| 1. |
- Aslani, Mohammad
(författare)
-
Computational and spatial analyses of rooftops for urban solar energy planning
- 2022
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In cities where land availability is limited, rooftop photovoltaic panels (RPVs) offer high potential for satisfying concentrated urban energy demand by using only rooftop areas. However, accurate estimation of RPVs potential in relation to their spatial distribution is indispensable for successful energy planning. Classification, plane segmentation, and spatial analysis are three important aspects in this context. Classification enables extracting rooftops and allows for estimating solar energy potential based on existing training samples. Plane segmentation helps to characterize rooftops by extracting their planar patches. Additionally, spatial analyses enable the identification of rooftop utilizable areas for placing RPVs. This dissertation aims to address some issues associated with these three aspects, particularly (a) training support vector machines (SVMs) in large datasets, (b) plane segmentation of rooftops, and (c) identification of utilizable areas for RPVs. SVMs are among the most potent classifiers and have a solid theoretical foundation. However, they have high time complexity in their training phase, making them inapplicable in large datasets. Two new instance selection methods were proposed to accelerate the training phase of SVMs. The methods are based on locality-sensitive hashing and are capable of handling large datasets. As an application, they were incorporated into a rooftop extraction procedure, followed by plane segmentation. Plane segmentation of rooftops for the purpose of solar energy potential estimation should have a low risk of overlooking superstructures, which play an essential role in the placement of RPVs. Two new methods for plane segmentation in high-resolution digital surface models were thus developed. They have an acceptable level of accuracy and can successfully extract planar segments by considering superstructures. Not all areas of planar segments are utilizable for mounting RPVs, and some factors may further limit their useability. Two spatial methods for identifying RPV-utilizable areas were developed in this realm. They scrutinize extracted planar segments by considering panel installation regulations, solar irradiation, roof geometry, and occlusion, which are necessary for a realistic assessment of RPVs potential. All six proposed methods in this thesis were thoroughly evaluated, and the experimental results show that they can successfully achieve the objectives for which they were designed.
|
|
| 2. |
- Chandel, Kuhelee, 1982-, et al.
(författare)
-
Augmented Reality and Indoor Positioning in Context of Smart Industry: A Review
- 2022
-
Ingår i: Management and Production Engineering Review. - : Polish Academy of Sciences. - 2080-8208 .- 2082-1344. ; 13:4, s. 72-87
-
Forskningsöversikt (refereegranskat)abstract
- Presently, digitalization is causing continuous transformation of industrial processes. However, it does pose challenges like spatially contextualizing data from industrial processes. There are various methods for calculating and delivering real-time location data. Indoor positioning systems (IPS) are one such method, used to locate objects and people within buildings. They have the potential to improve digital industrial processes, but they are currently under utilized. In addition, augmented reality (AR) is a critical technology in today’s digital industrial transformation. This article aims to investigate the use of IPS and AR in manufacturing, the methodologies and technologies employed, the issues and limitations encountered, and identify future research opportunities. This study concludes that, while there have been many studies on IPS and navigation AR, there has been a dearth of research efforts in combining the two. Furthermore, because controlled environments may not expose users to the practical issues they may face, more research in a real-world manufacturing environment is required to produce more reliable and sustainable results
|
|
| 3. |
- Chandel, Kuhelee, 1982-, et al.
(författare)
-
Evaluating the Tracking Abilities of Microsoft HoloLens-1 for Small-Scale Industrial Processes
- 2023
-
Konferensbidrag (refereegranskat)abstract
- This study evaluates the accuracy of Microsoft HoloLens (Version 1) for small-scale industrial activities, comparingits measurements to ground truth data from a Kuka Robotics arm. Two experiments were conducted to assess its positiontracking capabilities, revealing that the HoloLens device is effective for measuring the position of dynamic objects with smalldimensions. However, its precision is affected by the velocity of the trajectory and its position within the device's field of view.While the HoloLens device may be suitable for small-scale tasks, its limitations for more complex and demanding applicationsrequiring high precision and accuracy must be considered. The findings can guide the use of HoloLens devices in industrialapplications and contribute to the development of more effective and reliable position-tracking systems.
|
|
| 4. |
- Lim, Nancy Joy, et al.
