154 resultados para color signal


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Color segmentation of images usually requires a manual selection and classification of samples to train the system. This paper presents an automatic system that performs these tasks without the need of a long training, providing a useful tool to detect and identify figures. In real situations, it is necessary to repeat the training process if light conditions change, or if, in the same scenario, the colors of the figures and the background may have changed, being useful a fast training method. A direct application of this method is the detection and identification of football players.

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A single raised bog from the eastern Netherlands has been repeatedly analysed and 14C dated over the past few decades. Here we assess the within-site variability of fossil proxy data through comparing the regional
pollen, macrofossils and non-pollen palynomorphs of four of these profiles. High-resolution chronologies were obtained using 14C dating and Bayesian age-depth modelling. Where chronologies of profiles overlap, proxy curves are compared between the profiles using greyscale graphs that visualise chronological uncertainties. Even at this small spatial scale, there is considerable variability of the fossil proxy curves. Implications regarding signal (climate) and noise (internal dynamics) of the different types of fossil proxies are discussed. Single cores are of limited value for reconstructing centennial-scale climate change, and only by combining multiple cores and proxies can we obtain a reliable understanding of past environmental change and possible forcing factors (e.g., solar variability).

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The use of systolic arrays of 1-bit cells to implement a range of important signal processing functions is demonstrated. Two examples, a pipelined multiplier and a pipelined bit-slice transform circuit, are given. This approach has many important implications for silicon technology, and these are outlined.

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The highly structured nature of many digital signal processing operations allows these to be directly implemented as regular VLSI circuits. This feature has been successfully exploited in the design of a number of commercial chips, some examples of which are described. While many of the architectures on which such chips are based were originally derived on heuristic basis, there is an increasing interest in the development of systematic design techniques for the direct mapping of computations onto regular VLSI arrays. The purpose of this paper is to show how the the technique proposed by Kung can be readily extended to the design of VLSI signal processing chips where the organisation of computations at the level of individual data bits is of paramount importance. The technique in question allows architectures to be derived using the projection and retiming of data dependence graphs.

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This paper describes the design and the architecture of a bit-level systolic array processor. The bit-level systolic array described is directly applicable to a wide range of image processing operations where high performance and throughput are essential. The architecture is illustrated by describing the operation of the correlator and convolver chips which are being developed. The advantage of the system is also discussed.

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The design of a System-on-a-Chip (SoC) demonstrator for a baseline JPEG encoder core is presented. This combines a highly optimized Discrete Cosine Transform (DCT) and quantization unit with an entropy coder which has been realized using off-the-shelf synthesizable IP cores (Run-length coder, Huffman coder and data packer). When synthesized in a 0.35 µm CMOS process, the core can operate at speeds up to 100 MHz and contains 50 k gates plus 11.5 kbits of RAM. This is approximately 20% less than similar JPEG encoder designs reported in literature. When targeted at FPGA the core can operate up to 30 MHz and is capable of compressing 9-bit full-frame color input data at NTSC or PAL rates.

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Using 1-(4-styryl)-3-(3-nitrophenyl)urea as host monomer for the imprinting of Z-(D or L)-Glu, a polymeric receptor exhibiting strong enantioselectivity and a change in color intensity upon binding of the guest was obtained.

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Little is known about the microevolutionary processes shaping within river population genetic structure of aquatic organisms characterized by high levels of homing and spawning site fidelity. Using a microsatellite panel, we observed complex and highly significant levels of intrariver population genetic substructure and Isolation-by-Distance, in the Atlantic salmon stock of a large river system. Two evolutionary models have been considered explaining mechanisms promoting genetic substructuring in Atlantic salmon, the member-vagrant and metapopulation models. We show that both models can be simultaneously used to explain patterns and levels of population structuring within the Foyle system. We show that anthropogenic factors have had a large influence on contemporary population structure observed. In an analytical development, we found that the frequently used estimator of genetic differentiation, F-ST, routinely underestimated genetic differentiation by a factor three to four compared to the equivalent statistic Jost's D-est (Jost 2008). These statistics also showed a near-perfect correlation. Despite ongoing discussions regarding the usefulness of "adjusted" F-ST statistics, we argue that these could be useful to identify and quantify qualitative differences between populations, which are important from management and conservation perspectives as an indicator of existence of biologically significant variation among tributary populations or a warning of critical environmental damage.

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We carry out the first multi-dimensional radiative transfer calculations to simultaneously compute synthetic spectra and light curves for models of supernovae driven by fast bipolar outflows. These allow us to make self-consistent predictions for the orientation dependence of both color evolution and spectral features. We compare models with different degrees of asphericity and metallicity and find significant observable consequences of both. In aspherical models, we find spectral and light curve features that vary systematically with observer orientation. In particular, we find that the early-phase light curves are brighter and bluer when viewed close to the polar axis but that the peak flux is highest for equatorial (off-axis) inclinations. Spectral line features also depend systematically on observer orientation, including the velocity of the Si II 6355 Å line. Consequently, our models predict a correlation between line velocity and color that could assist the identification of supernovae associated with off-axis jet-driven explosions. The amplitude and range of this correlation depends on the degree of asphericity, the metallicity, and the epoch of observation but we find that it is always present and acts in the same direction. © 2012. The American Astronomical Society. All rights reserved..

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Infected airway epithelial cells up-regulate the expression of chemokines, chiefly IL-8, and antimicrobial molecules including ß-defensins (BD). Acinetobacter baumannii is a cause of hospital-acquired pneumonia. We examined whether A. baumannii induced the expressions of IL-8 and BD2 by airway epithelial cells and the receptors implicated in bacterial detection. A549 and human primary airway cells released IL-8 upon infection. A. baumannii-infected cells also increased the expression of BD2 which killed A. baummannii strains. IL-8 induction was via NF-B and mitogen-activated kinases p38 and p44/42-dependent pathways. A. baumannii engaged Toll-like receptor (TLR) 2 and TLR4 pathways and A549 cells could use soluble CD14 as TLRs co-receptor. A. baumannii lipopolysaccharide stimulated IL-8 release by A549 cells and sCD14 facilitated the recognition of the lipopolysaccharide. Mass spectrometry analysis revealed that A. baumannii lipid A structure matches those with endotoxic potential. These results demonstrate that airway epithelial cells produce mediators important for A. baumannii clearance. © 2010 March et al.

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Optical signals measured in apertureless scanning near field optical microscopy (ASNOM) under ambient conditions are found to be affected significantly by the thin water layer absorbed on the surface under investigation, the presence of which is detected through measurements of the shear force experienced by the tip. This water layer also results in a large hysteresis between optical signals measured during approach and withdrawal of the tip to the sample surface. The role of this effect in ASNOM is anticipated to be significant, with the possibility of resultant topographically induced artefacts for ASNOM involving intermittent contact of tip and sample, but also providing a potential mechanism for nanoscale optical resolution.