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darts_postprocessing.erode_mask

Erode the mask, also set the edges to invalid.

Parameters:

  • mask (xarray.DataArray) –

    The mask to erode.

  • size (int) –

    The size of the disk to use for erosion and the edge-cropping.

  • device (typing.Literal['cuda', 'cpu'] | int) –

    The device to use for erosion.

Returns:

Source code in darts-postprocessing/src/darts_postprocessing/postprocess.py 
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@stopuhr.funkuhr("Eroding mask", printer=logger.debug, print_kwargs=["size"])
def erode_mask(mask: xr.DataArray, size: int, device: Literal["cuda", "cpu"] | int) -> xr.DataArray:
    """Erode the mask, also set the edges to invalid.

    Args:
        mask (xr.DataArray): The mask to erode.
        size (int): The size of the disk to use for erosion and the edge-cropping.
        device (Literal["cuda", "cpu"] | int): The device to use for erosion.

    Returns:
        xr.DataArray: The dilated and inverted mask.

    """
    # Clone mask to avoid in-place operations
    mask = mask.copy()

    # Change to dtype uint8 for faster skimage operations
    mask = mask.astype("uint8")

    use_gpu = device == "cuda" or isinstance(device, int)

    # Warn user if use_gpu is set but no GPU is available
    if use_gpu and not CUCIM_AVAILABLE:
        logger.warning(
            f"Device was set to {device}, but GPU acceleration is not available. Calculating TPI and slope on CPU."
        )
        use_gpu = False

    # Dilate the mask with GPU
    if use_gpu:
        device_nr = device if isinstance(device, int) else 0
        logger.debug(f"Moving mask to GPU:{device}.")
        # Check if mask is dask, if not persist it, since dilation can't be calculated from cupy-dask arrays
        if mask.chunks is not None:
            mask = mask.persist()
        with cp.cuda.Device(device_nr):
            mask = mask.cupy.as_cupy()
            mask.values = binary_erosion_gpu(mask.data, disk_gpu(size))
            mask = mask.cupy.as_numpy()
            free_cupy()
    else:
        mask.values = binary_erosion(mask.values, disk(size))

    # Mask edges
    mask[:size, :] = 0
    mask[-size:, :] = 0
    mask[:, :size] = 0
    mask[:, -size:] = 0

    return mask