On the assessment of landmark salience for human navigation

In this paper, we propose a conceptual framework for assessing the salience of landmarks for navigation. Landmark salience is derived as a result of the observer's point of view, both physical and cognitive, the surrounding environment, and the objects contained therein. This is in contrast to the currently held view that salience is an inherent property of some spatial feature. Salience, in our approach, is expressed as a three-valued Saliency Vector. The components that determine this vector are Perceptual Salience, which defines the exogenous (or passive) potential of an object or region for acquisition of visual attention, Cognitive Salience, which is an endogenous (or active) mode of orienting attention, triggered by informative cues providing advance information about the target location, and Contextual Salience, which is tightly coupled to modality and task to be performed. This separation between voluntary and involuntary direction of visual attention in dependence of the context allows defining a framework that accounts for the interaction between observer, environment, and landmark. We identify the low-level factors that contribute to each type of salience and suggest a probabilistic approach for their integration. Finally, we discuss the implications, consider restrictions, and explore the scope of the framewor

On the assessment of landmark salience for human navigation

In this paper, we propose a conceptual framework for assessing the salience of landmarks for navigation. Landmark salience is derived as a result of the observer’s point of view, both physical and cognitive, the surrounding environment, and the objects contained therein. This is in contrast to the currently held view that salience is an inherent property of some spatial feature. Salience, in our approach, is expressed as a three-valued Saliency Vector. The components that determine this vector are Perceptual Salience, which defines the exogenous (or passive) potential of an object or region for acquisition of visual attention, Cognitive Salience, which is an endogenous (or active) mode of orienting attention, triggered by informative cues providing advance information about the target location, and Contextual Salience, which is tightly coupled to modality and task to be performed. This separation between voluntary and involuntary direction of visual attention in dependence of the context allows defining a framework that accounts for the interaction between observer, environment, and landmark. We identify the low-level factors that contribute to each type of salience and suggest a probabilistic approach for their integration. Finally, we discuss the implications, consider restrictions, and explore the scope of the framework

Navigational style influences eye movement pattern during exploration and learning of an environmental map

During navigation people may adopt three different spatial styles (i.e., Landmark, Route, and Survey). Landmark style (LS) people are able to recall familiar landmarks but cannot combine them with directional information; Route style (RS) people connect landmarks to each other using egocentric information about direction; Survey style (SS) people use a map-like representation of the environment. SS individuals generally navigate better than LS and RS people. Fifty-one college students (20 LS; 17 RS, and 14 SS) took part in the experiment. The spatial cognitive style (SCS) was assessed by means of the SCS test; participants then had to learn a schematic map of a city, and after 5 min had to recall the path depicted on it. During the learning and delayed recall phases, eye-movements were recorded. Our intent was to investigate whether there is a peculiar way to explore an environmental map related to the individual's spatial style. Results support the presence of differences in the strategy used by the three spatial styles for learning the path and its delayed recall. Specifically, LS individuals produced a greater number of fixations of short duration, while the opposite eye movement pattern characterized SS individuals. Moreover, SS individuals showed a more spread and comprehensive explorative pattern of the map, while LS individuals focused their exploration on the path and related targets. RS individuals showed a pattern of exploration at a level of proficiency between LS and SS individuals. We discuss the clinical and anatomical implications of our data

How touch and hearing influence visual processing in sensory substitution, synaesthesia and cross-modal correspondences

Sensory substitution devices (SSDs) systematically turn visual dimensions into patterns of tactile or auditory stimulation. After training, a user of these devices learns to translate these audio or tactile sensations back into a mental visual picture. Most previous SSDs translate greyscale images using intuitive cross-sensory mappings to help users learn the devices. However more recent SSDs have started to incorporate additional colour dimensions such as saturation and hue. Chapter two examines how previous SSDs have translated the complexities of colour into hearing or touch. The chapter explores if colour is useful for SSD users, how SSD and veridical colour perception differ and how optimal cross-sensory mappings might be considered. After long-term training, some blind users of SSDs report visual sensations from tactile or auditory stimulation. A related phenomena is that of synaesthesia, a condition where stimulation of one modality (i.e. touch) produces an automatic, consistent and vivid sensation in another modality (i.e. vision). Tactile-visual synaesthesia is an extremely rare variant that can shed light on how the tactile-visual system is altered when touch can elicit visual sensations. Chapter three reports a series of investigations on the tactile discrimination abilities and phenomenology of tactile-vision synaesthetes, alongside questionnaire data from synaesthetes unavailable for testing. Chapter four introduces a new SSD to test if the presentation of colour information in sensory substitution affects object and colour discrimination. Chapter five presents experiments on intuitive auditory-colour mappings across a wide variety of sounds. These findings are used to predict the reported colour hallucinations resulting from LSD use while listening to these sounds. Chapter six uses a new sensory substitution device designed to test the utility of these intuitive sound-colour links for visual processing. These findings are discussed with reference to how cross-sensory links, LSD and synaesthesia can inform optimal SSD design for visual processing

