Depth Images are viable representations that can be computed from the real world using cameras and/or other scanning devices. The depth map provides 2-1 2 D structure of the scene. A set of Depth Images can provide hole-free rendering of the scene. Multiple views need to blended to provide smooth hole-free rendering, however. Such a representation of the scene is bulky and needs good algorithms for real-time rendering and efficient representation. In this paper, we present a discussion on the Depth Image representation and provide a GPU-based algorithm that can render large models represented using DIs in real time. We then present a proxy-based compression scheme for Depth Images and provide results for the same. Results are shown on synthetic scenes under different conditions and on some scenes generated from images. Lastly, we initiate discussion on varying quality levels in IBR and show a way to create representations using DIs with different trade-offs between model size and rendering quality. This enables the use of this representation for a variety of rendering situations.

Spin-polarized tunnel injection and extraction of charge carriers can give rise to magneto-resistance in organic spin valves. To describe this magneto-resistance, the tunneling process is modeled as a transfer of electrons through a thin insulating layer between a ferromagnetic contact and an organic semiconductor. Transition rates between extended states in the metal and model “molecular” orbitals localized at the semiconductor/insulator interface are calculated based on a transfer Hamiltonian. The transition rates are then used in a rate equation model to calculate the injected current for the two spin types and the associated magneto-resistance of organic spin valves. Consistent with experimental data, it is found that the magneto-resistance can be of either sign and its magnitude strongly decreases with the applied bias.

A charged impurity outside the plane of a graphene layer contributes to scattering of electrons (and holes) in the graphene. The interaction occurs through two distinct mechanisms associated with the charge: (1) the (screened) Coulomb potential, and (2) the electric field perpendicular to the graphene plane that causes a spatially varying Rashba spin-orbit interaction. Both types of scattering are examined, with the screened potential self-consistently calculated in nonlinear Thomas-Fermi approximation. Different selection rules for the two mechanisms lead to qualitative differences in the differential scattering cross-sections. Using accepted parameters for the Rashba interaction, the latter is found to make only a very small contribution to the scattering associated with a remote charge.

Graphene is a promising material for electronic and spintronic applications due to its high carrier mobility and low intrinsic spin-orbit interaction. However, extrinsic effects may easily dominate intrinsic scattering mechanisms. The scattering mechanisms investigated here are associated non-magnetic, charged impurities in the substrate (e.g. SiO 2 ) beneath the graphene layer. Such impurities cause an electric field that extends through the graphene and has a nonvanishing perpendicular component. Consequently, the impurity, in addition to the conventional elastic, spin-conserving scattering can give rise to spin-flip processes. The latter is a consequence of a spatially varying Rashba spin-orbit interaction caused by the electric field of the impurity in the substrate. Scattering cross-sections are calculated and, for assumed impurity distributions, relaxation times are estimated.