Showing papers on "Centroid published in 1978"
TL;DR: A new notion of centrality called the telephone center is introduced and is shown to be equivalent to the centroid as well.
32 citations
TL;DR: In this article, a central limit theorem for the smoothed eigenstate density distribution in large model spaces is used to define the centroid and the width of the energy spectrum as quantities of fundamental importance and give credence to a geometry associated with averages of the product of the operators acting within a model space.
21 citations
TL;DR: This note describes two operators that respond to step edges, but not to ramps; the first is similar to the digital Laplacian, but uses the max of the x and y second differences, and the second uses the difference between the mean and median gray levels in a neighborhood.
Abstract: This note describes two operators that respond to step edges, but not to ramps. The first is similar to the digital Laplacian, but uses the max, rather than the sum, of the x and y second differences. The second uses the difference between the mean and median gray levels in a neighborhood. The outputs obtained from these operators applied to a set of test pictures are compared with each other and with the standard digital Laplacian and gradient. A third operator, which uses the distance between the center and centroid of a neighborhood as an edge value, is also briefly considered; it turns out to be equivalent to one of the standard digital approximations to the gradient.
20 citations
TL;DR: In 1917 D'Arcy Thompson reduced the problem of comparing two homologous shapes to the construction and depiction of a mathematical distortion in the plane to a function which accords with geometric homologies and has least integral roughness.
13 citations
11 citations