14221801
An opto-VLSI based tunable fiber ring laser
We demonstrate a novel Opto-VLSI tunable fiber ring laser structure in which an Opto-VLSI processor driven by steering phase holograms dynamically selects the lasing wavelengths. A proof-of-concept tunable fiber ring laser which has a wavelength tuning range of more than 4 nm around 1530 nm and a side-mode suppression ratio more than 25 dB is demonstrated at room temperature. The output power of the lasing wavelengths can be controlled within 0.5 dB uniformity by reconfiguring the phase hologram of the Opto-VLSI processor. Dual-wavelength laser tuning is also experimentally demonstrated.
41489302
Integrated Optical Routing Topology for MicroPhotonic Switches
In this paper, an integrated optical beam router for MicroPhotonic switching is described. The router employs a piecewise linear optic that steers and couples optical collimated beams to optical fiber ports with minimum loss. Experimental results show that for a 3-port MicroPhotonic switch, fiber-to-fiber optical coupling loss less than 0.5 dB and insertion loss uniformity better than 0.25 dB can be achieved, and the tolerance to fluctuations in design parameters is practical.
17941589
Novel integrated optical router for microphotonic switching
In this paper, a novel integrated optical beam router for microphotonic switching is presented. The router uses a piecewise linear optic that steers and couples optical collimated beams to optical fibre ports with minimum loss and excellent tolerance to fluctuations in design parameters. Experimental results show that for a 1/spl times/2 MicroPhotonic switch, fibre-to-fibre optical coupling loss less than 1.05 dB and insertion loss uniformity better than 0.2 dB can be achieved, and the measured loss penalty for changes /spl plusmn/0.5 mm in component position is negligible.
18979975
Integrated MicroPhotonic wideband RF interference mitigation filter
MicroPhotonic broadband RF signal processors utilize true-time-delay methods to perform processing functions that cannot be achieved by conventional electronic methods. In addition to their small physical size and immunity to EMI, Photonic signal processors offer the possibility of delaying broadband RF signals with almost no loss. In this paper, we present a novel MicroPhotonic structure that integrates a photoreceiver array, a Vertical Cavity Surface Emitting Laser (VCSEL) array, and a multi-cavity optical substrate to realize a low-cost adaptive wideband RF interference mitigation filter. Results show that for a 64-cavity MicroPhotonic structure, high-resolution, tunable interference mitigation filter with a shape factor as low as 2 and passband ripples less than 0.25 dB can be realised.
7391513
Asymptotic performance of hybrid-selection/maximal-ratio combining over fading channels
In this letter, we study the asymptotic performance of hybrid-selection/maximal-ratio combining (HS/MRC) and postdetection HS/equal-gain combining (HS/EGC) over generalized fading channels for large average signal-to-noise ratios (ASNRs). By evaluating the asymptotic moment generating function of the HS/MRC output SNR at high ASNR, we derive the diversity and coding gains for HS/MRC for a large class of modulation formats and versatile fading conditions, including different types of fading channels and nonidentical SNR statistics across diversity branches. Our analytical results reveal that the diversity gains of HS/MRC and HS/EGC are equivalent to that of MRC, and the difference in the coding gains for different modulation formats is manifested in terms of a modulation factor defined in this letter. Some new analytical results about effects of the number of combined branches for HS/MRC and noncoherent combining loss of HS/EGC are also provided.
27067527
A faster method for modeling virtual colony
A virtual colony composed by vivid personal characters with different facial texture and body size, will strongly enhance the reality of the whole virtual environment. This paper describes a fast, economic but realistic method for modeling virtual colony. The system has two major components: photographs based human model reconstruction and anthropometry based automatic human model edit, both of them were advanced to achieve more practical and realistic purpose. To demonstrate the power of this approach, the method was applied to generate some virtual colonies.
6164572
Video quality assessment using structural distortion measurement
Objective image/video quality measures play important roles in various image/video processing applications, such as compression, communication, printing, analysis, registration, restoration and enhancement. Most proposed quality assessment approaches in the literature are error sensitivity-based methods. We follow a new philosophy in designing image/video quality metrics, which uses structural distortion as an estimation of perceived visual distortion. We develop a new approach for video quality assessment. Experiments on the video quality experts group (VQEG) test data set shows that the new quality measure has higher correlation with subjective quality measurement than the proposed methods in VQEG's Phase I tests for full-reference video quality assessment.
29035045
Genetic algorithms for determining fuzzy measures from data
A synthetic evaluation of a given object in terms of multiple factors that contribute to some feature of the object (quality, performance, etc.) may be regarded as a system with multiple inputs and one output. Traditionally, the output is expressed as the weighted average of the inputs. Unfortunately, this method is severely limited as it cannot capture any inherent relation among the factors involved. This limitation can be overcome by using the Choquet integral or the fuzzy integral with respect to a fuzzy measure that captures the relation among the factors. The crux of this method is to determine the right fuzzy measure. In this paper, we describe an efficient genetic algorithm for constructing a suitable fuzzy measure from relevant input-output data. This algorithm has a broad applicability in various problem areas, such as decision making, cluster analysis, pattern recognition, image and speech processing, and expert systems.
5874458
Quality-aware images
We propose the concept of quality-aware image , in which certain extracted features of the original (high-quality) image are embedded into the image data as invisible hidden messages. When a distorted version of such an image is received, users can decode the hidden messages and use them to provide an objective measure of the quality of the distorted image. To demonstrate the idea, we build a practical quality-aware image encoding, decoding and quality analysis system, which employs: 1) a novel reduced-reference image quality assessment algorithm based on a statistical model of natural images and 2) a previously developed quantization watermarking-based data hiding technique in the wavelet transform domain.