2,954 research outputs found
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
Transformer Networks for Trajectory Forecasting
Most recent successes on forecasting the people motion are based on LSTM
models and all most recent progress has been achieved by modelling the social
interaction among people and the people interaction with the scene. We question
the use of the LSTM models and propose the novel use of Transformer Networks
for trajectory forecasting. This is a fundamental switch from the sequential
step-by-step processing of LSTMs to the only-attention-based memory mechanisms
of Transformers. In particular, we consider both the original Transformer
Network (TF) and the larger Bidirectional Transformer (BERT), state-of-the-art
on all natural language processing tasks. Our proposed Transformers predict the
trajectories of the individual people in the scene. These are "simple" model
because each person is modelled separately without any complex human-human nor
scene interaction terms. In particular, the TF model without bells and whistles
yields the best score on the largest and most challenging trajectory
forecasting benchmark of TrajNet. Additionally, its extension which predicts
multiple plausible future trajectories performs on par with more engineered
techniques on the 5 datasets of ETH + UCY. Finally, we show that Transformers
may deal with missing observations, as it may be the case with real sensor
data. Code is available at https://github.com/FGiuliari/Trajectory-Transformer.Comment: 18 pages, 3 figure
Recent Advances in Graph-based Machine Learning for Applications in Smart Urban Transportation Systems
The Intelligent Transportation System (ITS) is an important part of modern
transportation infrastructure, employing a combination of communication
technology, information processing and control systems to manage transportation
networks. This integration of various components such as roads, vehicles, and
communication systems, is expected to improve efficiency and safety by
providing better information, services, and coordination of transportation
modes. In recent years, graph-based machine learning has become an increasingly
important research focus in the field of ITS aiming at the development of
complex, data-driven solutions to address various ITS-related challenges. This
chapter presents background information on the key technical challenges for ITS
design, along with a review of research methods ranging from classic
statistical approaches to modern machine learning and deep learning-based
approaches. Specifically, we provide an in-depth review of graph-based machine
learning methods, including basic concepts of graphs, graph data
representation, graph neural network architectures and their relation to ITS
applications. Additionally, two case studies of graph-based ITS applications
proposed in our recent work are presented in detail to demonstrate the
potential of graph-based machine learning in the ITS domain
Recommended from our members
Explainable and Advisable Learning for Self-driving Vehicles
Deep neural perception and control networks are likely to be a key component of self-driving vehicles. These models need to be explainable - they should provide easy-to-interpret rationales for their behavior - so that passengers, insurance companies, law enforcement, developers, etc., can understand what triggered a particular behavior. Explanations may be triggered by the neural controller, namely introspective explanations, or informed by the neural controller's output, namely rationalizations. Our work has focused on the challenge of generating introspective explanations of deep models for self-driving vehicles. In Chapter 3, we begin by exploring the use of visual explanations. These explanations take the form of real-time highlighted regions of an image that causally influence the network's output (steering control). In the first stage, we use a visual attention model to train a convolution network end-to-end from images to steering angle. The attention model highlights image regions that potentially influence the network's output. Some of these are true influences, but some are spurious. We then apply a causal filtering step to determine which input regions actually influence the output. This produces more succinct visual explanations and more accurately exposes the network's behavior. In Chapter 4, we add an attention-based video-to-text model to produce textual explanations of model actions, e.g. "the car slows down because the road is wet". The attention maps of controller and explanation model are aligned so that explanations are grounded in the parts of the scene that mattered to the controller. We explore two approaches to attention alignment, strong- and weak-alignment. These explainable systems represent an externalization of tacit knowledge. The network's opaque reasoning is simplified to a situation-specific dependence on a visible object in the image. This makes them brittle and potentially unsafe in situations that do not match training data. In Chapter 5, we propose to address this issue by augmenting training data with natural language advice from a human. Advice includes guidance about what to do and where to attend. We present the first step toward advice-giving, where we train an end-to-end vehicle controller that accepts advice. The controller adapts the way it attends to the scene (visual attention) and the control (steering and speed). Further, in Chapter 6, we propose a new approach that learns vehicle control with the help of long-term (global) human advice. Specifically, our system learns to summarize its visual observations in natural language, predict an appropriate action response (e.g. "I see a pedestrian crossing, so I stop"), and predict the controls, accordingly
Pedestrian Trajectory Prediction in Pedestrian-Vehicle Mixed Environments: A Systematic Review
Planning an autonomous vehicle's (AV) path in a space shared with pedestrians
requires reasoning about pedestrians' future trajectories. A practical
pedestrian trajectory prediction algorithm for the use of AVs needs to consider
the effect of the vehicle's interactions with the pedestrians on pedestrians'
future motion behaviours. In this regard, this paper systematically reviews
different methods proposed in the literature for modelling pedestrian
trajectory prediction in presence of vehicles that can be applied for
unstructured environments. This paper also investigates specific considerations
for pedestrian-vehicle interaction (compared with pedestrian-pedestrian
interaction) and reviews how different variables such as prediction
uncertainties and behavioural differences are accounted for in the previously
proposed prediction models. PRISMA guidelines were followed. Articles that did
not consider vehicle and pedestrian interactions or actual trajectories, and
articles that only focused on road crossing were excluded. A total of 1260
unique peer-reviewed articles from ACM Digital Library, IEEE Xplore, and Scopus
databases were identified in the search. 64 articles were included in the final
review as they met the inclusion and exclusion criteria. An overview of
datasets containing trajectory data of both pedestrians and vehicles used by
the reviewed papers has been provided. Research gaps and directions for future
work, such as having more effective definition of interacting agents in deep
learning methods and the need for gathering more datasets of mixed traffic in
unstructured environments are discussed.Comment: Published in IEEE Transactions on Intelligent Transportation System
- …