(författare)
-
Geovisualisation of uncertainty in simulated flood maps
- 2014
-
Ingår i: Proceedings of the International Conferences on Interfaces and Human Computer Interaction 2014, Game and Entertainment Technologies 2014 and Computer Graphics, Visualization, Computer Vision and Image Processing 2014 - Part of the Multi Conference on Computer Science and Information Systems, MCCSIS 2014. - : IADIS Press. ; , s. 206-214
-
Konferensbidrag (refereegranskat)abstract
- The paper presents a three-dimensional (3D) geovisualisation model of uncertainties in simulated flood maps that can help communicate uncertain information in the data being used. An entropy-based measure was employed for uncertainty quantification. In developing the model, Visualisation Toolkit (VTK) was utilised. Different data derived from earlier simulation study and other maps were represented in the model. Cartographic principles were considered in the map design. A Graphical User Interface (GUI), which was developed in Tkinter, was also created to further support exploratory data analysis. The resulting model allowed visual identification of uncertain areas, as well as displaying spatial relationship between the entropy and the slope values. This geovisualisation has still to be tested to assess its effectiveness as a communication tool. However, this type of uncertainty visualisation in flood mapping is an initial step that can lead to its adoption in decision-making when presented comprehensively to its users. Thus, further improvement and development is still suggested for this kind of information presentation.
|
|
| 5. |
- Liu, Fei, 1984-
(författare)
-
Hand-held Augmented Reality for Facility Maintenance
- 2016
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Buildings and public infrastructures are crucial to our societies in that they provide habitations, workplaces, commodities and services indispensible to our daily life. As vital parts of facility management, operations and maintenance (O&M) ensure a facility to continuously function as intended, which take up the longest time in a facility’s life cycle and demand great expense. Therefore, computers and information technology have been actively adopted to automate traditional maintenance methods and processes, making O&M faster and more reliable.Augmented reality (AR) offers a new approach towards human-computer interaction through directly displaying information related to real objects that people are currently perceiving. People’s sensory perceptions are enhanced (augmented) with information of interest naturally without deliberately turning to computers. Hence, AR has been proved to be able to further improve O&M task performance.The research motif of this thesis is user evaluations of AR applications in the context of facility maintenance. The studies look into invisible target designation tasks assisted by developed AR tools in both indoor and outdoor scenarios. The focus is to examine user task performance, which is influenced by both AR system performance and human perceptive, cognitive and motoric factors.Target designation tasks for facility maintenance entail a visualization-interaction dilemma. Two AR systems built upon consumer-level hand-held devices using an off-the-shelf AR software development toolkit are evaluated indoors with two disparate solutions to the dilemma – remote laser pointing and the third person perspective (TPP). In the study with remote laser pointing, the parallax effect associated with AR “X-ray vision” visualization is also an emphasis.A third hand-held AR system developed in this thesis overlays infrared information on façade video, which is evaluated outdoors. Since in an outdoor environment marker-based tracking is less desirable, an infrared/visible image registration method is developed and adopted by the system to align infrared information correctly with the façade in the video. This system relies on the TPP to overcome the aforementioned dilemma.
|
|
| 6. |
- Ooms, Kristien, et al.
(författare)
-
Detecting Collapsed Buildings in Case of Disaster: Which Visualisation Works Best?
- 2018
-
Ingår i: Eye Tracking for Spatial Research. - Zurich.
-
Konferensbidrag (refereegranskat)abstract
- A user study is conducted to evaluate the efficiency and effectiveness of two types of visualizations to identify damage sites in case of disaster. The test consists out 36 trials (18 for each visualisation) and in each trial an area of 1x1km, located in Ghent, is displayed on a screen. This image shows the combined height information from before and after the disaster. The first visualisation, page flipping, is based on greyscale images with height information from the pre- and post-disaster situation between which users can switch manually. The second visualisation, difference image, is a result of subtracting the heights (before versus after) and assigning a blue-white-red colour ramp. In order to simulate the urgency with which the data is captured, systematic and random imperfections are introduced in the post-disaster data. All participants’ mouse and key interactions are logged, which is further complemented by the registration of their eye movements. This give insights the visualizations’ efficiency, effectiveness and the overall search strategies of the participants.
|
|
| 7. |
- Ooms, Kristien, et al.
