Navigation In Virtual Environments Research Articles

RPM: An open-source Rotation Platform for open- and closed-loop vestibular stimulation in head-fixed Mice

Head fixation allows the recording and presentation of controlled stimuli and is used to study neural processes underlying spatial navigation. However, it disrupts the head direction system because of the lack of vestibular stimulation. To overcome this limitation, we developed a novel rotation platform which can be driven by the experimenter (open-loop) or by animal movement (closed-loop). The platform is modular, affordable, easy to build and open source. Additional modules presented here include cameras for monitoring eye movements, visual virtual reality, and a micro-manipulator for positioning various probes for recording or optical interference. We demonstrate the utility of the platform by recording eye movements and showing the robust activation of head-direction cells. This novel experimental apparatus combines the advantages of head fixation and intact vestibular activity in the horizontal plane. The open-loop mode can be used to study e.g., vestibular sensory representation and processing, while the closed-loop mode allows animals to navigate in rotational space, providing a better substrate for 2-D navigation in virtual environments. The full build documentation is maintained at https://ranczlab.github.io/RPM/.

Changes in Navigation Controls and Field-of-View Modes Affect Cybersickness Severity and Spatiotemporal Gait Patterns After Exposure to Virtual Environments.

To examine the effects of navigation controls and field-of-view modes on cybersickness severity and gait dynamics after cessation of exposure to a virtual environment (VE). The applications of virtual reality are increasing in various fields; however, whether changes in interaction techniques and visual contents could mitigate the potential gait disturbance following VE exposure remains unclear. Thirty healthy adults wore a head-mounted display to complete six sessions of 12-min run-and-gun tasks using different navigation controls (gamepad, head, natural) and field-of-view modes (full, restricted). Forward and backward walking tasks were performed before and after VE exposure. The degrees of cybersickness and presence were evaluated using questionnaires, along with the in-session task performance. Spatiotemporal gait measures and their variabilities were calculated for each walking task. The participants experienced less cybersickness with the head and natural controls than with the gamepad. Natural control, based on matching body movements, was associated with the highest degree of presence and best performance. VE navigation using the gamepad showed reduced cadences and increased stride times during postexposure forward-walking tasks. When the VE was presented via the restricted field-of-view mode, increased gait variabilities were observed from backward-walking tasks after VE exposure. Body movement-based navigation controls may alleviate cybersickness. We observed gait adaptation during both ambulation tasks, which was influenced by the navigation control method and field-of-view mode. This study provides the first evidence for gait adaptation during balance-demanding tasks after VE exposure, which is valuable for designing guidelines for virtual reality interactions.

Trails, rails, and over-reliance: How navigation assistance affects route-finding and spatial learning in virtual environments

Many novices struggle with navigation in 3D virtual environments — they frequently get lost and are unable to find objects and locations. In some virtual environments, novices are provided with navigation assistance (e.g., mini-maps, directional markers, or glowing trails) that help them move around in the world. However, it is possible that providing navigation assistance could lead to over-reliance, where the novice’s dependence on the assist means that they never develop a mental model of the environment that would allow them to navigate on their own. To investigate both the benefits and potential risks of navigation assistance in virtual environments, we carried out two online studies in which participants carried out route-finding tasks with different types of navigation assistance. Participants completed training trials, in which they practised a set of routes with the assist, and transfer trials, in which they had to navigate without the assist. The studies focus on two questions: whether assistance improves performance and user experience when it is present, and whether assistance leads to over-reliance and a drop in performance when the assist is removed. For the first question, both studies found that navigation assistance substantially improved performance and subjective experience while it was present — clearly showing that assistance can improve virtual environments for novices. For the second question, we found mixed evidence regarding the problem of over-reliance: the first study showed no performance differences between the highest and lowest levels of navigation assistance when the assist was turned off; the second study showed that there was a performance reduction when the assist was removed, but that the size of the reduction was much smaller than the improvement provided during training. We found that even when the navigation assist was extreme (e.g., pressing a button to be automatically taken in the correct direction), participants were still able to navigate the trained routes, suggesting that incidental learning does successfully occur in virtual environments. Our studies suggest that designers of virtual environments should strongly consider providing navigation assistance: assists can improve a novice user’s performance and experience by reducing navigation problems, and the risks of over-reliance appear to be small in comparison to the benefits for inexperienced users.

