Antialiasing the Hough transform

The discretization of the Hough transform parameter plane is considered. It is shown that the popular accumulator method implies sampling of a nonbandlimited signal. The resultant aliasing accounts for several familiar difficulties in the algorithm. Bandlimiting the parameter plane would allow Nyquist sampling, thus aliasing could be avoided. An effectively alias-free Hough algorithm is presented and analyzed. The uncertainty principle of signal representation induces a compromise between image-space localization and parameter-space sampling density, as well as an upper bound on the performance of the algorithm. These results contribute to the development of a design methodology for hierarchical "coarse to fine" Hough algorithms.