Class NrrdReader

monai/data/image_reader.py:1457–1612

Load NRRD format images based on pynrrd library. Args: channel_dim: the channel dimension of the input image, default is None. This is used to set original_channel_dim in the metadata, EnsureChannelFirstD reads this field. If None, `original_channel_dim` wil

@require_pkg(pkg_name="nrrd")
class NrrdReader(ImageReader):
    """
    Load NRRD format images based on pynrrd library.

    Args:
        channel_dim: the channel dimension of the input image, default is None.
            This is used to set original_channel_dim in the metadata, EnsureChannelFirstD reads this field.
            If None, `original_channel_dim` will be either `no_channel` or `0`.
            NRRD files are usually "channel first".
        dtype: dtype of the data array when loading image.
        index_order: Specify whether the returned data array should be in C-order (‘C’) or Fortran-order (‘F’).
            Numpy is usually in C-order, but default on the NRRD header is F
        affine_lps_to_ras: whether to convert the affine matrix from "LPS" to "RAS". Defaults to ``True``.
            Set to ``True`` to be consistent with ``NibabelReader``, otherwise the affine matrix is unmodified.

        kwargs: additional args for `nrrd.read` API. more details about available args:
            https://github.com/mhe/pynrrd/blob/master/nrrd/reader.py

    """

    def __init__(
        self,
        channel_dim: str | int | None = None,
        dtype: np.dtype | type | str | None = np.float32,
        index_order: str = "F",
        affine_lps_to_ras: bool = True,
        **kwargs,
    ):
        self.channel_dim = float("nan") if channel_dim == "no_channel" else channel_dim
        self.dtype = dtype
        self.index_order = index_order
        self.affine_lps_to_ras = affine_lps_to_ras
        self.kwargs = kwargs

    def verify_suffix(self, filename: Sequence[PathLike] | PathLike) -> bool:
        """
        Verify whether the specified `filename` is supported by pynrrd reader.

        Args:
            filename: file name or a list of file names to read.
                if a list of files, verify all the suffixes.

        """
        suffixes: Sequence[str] = ["nrrd", "seg.nrrd"]
        return has_nrrd and is_supported_format(filename, suffixes)

    def read(self, data: Sequence[PathLike] | PathLike, **kwargs) -> Sequence[Any] | Any:
        """
        Read image data from specified file or files.
        Note that it returns a data object or a sequence of data objects.

        Args:
            data: file name or a list of file names to read.
            kwargs: additional args for actual `read` API of 3rd party libs.

        """
        img_: list = []
        filenames: Sequence[PathLike] = ensure_tuple(data)