8,593 research outputs found
Past, Present, and Future of Simultaneous Localization And Mapping: Towards the Robust-Perception Age
Simultaneous Localization and Mapping (SLAM)consists in the concurrent
construction of a model of the environment (the map), and the estimation of the
state of the robot moving within it. The SLAM community has made astonishing
progress over the last 30 years, enabling large-scale real-world applications,
and witnessing a steady transition of this technology to industry. We survey
the current state of SLAM. We start by presenting what is now the de-facto
standard formulation for SLAM. We then review related work, covering a broad
set of topics including robustness and scalability in long-term mapping, metric
and semantic representations for mapping, theoretical performance guarantees,
active SLAM and exploration, and other new frontiers. This paper simultaneously
serves as a position paper and tutorial to those who are users of SLAM. By
looking at the published research with a critical eye, we delineate open
challenges and new research issues, that still deserve careful scientific
investigation. The paper also contains the authors' take on two questions that
often animate discussions during robotics conferences: Do robots need SLAM? and
Is SLAM solved
Kinect Range Sensing: Structured-Light versus Time-of-Flight Kinect
Recently, the new Kinect One has been issued by Microsoft, providing the next
generation of real-time range sensing devices based on the Time-of-Flight (ToF)
principle. As the first Kinect version was using a structured light approach,
one would expect various differences in the characteristics of the range data
delivered by both devices. This paper presents a detailed and in-depth
comparison between both devices. In order to conduct the comparison, we propose
a framework of seven different experimental setups, which is a generic basis
for evaluating range cameras such as Kinect. The experiments have been designed
with the goal to capture individual effects of the Kinect devices as isolatedly
as possible and in a way, that they can also be adopted, in order to apply them
to any other range sensing device. The overall goal of this paper is to provide
a solid insight into the pros and cons of either device. Thus, scientists that
are interested in using Kinect range sensing cameras in their specific
application scenario can directly assess the expected, specific benefits and
potential problem of either device.Comment: 58 pages, 23 figures. Accepted for publication in Computer Vision and
Image Understanding (CVIU
The Comparative Exploration of the Ice Giant Planets with Twin Spacecraft: Unveiling the History of our Solar System
In the course of the selection of the scientific themes for the second and
third L-class missions of the Cosmic Vision 2015-2025 program of the European
Space Agency, the exploration of the ice giant planets Uranus and Neptune was
defined "a timely milestone, fully appropriate for an L class mission". Among
the proposed scientific themes, we presented the scientific case of exploring
both planets and their satellites in the framework of a single L-class mission
and proposed a mission scenario that could allow to achieve this result. In
this work we present an updated and more complete discussion of the scientific
rationale and of the mission concept for a comparative exploration of the ice
giant planets Uranus and Neptune and of their satellite systems with twin
spacecraft. The first goal of comparatively studying these two similar yet
extremely different systems is to shed new light on the ancient past of the
Solar System and on the processes that shaped its formation and evolution.
This, in turn, would reveal whether the Solar System and the very diverse
extrasolar systems discovered so far all share a common origin or if different
environments and mechanisms were responsible for their formation. A space
mission to the ice giants would also open up the possibility to use Uranus and
Neptune as templates in the study of one of the most abundant type of
extrasolar planets in the galaxy. Finally, such a mission would allow a
detailed study of the interplanetary and gravitational environments at a range
of distances from the Sun poorly covered by direct exploration, improving the
constraints on the fundamental theories of gravitation and on the behaviour of
the solar wind and the interplanetary magnetic field.Comment: 29 pages, 4 figures; accepted for publication on the special issue
"The outer Solar System X" of the journal Planetary and Space Science. This
article presents an updated and expanded discussion of the white paper "The
ODINUS Mission Concept" (arXiv:1402.2472) submitted in response to the ESA
call for ideas for the scientific themes of the future L2 and L3 space
mission
Peer Attention Modeling with Head Pose Trajectory Tracking Using Temporal Thermal Maps
Human head pose trajectories can represent a wealth of implicit information such as areas of attention, body language, potential future actions, and more. This signal is of high value for use in Human-Robot teams due to the implicit information encoded within it. Although team-based tasks require both explicit and implicit communication among peers, large team sizes, noisy environments, distance, and mission urgency can inhibit the frequency and quality of explicit communication. The goal for this thesis is to improve the capabilities of Human-Robot teams by making use of implicit communication. In support of this goal, the following hypotheses are investigated:
â Implicit information about a human subjectâs attention can be reliably extracted with software by tracking the subjectâs head pose trajectory, and
â Attention can be represented with a 3D temporal thermal map for implicitly determining a subjectâs Objects Of Interest (OOIs).
