rai_toolbox.augmentations.fourier.FourierBasis

class rai_toolbox.augmentations.fourier.FourierBasis(basis, position, sym_position, phase_shift)

Describes a 2D planewave generated via:

A * cos(2pi * freq_vector @ x + phase_shift)

Where A normalizes the 2D array to have an \(L^2\)-norm of 1, and x is evaluated on a grid of positions on [0, H] x [0, W].

Parameters:

basis: np.ndarray, shape-(H, W)

The amplitudes of the 2D planewave.

positionTuple[int, int]

The (k-row, k-col) coordinate in shifted k-space, where the freq-0 component has been shifted to reside at the center of the shape-(H, W) “k-image”.

sym_positionTuple[int, int]

The k-space coordinate symmetric to position, about the center of the k-space image.

phase_shiftfloat

The total phase-shift applied to the cosine-generated planewave.

__init__(*args, **kwargs)

Methods

__init__(*args, **kwargs)