Defining Reality in Virtual Reality: Exploring Visual Appearance and Spatial Experience Focusing on Colour

Today, different actors in the design process have communication difficulties in visualizing and predictinghow the not yet built environment will be experienced. Visually believable virtual environments (VEs) can make it easier for architects, users and clients to participate in the planning process. This thesis deals with the difficulties of translating reality into digital counterparts, focusing on visual appearance(particularly colour) and spatial experience. The goal is to develop knowledge of how differentaspects of a VE, especially light and colour, affect the spatial experience; and thus to contribute to a better understanding of the prerequisites for visualizing believable spatial VR-models. The main aims are to 1) identify problems and test solutions for simulating realistic spatial colour and light in VR; and 2) develop knowledge of the spatial conditions in VR required to convey believable experiences; and evaluate different ways of visualizing spatial experiences. The studies are conducted from an architecturalperspective; i.e. the whole of the spatial settings is considered, which is a complex task. One important contribution therefore concerns the methodology. Different approaches were used: 1) a literature review of relevant research areas; 2) a comparison between existing studies on colour appearance in 2D vs 3D; 3) a comparison between a real room and different VR-simulations; 4) elaborationswith an algorithm for colour correction; 5) reflections in action on a demonstrator for correct appearance and experience; and 6) an evaluation of texture-styles with non-photorealistic expressions. The results showed various problems related to the translation and comparison of reality to VR. The studies pointed out the significance of inter-reflections; colour variations; perceived colour of light and shadowing for the visual appearance in real rooms. Some differences in VR were connected to arbitrary parameter settings in the software; heavily simplified chromatic information on illumination; and incorrectinter-reflections. The models were experienced differently depending on the application. Various spatial differences between reality and VR could be solved by visual compensation. The study with texture-styles pointed out the significance of varying visual expressions in VR-models

Defining Reality in Virtual Reality: Exploring Visual Appearance and Spatial Experience Focusing on Colour

Today, different actors in the design process have communication difficulties in visualizing and predictinghow the not yet built environment will be experienced. Visually believable virtual environments (VEs) can make it easier for architects, users and clients to participate in the planning process. This thesis deals with the difficulties of translating reality into digital counterparts, focusing on visual appearance(particularly colour) and spatial experience. The goal is to develop knowledge of how differentaspects of a VE, especially light and colour, affect the spatial experience; and thus to contribute to a better understanding of the prerequisites for visualizing believable spatial VR-models. The main aims are to 1) identify problems and test solutions for simulating realistic spatial colour and light in VR; and 2) develop knowledge of the spatial conditions in VR required to convey believable experiences; and evaluate different ways of visualizing spatial experiences. The studies are conducted from an architecturalperspective; i.e. the whole of the spatial settings is considered, which is a complex task. One important contribution therefore concerns the methodology. Different approaches were used: 1) a literature review of relevant research areas; 2) a comparison between existing studies on colour appearance in 2D vs 3D; 3) a comparison between a real room and different VR-simulations; 4) elaborationswith an algorithm for colour correction; 5) reflections in action on a demonstrator for correct appearance and experience; and 6) an evaluation of texture-styles with non-photorealistic expressions. The results showed various problems related to the translation and comparison of reality to VR. The studies pointed out the significance of inter-reflections; colour variations; perceived colour of light and shadowing for the visual appearance in real rooms. Some differences in VR were connected to arbitrary parameter settings in the software; heavily simplified chromatic information on illumination; and incorrectinter-reflections. The models were experienced differently depending on the application. Various spatial differences between reality and VR could be solved by visual compensation. The study with texture-styles pointed out the significance of varying visual expressions in VR-models

