Browsing by Subject "Optical propagation"

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    ItemOpen Access
    3-D motion estimation and wireframe adaptation including photometric effects for model-based coding of facial image sequences
    (IEEE, 1994-06) Bozdağı, G.; Tekalp, A. M.; Onural, L.
    We propose a novel formulation where 3-D global and local motion estimation and the adaptation of a generic wireframe model to a particular speaker are considered simultaneously within an optical flow based framework including the photometric effects of the motion. We use a flexible wireframe model whose local structure is characterized by the normal vectors of the patches which are related to the coordinates of the nodes. Geometrical constraints that describe the propagation of the movement of the nodes are introduced, which are then efficiently utilized to reduce the number of independent structure parameters. A stochastic relaxation algorithm has been used to determine optimum global motion estimates and the parameters describing the structure of the wireframe model. Results with both simulated and real facial image sequences are provided.
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    Slow surface plasmons on Moiré surfaces
    (IEEE, 2009) Şenlik, S. Seçkin; Kocabaş, A.; Aydınlı, Atilla
    In this report, the authors present the design, fabrication and realization of coupled plasmonic cavities using metallic Moire structures. The phase shifts at the nodes of Moire pattern enable localization of SPPs resulting in a mini band in the band gap region. The authors find group velocities around V g =0.44c at the center of the mini band and approaches to zero at the edges of mini band.