These hypotheses are investigated by experimentation with a new tool for peer attention modeling by Head Pose Trajectory Tracking using Temporal Thermal Maps (HPT4M). This system allows a robot Observing Agent (OA) to view a human teammate and temporally model their Regions Of Interest (ROIs) by generating a 3D thermal map based on the subjectâs head pose trajectory.
The findings in this work are that HPT4M can be used by an OA to contribute to a team search mission by implicitly discovering a human subjectâs OOI type, mapping the itemâs location within the searched space, and labeling the itemâs discovery state. Furthermore, this work discusses some of the discovered limitations of this technology and hurdles that must be overcome before implementing HPT4M in a reliable real-world system.
Finally, the techniques used in this work are provided as an open source Robot Operating System (ROS) node at github.com/HPT4M with the intent that it will aid other developers in the robotics community with improving Human-Robot teams. Furthermore, the proofs of principle and tools developed in this thesis are a foundational platform for deeper investigation in future research on improving Human-Robot teams via implicit communication techniques
The <i>Castalia</i> mission to Main Belt Comet 133P/Elst-Pizarro
We describe Castalia, a proposed mission to rendezvous with a Main Belt Comet (MBC), 133P/Elst-Pizarro. MBCs are a recently discovered population of apparently icy bodies within the main asteroid belt between Mars and Jupiter, which may represent the remnants of the population which supplied the early Earth with water. Castalia will perform the first exploration of this population by characterising 133P in detail, solving the puzzle of the MBCâs activity, and making the first in situ measurements of water in the asteroid belt. In many ways a successor to ESAâs highly successful Rosetta mission, Castalia will allow direct comparison between very different classes of comet, including measuring critical isotope ratios, plasma and dust properties. It will also feature the first radar system to visit a minor body, mapping the ice in the interior. Castalia was proposed, in slightly different versions, to the ESA M4 and M5 calls within the Cosmic Vision programme. We describe the science motivation for the mission, the measurements required to achieve the scientific goals, and the proposed instrument payload and spacecraft to achieve these
Resilient Perception for Outdoor Unmanned Ground Vehicles
This thesis promotes the development of resilience for perception systems with a focus on Unmanned Ground Vehicles (UGVs) in adverse environmental conditions. Perception is the interpretation of sensor data to produce a representation of the environment that is necessary for subsequent decision making. Long-term autonomy requires perception systems that correctly function in unusual but realistic conditions that will eventually occur during extended missions. State-of-the-art UGV systems can fail when the sensor data are beyond the operational capacity of the perception models. The key to resilient perception system lies in the use of multiple sensor modalities and the pre-selection of appropriate sensor data to minimise the chance of failure. This thesis proposes a framework based on diagnostic principles to evaluate and preselect sensor data prior to interpretation by the perception system. Image-based quality metrics are explored and evaluated experimentally using infrared (IR) and visual cameras onboard a UGV in the presence of smoke and airborne dust. A novel quality metric, Spatial Entropy (SE), is introduced and evaluated. The proposed framework is applied to a state-of-the-art Visual-SLAM algorithm combining visual and IR imaging as a real-world example. An extensive experimental evaluation demonstrates that the framework allows for camera-based localisation that is resilient to a range of low-visibility conditions when compared to other methods that use a single sensor or combine sensor data without selection. The proposed framework allows for a resilient localisation in adverse conditions using image data but also has significant potential to benefit many perception applications. Employing multiple sensing modalities along with pre-selection of appropriate data is a powerful method to create resilient perception systems by anticipating and mitigating errors. The development of such resilient perception systems is a requirement for next-generation outdoor UGVs
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A holographic system for subsea recording and analysis of plankton and other marine particles
We report here details of the design, development, initial testing and field-deployment of the HOLOMAR system for in-situ subsea holography and analysis of marine plankton and nonliving particles. HOLOMAR comprises a submersible holographic camera ("HoloCam") able to record in-line and off-axis holograms at depths down to 100 m, together with specialised reconstruction hardware ("HoloScan") linked to custom image processing and classification software. The HoloCam consists of a laser and power supply, holographic recording optics and holographic plate holders, a water-tight housing and a support frame. It utilises two basic holographic geometries, in-line and off-axis such that a wide range of species, sizes and concentrations can be recorded. After holograms have been recorded and processed they are reconstructed in full three-dimensional detail in air in a dedicated replay facility. A computer-controlled microscope, using video cameras to record the image at a given depth, is used to digitise the scene. Specially written software extracts a binarised image of an object in its true focal plane and is classified using a neural network. The HoloCam was deployed on two separate cruises in a Scottish sea loch (Loch Etive) to a depth of 100 m and over 300 holograms were recorded
