Radon Transform - Relationship With The Fourier Transform

Relationship With The Fourier Transform

The Radon transform is closely related to the Fourier transform. For a function of one variable the Fourier transform is defined by

\hat{f}(\omega)=\int_{-\infty}^\infty f(x)e^{-2\pi ix\omega }\,dx.

and for a function of a 2-vector ,

\hat{f}(\mathbf{w})=\int\limits_{-\infty}^{\infty} \int\limits_{-\infty }^{\infty} f(\mathbf{x})e^{-2\pi i\mathbf{x}\cdot\mathbf{w}}\,dx\, dy.

For convenience define as it is only meaningful to take the Fourier transform in the variable. The Fourier slice theorem then states

\widehat{R_{\alpha}}(\sigma)=\hat{f}(\sigma\mathbf{n}(\alpha))

where

Thus the two-dimensional Fourier transform of the initial function is the one variable Fourier transform of the Radon transform of that function. More generally, one has the result valid in n dimensions

Indeed, the result follows at once by computing the two variable Fourier integral along appropriate slices:

An application of the Fourier inversion formula also gives an explicit inversion formula for the Radon transform, and thus shows that it is invertible on suitably chosen spaces of functions. However this form is not particularly useful for numerical inversion, and faster discrete inversion methods exist.

Read more about this topic:  Radon Transform

Famous quotes containing the words relationship with, relationship and/or transform:

    “Some [adolescent] girls are depressed because they have lost their warm, open relationship with their parents. They have loved and been loved by people whom they now must betray to fit into peer culture. Furthermore, they are discouraged by peers from expressing sadness at the loss of family relationships—even to say they are sad is to admit weakness and dependency.”
    —Mary Pipher (20th century)

    “It is possible to make friends with our children—but probably not while they are children.... Friendship is a relationship of mutual dependence-interdependence. A family is a relationship in which some of the participants are dependent on others. It is the job of parents to provide for their children. It is not appropriate for adults to enter into parenthood recognizing they have made a decision to accept dependents and then try to pretend that their children are not dependent on them.”
    —Donald C. Medeiros (20th century)

    “It is necessary to turn political crisis into armed crisis by performing violent actions that will force those in power to transform the military situation into a political situation. That will alienate the masses, who, from then on, will revolt against the army and the police and blame them for this state of things.”
    —Carlos Marighella (d. 1969)