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This work reports on a hardware implementation of a No-Reference technique for video quality assessment. The video quality evaluation metric and the way it is implemented in an optimal way using the VHDL language are described. Simulation results shows good accuracy concerning the extraction of both spatial and temporal features, creating a reliable basis for future real-time video quality evaluation.
Nowadays low cost components are needed for the commercial implementation of PONs and uncooled components offer a practical and important alternative. In this paper we present experimental results on the temperature and bias current behavior of VCSEL, Fabry Perot and DFB devices. The results are useful in understanding and developing techniques that may help to correct the temperature-dependent behavior...
This paper reports on the writing of long period gratings (LPGs) in a six-ring pure silica solid core, and large mode area photonic crystal fiber (fiber core diameter ρ = 10.1 μm) using a CO2 laser system, and the characterization of their strain and temperature sensitivities. Temperature and strain sensitivities in the order of −19.6 pm/°C and −88 pm/μɛ, respectively, were obtained, which were comparable...
Video quality evaluation is an important subject in video broadcasting. No-Reference (NR) metrics are especially interesting, given that it does not demand the original video for the quality assessment, thus it is adequate for industrial applications. This work describes the implementation of a NR technique in an FPGA platform that can be potentially employed in real time video quality assessment...
Currently there is an significant effort by system operators to deploy cost effective Passive Optical Networks (PON). In this way, next generation PON is the subject of studies by researchers and system designers. Among them, Wavelength Division Multiplexing in Passive Optical Networks (WDM-PON) are of particular interest once they can provide larger capacity. This work presents a performance and...
Currently there is an effort by system operators to deploy cost effective Passive Optical Networks (PON). In this way, next generation PON is the subject of studies by researchers and system designers. Among them, Wavelength division multiplexing on Passive Optical Network (WDM-PON) are of particular interest once they can provide larger bandwidths. This work presents a comparison of WDM-PON configurations...
A model is presented to explain the dynamically induced bandwidth increase of fibre Bragg grating spectra, when those are excited by acoustic waves at low frequencies. The approach considers the existence of both flexural and longitudinal waves propagating simultaneously in the fibre.
This work presents an analysis of signal propagation in an indoor environment. Three empirical models were implemented: Modified Keenan-Motley, Log-Distance and Linear Attenuation. The simulation delivers a coverage map showing the reception power in the corresponding area, whose results are validated with experimental data acquired with a low cost test environment.
Results on the measurement of flexural and longitudinal acoustic waves propagating in an optical fibre are presented. Using the extrinsic Fabry-Perot interferometric technique, parameters such as the acoustical wavelength and the acoustical phase velocity can be assessed.
Recent results on the application of the acousto-optic effect to fibre Bragg gratings are presented, which include the control of phase shifts, the permanent creation of multiple sidebands during the grating writing process and the control of dispersion parameters by acoustical waves.
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