612 research outputs found
Convolutional Deblurring for Natural Imaging
In this paper, we propose a novel design of image deblurring in the form of
one-shot convolution filtering that can directly convolve with naturally
blurred images for restoration. The problem of optical blurring is a common
disadvantage to many imaging applications that suffer from optical
imperfections. Despite numerous deconvolution methods that blindly estimate
blurring in either inclusive or exclusive forms, they are practically
challenging due to high computational cost and low image reconstruction
quality. Both conditions of high accuracy and high speed are prerequisites for
high-throughput imaging platforms in digital archiving. In such platforms,
deblurring is required after image acquisition before being stored, previewed,
or processed for high-level interpretation. Therefore, on-the-fly correction of
such images is important to avoid possible time delays, mitigate computational
expenses, and increase image perception quality. We bridge this gap by
synthesizing a deconvolution kernel as a linear combination of Finite Impulse
Response (FIR) even-derivative filters that can be directly convolved with
blurry input images to boost the frequency fall-off of the Point Spread
Function (PSF) associated with the optical blur. We employ a Gaussian low-pass
filter to decouple the image denoising problem for image edge deblurring.
Furthermore, we propose a blind approach to estimate the PSF statistics for two
Gaussian and Laplacian models that are common in many imaging pipelines.
Thorough experiments are designed to test and validate the efficiency of the
proposed method using 2054 naturally blurred images across six imaging
applications and seven state-of-the-art deconvolution methods.Comment: 15 pages, for publication in IEEE Transaction Image Processin
Strain induced mobility modulation in single-layer MoS
In this paper the effect of biaxial and uniaxial strain on the mobility of
single-layer MoS for temperatures T 100 K is investigated. Scattering
from intrinsic phonon modes, remote phonon and charged impurities are
considered along with static screening. Ab-initio simulations are utilized to
investigate the strain induced effects on the electronic bandstructure and the
linearized Boltzmann transport equation is used to evaluate the low-field
mobility under various strain conditions. The results indicate that the
mobility increases with tensile biaxial and tensile uniaxial strain along the
armchair direction. Under compressive strain, however, the mobility exhibits a
non-monotonic behavior when the strain magnitude is varied. In particular, with
a relatively small compressive strain of 1% the mobility is reduced by about a
factor of two compared to the unstrained condition, but with a larger
compressive strain the mobility partly recovers such a degradation
Pigment Melanin: Pattern for Iris Recognition
Recognition of iris based on Visible Light (VL) imaging is a difficult
problem because of the light reflection from the cornea. Nonetheless, pigment
melanin provides a rich feature source in VL, unavailable in Near-Infrared
(NIR) imaging. This is due to biological spectroscopy of eumelanin, a chemical
not stimulated in NIR. In this case, a plausible solution to observe such
patterns may be provided by an adaptive procedure using a variational technique
on the image histogram. To describe the patterns, a shape analysis method is
used to derive feature-code for each subject. An important question is how much
the melanin patterns, extracted from VL, are independent of iris texture in
NIR. With this question in mind, the present investigation proposes fusion of
features extracted from NIR and VL to boost the recognition performance. We
have collected our own database (UTIRIS) consisting of both NIR and VL images
of 158 eyes of 79 individuals. This investigation demonstrates that the
proposed algorithm is highly sensitive to the patterns of cromophores and
improves the iris recognition rate.Comment: To be Published on Special Issue on Biometrics, IEEE Transaction on
Instruments and Measurements, Volume 59, Issue number 4, April 201
Large conditional single-photon cross-phase modulation
Deterministic optical quantum logic requires a nonlinear quantum process that
alters the phase of a quantum optical state by through interaction with
only one photon. Here, we demonstrate a large conditional cross-phase
modulation between a signal field, stored inside an atomic quantum memory, and
a control photon that traverses a high-finesse optical cavity containing the
atomic memory. This approach avoids fundamental limitations associated with
multimode effects for traveling optical photons. We measure a conditional
cross-phase shift of up to between the retrieved signal and control
photons, and confirm deterministic entanglement between the signal and control
modes by extracting a positive concurrence. With a moderate improvement in
cavity finesse, our system can reach a coherent phase shift of at low
loss, enabling deterministic and universal photonic quantum logic.Comment: 22 pages, 5 figures, 1 table, includes supplementary informatio
The effects of performance criteria including accounting, market, and economy on the quality of financial reporting: A case study on Tehran Stock Exchange
This research studies the effects of performance criteria (accounting, market and economy) on the quality of financial reporting in Iran. To evaluate the variable financial reporting quality, the scores given to each company are applied based on the checklist introduced by Iranian Association of Certified Public Accountants and used for the disclosure of the information of the annual financial statements of companies. The statistical population of this research consists of the companies listed on Tehran Stock Exchange over the period 2006-2011. This research, which is classified as applied research, uses the methods of multivariate regression test. The data and hypotheses of this research are analyzed and tested using correlation test and means difference test. The results of the tests conducted on 99 companies indicate that there is a significant and positive relation between the rate of return on equity and the equality of financial reporting. There is also a significant and positive relation between earnings per share and the equality of financial reporting. However, there is no relationship between QTOBIN and the equality of financial reporting. Finally, our results indicate there is a significant and positive relation between market value-added and the equality of financial reporting
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