Selective targeting the retinal pigment epithelium (RPE) while sparing adjacent tissue such as the photoreceptors has been demonstrated by repetitively irradiating the fundus with a train of green microsecond(s) -laser pulses. The aim of this study was to investigate selective RPE effects alternatively by means of rapidly scanning a cw-laser beam across the RPE to obtain the required microsecond(s) -illumination times. The radiation of an Ar+ laser (514 nm) was transmitted through a 25-micrometers core diameter fiber to a scanner unit. The fiber tip was imaged onto the object plane with a magnification of 0.75. The beam was repetitively scanned across porcine RPE samples in vitro providing an irradiation time of 1.6 microsecond(s) . Cell damage was investigated with a fluorescence viability assay.
The problem of low metal content mine characterization form broadband electromagnetic induction (BEMI) data is addressed. A stochastic model describing the spatial distribution of clutter is developed and methods for estimating and removing this unwanted interference are described and tested. After removing the clutter from the signal, a technique is introduced for extracting from BEMI data information describing the location, orientation and structure of the buried object. Examples are provided for spherical and ellipsoidal mines.
The problem of mine localization and characterization form electromagnetic induction data is addressed. We consider processing techniques based on an inductive sensor model originally proposed by Das et. al. Given this model we examine estimation-theoretic methods for determining an object's center, its orientation, and scattering characteristics from low frequency spectroscopic data obtained over a grid of spatial locations. Under this model, the data are linear functions of the multiple moment spectra and non-linearity related to object's location and rotation angles. An estimation procedure based on a low-dimensional non-linear optimization routine for the determination of the object center and rotation angles is employed with a linear lest squares inversion method used to estimate the multiple moment spectra. Examples are provided for ellipsoidal objects.
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