Main Page | See live article | Alphabetical index In mathematics and statistics, the discrete Hankel transform acts on a vector of sampled data, where the samples are assumed to have been taken at points related to the zeroes of a Bessel function of fixed order; compare this to the case of the discrete Fourier transform, where samples are taken at points related to the zeroes of the sine or cosine function. Specifically, let f(t) be a function on the unit interval. Then the finite ν-Hankel transform of f(t) is defined to be the set of numbers gm given by so that Suppose that f is band-limited in the sense that gm = 0 for m > M. Then we have the following fundamental sampling theorem: It is this discrete expression which defines the discrete Hankel transform. The kernel in the summation above defines the matrix of the ν-Hankel transform of size M - 1. Notice that by assumption f(t) vanishes at the endpoints of the interval, consistent with the inversion formula and the sampling formula given above. Therefore, this transform corresponds to an orthogonal expansion in eigenfunctions of the Dirichlet problem for the Bessel differential equation. Further reading H. Fisk Johnson, Comp. Phys. Comm. 43, 181 (1987). D. Lemoine, J. Chem. Phys. 101, 3936 (1994). The above text or an earlier revision of it was taken from the GNU Scientific Library manual, which is licensed under the GNU FDL. This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.