Translating spatial navigation evaluation from experimental to clinical settings: The virtual environments navigation assessment (VIENNA)

Spatial navigation abilities are frequently impaired in neurological disorders and they also decline with normal aging. Researchers and clinicians therefore need valid and easy-to-use spatial navigation assessment tools to study the impact of different neuropathologies and prevent relevant cognitive impairments from going undetected. However, current experimental paradigms rarely address which cognitive processes they recruit, often have resource-intensive setups, and usually require active navigation, e.g., using a joystick or keyboard, thus confounding cognitive performance with fine motor skills. Yet, for clinical feasibility, time-efficient paradigms are needed that are informative and easy to administer in participants with limited technical experience and diverging impairments. Here, we introduce the virtual environments navigation assessment (VIENNA), a virtual adaptation of a brief, standardized, and intuitive spatial navigation paradigm (https://osf.io/kp4c5/). VIENNA is designed to assess spatial navigation without episodic memory demands, requires no interface device, and takes about 16 min to complete. We evaluated VIENNA in 79 healthy middle-aged to older participants (50–85 years) and provide evidence for its feasibility and construct validity. Tests of visuospatial and executive functions, but not episodic memory or selective attention, were identified as cognitive correlates of VIENNA, even when controlling for participant age and overall cognitive performance. Furthermore, VIENNA scores correlated with subjective navigation ability and age, but not with depressiveness, cognitive complaints, or education. The straightforward administration of VIENNA allows for its integration into routine neuropsychological assessments and enables differentiated evaluation of spatial navigation performance in patients with motor impairments and episodic memory deficits.

Using spontaneous eye blink-related brain activity to investigate cognitive load during mobile map-assisted navigation.

The continuous assessment of pedestrians' cognitive load during a naturalistic mobile map-assisted navigation task is challenging because of limited experimental control over stimulus presentation, human-map-interactions, and other participant responses. To overcome this challenge, the present study takes advantage of navigators' spontaneous eye blinks during navigation to serve as event markers in continuously recorded electroencephalography (EEG) data to assess cognitive load in a mobile map-assisted navigation task. We examined if and how displaying different numbers of landmarks (3 vs. 5 vs. 7) on mobile maps along a given route would influence navigators' cognitive load during navigation in virtual urban environments. Cognitive load was assessed by the peak amplitudes of the blink-related fronto-central N2 and parieto-occipital P3. Our results show increased parieto-occipital P3 amplitude indicating higher cognitive load in the 7-landmark condition, compared to showing 3 or 5 landmarks. Our prior research already demonstrated that participants acquire more spatial knowledge in the 5- and 7-landmark conditions compared to the 3-landmark condition. Together with the current study, we find that showing 5 landmarks, compared to 3 or 7 landmarks, improved spatial learning without overtaxing cognitive load during navigation in different urban environments. Our findings also indicate a possible cognitive load spillover effect during map-assisted wayfinding whereby cognitive load during map viewing might have affected cognitive load during goal-directed locomotion in the environment or vice versa. Our research demonstrates that users' cognitive load and spatial learning should be considered together when designing the display of future navigation aids and that navigators' eye blinks can serve as useful event makers to parse continuous human brain dynamics reflecting cognitive load in naturalistic settings.

Gesture-based guidance for navigation in virtual environments

Gesture-based guidance for navigation in virtual environments

Synthesizing scene-aware virtual reality teleport graphs

We present a novel approach for synthesizing scene-aware virtual reality teleport graphs, which facilitate navigation in indoor virtual environments by suggesting desirable teleport positions. Our approach analyzes panoramic views at candidate teleport positions by extracting scene perception graphs, which encode scene perception relationships between the observer and the surrounding objects, and predict how desirable the views at these positions are. We train a graph convolutional model to predict the scene perception scores of different teleport positions. Based on such predictions, we apply an optimization approach to sample a set of desirable teleport positions while considering other navigation properties such as coverage and connectivity to synthesize a teleport graph. Using teleport graphs, users can navigate virtual environments efficaciously. We demonstrate our approach for synthesizing teleport graphs for common indoor scenes. By conducting a user study, we validate the efficacy and desirability of navigating virtual environments via the synthesized teleport graphs. We also extend our approach to cope with different constraints, user preferences, and practical scenarios.

