def get_offset(hdr):
    """
    Extracts the image offset (akak origin) from an image header.

    Notes
    -----
    It is recommended to call `hdr.get_offset()` instead
    of this function.
    It can be assumed that the offset is measured from the center point of
    the first pixel, which SimpleITK promises independent of the file format.
    Some formats do not specify a header field for the offset, thus zeros
    are returned.
    
    Parameters
    ----------
    hdr : medpy.io.Header
        An image header as returned by `load`.
    
    Returns
    -------
    offset : tuple of floats
        The image's offset.
    """
    return hdr.get_offset()