3D visualization of cadastre : assessing the suitability of visual variables and enhancement techniques in the 3D model of condominium property units

La visualisation 3D de données cadastrales a été exploitée dans de nombreuses études, car elle offre de nouvelles possibilités d’examiner des situations de supervision verticale des propriétés. Les chercheurs actifs dans ce domaine estiment que la visualisation 3D pourrait fournir aux utilisateurs une compréhension plus intuitive d’une situation où des propriétés se superposent, ainsi qu’une plus grande capacité et avec moins d’ambiguïté de montrer des problèmes potentiels de chevauchement des unités de propriété. Cependant, la visualisation 3D est une approche qui apporte de nombreux défis par rapport à la visualisation 2D. Les précédentes recherches effectuées en cadastre 3D, et qui utilisent la visualisation 3D, ont très peu enquêté l’impact du choix des variables visuelles (ex. couleur, style) sur la prise de décision. Dans l’optique d'améliorer la visualisation 3D de données cadastres, cette thèse de doctorat examine l’adéquation du choix des variables visuelles et des techniques de rehaussement associées afin de produire un modèle de condominium 3D optimal, et ce, en fonction de certaines tâches spécifiques de visualisation. Les tâches visées sont celles dédiées à la compréhension dans l’espace 3D des limites de propriété du condominium. En ce sens, ce sont principalement des tâches notariales qui ont été ciblées. De plus, cette thèse va mettre en lumière les différences de l’impact des variables visuelles entre une visualisation 2D et 3D. Cette thèse identifie dans un premier temps un cadre théorique pour l'interprétation des variables visuelles dans le contexte d’une visualisation 3D et de données cadastrales au regard d’une revue de littéraire. Dans un deuxième temps, des expérimentations ont été réalisées afin de mettre à l’épreuve la performance des variables visuelles (ex. couleur, valeur, texture) et des techniques de rehaussement (transparence, annotation, déplacement). Trois approches distinctes ont été utilisées : 1) discussion directe avec des personnes œuvrant en géomatique, 2) entrevue face à face avec des notaires et 3) questionnaire en ligne avec des groupes ciblés. L’utilisabilité mesurée en termes d’efficacité, d’efficience et de degré de satisfaction a servi aux comparaisons des expérimentations. Les principaux résultats de cette recherche sont : 1) Une liste de tâches visuelles notariales utiles à la délimitation des unités de propriété dans le contexte de la visualisation 3D de condominium ; 2) Des recommandations quant à l'adéquation de huit variables visuelles et de trois techniques de rehaussement afin d’optimiser la réalisation d’un certain nombre de tâches notariales ; 3) Une analyse comparative de la performance de ces variables entre une visualisation 2D et 3D.3D visualization is being widely used in GIS (geographic information system) and CAD (computer-aided design) applications. It has also been introduced in cadastre studies to better communicate overlaps to the viewer, where the property units vertically stretch over or cover one part of the land parcel. Researchers believe that 3D visualization could provide viewers with a more intuitive perception, and it has the capability to demonstrate overlapping property units in condominiums unambiguously. However, 3D visualization has many challenges compared with 2D visualization. Many cadastre researchers adopted 3D visualization without thoroughly investigating the potential users, the visual tasks for