Optical Fourier transform processing of radiotelescope visibility function data is reviewed. Emphasis is placed on the aspects of the processor design that arise from the unusual characteristics of the data. The complex visibility function is available only over a partially filled aperture consisting of a set of elliptical paths. It is recorded at the input to the optical processor on a carrier...

BACKGROUND Blue laser imaging (BLI) and linked color imaging (LCI) are the color enhancement features of the LASEREO endoscopic system, which provide a narrow band light observation function and expansion and reduction of the color information, respectively. METHODS We examined 82 patients with early gastric cancer (EGC) diagnosed between April 2014 and August 2015. Five expert and 5 non-expe...

We introduce a framework and construct algorithms based on it to handle optimization problems that deal with the maximization of visibility information for observers when obstacles to vision are present in the environment. This framework uses at its core the approach developed in [14] which adopts the level set framework of [10] to construct a function that encodes visibility information in a c...

We study the connectivity properties of a family of random graphs which closely model the Bluetooth’s device discovery process, where each device tries to connect to other devices within its visibility range in order to establish reliable communication channels yielding a connected topology. Specifically, we provide both analytical and experimental evidence that when the visibility range of eac...

We present a method for rendering approximate soft shadows and diffuse indirect illumination in dynamic scenes. The proposed method approximates the original scene geometry with a set of tightly fitting spheres. In previous work, such spheres have been used to dynamically evaluate the visibility function to render soft shadows. In this paper, each sphere also acts as a low-frequency secondary l...

We experimentally demonstrate optical Mach-Zehnder interferometer utilizing displaced Sagnac configuration to enhance its phase stability. The interferometer with footprint of 27×40 cm offers individually accessible paths and shows phase deviation less than 0.4° during a 250 s long measurement. The phase drift, evaluated by means of Allan deviation, stays below 3° or 7 nm for 1.5 h without any ...

We review theoretical models to show that contrast reduction at a specific wavelength in the horizontal direction depends directly on the beam attenuation coefficient at that wavelength. If a black target is used, the inherent contrast is always negative unity, so that the visibility of a black target in the horizontal direction depends on a single parameter only. That is not the case for any o...

Aims. We present the first theoretical study on center-to-limb variation (CLV) properties and relative radius interpretation for narrow and broad-band filters, on the basis of a set of dynamic model atmospheres of C-rich AGB stars. We computed visibility profiles and the equivalent uniform disc radii (UD-radii) in order to investigate the dependence of these quantities upon the wavelength and p...

The visibility restoration of images is effected by various kinds of weather conditions like fog, mist, sandstorm, rain etc. This poor visibility will cause failure in the image processing applications like video surveillance, object detection, object recognition, intelligent transportation etc. The traditional visibility restoration will not requisitely restore the hazy images, because of the ...

In the paper, we consider the problem of computing visibility information on digital terrain models. Visibility problems on polyhedral terrains are classi ed according to the kind of visibility information computed into point visibility, line visibility and region visibility. A survey of the state-of-the-art of the algorithms for computing visibility is presented, according to the classi cation...