Some New Methods of Detecting Step Edges.
Abstract
This note describes three 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 betwween the mean and median gray levels in a neighborhood as an edge value at the center of the neighborhood. The third method computes moments of inertia of the neighborhood about a set of lines through its center, and takes the difference between the greatest and smallest of these as the edge value at the center. 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 fourth 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. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1976
- Accession Number
- ADA032747
Entities
People
- Azriel Rosenfeld
- Bruce J. Schachter
Organizations
- University of Maryland