1,640 research outputs found
The Right (Angled) Perspective: Improving the Understanding of Road Scenes Using Boosted Inverse Perspective Mapping
Many tasks performed by autonomous vehicles such as road marking detection,
object tracking, and path planning are simpler in bird's-eye view. Hence,
Inverse Perspective Mapping (IPM) is often applied to remove the perspective
effect from a vehicle's front-facing camera and to remap its images into a 2D
domain, resulting in a top-down view. Unfortunately, however, this leads to
unnatural blurring and stretching of objects at further distance, due to the
resolution of the camera, limiting applicability. In this paper, we present an
adversarial learning approach for generating a significantly improved IPM from
a single camera image in real time. The generated bird's-eye-view images
contain sharper features (e.g. road markings) and a more homogeneous
illumination, while (dynamic) objects are automatically removed from the scene,
thus revealing the underlying road layout in an improved fashion. We
demonstrate our framework using real-world data from the Oxford RobotCar
Dataset and show that scene understanding tasks directly benefit from our
boosted IPM approach.Comment: equal contribution of first two authors, 8 full pages, 6 figures,
accepted at IV 201
The phenazine pyocyanin is a terminal signalling factor in the quorum sensing network of Pseudomonas aeruginosa
Certain members of the fluorescent pseudomonads produce and secrete phenazines. These heterocyclic, redox-active compounds are toxic to competing organisms, and the cause of these antibiotic effects has been the focus of intense research efforts. It is largely unknown, however, how pseudomonads themselves respond to β and survive in the presence of β these compounds. Using Pseudomonas aeruginosa DNA microarrays and quantitative RT-PCR, we demonstrate that the phenazine pyocyanin elicits the upregulation of genes/operons that function in transport [such as the resistance-nodulation-cell division (RND) efflux pump MexGHI-OpmD] and possibly in redox control (such as PA2274, a putative flavin-dependant monooxygenase), and downregulates genes involved in ferric iron acquisition. Strikingly, mexGHI-opmD and PA2274 were previously shown to be regulated by the PA14 quorum sensing network that controls the production of virulence factors (including phenazines). Through mutational analysis, we show that pyocyanin is the physiological signal for the upregulation of these quorum sensing-controlled genes during stationary phase and that the response is mediated by the transcription factor SoxR. Our results implicate phenazines as signalling molecules in both P. aeruginosa PA14 and PAO1
Online Inference and Detection of Curbs in Partially Occluded Scenes with Sparse LIDAR
Road boundaries, or curbs, provide autonomous vehicles with essential
information when interpreting road scenes and generating behaviour plans.
Although curbs convey important information, they are difficult to detect in
complex urban environments (in particular in comparison to other elements of
the road such as traffic signs and road markings). These difficulties arise
from occlusions by other traffic participants as well as changing lighting
and/or weather conditions. Moreover, road boundaries have various shapes,
colours and structures while motion planning algorithms require accurate and
precise metric information in real-time to generate their plans.
In this paper, we present a real-time LIDAR-based approach for accurate curb
detection around the vehicle (360 degree). Our approach deals with both
occlusions from traffic and changing environmental conditions. To this end, we
project 3D LIDAR pointcloud data into 2D bird's-eye view images (akin to
Inverse Perspective Mapping). These images are then processed by trained deep
networks to infer both visible and occluded road boundaries. Finally, a
post-processing step filters detected curb segments and tracks them over time.
Experimental results demonstrate the effectiveness of the proposed approach on
real-world driving data. Hence, we believe that our LIDAR-based approach
provides an efficient and effective way to detect visible and occluded curbs
around the vehicles in challenging driving scenarios.Comment: Accepted at the 22nd IEEE Intelligent Transportation Systems
Conference (ITSC19), October, 2019, Auckland, New Zealan
LiDAR Lateral Localisation Despite Challenging Occlusion from Traffic
This paper presents a system for improving the robustness of LiDAR lateral
localisation systems. This is made possible by including detections of road
boundaries which are invisible to the sensor (due to occlusion, e.g. traffic)
but can be located by our Occluded Road Boundary Inference Deep Neural Network.
We show an example application in which fusion of a camera stream is used to
initialise the lateral localisation. We demonstrate over four driven forays
through central Oxford - totalling 40 km of driving - a gain in performance
that inferring of occluded road boundaries brings.Comment: accepted for publication at the IEEE/ION Position, Location and
Navigation Symposium (PLANS) 202
Generating All the Roads to Rome: Road Layout Randomization for Improved Road Marking Segmentation
Road markings provide guidance to traffic participants and enforce safe
driving behaviour, understanding their semantic meaning is therefore paramount
in (automated) driving. However, producing the vast quantities of road marking
labels required for training state-of-the-art deep networks is costly,
time-consuming, and simply infeasible for every domain and condition. In
addition, training data retrieved from virtual worlds often lack the richness
and complexity of the real world and consequently cannot be used directly. In
this paper, we provide an alternative approach in which new road marking
training pairs are automatically generated. To this end, we apply principles of
domain randomization to the road layout and synthesize new images from altered
semantic labels. We demonstrate that training on these synthetic pairs improves
mIoU of the segmentation of rare road marking classes during real-world
deployment in complex urban environments by more than 12 percentage points,
while performance for other classes is retained. This framework can easily be
scaled to all domains and conditions to generate large-scale road marking
datasets, while avoiding manual labelling effort.Comment: presented at ITSC 201
Subsurface geology of Upper Valmeyeran and Lower Chesterian (Late Mississippian) strata from a portion of central Illinois
Plates are in separate envelopes accompanying the thesis.Typescript.Thesis (B.S.) in Geology--University of Illinois at Urbana-Champaign, 1983.Bibliography: leaf 46
Sense-Assess-eXplain (SAX): Building Trust in Autonomous Vehicles in Challenging Real-World Driving Scenarios
This paper discusses ongoing work in demonstrating research in mobile
autonomy in challenging driving scenarios. In our approach, we address
fundamental technical issues to overcome critical barriers to assurance and
regulation for large-scale deployments of autonomous systems. To this end, we
present how we build robots that (1) can robustly sense and interpret their
environment using traditional as well as unconventional sensors; (2) can assess
their own capabilities; and (3), vitally in the purpose of assurance and trust,
can provide causal explanations of their interpretations and assessments. As it
is essential that robots are safe and trusted, we design, develop, and
demonstrate fundamental technologies in real-world applications to overcome
critical barriers which impede the current deployment of robots in economically
and socially important areas. Finally, we describe ongoing work in the
collection of an unusual, rare, and highly valuable dataset.Comment: accepted for publication at the IEEE Intelligent Vehicles Symposium
(IV), Workshop on Ensuring and Validating Safety for Automated Vehicles
(EVSAV), 2020, project URL:
https://ori.ox.ac.uk/projects/sense-assess-explain-sa
Phenazines affect biofilm formation by Pseudomonas aeruginosa in similar ways at various scales
Some pseudomonads produce phenazines, a group of small, redox-active compounds with diverse physiological functions. In this study, we compared the phenotypes of Pseudomonas aeruginosa strain PA14 and a mutant unable to synthesize phenazines in flow cell and colony biofilms quantitatively. Although phenazine production does not impact the ability of PA14 to attach to surfaces, as has been shown for Pseudomonas chlororaphis Maddula et al., 2006 and Maddula et al., 2008, it influences swarming motility and the surface-to-volume ratio of mature biofilms. These results indicate that phenazines affect biofilm development across a large range of scales, but in unique ways for different Pseudomonas species
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