scholarly journals VOXEL-BASED INDOOR RECONSTRUCTION FROM HOLOLENS TRIANGLE MESHES

2020 ◽  
Vol V-4-2020 ◽  
pp. 79-86
Author(s):  
P. Hübner ◽  
M. Weinmann ◽  
S. Wursthorn
Keyword(s):  
Three Dimensional ◽  
Automatic Generation ◽  
Triangle Meshes ◽  
Semantic Class ◽  
Sweep Algorithm ◽  
Voxel Representation ◽  
Class Labels ◽  
Microsoft Hololens ◽  
Voxel Grid ◽  
Indoor Reconstruction

Abstract. Current mobile augmented reality devices are often equipped with range sensors. The Microsoft HoloLens for instance is equipped with a Time-of-Flight (ToF) range camera providing coarse triangle meshes that can be used in custom applications. We suggest to use these triangle meshes for the automatic generation of indoor models that can serve as basis for augmenting their physical counterpart with location-dependent information. In this paper, we present a novel voxel-based approach for automated indoor reconstruction from unstructured three-dimensional geometries like triangle meshes. After an initial voxelisation of the input data, rooms are detected in the resulting voxel grid by segmenting connected voxel components of ceiling candidates and extruding them downwards to find floor candidates. Semantic class labels like ’Wall’, ’Wall Opening’, ’Interior Object’ and ’Empty Interior’ are then assigned to the room voxels in-between ceiling and floor by a rule-based voxel sweep algorithm. Finally, the geometry of the detected walls and their openings is refined in voxel representation. The proposed approach is not restricted to Manhattan World scenarios and does not rely on room surfaces being planar.

scholarly journals Evaluation of HoloLens Tracking and Depth Sensing for Indoor Mapping Applications

Sensors ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 1021 ◽  
Author(s):  
Patrick Hübner ◽  
Kate Clintworth ◽  
Qingyi Liu ◽  
Martin Weinmann ◽  
Sven Wursthorn
Keyword(s):  
Complete System ◽  
Tracking System ◽  
Three Dimensional ◽  
Indoor Environments ◽  
Mobile Augmented Reality ◽  
Depth Sensor ◽  
Depth Sensing ◽  
Triangle Meshes ◽  
Microsoft Hololens

The Microsoft HoloLens is a head-worn mobile augmented reality device that is capable of mapping its direct environment in real-time as triangle meshes and localize itself within these three-dimensional meshes simultaneously. The device is equipped with a variety of sensors including four tracking cameras and a time-of-flight (ToF) range camera. Sensor images and their poses estimated by the built-in tracking system can be accessed by the user. This makes the HoloLens potentially interesting as an indoor mapping device. In this paper, we introduce the different sensors of the device and evaluate the complete system in respect of the task of mapping indoor environments. The overall quality of such a system depends mainly on the quality of the depth sensor together with its associated pose derived from the tracking system. For this purpose, we first evaluate the performance of the HoloLens depth sensor and its tracking system separately. Finally, we evaluate the overall system regarding its capability for mapping multi-room environments.

Development of program-driven plug-in for conical counter-rotating twin screw based on SolidWorks

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Liqun Dong ◽  
Junwei Zhang ◽  
Liang Qin ◽  
Ping Xue ◽  
Yun Ma ◽  
...  
Keyword(s):  
Parametric Design ◽  
Cone Angle ◽  
Three Dimensional ◽  
Visual Basic ◽  
Automatic Generation ◽  
Three Dimensional Model ◽  
Modeling Process ◽  
Basic Language ◽  
Twin Screw ◽  
Visual Basic Language

Abstract Owing to the existence of the cone angle, the size of a conical counter-rotating twin screw continuously changes along the axis, so it is not easy to model using SolidWorks. In this study, the parametric design of the modeling process is completed based on the Visual Basic language and a program-driven method. Finally, the SolidWorks program plug-in and user interface are developed to complete the automatic generation of the three-dimensional model of a conical counter-rotating twin screw.