WHERE DO YOU LOOK? RELATING VISUAL ATTENTION TO LEARNING OUTCOMES AND URL PARSING

Visual behavior provides a dynamic trail of where attention is directed. It is considered the behavioral interface between engagement and gaining information, and researchers have used it for several decades to study user\u27s behavior. This thesis focuses on employing visual attention to understand user\u27s behavior in two contexts: 3D learning and gauging URL safety. Such understanding is valuable for improving interactive tools and interface designs. In the first chapter, we present results from studying learners\u27 visual behavior while engaging with tangible and virtual 3D representations of objects. This is a replication of a recent study, and we extended it using eye tracking. By analyzing the visual behavior, we confirmed the original study results and added more quantitative explanations for the corresponding learning outcomes. Among other things, our results indicated that the users allocate similar visual attention while analyzing virtual and tangible learning material. In the next chapter, we present a user study\u27s outcomes wherein participants are instructed to classify a set of URLs wearing an eye tracker. Much effort is spent on teaching users how to detect malicious URLs. There has been significantly less focus on understanding exactly how and why users routinely fail to vet URLs properly. This user study aims to fill the void by shedding light on the underlying processes that users employ to gauge the UR L\u27s trustworthiness at the time of scanning. Our findings suggest that users have a cap on the amount of cognitive resources they are willing to expend on vetting a URL. Also, they tend to believe that the presence of www in the domain name indicates that the URL is safe

Die Virtuelle Videokamera: ein System zur Blickpunktsynthese in beliebigen, dynamischen Szenen

The Virtual Video Camera project strives to create free viewpoint video from casually captured multi-view data. Multiple video streams of a dynamic scene are captured with off-the-shelf camcorders, and the user can re-render the scene from novel perspectives. In this thesis the algorithmic core of the Virtual Video Camera is presented. This includes the algorithm for image correspondence estimation as well as the image-based renderer. Furthermore, its application in the context of an actual video production is showcased, and the rendering and image processing pipeline is extended to incorporate depth information.Das Virtual Video Camera Projekt dient der Erzeugung von Free Viewpoint Video Ansichten von Multi-View Aufnahmen: Material mehrerer Videoströme wird hierzu mit handelsüblichen Camcordern aufgezeichnet. Im Anschluss kann die Szene aus beliebigen, von den ursprünglichen Kameras nicht abgedeckten Blickwinkeln betrachtet werden. In dieser Dissertation wird der algorithmische Kern der Virtual Video Camera vorgestellt. Dies beinhaltet das Verfahren zur Bildkorrespondenzschätzung sowie den bildbasierten Renderer. Darüber hinaus wird die Anwendung im Kontext einer Videoproduktion beleuchtet. Dazu wird die bildbasierte Erzeugung neuer Blickpunkte um die Erzeugung und Einbindung von Tiefeninformationen erweitert

Information theory assisted data visualization and exploration

This thesis introduces techniques to utilize information theory, particularly entropy for enhancing data visualization and exploration. The ultimate goal with this work is to enable users to perceive as much as information available for recognizing objects, detecting regular or non-regular patterns and reducing user effort while executing the required tasks. We believe that the metrics to be set for enhancing computer generated visualizations should be quantifiable and that quantification should measure the information perception of the user. The proper way to solve this problem is utilizing information theory, particularly entropy. Entropy offers quantification of the information amount in a general communication system. In the communication model, information sender and information receiver are connected with a channel. We are inspired from this model and exploited it in a different way, namely we set the information sender as the data to be visualized, the information receiver as the viewer and the communication channel as the screen where the visualized image is displayed. In this thesis we explore the usage of entropy in three different visualization problems, -Enhancing the visualization of large scale social networks for better perception, -Finding the best representational images of a 3D object to visually inspect with minimal loss of information, -Automatic navigation over a 3D terrain with minimal loss of information. Visualization of large scale social networks is still a major challenge for information visualization researchers. When a thousand nodes are displayed on the screen with the lack of coloring, sizing and filtering mechanisms, the users generally do not perceive much on the first look. They usually use pointing devices or keyboard for zooming and panning to find the information that they are looking for. With this thesis we tried to present a visualization approach that uses coloring, sizing and filtering to help the users recognize the presented information. The second problem that we tried to tackle is finding the best representational images of 3D models. This problem is highly subjective in cognitive manner. The best or good definitions do not depend on any metric or any quantification, furthermore, when the same image is presented to two different users it can be identified differently. However in this thesis we tried to map some metrics to best or good definitions for representational images, such as showing the maximum faces, maximum saliency or combination of both in an image. The third problem that we tried to find a solution is automatic terrain navigation with minimal loss of information. The information to be quantified on this problem is taken as the surface visibility of a terrain. However the visibility problem is changed with the heuristic that users generally focus on city centers, buildings and interesting points during terrain exploration. In order to improve the information amount at the time of navigation, we should focus on those areas. Hence we employed the road network data, and set the heuristic that intersections of road network segments are the residential places. In this problem, region extraction using road network data, viewpoint entropy for camera positions, and automatic camera path generation methods are investigated

