A new approach for reflecting the colour tone of a reference image on the input image is proposed. Depending on the source and reference image pairs, conventional statistical colour transfer methods ...often lead to undesirable colour transfer. Conversely, deep learning methods depend on prior learning, which results in unnatural output images when inappropriate images are learned; moreover, in such situations, analysing what kind of colour transformation has actually been performed is difficult. This state of the art motivates the proposal of a new colour transfer method that estimates tone curves based on generative adversarial nets. This method does not require any data set other than input and reference images, thus enabling a more appropriate colour transfer. The superior output of the proposed method compared with some baseline approaches is demonstrated through experiments.
Protons with energies up to ∼1015 eV are the main component of cosmic rays, but evidence for the specific locations where they could have been accelerated to these energies has been lacking. ...Electrons are known to be accelerated to cosmic-ray energies in supernova remnants, and the shock waves associated with such remnants, when they hit the surrounding interstellar medium, could also provide the energy to accelerate protons. The signature of such a process would be the decay of pions (π0), which are generated when the protons collide with atoms and molecules in an interstellar cloud: pion decay results in γ-rays with a particular spectral-energy distribution. Here we report the observation of cascade showers of optical photons resulting from γ-rays at energies of ∼1012 eV hitting Earth's upper atmosphere, in the direction of the supernova remnant RX J1713.7-3946. The spectrum is a good match to that predicted by pion decay, and cannot be explained by other mechanisms.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
CANGAROO-III is an imaging atmospheric Cherenkov telescope array of four 10-m telescopes for very high energy (sub-TeV) γ-ray astronomy. A design study of the CANGAROO-III telescope system was ...carried out using the Monte Carlo technique in order to optimize the pixel size and the telescope spacing. Studies were also made of observations at low elevation angles.
This paper proposes a new image colorization algorithm based on the mixed L 0 /L 1 norm minimization. Introducing some assumptions, a problem of recovering a color image from a grayscale image with ...the small number of known color pixels is formulated as a mixed L 0 /L 1 norm minimization, which is solved approximately by an iterative reweighted least squares (IRLS) algorithm. Numerical examples show that the proposed algorithm colorizes a grayscale image well using a small number of color pixels.
A novel flavonol glycoside named camellianoside and three known flavonol glycosides were isolated from the leaves of Camellia japonica. The structure of camellianoside was established as ...quercetin-3-0-beta-D-xylopyranosyl-(1-3)-O-alpha-L-rhamnopyranosyl-(1-6)-O-beta-D-glucopyranoside by spectroscopic and chemical methods. The antioxidant activities of these glycosides evaluated by the diphenylpicrylhydrazyl (DPPH) radical scavenging reaction was higher than those of L-cysteine and L-ascorbic acid used as the reference antioxidants.
Astrophys.J. 579 (2002) L9-L12 We have observed Markarian 421 in January and March 2001 with the CANGAROO-II
imaging Cherenkov telescope during an extraordinarily high state at TeV
energies. From 14 ...hours observations at very large zenith angles,
$\sim70^\circ$, a signal of 298 $\pm$ 52 gamma-ray--like events (5.7 $\sigma$)
was detected at $E>10$ TeV, where a higher sensitivity is achieved than those
of usual observations near the zenith, owing to a greatly increased collecting
area. Under the assumption of an intrinsic power-law spectrum, we derived a
differential energy spectrum $dN/dE =
(3.3 \pm 0.9_{stat.} \pm 0.3_{syst.})\times10^{-13} (E/10 {Te V})^{-(4.0
^{+0.9}_{-0.6}_{stat.} \pm 0.3_{syst.})}$ ph./cm$^2$/sec/TeV, which is steeper
than those previously measured around 1 TeV, and supports the evidence for a
cutoff in the spectrum of Markarian 421. However, the 4 $\sigma$ excess at
energies greater than 20 TeV in our data favors a cutoff energy of $\sim$8 TeV,
at the upper end of the range previously reported from measurements at TeV
energies.
A preliminary result from Markarian 421 observations in the energy region
above 10 TeV with the CANGAROO-II 10 m telescope is presented. In January 2001,
the HEGRA group reported that Markarian 421 ...had become very active, with flux
levels up to 4 times that of the Crab Nebula. As a result, we observed Mkn 421
during six nights from January 24th to February 1st, and four nights from March
1st to 4th. Observations were carried out using the very large zenith angle
technique ($\sim$70 degree) and the energy threshold is estimated from Monte
Carlo simulations to be around 10 TeV. We have detected gamma-ray emission in
this energy range.
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