Automatic Three-Dimensional Optimisation of a Modern Tandem Compressor Vane

2014 ◽  
Author(s):  
R. C. Schlaps ◽  
S. Shahpar ◽  
V. Gümmer
Keyword(s):  
Pressure Ratio ◽  
Three Dimensional ◽  
Trust Region ◽  
Automatic Generation ◽  
Navier Stokes ◽  
Design Parameters ◽  
High Fidelity ◽  
Stall Margin ◽  
Design Choice ◽  
Multipoint Approximation

In order to increase the performance of a modern gas turbine, compressors are required to provide higher pressure ratio and avoid incurring higher losses. The tandem aerofoil has the potential to achieve a higher blade loading in combination with lower losses compared to single vanes. The main reason for this is due to the fact that a new boundary layer is generated on the second blade surface and the turning can be achieved with smaller separation occurring. The lift split between the two vanes with respect to the overall turning is an important design choice. In this paper an automated three-dimensional optimisation of a highly loaded compressor stator is presented. For optimisation a novel methodology based on the Multipoint Approximation Method (MAM) is used. MAM makes use of an automatic design of experiments, response surface modelling and a trust region to represent the design space. The CFD solutions are obtained with the high-fidelity 3D Navier-Stokes solver HYDRA. In order to increase the stage performance the 3D shape of the tandem vane is modified changing both the front and rear aerofoils. Moreover the relative location of the two aerofoils is controlled modifying the axial and tangential relative positions. It is shown that the novel optimisation methodology is able to cope with a large number of design parameters and produce designs which performs better than its single vane counterpart in terms of efficiency and numerical stall margin. One of the key challenges in producing an automatic optimisation process has been the automatic generation of high-fidelity computational meshes. The multi block-structured, high-fidelity meshing tool PADRAM is enhanced to cope with the tandem blade topologies. The wakes of each aerofoil is properly resolved and the interaction and the mixing of the front aerofoil wake and the second tandem vane are adequately resolved.

Automatic tourist attraction and representative icon determination for tourist map generation

2013 ◽  
Vol 13 (1) ◽  
pp. 18-28 ◽  
Author(s):  
Chao-Hung Lin ◽  
Jyun-Yuan Chen ◽  
Shun-Siang Hsu ◽  
Yun-Huan Chung
Keyword(s):  
User Study ◽  
Three Dimensional ◽  
Automatic Generation ◽  
Visual Features ◽  
Tourist Attraction ◽  
Tourist Attractions ◽  
Photo Sharing ◽  
Map Generation ◽  
Three Dimensional Models ◽  
Better Than

Tourist maps are designed to direct tourists to tourist attractions in unfamiliar areas. A well-designed tourist map can provide tourists with sufficient and intuitive information about places of interest. Thus, providing up-to-date information on places of interest and selecting their representative icons are fundamental and important in automatic generation of tourist maps. In this article, approaches for determining places of interest and for determining their representative icons are introduced. In contrast to general digital tourist maps that use text, simple shapes, or three-dimensional models, we use photos that offer abundant visual features of places of interest as icons in tourist maps. The photos are automatically extracted from a repository of photos downloaded from photo-sharing communities. Tourist attractions and their corresponding image icons are determined by means of photo voting and photo quality assessment. Qualitative analyses, including a user study and experiments in several areas with numerous tourist attractions, indicated that the proposed method can generate visually pleasant and elaborate tourist maps. In addition, the analyses indicated that the map produced by our method is better than maps generated by related methods and is comparable to hand-designed tourist maps.

Modeling of Flowers with Inverse Grammar Generation Interface

2012 ◽  
Vol 3 (2) ◽  
pp. 23-41
Author(s):  
Olga Petrenko ◽  
Mateu Sbert ◽  
Olivier Terraz ◽  
Djamchid Ghazanfarpour
Keyword(s):  
Inverse Modeling ◽  
Three Dimensional ◽  
Automatic Generation ◽  
Flowering Plants ◽  
Natural Phenomena ◽  
Production Rules ◽  
Procedural Modeling ◽  
Model Based ◽  
L Systems ◽  
Generalized Maps

