Biblio

In the indoor scenario, visible light communications (VLC) is regarded as one of the most promising candidates for future wireless communications. Recently, the physical layer security for indoor VLC has drawn considerable attention. In this paper, the secrecy capacity of indoor VLC is analyzed. Initially, an VLC system with a transmitter, a legitimate receiver, and an eavesdropper is established. In the system, the nonnegativity, the peak optical intensity constraint and the dimmable average optical intensity constraint are considered. Based on the principle of information theory, the closed-form expressions of the upper and the lower bounds on the secrecy capacity are derived, respectively. Numerical results show that the upper and the lower bounds on secrecy capacity are very tight, which verify the accuracy of the derived closed-form expressions.

This paper proposes an improved mesh simplification algorithm based on quadric error metrics (QEM) to efficiently processing the huge data in 3D image processing. This method fully uses geometric information around vertices to avoid model edge from being simplified and to keep details. Meanwhile, the differences between simplified triangular meshes and equilateral triangles are added as weights of errors to decrease the possibilities of narrow triangle and then to avoid the visual mutation. Experiments show that our algorithm has obvious advantages over the time cost, and can better save the visual characteristics of model, which is suitable for solving most image processing, that is, "Real-time interactive" problem.