decision-making, and the appropriateness of their representation design. Neither designers nor users may be aware of the risk of producing an inadequate 3D visualization, especially in an era when 3D visualization is relatively novel in the cadastre domain. With a general aim to improve the 3D visualization of cadastre data, this dissertation addresses the design of the 3D cadastre model from a graphics semiotics viewpoint including visual variables and enhancement techniques. The research questions are, firstly, what is the suitability of the visual variables and enhancement techniques in the 3D cadastre model to support the intended users' decision-making goal of delimitating condominium property units, and secondly, what are the perceptual properties of visual variables in 3D visualization compared with 2D visualization? This dissertation firstly identifies the theoretical framework for the interpretation of visual variables in 3D visualization as well as cadastre-related knowledge with literature review. Then, we carry out a preliminary evaluation of the feasibility of visual variables and enhancement techniques in a form of an expert-group review. With the result of the preliminary evaluation, this research then performs the hypothetico-deductive scientific approach to establishing a list of hypotheses to be validated by empirical tests regarding the suitability of visual variables and enhancement techniques in a cartographic representation of property units in condominiums for 3D visualization. The evaluation is based on the usability specification, which contains three measurements: effectiveness, efficiency, and preference. Several empirical tests are conducted with cadastral users in the forms of face-to-face interviews and online questionnaires, followed by statistical analysis. Size, shape, brightness, saturation, hue, orientation, texture, and transparency are the most discussed and used visual variables in existing cartographic research and implementations; thus, these eight visual variables have been involved in the tests. Their perceptual properties exhibited in the empirical test with concrete 3D models in this work are compared with those in a 2D visualization, which is derived from a literature-based synthesis. Three enhancement techniques, including labeling, 3D explosion, and highlighting, are tested as well. There are three main outcomes of this work. First, we established a list of visual tasks adapted to notaries for delimiting property units in the context of 3D visualization of condominium cadastres. Second, we describe the suitability of eight visual variables (Size, Shape, Brightness, Saturation, Hue, Orientation, Texture, and Transparency) of the property units and three enhancement techniques (labeling, 3D explosion and highlighting) in the context of 3D visualisation of condominium property units, based on the usability specification for delimitating visual tasks. For example, brightness only shows good performance in helping users distinguish private and common parts in the context of 3D visualization of property units in condominiums. As well, color hue and saturation are effective and preferable. The third outcome is a statement of the perceptual properties’ differences of visual variables between 3D visualization and 2D visualization. For example, according to Bertin (1983)’s definition, orientation is associative and selective in 2D, yet it does not perform in a 3D visualization. In addition, 3D visualization affects the performance of brightness, making it marginally dissociative and selective