(författare)
-
Efficiency and effectiveness in case of disaster: a visual damage assessment test
- 2018
-
Ingår i: Proceedings of the International Cartographic Association (Proceedings of the ICA). - : Copernicus GmbH.
-
Konferensbidrag (refereegranskat)abstract
- A user study is conducted to evaluate the efficiency and effectiveness of two types of visualizations to identify damages sites in case of disaster. The test consists out 36 trials (18 for each visualisation) and in each trial an area of 1×1km, located in Ghent, is displayed on a screen. This image shows the combined height information from before and after the disaster. The first visualisation, page flipping, is based on greyscale images with height information from the pre- and post-disaster situation between which users can switch manually. The second visualisation, difference image, is a result of subtracting the heights (before versus after) and assigning a blue-white-red colour ramp. In order to simulate the urgency with which the data is captured, systematic and random imperfections are introduced in the post-disaster data. All participants’ mouse and key interactions are logged, which is further complemented by the registration of their eye movements. This give insights the visualizations’ efficiency, effectiveness and the overall search strategies of the participants.
|
|
| 8. |
- Seffers, Gaëlle, et al.
(författare)
-
Assessing Damage – Can the Crowd Interpret Colour and 3D Information?
- 2021
-
Ingår i: Cartographic Journal. - : Taylor & Francis. - 0008-7041 .- 1743-2774. ; 58:1, s. 69-82
-
Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT The goal of this study is to investigate how efficiently and effectively collapsed buildings ? due to the occurrence of a disaster ? can be localized by a general crowd. Two types of visualization parameters are evaluated in an online user study: (1) greyscale images (indicating height information) versus true colours; (2) variation in the vertical viewing angle (0°, 30° and 60°). Additionally, the influence of map use expertise on how the visualizations are interpreted, is investigated. The results indicate that the use of the greyscale image helps to locate collapsed buildings in an efficient and effective manner. The use of the viewing angle of 60° is the least appropriate. A person with a map use expertise will prefer the greyscale image over the colour image. To confirm the benefits of the use of three-dimensional visualizations and the use of the colour image, more research is needed.
|
|
| 9. |
- Zdravkovic, Jelena, et al.
(författare)
-
Modeling Image Processing Tasks As Flexible Workflows for Improved Quality of Service
- 2004
-
Ingår i: The IADIS Applied Computing. - 9729894736 ; , s. 363-370
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Processing of nontrivial images is a difficult task performed throughout a set of ordered steps. Besides the basic functionality that a process must satisfy, quality of service goals are to be met. Images should be processed within a certain time and a certain quality should be attained. To manage image-processing tasks in the optimal way, the process goals must be defined explicitly and their fulfillment has be controlled. Modeling image-processing tasks with workflows would enable control of the fulfillment of goals. In addition, by introducing flexible semantics in the workflow, the process could be executed along optimal execution alternatives. In this paper, we propose an approach to model the class of image processing tasks with workflows that would, based on the extended semantics, allow for flexibility in the process execution toward optimal goals fulfillment.
|
|
| 10. |
- Åhlén, Julia, et al.
(författare)
-
Application of underwater hyperspectral data for color correction purposes
- 2007
-
Ingår i: Pattern Recognition and Image Analysis. - 1054-6618 .- 1555-6212. ; 17:1, s. 170-173
-
Tidskriftsartikel (refereegranskat)abstract
- Color correction of underwater images has been considered a difficult task for a number of reasons. Those include severe absorption of the water column, the unpredictable behavior of light under the water surface, limited access to reliable data for correction purposes, and the fact that we are only able to process three spectral channels, which is insufficient for most color correction applications. Here, the authors present a method to estimate a hyperspectral image from an RGB image and pointwise hyperspectral data. This is then used to color correct the hyperspectral underwater image and transform it back into RGB color space.
|
|
