6,474 research outputs found
Speaker-following Video Subtitles
We propose a new method for improving the presentation of subtitles in video
(e.g. TV and movies). With conventional subtitles, the viewer has to constantly
look away from the main viewing area to read the subtitles at the bottom of the
screen, which disrupts the viewing experience and causes unnecessary eyestrain.
Our method places on-screen subtitles next to the respective speakers to allow
the viewer to follow the visual content while simultaneously reading the
subtitles. We use novel identification algorithms to detect the speakers based
on audio and visual information. Then the placement of the subtitles is
determined using global optimization. A comprehensive usability study indicated
that our subtitle placement method outperformed both conventional
fixed-position subtitling and another previous dynamic subtitling method in
terms of enhancing the overall viewing experience and reducing eyestrain
Locally Non-rigid Registration for Mobile HDR Photography
Image registration for stack-based HDR photography is challenging. If not
properly accounted for, camera motion and scene changes result in artifacts in
the composite image. Unfortunately, existing methods to address this problem
are either accurate, but too slow for mobile devices, or fast, but prone to
failing. We propose a method that fills this void: our approach is extremely
fast---under 700ms on a commercial tablet for a pair of 5MP images---and
prevents the artifacts that arise from insufficient registration quality
How input fluctuations reshape the dynamics of a biological switching system
An important task in quantitative biology is to understand the role of
stochasticity in biochemical regulation. Here, as an extension of our recent
work [Phys. Rev. Lett. 107, 148101 (2011)], we study how input fluctuations
affect the stochastic dynamics of a simple biological switch. In our model, the
on transition rate of the switch is directly regulated by a noisy input signal,
which is described as a nonnegative mean-reverting diffusion process. This
continuous process can be a good approximation of the discrete birth-death
process and is much more analytically tractable. Within this new setup, we
apply the Feynman-Kac theorem to investigate the statistical features of the
output switching dynamics. Consistent with our previous findings, the input
noise is found to effectively suppress the input-dependent transitions. We show
analytically that this effect becomes significant when the input signal
fluctuates greatly in amplitude and reverts slowly to its mean.Comment: 7 pages, 4 figures, submitted to Physical Review
A method to extract pure Raman spectrum of epitaxial graphene on SiC
A method is proposed to extract pure Raman spectrum of epitaxial graphene on
SiC by using a Non-negative Matrix Factorization. It overcomes problems of
negative spectral intensity and poorly resolved spectra resulting from a simple
subtraction of a SiC background from the experimental data. We also show that
the method is similar to deconvolution, for spectra composed of multiple sub-
micrometer areas, with the advantage that no prior information on the impulse
response functions is needed. We have used this property to characterize the
Raman laser beam. The method capability in efficient data smoothing is also
demonstrated.Comment: 3 figures, regular pape
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