3,114 research outputs found
Frustum PointNets for 3D Object Detection from RGB-D Data
In this work, we study 3D object detection from RGB-D data in both indoor and
outdoor scenes. While previous methods focus on images or 3D voxels, often
obscuring natural 3D patterns and invariances of 3D data, we directly operate
on raw point clouds by popping up RGB-D scans. However, a key challenge of this
approach is how to efficiently localize objects in point clouds of large-scale
scenes (region proposal). Instead of solely relying on 3D proposals, our method
leverages both mature 2D object detectors and advanced 3D deep learning for
object localization, achieving efficiency as well as high recall for even small
objects. Benefited from learning directly in raw point clouds, our method is
also able to precisely estimate 3D bounding boxes even under strong occlusion
or with very sparse points. Evaluated on KITTI and SUN RGB-D 3D detection
benchmarks, our method outperforms the state of the art by remarkable margins
while having real-time capability.Comment: 15 pages, 12 figures, 14 table
Multi-wavelength observations of 2HWC J1928+177: dark accelerator or new TeV gamma-ray binary?
2HWC J1928+177 is a Galactic TeV gamma-ray source detected by the High
Altitude Water Cherenkov (HAWC) Observatory up to ~ 56 TeV. The HAWC source,
later confirmed by H.E.S.S., still remains unidentified as a dark accelerator
since there is no apparent supernova remnant or pulsar wind nebula detected in
the lower energy bands. The radio pulsar PSR J1928+1746, coinciding with the
HAWC source position, has no X-ray counterpart. Our SED modeling shows that
inverse Compton scattering in the putative pulsar wind nebula can account for
the TeV emission only if the unseen nebula is extended beyond r ~ 4 [arcmin].
Alternatively, TeV gamma rays may be produced by hadronic interactions between
relativistic protons from an undetected supernova remnant associated with the
radio pulsar and a nearby molecular cloud G52.9+0.1. NuSTAR and Chandra
observations detected a variable X-ray point source within the HAWC error
circle, potentially associated with a bright IR source. The X-ray spectra can
be fitted with an absorbed power-law model with cm and and exhibit
long-term X-ray flux variability over the last decade. If the X-ray source,
possibly associated with the IR source (likely an O star), is the counterpart
of the HAWC source, it may be a new TeV gamma-ray binary powered by collisions
between the pulsar wind and stellar wind. Follow-up X-ray observations are
warranted to search for diffuse X-ray emission and determine the nature of the
HAWC source.Comment: accepted to ApJ, 8 pages, 7 figure
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