anatomical.py 文件源码

def image_gradient(in_file, snr, out_file=None):
    """Computes the magnitude gradient of an image using numpy"""
    import os.path as op
    import numpy as np
    import nibabel as nb
    from scipy.ndimage import gaussian_gradient_magnitude as gradient

    if out_file is None:
        fname, ext = op.splitext(op.basename(in_file))
        if ext == '.gz':
            fname, ext2 = op.splitext(fname)
            ext = ext2 + ext
        out_file = op.abspath('{}_grad{}'.format(fname, ext))

    imnii = nb.load(in_file)
    data = imnii.get_data().astype(np.float32)  # pylint: disable=no-member
    datamax = np.percentile(data.reshape(-1), 99.5)
    data *= 100 / datamax
    grad = gradient(data, 3.0)
    gradmax = np.percentile(grad.reshape(-1), 99.5)
    grad *= 100.
    grad /= gradmax

    nb.Nifti1Image(grad, imnii.get_affine(), imnii.get_header()).to_filename(out_file)
    return out_file