Marshall Space Flight Center Research and Technology Report 2019
Today, our calling to explore is greater than ever before, and here at Marshall Space Flight Centerwe make human deep space exploration possible. A key goal for Artemis is demonstrating and perfecting capabilities on the Moon for technologies needed for humans to get to Mars. This years report features 10 of the Agencys 16 Technology Areas, and I am proud of Marshalls role in creating solutions for so many of these daunting technical challenges. Many of these projects will lead to sustainable in-space architecture for human space exploration that will allow us to travel to the Moon, on to Mars, and beyond. Others are developing new scientific instruments capable of providing an unprecedented glimpse into our universe. NASA has led the charge in space exploration for more than six decades, and through the Artemis program we will help build on our work in low Earth orbit and pave the way to the Moon and Mars. At Marshall, we leverage the skills and interest of the international community to conduct scientific research, develop and demonstrate technology, and train international crews to operate further from Earth for longer periods of time than ever before first at the lunar surface, then on to our next giant leap, human exploration of Mars. While each project in this report seeks to advance new technology and challenge conventions, it is important to recognize the diversity of activities and people supporting our mission. This report not only showcases the Centers capabilities and our partnerships, it also highlights the progress our people have achieved in the past year. These scientists, researchers and innovators are why Marshall and NASA will continue to be a leader in innovation, exploration, and discovery for years to come
Sistema de Deteção de Quedas AutomĂĄtico Baseado em VĂdeo
The elderly population faces difficulties in completing certain tasks independently, often re quiring supervision to not only assist them but also to mitigate and notify about potential
health risks. Falls, a prevalent and severe problem, pose a high risk of causing hospitaliza tions and fatalities. However, the aging population in developed countries is growing at an
unprecedented rate, while the proportion of active age individuals continues to decline. Con sequently, elderly care has become less accessible as caregivers are confronted with a larger
number of patients. Nonetheless, conventional fall detection methods, typically triggered
by victims themselves, are unreliable and inadequate. This thesis proposes an automatic
alternative to existing methods, presenting a computer vision-based Fall Detection System
(FDS) that utilizes a two-stream Inflated 3D Convolutional Neural Network (I3D) in con junction with a Recurrent Neural Network (RNN). To enhance the available datasets, a new
collection of simulated falls was created. Experimental evaluations demonstrate the superi ority of this hybrid model over state-of-the-art fall detection models, achieving an accuracy
of 94% and a recall value of 96%. By promptly and accurately detecting falls, a system
employing this model could significantly reduce the risk of severe injuries posed to the elderly
and physically disabled individuals.Os idosos enfrentam dificuldades em completar certas tarefas sozinhos e precisam de su pervisĂŁo frequente, nĂŁo sĂł para assistĂ-los, mas tambĂ©m para mitigar e alertar para riscos
potenciais de saĂșde. Quedas sĂŁo problemas prevalentes e sĂ©rios, muitas vezes resultando
em hospitalizaçÔes ou mortes. Contudo, nos paĂses desenvolvidos, a população idosa estĂĄ
a crescer e a proporção de cidadĂŁos de idade ativa a diminuir. Por consequĂȘncia, cuidados
a idosos tornam-se mais inacessĂveis, jĂĄ que enfermeiros sĂŁo confrontados com um maior
nĂșmero de pacientes. NĂŁo obstante, mĂ©todos convencionais de deteção de quedas, que
requerem, normalmente, a ativação por parte da vĂtima, nĂŁo sĂŁo confiĂĄveis nem adequados.
Esta tese propÔe uma alternativa automåtica a estes métodos na forma de um sistema de
deteção de quedas que incorpora uma rede neuronal convolucional 3D juntamente com uma
rede neuronal recorrente. Para melhorar os datasets jå existentes, uma nova coleção de
vĂdeos de quedas foi criada. Este modelo hĂbrido revela ter performances superiores Ă s de
outros modelos, conseguindo uma acurĂĄcia de 94% e uma sensitividade de 96%. Ao ser
capaz de detetar quedas precisa e imediatamente, um sistema que inclui este modelo poderĂĄ
reduzir drasticamente o risco de ferimentos graves aos idosos e pessoas com deficiĂȘncias
fĂsicas
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