Class AsChannelLast

monai/transforms/utility/array.py:145–172

Change the channel dimension of the image to the last dimension. Some of other 3rd party transforms assume the input image is in the channel-last format with shape (spatial_dim_1[, spatial_dim_2, ...], num_channels). This transform could be used to convert, for example, a channel-

class AsChannelLast(Transform):
    """
    Change the channel dimension of the image to the last dimension.

    Some of other 3rd party transforms assume the input image is in the channel-last format with shape
    (spatial_dim_1[, spatial_dim_2, ...], num_channels).

    This transform could be used to convert, for example, a channel-first image array in shape
    (num_channels, spatial_dim_1[, spatial_dim_2, ...]) into the channel-last format,
    so that MONAI transforms can construct a chain with other 3rd party transforms together.

    Args:
        channel_dim: which dimension of input image is the channel, default is the first dimension.
    """

    backend = [TransformBackends.TORCH, TransformBackends.NUMPY]

    def __init__(self, channel_dim: int = 0) -> None:
        if not (isinstance(channel_dim, int) and channel_dim >= -1):
            raise ValueError(f"invalid channel dimension ({channel_dim}).")
        self.channel_dim = channel_dim

    def __call__(self, img: NdarrayOrTensor) -> NdarrayOrTensor:
        """
        Apply the transform to `img`.
        """
        out: NdarrayOrTensor = convert_to_tensor(moveaxis(img, self.channel_dim, -1), track_meta=get_track_meta())
        return out


class EnsureChannelFirst(Transform):