3,499 research outputs found
FactorMatte: Redefining Video Matting for Re-Composition Tasks
We propose "factor matting", an alternative formulation of the video matting
problem in terms of counterfactual video synthesis that is better suited for
re-composition tasks. The goal of factor matting is to separate the contents of
video into independent components, each visualizing a counterfactual version of
the scene where contents of other components have been removed. We show that
factor matting maps well to a more general Bayesian framing of the matting
problem that accounts for complex conditional interactions between layers.
Based on this observation, we present a method for solving the factor matting
problem that produces useful decompositions even for video with complex
cross-layer interactions like splashes, shadows, and reflections. Our method is
trained per-video and requires neither pre-training on external large datasets,
nor knowledge about the 3D structure of the scene. We conduct extensive
experiments, and show that our method not only can disentangle scenes with
complex interactions, but also outperforms top methods on existing tasks such
as classical video matting and background subtraction. In addition, we
demonstrate the benefits of our approach on a range of downstream tasks. Please
refer to our project webpage for more details: https://factormatte.github.ioComment: Project webpage: https://factormatte.github.i
Visual Chirality
How can we tell whether an image has been mirrored? While we understand the
geometry of mirror reflections very well, less has been said about how it
affects distributions of imagery at scale, despite widespread use for data
augmentation in computer vision. In this paper, we investigate how the
statistics of visual data are changed by reflection. We refer to these changes
as "visual chirality", after the concept of geometric chirality - the notion of
objects that are distinct from their mirror image. Our analysis of visual
chirality reveals surprising results, including low-level chiral signals
pervading imagery stemming from image processing in cameras, to the ability to
discover visual chirality in images of people and faces. Our work has
implications for data augmentation, self-supervised learning, and image
forensics.Comment: Published at CVPR 2020, Best Paper Nomination, Oral Presentation.
Project Page: https://linzhiqiu.github.io/papers/chirality
Escort--Husimi distributions, Fisher information and nonextensivity
We evaluate generalized information measures constructed with Husimi
distributions and connect them with the Wehrl entropy, on the one hand, and
with thermal uncertainty relations, on the other one. The concept of escort
distribution plays a central role in such a study. A new interpretation
concerning the meaning of the nonextensivity index is thereby provided. A
physical lower bound for is also established, together with a ``state
equation" for that transforms the escort-Cramer--Rao bound into a thermal
uncertainty relation.Comment: Physics Letters A (2004), in pres
More Accurate Theory for Bose-Einstein Condensation Fraction
In the thermodynamic limit the ratio of system size to thermal de Broglie
wavelength tends to infinity and the volume per particle of the system is
constant. Our familiar Bose-Einstein statistics is absolutely valid in the
thermodynamic limit. For finite thermodynamical system this ratio as well as
the number of particles is much greater than 1. However, according to the
experimental setup of Bose-Einstein condensation of harmonically trapped Bose
gas of alkali atoms this ratio near the condensation temperature()
typically is and at ultralow temperatures well below a large
fraction of particles come down to the single particle ground state, and this
ratio becomes comparable to 1. We justify the finite size as well as ultralow
temperature correction to Bose-Einstein statistics. From this corrected
statistics we plot condensation fraction versus temperature graph. This
theoretical plot satisfies well with the experimental plot(A. Griesmaier et
al..,Phys.Rev.Lett. {\bf{{94}}}{(2005){160401}}).Comment: 5 pages, 3 figure
Just A Little Bit O\u27 Driftwood
Photograph of George Olsen; Red faded circular illustrations on right and left side of coverhttps://scholarsjunction.msstate.edu/cht-sheet-music/7829/thumbnail.jp
Just A Little Bit O\u27 Driftwood
Photo of Abe Lymanhttps://scholarsjunction.msstate.edu/cht-sheet-music/1417/thumbnail.jp
Ray Conditioning: Trading Photo-consistency for Photo-realism in Multi-view Image Generation
Multi-view image generation attracts particular attention these days due to
its promising 3D-related applications, e.g., image viewpoint editing. Most
existing methods follow a paradigm where a 3D representation is first
synthesized, and then rendered into 2D images to ensure photo-consistency
across viewpoints. However, such explicit bias for photo-consistency sacrifices
photo-realism, causing geometry artifacts and loss of fine-scale details when
these methods are applied to edit real images. To address this issue, we
propose ray conditioning, a geometry-free alternative that relaxes the
photo-consistency constraint. Our method generates multi-view images by
conditioning a 2D GAN on a light field prior. With explicit viewpoint control,
state-of-the-art photo-realism and identity consistency, our method is
particularly suited for the viewpoint editing task.Comment: Project page at https://ray-cond.github.io
Structural Health Monitoring from the Window Seat of a Passenger Airplane
Recent advances in computer vision and graphics have shown that regular, monocular cameras and video (e.g. cell phone cameras and Digital SLRs) can be used to identify the resonant frequencies of structures, and even image visually subtle operational deflection shapes. This paper is offered as a teaser for that work, focusing specifically on an example that may be of interest to people in the structural health monitoring (SHM) community. The discussion is high-level, and presented in an intentionally casual tone (much of the paper presents an anecdote-about recovering the operational deflection shape of an airplane wing using a cell phone and a dish sponge-using the first person). Our hope is to make this text as accessible and painless to read as possible, with hopes of introducing readers from different engineering disciplines to our related work in computer vision and graphics
Slepton pair production in e+e- collision in supersymmetric left-right model
The pair production of sleptons in electron-positron collisions is
investigated in a supersymmetric left-right model. The cross section is found
considerably larger than in the minimal supersymmetric version of the Standard
Model (MSSM) because of more contributing graphs. A novel process is a doubly
charged higgsino exchange in u-channel, which makes the angular distribution of
the final state particles and the final state asymmetries to differ from those
of the MSSM. It also allows for the flavour non-diagonal final states , and , forbidden in the
MSSM. These processes also give indirect information about neutrino mixings
since they depend on the same couplings as the Majorana mass terms of the
right-handed neutrinos.Comment: 13 pages + 4figures available upon request, HU-SEFT R 1993-1
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