Change blindness: eradication of gestalt strategies

Arrays of eight, texture-defined rectangles were used as stimuli in a one-shot change blindness (CB) task where there was a 50% chance that one rectangle would change orientation between two successive presentations separated by an interval. CB was eliminated by cueing the target rectangle in the first stimulus, reduced by cueing in the interval and unaffected by cueing in the second presentation. This supports the idea that a representation was formed that persisted through the interval before being 'overwritten' by the second presentation (Landman et al, 2003 Vision Research 43149–164]. Another possibility is that participants used some kind of grouping or Gestalt strategy. To test this we changed the spatial position of the rectangles in the second presentation by shifting them along imaginary spokes (by ±1 degree) emanating from the central fixation point. There was no significant difference seen in performance between this and the standard task [F(1,4)=2.565, p=0.185]. This may suggest two things: (i) Gestalt grouping is not used as a strategy in these tasks, and (ii) it gives further weight to the argument that objects may be stored and retrieved from a pre-attentional store during this task

Assessing landmark salience for human navigation

Prominent spatial features play an important role for a plethora of spatially related tasks, including spatial learning, wayfinding and navigation, and the communication of route directions. Human judgment of the prominence or importance of these spatial features, for which the term landmark became popular, is typically based on subjective impressions and experience. The computational assessment of the prominence of these spatial objects is of interest to various scientific disciplines and applications, including spatially related information and navigation systems. Computational salience assessment, however, is highly challenging, as information systems need objective criteria and formalized techniques to reproduce human judgment of landmark salience. We propose a conceptual framework for assessing the salience of landmarks for navigation. Landmark salience is derived as a result of the observer's point of view, both physical and cognitive, the surrounding environment, and the objects contained therein. This is in contrast to the currently held view that salience is an inherent property of some spatial feature. Salience, in our approach, is expressed as a three-valued Saliency Vector. The components that determine this vector are Perceptual Salience, which defines the exogenous (or passive) potential of an object or region for acquisition of visual attention, Cognitive Salience, which is an endogenous (or active) mode of orienting attention, triggered by informative cues providing advance information about the target location, and Contextual Salience, which is tightly coupled to modality and task to be performed. This separation between voluntary and involuntary direction of visual attention in dependence of the context allows defining a framework that accounts for the interaction between observer, environment, and landmark. We identify the low-level factors that contribute to each type of salience and suggest a probabilistic approach for their integration. The framework serves as a bridge between findings from spatial cognition research and practical applications, and forms the basis for a computational model, which is used as test-bed for the evaluation of the concepts and methods developed within the scope of this work. The evaluation includes a comparison with human assessment of salience and provides the evidence for assessing the quality of the model. The results of this comparison suggest that the conceptual framework provides reasonably accurate assessments of saliency for perceptually distinct objects, but also identifies two major issues. The first relates to a systematic weighting issue of low-level components due to the proposed technique for the integrated saliency assessment, and the second aspect is the indication that the model lacks explanatory power due to the limited number of low- level components, in particular for cognitive components.Prominente räumliche Objekte spielen eine wichtig Rolle bei einer Vielzahl von raumbezogenen Aufgaben, wie zum Beispiel beim Erlernen der räumlichen Umgebung, bei der Wegfindung und Navigation, oder auch bei der Kommunikation von Routenbeschreibungen. Menschen beurteilen die Prominenz solcher Objekte, welche oft auch als Landmarken bezeichnet werden, aufgrund subjektiver Eindrücke und Erfahrungen. Die automatische Abschätzung dieser Prominenz mithilfe von Berechnungsmodelle und Algorithmen ist ausschlaggebend für die Entwicklung und Implementierung von Informationssystemen der nächsten Generation. Allerdings ist diese automatische Abschätzung sehr komplex und anspruchsvoll, da Informationssysteme weder subjektive Eindrücke verarbeiten noch über Erfahrungen verfügen, sondern auf formalisierte Methoden und Techniken angewiesen sind. Diese Dissertation befasst sich mit den konzeptuellen Rahmenbedingungen die zu einer akkuraten automatischen Abschätzung der Prominenz von Landmarken notwendig sind, wobei Prominenz als Salienz verstanden wird, also das Hervorspringen oder Hervorstehen eines Objekts aus einer Gruppe von Objekten. Die Salienz von räumlichen Objekten ist abgeleitet von drei zentralen Komponenten, nämlich 1) vom physischen und kognitivem Standpunkt des Beobachters, 2) von den Gegebenheiten der räumlichen Umgebung, und 3) von den einzelnen Objekten die sich im Wahrnehmungsbereich des Beobachters befinden. Die Salienz ist dementsprechend als drei-dimensionaler Vektor definiert, bestehend aus einer Wahrnehmungskomponente, einer Kognitionskomponente, und einer Kontextkomponente. Der konzeptuelle Rahmen diente dazu, Forschungsresultate aus verschiedenen wissenschaftlichen Disziplinen zu integrieren und ein Berechnungsmodel und Prototyp zu erstellen, welches als Testumgebung für die Evaluierung der angewandten Konzepte und Methoden, sowie für weitere Forschungsprojekte benutzt werden kann. Die Evaluierung besteht aus einem Vergleich der Resultate mit den Resultaten einer entsprechenden Umfrage und dient dazu, die Qualität des Berechnungsmodels abzuschätzen. Die Ergebnisse der Evaluierung zeigen dass der konzeptuelle Rahmen und das Berechnungsmodell tendenziell korrekte Abschätzungen der Salienz von Landmarken produzieren. Die Ergebnisse zeigen aber auch auf dass das Model Schwächen und Lücken hat, vor allem in Bezug auf die einzelnen Komponenten die zur Salienz beitragen

