jybeam2k.py 文件源码

def open_image(infile):
    """
    Open the FITS image and return its header and data, but requiring
    the input image has only ONE frequency.

    The input FITS image may have following dimensions:
    * NAXIS=2: [Y, X]
    * NAXIS=3: [FREQ=1, Y, X]
    * NAXIS=4: [STOKES, FREQ=1, Y, X]
    """
    with fits.open(infile) as f:
        header = f[0].header
        data = f[0].data
    if ((data.ndim == 3 and data.shape[0] != 1) or
            (data.ndim == 4 and data.shape[1] != 1)):
        # NAXIS=3: [FREQ!=1, Y, X]
        # NAXIS=4: [STOKES, FREQ!=1, Y, X]
        raise ValueError("input file '{0}' has invalid dimensions: {1}".format(
            infile, data.shape))
    print("Read in FITS image from: %s" % infile)
    return (header, data)