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We show that the region lit by a point light source inside a simple n-gon after at most k reeections oo the boundary has combinatorial complexity O(n 2k), for any k 1. A lower bound of ((n=k ? (1)) 2k) is also established which matches the upper bound for any xed k. A simple near-optimal algorithm for computing the illuminated region is presented, which… (More)

We consider direct visibility in simple orthogonal polygons and derive tight lower and upper bounds on the number of strictly internal and external visibility edges. We also show a lower bound of ⌈ n 2 ⌉ − 1 on the number of diffuse reflections required for completely illuminating an orthogonal polygon from an arbitrary point inside it. Further, we derive… (More)

- Subir Kumar Ghosh, Partha Pratim Goswami, Anil Maheshwari, Subhas Chandra Nandy, Sudebkumar Prasant Pal, Swami Sarvattomananda
- The Visual Computer
- 2009

Let s be a point source of light inside a polygon P of n vertices. A polygonal path from s to some point t inside P is called a diffuse reflection path if the turning points of the path lie on edges of P. A diffuse reflection path is said to be optimal if it has the minimum number of reflections on the path. The problem of computing a diffuse reflection… (More)

We extend the concept of the polygon visible from a source point S in a simple polygon by considering visibility with two types of reflection, specular and dzffuse. In specular reflection a light ray reflects from an edge of the polygon according to Snell's law: the angle of incidence equals the angle of reflection. In diffuse reflection a light ray… (More)

Let the bicoloring cover number χ c (G) for a hypergraph G(V, E) be the minimum number of bicolorings of vertices of G such that every hyperedge e ∈ E of G is properly bicolored in at least one of the χ c (G) bicolorings. We establish a tight bound for χ c (K k n), where K k n is the complete k-uniform hypergraph on n vertices. We investigate the… (More)