeneous biological samples for 3D electron microscopy: a case study for insects

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alexey A. Polilov ◽  
Anastasia A. Makarova ◽  
Song Pang ◽  
C. Shan Xu ◽  
Harald Hess
Keyword(s):  
Electron Microscopy ◽  
Biological Samples ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Three Dimensional ◽  
Entire Volume ◽  
Simple Protocol ◽  
3D Electron Microscopy ◽  
3D Em

AbstractModern morphological and structural studies are coming to a new level by incorporating the latest methods of three-dimensional electron microscopy (3D-EM). One of the key problems for the wide usage of these methods is posed by difficulties with sample preparation, since the methods work poorly with heterogeneous (consisting of tissues different in structure and in chemical composition) samples and require expensive equipment and usually much time. We have developed a simple protocol allows preparing heterogeneous biological samples suitable for 3D-EM in a laboratory that has a standard supply of equipment and reagents for electron microscopy. This protocol, combined with focused ion-beam scanning electron microscopy, makes it possible to study 3D ultrastructure of complex biological samples, e.g., whole insect heads, over their entire volume at the cellular and subcellular levels. The protocol provides new opportunities for many areas of study, including connectomics.

Sign in / Sign up

Export Citation Format

Share Document