This paper introduces a visibility relation v (and the strong visibility relation ⩕ v) on proximal Delaunay meshes. A main result in this paper is that the visibility relation v is equivalent to Wallman proximity. In addition, a Delaunay triangulation region endowed with the visibility relation v has a local Leader uniform topology.

Part of the latest research efforts in occlusion culling focus on using hardware visibility query. In this paper, we present a novel method to prioritize the visibility query to work effectively together with an occlusion culling approach. We demonstrate that an addition of query priority to a simple front-to-back slab visibility processing can greatly reduce the number of unfruitful visibility...

A visibility drawing of a plane graph G is a drawing of G where each vertex is drawn as a horizontal line segment and each edge is drawn as a vertical line segment such that the line segments use only grid points as their endpoints. The area of a visibility drawing is the area of the smallest rectangle on the grid which encloses the drawing. A minimum-area visibility drawing of a plane graph G ...

In this paper, we consider the special class of visibility problems that is when there are a number of circular obstacles in the plane limiting the visibility area of an observer. Here we propose an algorithm to compute the visibility area, in O(nlogn) time. For the query version of the problem, data structure of size O(n) can be built in time O(nlogn) so that the visibility sequence of every p...

Visibility data collected from Kaohsiung City, Taiwan, for the past two decades indicated that the air pollutants have significantly degraded visibility in recent years. During our study period, the seasonal mean visibilities in spring, summer, fall, and winter were only 5.4, 9.1, 8.2, and 3.4 km, respectively. To ascertain how urban aerosols influence the visibility, we conducted concurrent vi...

PURPOSE To compare the visibility of the lamina cribrosa (LC) in optic disc images acquired from 60 glaucoma and 60 control subjects using three optical coherence tomography (OCT) devices, with and without enhanced depth imaging (EDI) and adaptive compensation (AC). METHODS A horizontal B-scan was acquired through the center of the disc using two spectral-domain (Spectralis and Cirrus; with a...

In this paper, we present three necessary conditions for recognizing point visibility graphs. We show that this recognition problem lies in PSPACE. We state new properties of point visibility graphs along with some known properties that are important in understanding point visibility graphs. For planar point visibility graphs, we present a complete characterization which leads to a linear time ...

Fog is a challenging problem for road safety. To estimate the fog density and estimate the meteorological visibility distance, some attempts using an in-vehicle cameras are being developed. To complete the notion of meteorological visibility, we propose to estimate the distance to the most distant visible object belonging to the road surface. We call this distance the mobilized visibility dista...

We devise dynamic algorithms for the following (weak) visibility polygon computation problems: • Maintaining visibility polygon of a fixed point located interior to simple polygon amid vertex insertions and deletions to simple polygon. • Answering visibility polygon query corresponding to any point located exterior to simple polygon amid vertex insertions and deletions to simple polygon. • Main...