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Perspective Switching in Virtual Environments
When exploring new environments, people regularly alternate among many sources of spatial information including direct visual input, navigation aids such as maps and mobile devices, and verbal route descriptions. These spatial representations typically depict the environment from one of two perspectives: first-person, embedded route perspective or top-down, bird's eye survey perspective. Visual spatial cognition research has explored the nature of learning within each of these perspectives independently, but little work has been done to explore how on-line visual processing of combined perspectives affects cognition, meaning there is little understanding of the cognitive costs of using different navigation tools to learn large-scale environments. This dissertation addresses such questions through two experiments that guide participants through simple paths in large-scale environments, each consisting of a simple path through a small virtual town presented on a desktop computer display. By timing participants' movement through each environment and how they respond to either externally-controlled or participant-controlled perspective switches, the experiments measure the cognitive load of visually processing dynamic perspectives during navigation. These on-line processing measures are complemented by tests of visual recognition and recall memory, which reveal how switching perspectives affects the accuracy of the resulting spatial mental model. The results indicate that the cognitive load associated with changing perspectives is primarily dependent on the quantity of visual information the change introduces -- the transformation itself is not particularly disorienting after the first exposure to the environment. Furthermore, although forced perspective switches do not appear to significantly affect spatial memory accuracy relative to viewing the environment from a consistent perspective, navigator-controlled switching results in significantly more accurate spatial memory, indicating that navigation aids which allow for perspective control might better support spatial learning than fixed-perspective interfaces. The findings also support previous research showing that route perspective navigation generally yields more accurate spatial memory than survey perspective learning, particularly after extensive experience in the environment. Overall, the findings demonstrate many new aspects of how perspective affects spatial cognition, with implications for spatial learning and the design of navigation aids
Catch Me If You Hear Me: Audio-Visual Navigation in Complex Unmapped Environments with Moving Sounds
Audio-visual navigation combines sight and hearing to navigate to a
sound-emitting source in an unmapped environment. While recent approaches have
demonstrated the benefits of audio input to detect and find the goal, they
focus on clean and static sound sources and struggle to generalize to unheard
sounds. In this work, we propose the novel dynamic audio-visual navigation
benchmark which requires catching a moving sound source in an environment with
noisy and distracting sounds, posing a range of new challenges. We introduce a
reinforcement learning approach that learns a robust navigation policy for
these complex settings. To achieve this, we propose an architecture that fuses
audio-visual information in the spatial feature space to learn correlations of
geometric information inherent in both local maps and audio signals. We
demonstrate that our approach consistently outperforms the current
state-of-the-art by a large margin across all tasks of moving sounds, unheard
sounds, and noisy environments, on two challenging 3D scanned real-world
environments, namely Matterport3D and Replica. The benchmark is available at
http://dav-nav.cs.uni-freiburg.de
Human Motion Trajectory Prediction: A Survey
With growing numbers of intelligent autonomous systems in human environments,
the ability of such systems to perceive, understand and anticipate human
behavior becomes increasingly important. Specifically, predicting future
positions of dynamic agents and planning considering such predictions are key
tasks for self-driving vehicles, service robots and advanced surveillance
systems. This paper provides a survey of human motion trajectory prediction. We
review, analyze and structure a large selection of work from different
communities and propose a taxonomy that categorizes existing methods based on
the motion modeling approach and level of contextual information used. We
provide an overview of the existing datasets and performance metrics. We
discuss limitations of the state of the art and outline directions for further
research.Comment: Submitted to the International Journal of Robotics Research (IJRR),
37 page
Social Attention: Modeling Attention in Human Crowds
Robots that navigate through human crowds need to be able to plan safe,
efficient, and human predictable trajectories. This is a particularly
challenging problem as it requires the robot to predict future human
trajectories within a crowd where everyone implicitly cooperates with each
other to avoid collisions. Previous approaches to human trajectory prediction
have modeled the interactions between humans as a function of proximity.
However, that is not necessarily true as some people in our immediate vicinity
moving in the same direction might not be as important as other people that are
further away, but that might collide with us in the future. In this work, we
propose Social Attention, a novel trajectory prediction model that captures the
relative importance of each person when navigating in the crowd, irrespective
of their proximity. We demonstrate the performance of our method against a
state-of-the-art approach on two publicly available crowd datasets and analyze
the trained attention model to gain a better understanding of which surrounding
agents humans attend to, when navigating in a crowd
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