Spatial cognition in virtual environments

Since the last decades of the past century, Virtual Reality (VR) has been developed also as a methodology in research, besides a set of helpful applications in medical field (trainings for surgeons, but also rehabilitation tools). In science, there is still no agreement if the use of this technology in research on cognitive processes allows us to generalize results found in a Virtual Environment (VE) to the human behavior or cognition in the real world. This happens because of a series of differences found in basic perceptual processes (for example, depth perception) suggest a big difference in visual environmental representation capabilities of Virtual scenarios. On the other side, in literature quite a lot of studies can be found, which give a proof of VEs reliability in more than one field (trainings and rehabilitation, but also in some research paradigms). The main aim of this thesis is to investigate if, and in which cases, these two different views can be integrated and shed a new light and insights on the use of VR in research. Through the many experiments conducted in the "Virtual Development and Training Center" of the Fraunhofer Institute in Magdeburg, we addressed both low-level spatial processes (within an "evaluation of distances paradigm") and high-level spatial cognition (using a navigation and visuospatial planning task, called "3D Maps"), trying to address, at the same time, also practical problems as, for example, the use of stereoscopy in VEs or the problem of "Simulator Sickness" during navigation in immersive VEs. The results obtained with our research fill some gaps in literature about spatial cognition in VR and allow us to suggest that the use of VEs in research is quite reliable, mainly if the investigated processes are from the higher level of complexity. In this case, in fact, human brain "adapts" pretty well even to a "new" reality like the one offered by the VR, providing of course a familiarization period and the possibility to interact with the environment; the behavior will then be “like if” the environment was real: what is strongly lacking, at the moment, is the possibility to give a completely multisensorial experience, which is a very important issue in order to get the best from this kind of “visualization” of an artificial world. From a low-level point of view, we can confirm what already found in literature, that there are some basic differences in how our visual system perceives important spatial cues as depth and relationships between objects, and, therefore, we cannot talk about "similar environments" talking about VR and reality. The idea that VR is a "different" reality, offering potentially unlimited possibilities of use, even overcoming some physical limits of the real world, in which this "new" reality can be acquired by our cognitive system just by interacting with it, is therefore discussed in the conclusions of this work

Spatial cognition in virtual environments

Since the last decades of the past century, Virtual Reality (VR) has been developed also as a methodology in research, besides a set of helpful applications in medical field (trainings for surgeons, but also rehabilitation tools). In science, there is still no agreement if the use of this technology in research on cognitive processes allows us to generalize results found in a Virtual Environment (VE) to the human behavior or cognition in the real world. This happens because of a series of differences found in basic perceptual processes (for example, depth perception) suggest a big difference in visual environmental representation capabilities of Virtual scenarios. On the other side, in literature quite a lot of studies can be found, which give a proof of VEs reliability in more than one field (trainings and rehabilitation, but also in some research paradigms). The main aim of this thesis is to investigate if, and in which cases, these two different views can be integrated and shed a new light and insights on the use of VR in research. Through the many experiments conducted in the "Virtual Development and Training Center" of the Fraunhofer Institute in Magdeburg, we addressed both low-level spatial processes (within an "evaluation of distances paradigm") and high-level spatial cognition (using a navigation and visuospatial planning task, called "3D Maps"), trying to address, at the same time, also practical problems as, for example, the use of stereoscopy in VEs or the problem of "Simulator Sickness" during navigation in immersive VEs. The results obtained with our research fill some gaps in literature about spatial cognition in VR and allow us to suggest that the use of VEs in research is quite reliable, mainly if the investigated processes are from the higher level of complexity. In this case, in fact, human brain "adapts" pretty well even to a "new" reality like the one offered by the VR, providing of course a familiarization period and the possibility to interact with the environment; the behavior will then be “like if” the environment was real: what is strongly lacking, at the moment, is the possibility to give a completely multisensorial experience, which is a very important issue in order to get the best from this kind of “visualization” of an artificial world. From a low-level point of view, we can confirm what already found in literature, that there are some basic differences in how our visual system perceives important spatial cues as depth and relationships between objects, and, therefore, we cannot talk about "similar environments" talking about VR and reality. The idea that VR is a "different" reality, offering potentially unlimited possibilities of use, even overcoming some physical limits of the real world, in which this "new" reality can be acquired by our cognitive system just by interacting with it, is therefore discussed in the conclusions of this work