Evaluation of locomotion methods in virtual reality navigation environments: An involuntary position shift and task performance

• Effects of four locomotion methods on user safety and performance were examined • Walking in place and running in place can cause involuntary movements of the user • For each locomotion method, larger involuntary movements were found in the turning course than in the straight course • Teleportation required the shortest task completion time, but the error time ratio was the largest • The safety issue of the users’ involuntary movement should be solved Navigation is a representative task in a virtual environment (VE). The locomotion methods affect the navigation performance and can cause involuntary movements by the users, which may cause critical safety problems. Thus, this study examined the effects of different locomotion methods on the users’ involuntary position shift (IPS) and navigation performance in a VE. Twenty-one healthy participants performed the navigation task with four locomotion methods: walking in place (WIP), running in place (RIP), joystick, and teleportation. The results showed that a larger amount of IPS occurred with VE navigation under WIP and RIP conditions than joystick and teleportation conditions, which may cause critical safety problems, such as collisions with walls. Moreover, teleportation took the shortest task completion time, but its error time ratio was the largest. These results are expected to help develop basic guidelines for applying locomotion methods to specific situations and establishing safety precautions for virtual reality experiences.

Natural Interaction Design for Navigation in Virtual Environment of Sino-Portuguese Architecture in Museum

Virtual Environment (VE) is an artificial environment created for providing the information in Virtual Reality (VR). The audiences are able to obtain the information via interaction to the environment. Virtual Reality for Culture heritage buildings, which are inherited from past generations and maintained in the present, is an interested topic because its contents often built for giving the information and knowledge about the past to the new generation in virtual museums. However, there is a limitation of Virtual Reality (VR) applications in reproducing cultural sites as most of these applications are not successful in catching public’s attention and involvement. In this research, we focus on using Natural Interaction (NI) interfaces based on a body movement in Virtual Reality for museums to grab attention from audience and to increase public’s involvement. This paper presents the development of Natural Interaction using Microsoft Kinect to define the new grammar of gesture for Sino Portuguese Architecture which is a cultural heritage of Thailand. Results of early tests improved the prototype in progress which alllows more complexity in natural interchanges and connection between users and virtual world. The final result was evaluated after the system was installed in Peranakannitat museum and by interviewing 6 docents. It was found that our system was easy to use as it took only about 3 - 5 min to familiarize the system for navigation in the virtual environment without recognizing the grammar of gesture commands.

A comparative study on user gestural inputs for navigation in NUI-based 3D virtual environments

This paper describes the results of a case study intended to compare three different user movement paradigms (metaphoric, symbolic and natural) designed to control the visit of virtual environments for a NUI-based museum installation. It also evaluates the effects of previous expertise with 3D video games in the results for users that took part in the study. The study evaluates the performance of each movement scheme for the navigation of the environment, the degree of intuitiveness perceived by the users, and the user experience. The analysis is based on the data collected in an experiment with 28 participants sorted into two groups, separating users with less previous expertise in 3D videogames from those who considered themselves as frequent players. During the experiment, the participants completed two different tasks with every movement scheme in random order. During the course of the test, the system monitored and recorded the user movements in order to extract relevant data about time to complete the task, number of collisions and time spent in a collision condition. A post-task questionnaire was carried out immediately after completion of every task. At the end of the session, users also took a test questionnaire. In addition, the authors asked users for general comments and recommendations for improvement. The results show that the natural movement scheme stands out as the most adequate for the contemplation of the virtual environment and the most balanced at a general level for the three variables considered. The symbolic scheme proved the most efficient. The natural movement scheme and symbolic scheme appear to be the most appropriate to navigate such digital environments as those present in museum installations for any kind of user.

User Lighting Preferences Based on Navigation and Space Quality in Virtual Exhibition Environments

Just as any other interior environment, lighting of exhibition spaces must be examined to enhance its visual quality and comfort. In this study, user behaviour, perception and impressions are analyzed for more comprehensive understanding by including subjective reasoning. Due to the chaotic progress and contradictory choices in exhibition lighting, daylight is mostly avoided while the role of users and relation between quantitative and qualitative parameters are often neglected. A series of sample exhibition spaces illuminated either artificially or by daylight are modelled virtually in Lumion software to be evaluated in a three-step questionnaire. A total of 90 participants are selected from three different professions (architects, visitors, artists), their reaction like movement, preference and impressions are gathered via questionnaire while moving through the model. The study aims to find out the role of lighting type in exhibition navigation and its relation with non-lighting parameters using statistical analysis methods. Results show that natural light is preferred more in sculpture exhibition while artificial light is preferred in painting exhibition. Movement towards daylight increases in transition areas and towards the end of the exhibition. A significant difference in navigation choices are found between professions, architects preferred to move towards more natural light while artists preferred artificial light.

