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 $q$ is thereby provided. A physical lower bound for $q$ is also established, together with a ``state equation" for $q$ that transforms the escort-Cramer--Rao bound into a thermal uncertainty relation.Comment: Physics Letters A (2004), in pres

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

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($T_c$) typically is $\sim 32$ and at ultralow temperatures well below $T_c$ 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

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 $\tilde e\tilde\mu$, $\tilde e\tilde\tau$ and $\tilde \mu\tilde\tau$, 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