The Hough Transform, originally described in a patent by Paul Hough, is a point-to-curve transformation, that has many applications in pattern recognition. It can detect the presence of a parametrically representable group of point in a bitmap image, such as a straight line or a circle, through a mapping to a parameter space. This is regarded as an n-dimensional matrix of accumulator (where n = number of parameters of the shape of interest). Each significant point from the original set casts a vote in one or more slots in the accumulator matrix. Thus, looking for a pattern of interest in the original space corresponds to searching for peak values in the n-dimensional space.