Efficient approximation of Jacobian matrices involving a non-uniform fast Fourier transform (NUFFT)

Understand

There is growing interest in learning Fourier domain sampling strategies (particularly for magnetic resonance imaging, MRI) using optimization approaches.

• For non-Cartesian sampling patterns, the system models typically involve non-uniform FFT (NUFFT) operations.
• Commonly used NUFFT algorithms contain frequency domain interpolation, which is not differentiable with respect to the sampling pattern, complicating the use of gradient methods.
• This paper describes an efficient and accurate approach for computing approximate gradients involving NUFFTs.