sigpy.mri.poisson

sigpy.mri.poisson(img_shape, accel, calib=(0, 0), dtype=<class 'complex'>, crop_corner=True, return_density=False, seed=0, max_attempts=30, tol=0.1)[source]

Generate variable-density Poisson-disc sampling pattern.

The function generates a variable density Poisson-disc sampling mask with density proportional to \(1 / (1 + s |r|)\), where \(r\) represents the k-space radius, and \(s\) represents the slope. A binary search is performed on the slope \(s\) such that the resulting acceleration factor is close to the prescribed acceleration factor accel. The parameter tol determines how much they can deviate.

Parameters:
  • img_shape (tuple of ints) – length-2 image shape.
  • accel (float) – Target acceleration factor. Must be greater than 1.
  • calib (tuple of ints) – length-2 calibration shape.
  • dtype (Dtype) – data type.
  • crop_corner (bool) – Toggle whether to crop sampling corners.
  • seed (int) – Random seed.
  • max_attempts (float) – maximum number of samples to reject in Poisson disc calculation.
  • tol (float) – Tolerance for how much the resulting acceleration can deviate form accel.
Returns:

Poisson-disc sampling mask.
Return type:

array

References

Bridson, Robert. “Fast Poisson disk sampling in arbitrary dimensions.” SIGGRAPH sketches. 2007.