Hartley transform

Hartley transform [ ]

(mathematics)

An analog of the Fourier transform for finite, real-valued data sets; for a function ƒ defined atNdata values, 0, 1, 2, …,N - 1, the Hartley transform is a function,F, also defined on the set (0, 1, 2, …,N - 1), whose value atnis the sum over the variabler, from 0 throughN - 1, of the quantityN^-1f(r) cas (2πnr/N), where cas θ=cosθ+sinθ.