Physical modeling of a microlens array setup for use in computer generated IP

One of the most promising techniques for visualizing three-dimensional objects is Integral Photography (IP). Two of the most common methods used in Computer Generated IP involve the development of simplified ray tracing algorithms for elementary 3D objects or the realization of pinhole arrays. We present an alternative technique based on the POV-Ray software package for ray tracing to generate synthetic, high quality and photorealistic integral images, by accurately modeling all the optical elements of the capturing setup. Our work constitutes a straightforward approach for translating a computer generated 3D model to an IP image and a robust method to develop modules that can be easily integrated in existing ray-tracers. The proposed technique simulates the procedure of a single stage IP capture for producing orthoscopic IP images, real or virtual. Full control is provided over geometry selection, size and refractive index of the elementary microlenses. Specifically our efforts have been focused on the development of arrays with different geometries (square or hexagonal) that demonstrates the parameterization capabilities of the proposed IP setup. Moreover detailed benchmarking is provided over a variety of sizes and geometries of microlens arrays

The structure of katabatic flows down a simple slope

An analysis of the katabatic flow structure is presented, based on data collected along a simple slope over a two-month period. Four meteorological stations were deployed along the nearly two-dimensional east slope of Mt. Hymettos in Greece. The study focuses on the momentum and energy budgets of the flows during carefully selected stationary periods with negligible ambient winds. In order to achieve a proper selection, the mean features of the observed flows are presented along with their response to external winds. The observed profiles are successfully compared with the theoretical Prandtl profiles. Bulk quantities of the katabatic layer are compared with proposed experimental values in order to check the representativity of the observed flows. These comparisons offer a further test of theoretical considerations and assist in discussions of processes affecting mean-flow features. The flows were similar to 20 m deep, with velocities 1-2 m s(-1). During steady-state periods the katabatic acceleration was mainly balanced by the surface friction, the contribution of advective terms being small. The estimated interfacial drag was less important than the surface drag, which proved large compared with usually suggested values. Within the experimental uncertainties, values of the drag coefficient of the order of 10(-2) seem appropriate. The steady-state energy balance showed that the downslope advection balanced the turbulent heat flux to the ground surface

A laser-scanning endoscope with enhanced attributes

Contemporary methods for minimally invasive interventions are gaining wide acceptance in various everyday operations, offering extremely localised treatment, reduced suffering and practically no risk for the patient as well as great benefits to diagnostic examinations and surgeries that require continuous monitoring. Many established endoscope systems offer the aforementioned advantages without the risks and restrictions of the computer-aided tomography techniques but with limitations in the resolution and chromatic representation provided. A microscanning specific-endoscope device has been developed aiming to provide superior resolution and chromatic representation in comparison with the above endoscopes. The key technology employed in the design of this endoscope relies on the use of tinny microelectro-mechanical silicon mirrors for the scanning of three laser beams over the target tissue area. The so-developed microscanning endoscope system provides color imaging with high resolution at near video rates targeting at macroendoscopy applications. The optical design and implementation of this endoscope system will be presented in this communication together with a brief description of the overall endoscope device developed. In addition results are given from the study of the metamery effect,that is utilised in the realised endoscope, together with a presentation of the procedure followed for the objective evaluation of its optical performance and first results from system operation