Reduction of Interlayer Crosstalk of Multilayer Optical Disc by Using Phase-Diversity Homodyne Detection

Abstract

Scatter correction techniques in iterative positron emission tomography (PET) reconstruction increasingly utilize Monte Carlo (MC) simulations which are very well suited to model scatter in the inhomogeneous patient. Due to memory constraints the results of these simulations are not stored in the system matrix, but added or subtracted as a constant term or recalculated in the projector at each iteration. This implies that scatter is not considered in the back-projector. The presented scheme provides a method to store the simulated Monte Carlo scatter in a compressed scatter system matrix. The compression is based on parametrization and B-spline approximation and allows the formation of the scatter matrix based on low statistics simulations. The compression as well as the retrieval of the matrix elements are parallelizable. It is shown that the proposed compression scheme provides sufficient compression so that the storage in memory of a scatter system matrix for a 3D scanner is feasible. Scatter matrices of two different 2D scanner geometries were compressed and used for reconstruction as a proof of concept. Compression ratios of 0.1% could be achieved and scatter induced artifacts in the images were successfully reduced by using the compressed matrices in the reconstruction algorithm.

Microholographic Optical Data Storage with Spatial Mode Multiplexing

“…The mixed beam is coherently detected by a phase-diversity homodyne detection system. [20][21][22][23][24][25][26] Then, the output signal corresponding to the net electric field amplitude of the signal light is obtained:…”

A Feasibility Study of 25 GB/Layer Dynamic Recording Using Two-Photon Material and Heat-Mode Bump Formation Method

“…[1][2][3][4][5][6][7][8][9][10][11][12][13] Multilayer optical discs are among the most promising tools for increasing capacity. [14][15][16][17] Because the optical absorption in a defocusing area is very low and the transparency is high owing to the nonlinear optical absorption characteristic, two-photon absorption materials are considered appropriate for such multilayer media. [18][19][20][21][22] We have examined two-photon sensitized fluorescent materials for multilayer media.…”