Elements of design for indoor visualisation

Indoor visualisation has received little attention. Research related to indoor environments have primarily focussed on the data structuring, localisation and navigation components (Zlatanova et al., 2013). Visualisation is an integral component in addressing the diverse array of indoor environments. In simple words, 'What is the most efficient way to visualise the surrounding indoor environment so that the user can concisely understand their surroundings as well as facilitating the process of navigation?' This dissertation proposes a holistic approach that consists of two components. The significance of this approach is that it provides a robust and adaptable method in providing a standard to which indoor visualisation can be referenced against. The first component is a theoretical framework focussing on indoor visualisation and it comprises of principles from several disciplines such as geovisualisation, human-perception theory, spatial cognition, dynamic and 3D environments as well as accommodating emotional processes resulting from human-computer interaction. The second component is based on the theoretical framework and adopts a practical approach towards indoor visualisation. It consists of a set of design properties that can be used for the design of effective indoor visualisations. The framework is referred to as the "Elements of Design" framework. Both these components aim to provide a set of principles and guidelines that can be used as best practices for the design of indoor visualisations. In order to practically demonstrate the holistic indoor visualisation approach, multiple indoor visualisation renderings were developed. The visualisation renderings were represented in a three-dimensional virtual environment from a first-person perspective. Each rendering used the design framework differently. Also, each rendering was graded using a parallel chart that compares how the different visual elements were used per the rendering. The main findings were that the techniques/ renderings that used the visual elements effectively (enhanced human-perception) resulted in better acquisition and construction of knowledge about the surrounding indoor environment

The Aha! Experience of Spatial Reorientation

The experience of spatial re-orientation is investigated as an instance of the wellknown phenomenon of the Aha! moment. The research question is: What are the visuospatial conditions that are most likely to trigger the spatial Aha! experience? The literature suggests that spatial re-orientation relies mainly on the geometry of the environment and a visibility graph analysis is used to quantify the visuospatial information. Theories from environmental psychology point towards two hypotheses. The Aha! experience may be triggered by a change in the amount of visual information, described by the isovist properties of area and revelation, or by a change in the complexity of the visual information associated with the isovist properties of clustering coefficient and visual control. Data from participants’ exploratory behaviour and EEG recordings are collected during wayfinding in virtual reality urban environments. Two types of events are of interest here: (a) sudden changes of the visuospatial information preceding subjects' response to investigate changes in EEG power; and (b) participants brain dynamics (Aha! effect) just before the response to examine differences in isovist values at this location. Research on insights, time-frequency analysis of the P3 component and findings from navigation and orientation studies suggest that the spatial Aha! experience may be reflected by: a parietal alpha power decrease associated with the switch of the representation and a frontocentral theta increase indexing spatial processing during decision-making. Single-trial time-frequency analysis is used to classify trials into two conditions based on the alpha/theta power differences between a 3s time-period before participants’ response and a time-period of equal duration before that. Behavioural results show that participants are more likely to respond at locations with low values of clustering coefficient and high values of visual control. The EEG analysis suggests that the alpha decrease/theta increase condition occurs at locations with significantly lower values of clustering coefficient and higher values of visual control. Small and large decreases in clustering coefficient, just before the response, are associated with significant differences in delta/theta power. The values of area and revelation do not show significant differences. Both behavioural and EEG results suggest that the Aha! experience of re-orientation is more likely to be triggered by a change in the complexity of the visual-spatial environment rather than a change in the amount, as measured by the relevant isovist properties

Architecture and urban design as influences on the communication of place and experience in graphic design

Most architects and urban designers are challenged to design schemas and structures to create a particular experience and sense of place. It is through the manipulation and design of actual three-dimensional spaces that they are able to achieve this. How then is a three-dimensional experience of a place conveyed in two dimensions? Distilling an actual experience into a graphic solution can be exceptionally challenging, but graphic designers may need to accomplish this for particular clients. Examining the ideologies and methodologies of architecture and urban design may offer new and thoughtful approaches for graphic interpretations of three-dimensional experiences. This thesis first examines how a sense of place is created by architecture and urban design solutions through careful considerations related to culture, history, community and environment. The realm of actual places exists in three-dimensions, rather than two-dimensions. However, there are many instances when it is beneficial to distill three-dimensional experiences into two-dimensional formats (i.e. tourism materials, cookbooks, school catalogues) to help visually and verbally summarize and communicate an environment or experience to an audience. This study draws parallels to the field of graphic design from architecture and urban design, to establish ways in which these goals can be effectively communicated through a graphic design solution