474 research outputs found
Fish eye optics
We report on small student (high school) project of the Czech Academy of Sciences dealing with animal (fish) eyes and possible application in science and technology. Albeit most fishes have refractive eyes, the recent discoveries confirm that some fishes have reflective eyes with strange arrangements as well
Extension of Impulse Detectors to Spatial Dimension and their Utilization as Switch in the LMS L-SD Filter
In this paper, one kind of adaptive LMS filters based on order statistics is used for two-dimensional filtration of noisy greyscale images degraded by mixed noise. The signal-dependent adaptive LMS L-filter (L-SD) consists of two normalized constrained adaptive LMS L-filters, because they have better convergence properties than simple LMS algorithm. Moreover, first filter suppresses the noise in homogeneous regions and second filter preserves the high components of filtered image. Some versions of spatial order statistic detectors were developed from the impulse detectors and were employed as switch between output these filters
Adaptive Order-Statistic LMS Filters
The LMS-based adaptive order-statistic filters are presented in this paper. The adaptive Ll-filters as extension of the adaptive L-filter for two-dimensional filtering of noisy greyscale images is studied too. Their adaptation properties are studied by three types of noise, the additive white Gaussian noise, the impulsive noise or both, respectively. Moreover, the impulsive noise has the fixed noise value (Salt & Pepper noise). The problem of pixel value multiplicity and determination its position in the ordered input vector for adaptive Ll-filter is shown in this article. The two types of images with different of image complexity are used to demonstration of the power of time-spatial ordering
A Novel System for Non-Invasive Method of Animal Tracking and Classification in Designated Area Using Intelligent Camera System
This paper proposed a novel system for non-invasive method of animal tracking and classification in designated area. The system is based on intelligent devices with cameras, which are situated in a designated area and a main computing unit (MCU) acting as a system master. Intelligent devices track animals and then send data to MCU to evaluation. The main purpose of this system is detection and classification of moving animals in a designated area and then creation of migration corridors of wild animals. In the intelligent devices, background subtraction method and CAMShift algorithm are used to detect and track animals in the scene. Then, visual descriptors are used to create representation of unknown objects. In order to achieve the best accuracy in classification, key frame extraction method is used to filtrate an object from detection module. Afterwards, Support Vector Machine is used to classify unknown moving animals
Fish eye optics
We report on small student (high-school) project of the Czech Academy of Sciences dealing with animal (fish) eyes and possible application in science and technology. Albeit most fishes have refractive eyes, the recent discoveries confirm that some fishes have reflective eyes with strange arrangements as well
ESA satellites SMILE and THESEUS
SMILE is a space mission which aims to measure Earth’s global system responses to solar wind
and geomagnetic variations with innovative instrumentation, e.g. wide–field X-ray telescope of
Lobster–Eye type, on board. It is a collaborative project of the European Space Agency and
the Chinese Academy of Sciences. Transient High-Energy Sky and Early Universe Surveyor
(THESEUS) is a space mission proposal accepted by the European Space Agency for a phase
A study that would study gamma-ray bursts and X–rays for investigating the early universe and
for the multi–messenger astrophysics. It involves a Lobster–Eye X–ray telescope as well. The
SMILE and THESEUS international consortia involve the Czech Technical University in Prague
and the Czech teams are expected to contribute to the projects, mainly to the X–ray telescopes
and related science and software
Measuring the spin of the primary black hole in OJ287
The compact binary system in OJ287 is modelled to contain a spinning primary
black hole with an accretion disk and a non-spinning secondary black hole.
Using Post Newtonian (PN) accurate equations that include 2.5PN accurate
non-spinning contributions, the leading order general relativistic and
classical spin-orbit terms, the orbit of the binary black hole in OJ287 is
calculated and as expected it depends on the spin of the primary black hole.
Using the orbital solution, the specific times when the orbit of the secondary
crosses the accretion disk of the primary are evaluated such that the record of
observed outbursts from 1913 up to 2007 is reproduced. The timings of the
outbursts are quite sensitive to the spin value. In order to reproduce all the
known outbursts, including a newly discovered one in 1957, the Kerr parameter
of the primary has to be . The quadrupole-moment contributions
to the equations of motion allow us to constrain the `no-hair' parameter to be
where 0.3 is the one sigma error. This supports the `black hole
no-hair theorem' within the achievable precision.
It should be possible to test the present estimate in 2015 when the next
outburst is due. The timing of the 2015 outburst is a strong function of the
spin: if the spin is 0.36 of the maximal value allowed in general relativity,
the outburst begins in early November 2015, while the same event starts in the
end of January 2016 if the spin is 0.2Comment: 12 pages, 6 figure
- …