address review comments

try:

    import bm3d_streak_removal as bm3dsr

except ImportError:

    # add a log?

    bm3dsr = None

from multiprocessing.managers import SharedMemoryManager

from tqdm.contrib.concurrent import process_map

    """

    Remove ring artifact from sinograms using BM3D method.

    This method requires BM3D suite, which can be installed by ``pip install bm3d_streak_removal``.

    ref: `10.1107/S1600577521001910 <http://doi.org/10.1107/S1600577521001910>`_

    Parameters

    ----------

    arrays: np.ndarray

        Input radiograph stack.

    extreme_streak_iterations: int

        Number of iterations for extreme streak attenuation.

    extreme_detect_lambda: float

        Consider streaks which are stronger than lambda * local_std as extreme.

    extreme_detect_size: int

        Half window size for extreme streak detection -- total (2*s + 1).

    extreme_replace_size: int

        Half window size for extreme streak replacement -- total (2*s + 1).

    max_bin_iter_horizontal: int

        The number of total horizontal scales (counting the full scale).

    bin_vertical: int

        The factor of vertical binning, e.g. bin_vertical=32 would perform denoising in 1/32th of the original vertical size.

    filter_strength: float

        Strength of BM4D denoising (>0), where 1 is the standard application, >1 is stronger, and <1 is weaker.

    use_slices: bool

        If True, the sinograms will be split horizontally across each binning iteration into overlapping.

    slice_sizes: list

        A list of horizontal sizes for use of the slicing if use_slices=True. By default, slice size is either 39 pixels or 1/5th of the total width of the current iteration, whichever is larger.

    slice_step_sizes: list

        List of number of pixels between slices obtained with use_slices=True, one for each binning iteration. By default 1/4th of the corresponding slice size.

    denoise_indices: list

        Indices of sinograms to denoise; by default, denoises the full stack provided.

    Returns

    -------

    def __call__(self, **params):

        """See class level documentation for help."""

        if not bm3dsr:

            logger.warning("something informative")

            raise RuntimeError("probably same as warning")

            logger.warning("To use method, make sure to install bm3d_streak_removal package via pip.")

            raise RuntimeError("BM3D suite not installed, please install with pip install bm3d_streak_removal")

        else:

            logger.info("Executing Filter: Remove Ring Artifact with BM3D")

        _ = self.instance(**params)

    assert err_correction < err_no_correction

@pytest.mark.skipif(not bm3dsr, reason="something meaningful array")

@pytest.mark.skipif(not bm3dsr, reason="bm3d not installed, skipping test.")

def test_bm3d_ring_removal():

    # step_0: prepare synthetic data

    # note: we need a tiny test data as bm3d is very slow