Flowers belong to one of the natural phenomena that cannot be captured completely, as there is enormous variety of shapes both within and between individuals. The authors propose a procedural modeling of flowering plants using an extension of L-Systems – a model based on three-dimensional generalized maps. Conventionally, in order to build a model the user has to write the grammar, which consists of the description of 3Gmaps and all the production rules. The process of writing a grammar is usually quite laborious and tedious. In order to avoid this the authors propose new interface functionality: the inverse modeling by automatic generation of L-systems. The user describes the flower he wants to model, by assigning the properties of its organs. The algorithm uses this information as an input, which is then analyzed and coded as L-systems grammar.

scholarly journals Weakly Supervised Conditional Random Fields Model for Semantic Segmentation with Image Patches

2020 ◽  
Vol 10 (5) ◽  
pp. 1679
Author(s):  
Xinying Xu ◽  
Yujing Xue ◽  
Xiaoxia Han ◽  
Zhe Zhang ◽  
Jun Xie ◽  
...  
Keyword(s):  
Random Fields ◽  
Conditional Random Fields ◽  
Semantic Category ◽  
Semantic Segmentation ◽  
Potential Energy Function ◽  
Semantic Class ◽  
Image Patches ◽  
Benchmark Datasets ◽  
Weakly Supervised ◽  
Class Labels

Image semantic segmentation (ISS) is used to segment an image into regions with differently labeled semantic category. Most of the existing ISS methods are based on fully supervised learning, which requires pixel-level labeling for training the model. As a result, it is often very time-consuming and labor-intensive, yet still subject to manual errors and subjective inconsistency. To tackle such difficulties, a weakly supervised ISS approach is proposed, in which the challenging problem of label inference from image-level to pixel-level will be particularly addressed, using image patches and conditional random fields (CRF). An improved simple linear iterative cluster (SLIC) algorithm is employed to extract superpixels. for image segmentation. Specifically, it generates various numbers of superpixels according to different images, which can be used to guide the process of image patch extraction based on the image-level labeled information. Based on the extracted image patches, the CRF model is constructed for inferring semantic class labels, which uses the potential energy function to map from the image-level to pixel-level image labels. Finally, patch based CRF (PBCRF) model is used to accomplish the weakly supervised ISS. Experiments conducted on two publicly available benchmark datasets, MSRC and PASCAL VOC 2012, have demonstrated that our proposed algorithm can yield very promising results compared to quite a few state-of-the-art ISS methods, including some deep learning-based models.

Three-Dimensional Stress Analysis and Configuration Optimization of Cross Wavy Primary Surface Recuperator for Microturbine System

2008 ◽  
Author(s):  
D. J. Zhang ◽  
M. Zeng ◽  
Q. W. Wang
Keyword(s):  
High Temperature ◽  
Stress Distribution ◽  
Stress Analysis ◽  
Parametric Design ◽  
Minimum Principle ◽  
High Stress ◽  
Three Dimensional ◽  
Automatic Generation ◽  
Temperature And Pressure ◽  
Air Passage

Recuperator in a microturbine system, which has to work under a high temperature and high pressure condition, is a key component to improve the electricity efficiency of the system. High temperature and pressure may cause high stress inside the Cross-Wavy Primary Surface (CWPS) sheet, and it is essential to analyze the stress distribution to ensure the security while the recuperator is working. In this paper the combined thermomechanical design of a CWPS recuperator for a 100kW microturbine system is presented. With the ANSYS Parametric Design Language (APDL), calculation procedures for heat transfer and stress analysis are combined in order to perform a reliable strength prediction of the recuperator. A program has been generated, which allows the automatic generation of the numerical model, the mesh and the boundary conditions. Also with the energy minimum principle, an optimal configuration of the air and gas passages is obtained. The results show that the material of the primary sheet (0Cr18Ni11Nb) is reliable. The stress distribution changes with the different configuration of the passages. Since the air pressure is much higher than that of the exhaust gas, the configuration of the primary sheet is much better when the sectional area of the gas passage is larger than that of the air passage. If the pitch of the sheet is maintained at 2mm, the best configuration is obtained when the dimension of passage is at r = 0.35–0.42mm, R = 0.55–0.48mm.

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