A Simple Edge Model
Although certain literature has considered the detection of ideal step edges, the edges obtained from natural images are usually not at all ideal step edges. Instead they are normally affected by one or several of the following effects:
- focal blur caused by a finite depth-of-field and finite point spread function.
- penumbral blur caused by shadows created by light sources of non-zero radius.
- shading at a smooth object
A number of researchers have used a Gaussian smoothed step edge (an error function) as the simplest extension of the ideal step edge model for modeling the effects of edge blur in practical applications. Thus, a one-dimensional image which has exactly one edge placed at may be modeled as:
At the left side of the edge, the intensity is, and right of the edge it is . The scale parameter is called the blur scale of the edge.
Read more about this topic: Edge Detection
Famous quotes containing the words simple, edge and/or model:
“But the whim we have of happiness is somewhat thus. By certain valuations, and averages, of our own striking, we come upon some sort of average terrestrial lot; this we fancy belongs to us by nature, and of indefeasible rights. It is simple payment of our wages, of our deserts; requires neither thanks nor complaint.... Foolish soul! What act of legislature was there that thou shouldst be happy? A little while ago thou hadst no right to be at all.”
—Thomas Carlyle (1795–1881)
“The self-consciousness of Pine Ridge manifests itself at the village’s edge in such signs as “Drive Keerful,” “Don’t Hit Our Young ‘uns,” and “You-all Hurry Back”Mlocutions which nearly all Arkansas hill people use daily but would never dream of putting in print.”
—Administration in the State of Arka, U.S. public relief program (1935-1943)
“One of the most important things we adults can do for young children is to model the kind of person we would like them to be.”
—Carol B. Hillman (20th century)