Evaluating the user experience of omnidirectional VR walking simulators

Omnidirectional treadmills (ODTs) have been traditionally proposed as a promising solution for users’ navigation in large-scale virtual environments. These mechanical devices enable users to perform locomotive motion with 360-deg freedom, while keeping their position fixed in the physical world. However, most locomotion approaches based on omnidirectional treadmills have presented either high acquisition or maintenance costs, being the capabilities of the general public, or a limited reliability. In this paper, we present a comparative usability and acceptance study with real users evaluating the two most common approaches for the development of this type of Virtual Reality (VR) walking simulators, whether flat-based or bowl-based omnidirectional treadmills. The results of our study indicate that both design alternatives accomplish a similar performance and can be considered as personal, low-cost walking simulators for navigation in virtual environments. Nevertheless, when compared between themselves, the users preferred the bowl-based omnidirectional VR treadmill when following three different selection criteria: overall preference, recommendation, and usefulness. Last, a correlation analysis showed statically significant correspondences among the parameters concerning to the simulation presence, which in turn, are related to the global scores and responses given by the participants of the Virtual Reality experiment.

Psychometric evaluation of Simulator Sickness Questionnaire and its variants as a measure of cybersickness in consumer virtual environments

Cybersickness, i.e. visually induced motion sickness, remains as a negative effect that is detrimental to the user experience of VEs (virtual environments) developed for VR (virtual reality) consumers. As the VR technology evolves, it is rather triggered by application aspects rather than hardware limitations. For this reason, there is still a need for a measurement method to assess and compare VEs for cybersickness effects.SSQ (Simulation Sickness Questionnaire) is used for measuring users’ level of sickness symptoms and is highly appreciated in VR research. However, it is criticized for its psychometric qualities and applicability in VR, as a measure of cybersickness. Recently, two variants of SSQ were offered for measuring cybersickness, CSQ (Cybersickness Questionnaire) and VRSQ (Virtual Reality Sickness Questionnaire). There is also another variant with a different factor structure, which we call FSSQ, that is based on French translation of SSQ.Our study compares SSQ and these variants for their psychometric qualities; construct validity, discriminant validity, internal reliability, test-retest reliability and sensitivity to distinguish application aspects of VEs that are related to cybersickness. Using a within-subjects experiment design, we evaluated 7 different VEs with 32 participants through 9 sessions, resulting with 288 responses to the 16-item SSQ. Results suggested that both VRSQ and CSQ were valid and reliable measures of cybersickness, as well as being sensitive to application aspects such as translational and rotational movements required by users for navigation in VEs. Compared to SSQ and FSSQ; the cybersickness questionnaires, CSQ and VRSQ, revealed better indicators of validity. On the other hand, we assume that the development of the two cybersickness scales had limitations in sample size to represent VR consumers and limitations in stimuli to represent the applications aspects of consumer VEs. We suggest further evaluation of cybersickness symptoms with larger samples and broader range of applications to identify the symptoms and the construct of a subjective measurement tool.

DOP: Discover Objects and Paths, a model for automated navigation and selection in virtual environments

DOP: Discover Objects and Paths, a model for automated navigation and selection in virtual environments

Evaluation of diagnostician user interface aspects in a virtual reality-based tele-ultrasonography simulation

ABSTRACT Ultrasonography (USG) is a common medical examination that can be performed remotely and that highly benefits from robotics. In this paper, we evaluate a novel interface for a telediagnosis system that features haptic feedback and a 2D/3D visualization of the remote site. A Virtual Environment (VE) representing the patient site was used for the validation to stress the interaction capabilities of the interface and to decouple expert's interface performance from the effects of the whole teleoperation loop of a telediagnosis system. The interface evaluation measures include the accuracy that doctors achieve when positioning the interface's end-effector in the VE and the success of experts to perform tasks related to cardiac USG that require force feedback. Twelve experienced sonographers performed four experiments in which visualization modality and VE navigation technique varied. Given the limitations of an evaluation in simulated settings, both quantitative results and experts' opinions suggest that the interface is suitable for integration in tele-USG systems. After a positive evaluation of latencies and rendered forces, we show how navigation condition influences the accuracy of the end-effector positioning as well as the covered distance and the elapsed time to accomplish the tasks. Similarly, we highlight the effect of visualization on accuracy.

