Hough Transform
Parametric Model
A parametric model can represent a class of instances where each is defined by a value of the parameters.
Examples include lines, or circles, or even a parameterized template.
Fitting a parametric model
Choose a parametric model to represent a set of features。
Membership criterion is not local:
Cannot tell whether a point in the image belongs to a given model just by looking at that point
Computational complexity is important
Not feasible to examine possible parameter setting