A new approach for restoring block-transform coded images with estimation of correlation matrices

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Reduction of block-transform image coding artifacts by using local statistics of transform coefficients

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An improved quantitative measure of image restoration quality

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New adaptive iterative image restoration algorithm

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Multiphysics Modeling of Plasmonic Organic Solar Cells with a Unified Finite-Difference Method

Invited Paper 13A multiphysics study carries out on plasmonic organic solar cells (OSCs) by solving Maxwell's equations and semiconductor (Poisson, drift-diffusion, and continuity) equations simultaneously with unified finite-difference framework. Regarding the Maxwell's equations, the perfectly matched layer and periodic boundary conditions are imposed at the vertical and lateral directions of OSCs to simulate the infinite air region and metallic grating electrode, respectively. In view of the semiconductor equations, the Scharfetter-Gummel scheme and semi-implicit strategy are adopted respectively in the space and time domains. To model the bulk heterojunction OSCs, the Langevin bimolecular recombination and Onsager-Braun exciton dissociation models are fully taken into account. The exciton generation rate depending on the optical absorption of the organic active material can be obtained by solving the Maxwell's equations and will be inserted into the semiconductor equations. Through the multiphysics model, we observed the increased shortcircuit current and dropped fill factor when OSCs incorporate a metallic grating anode supporting surface plasmon resonances. This work provides fundamental multiphysics modeling and understanding for plasmonic organic photovoltaics.published_or_final_versio

The roles of metallic rectangular-grating and planar anodes in the photocarrier generation and transport of organic solar cells

A multiphysics study carries out on organic solar cells (OSCs) by solving Maxwells and semiconductor equations simultaneously. By introducing a metallic rectangular-grating as the anode, surface plasmons are excited resulting in nonuniform exciton generation. Meanwhile, the internal E-field of plasmonic OSCs is modified with the modulated anode boundary. The plasmonic OSC improves 13 of short-circuit current but reduces 7 of fill factor (FF) compared to the standard one with a planar anode. The uneven photocarrier generation and transport by the grating anode are physical origins of the dropped FF. This work provides fundamental multiphysics modeling and understanding for plasmonic OSCs. © 2012 American Institute of Physics.published_or_final_versio

Optimal choice of local regularization weights in iterative image restoration

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New image restoration performance measures with high precision

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Angular response of thin-film organic solar cells with periodic metal back nanostrips

We theoretically study the angular response of thin-film organic solar cells with periodic Au back nanostrips. In particular, the equation of the generalized Lambert's cosine law for arbitrary periodic nanostructure is formulated. We show that the periodic strip structure achieves wide-angle absorption enhancement compared with the planar nonstrip structure for both the s-and p-polarized light, which is mainly attributed to the resonant Wood's anomalies and surface plasmon resonances, respectively. The work is important for designing and optimizing high-efficiency photovoltaic cells. © 2011 Optical Society of America.published_or_final_versio

Image restoration by regularisation in uncorrelated transform domain

Author name used in this publication: S. O. ChoyAuthor name used in this publication: Y. H. ChanAuthor name used in this publication: W. C. SiuCentre for Multimedia Signal Processing, Department of Electronic and Information Engineering2000-2001 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe