tools.ecalib

tools.ecalib#

bartorch.tools.ecalib()#

Coil sensitivities by ESPIRiT.

Parameters:
  • kspace (torch.Tensor) – k-space with a fully sampled centre, (coils, z, y, x), or (coils, y, x) for one slice.

  • maps (int, default=None) – Number of sets of sensitivities (-m); BART’s default is 2.

  • calib_size (int or tuple of int, default=None) – Size of the calibration region (-r), one for every axis or one per axis in C order; BART’s default is 24 on every axis.

  • threshold (float, default=None) – Singular-value threshold of the calibration matrix, which sets the size of its null space (-t); BART’s default is 0.001.

  • crop (float, default=None) – Eigenvalue below which a sensitivity is set to zero (-c); BART’s default is 0.8.

  • kernel_size (int, default=None) – Size of the calibration kernel (-k); BART’s default is 6.

  • softsense (bool, default=False) – Weight the maps by a smooth function of the eigenvalue about crop rather than cropping them (Soft-SENSE, -S).

  • intensity_correction (bool, default=False) – Normalise the maps to unit l1 norm over the coils, times the square root of the coil count, rather than unit l2 norm (-I).

  • return_eigenvalues (bool, default=False) – Also return the eigenvalue maps, BART’s optional second output.

  • **extra – Further BART ecalib options, by name. e, the axis the second step is split along, takes an axis of kspace.

Returns:

The sensitivities, (maps, coils, z, y, x) with the maps axis dropped when it has size one, and the eigenvalue maps when asked for; without a z axis when kspace has none.

Return type:

torch.Tensor or tuple of torch.Tensor

Examples

>>> maps = ecalib(kspace, maps=1, crop=0.8)

Examples using ecalib#

2. From k-space to an image

2. From k-space to an image

3. Coil sensitivities

3. Coil sensitivities

4. Joint reconstruction of image and sensitivity maps

4. Joint reconstruction of image and sensitivity maps

5. Choosing a regularizer

5. Choosing a regularizer

6. Custom encoding and solver

6. Custom encoding and solver

Noise prewhitening

Noise prewhitening