Spatial Analysis of Navigation in Virtual Geographic Environments

Human performance and navigation activity in virtual environments can be measured and assessed with the aim to draw specific conclusions about human cognition. This paper presents an original virtual geographic environment (VGE) designed and used for this purpose. The presented research is rooted in an interdisciplinary approach combining knowledge and principles from the fields of psychology, cartography, and information technologies. The VGE was embedded with user logging functionality to provide a basis from which conclusions about human cognitive processes in a VGE could be drawn. The scope of this solution is introduced, described, and discussed under a behavioral measurement framework. An exploratory research design was adopted to demonstrate the environment’s utility in proof-of-concept user testing. Twenty participants were observed in interactive, semi-interactive and non-interactive tasks, their performance and individual differences were analyzed. The behavioral measurements were supplemented by Object-Spatial Imagery and a Verbal Questionnaire to determine the participants’ cognitive styles. In this sample, significant differences in exploration strategies between men and women were detected. Differences between experienced and non-experienced users were also found in their ability to identify spatial relations in virtual scenes. Finally, areas for future research areas and development were pinpointed.

Active Navigation in Virtual Environments Benefits Spatial Memory in Older Adults.

We investigated age differences in memory for spatial routes that were either actively or passively encoded. A series of virtual environments were created and presented to 20 younger (Mean age = 19.71) and 20 older (Mean age = 74.55) adults, through a cardboard viewer. During encoding, participants explored routes presented within city, park, and mall virtual environments, and were later asked to re-trace their travelled routes. Critically, participants encoded half the virtual environments by passively viewing a guided tour along a pre-selected route, and half through active exploration with volitional control of their movements by using a button press on the viewer. During retrieval, participants were placed in the same starting location and asked to retrace the previously traveled route. We calculated the percentage overlap in the paths travelled at encoding and retrieval, as an indicator of spatial memory accuracy, and examined various measures indexing individual differences in their cognitive approach and visuo-spatial processing abilities. Results showed that active navigation, compared to passive viewing during encoding, resulted in a higher accuracy in spatial memory, with the magnitude of this memory enhancement being significantly larger in older than in younger adults. Regression analyses showed that age and score on the Hooper Visual Organizational test predicted spatial memory accuracy, following the passive and active encoding of routes. The model predicting accuracy following active encoding additionally included the distance of stops from an intersection as a significant predictor, illuminating a cognitive approach that specifically contributes to memory benefits in following active navigation. Results suggest that age-related deficits in spatial memory can be reduced by active encoding.

Navigating Virtual Environments Using Leg Poses and Smartphone Sensors.

Realization of navigation in virtual environments remains a challenge as it involves complex operating conditions. Decomposition of such complexity is attainable by fusion of sensors and machine learning techniques. Identifying the right combination of sensory information and the appropriate machine learning technique is a vital ingredient for translating physical actions to virtual movements. The contributions of our work include: (i) Synchronization of actions and movements using suitable multiple sensor units, and (ii) selection of the significant features and an appropriate algorithm to process them. This work proposes an innovative approach that allows users to move in virtual environments by simply moving their legs towards the desired direction. The necessary hardware includes only a smartphone that is strapped to the subjects’ lower leg. Data from the gyroscope, accelerometer and campus sensors of the mobile device are transmitted to a PC where the movement is accurately identified using a combination of machine learning techniques. Once the desired movement is identified, the movement of the virtual avatar in the virtual environment is realized. After pre-processing the sensor data using the box plot outliers approach, it is observed that Artificial Neural Networks provided the highest movement identification accuracy of 84.2% on the training dataset and 84.1% on testing dataset.

Two Hand Gesture Based 3D Navigation in Virtual Environments

Natural interaction is gaining popularity due to its simple, attractive, and realistic nature, which realizes direct Human Computer Interaction (HCI). In this paper, we presented a novel two hand gesture based interaction technique for 3 dimensional (3D) navigation in Virtual Environments (VEs). The system used computer vision techniques for the detection of hand gestures (colored thumbs) from real scene and performed different navigation (forward, backward, up, down, left, and right) tasks in the VE. The proposed technique also allow users to efficiently control speed during navigation. The proposed technique is implemented via a VE for experimental purposes. Forty (40) participants performed the experimental study. Experiments revealed that the proposed technique is feasible, easy to learn and use, having less cognitive load on users. Finally gesture recognition engines were used to assess the accuracy and performance of the proposed gestures. kNN achieved high accuracy rates (95.7%) as compared to SVM (95.3%). kNN also has high performance rates in terms of training time (3.16 secs) and prediction speed (6600 obs/sec) as compared to SVM with 6.40 secs and 2900 obs/sec.

MazeSuite 3: A design, presentation and analysis platform for spatial navigation, cognitive neuroscience and neuroengineering applications

MazeSuite 3: A design, presentation and analysis platform for spatial navigation, cognitive neuroscience and neuroengineering applications