运行Nipype教程时Nibabel中的错误

Question

有问题的切片niimg从nibabel.get_data()。

当使用Nipype教程的这个功能时，

def plot_slice(fname, z_idx=5):
    # Load the image and collect the data
    # and orientation information
    img = nib.load(fname)
    data = img.get_data()
    aff = img.get_affine()

    # Find the center of the brain matrix
    ctr = np.dot(np.linalg.inv(aff), [0, 0, 0, 1])[:3]

    # Plot the data
    vmin, vmax = (0, 1) if data.dtype == np.int16 else (30, 150)
    plt.imshow(np.rot90(data[:, :, ctr[2] + z_idx]), cmap="gray", vmin=vmin, vmax=vmax)
    plt.gca().set_axis_off()

要运行

plot_slice("output/run001_bet.nii.gz")

结果是这样的；

---------------------------------------------------------------------------
IndexError                                Traceback (most recent call last)
<ipython-input-10-5b2c71c131be> in <module>()
----> 1 plot_slice("output/run001_bet.nii.gz")

<ipython-input-8-4c2563317c99> in plot_slice(fname, z_idx)
     12     # Plot the data
     13     vmin, vmax = (0, 1) if data.dtype == np.int16 else (30, 150)
---> 14     plt.imshow(np.rot90(data[:, :, ctr[2] + z_idx]), 
     15                cmap="gray", vmin=vmin, vmax=vmax)
     16     plt.gca().set_axis_off()

IndexError: only integers, slices (`:`), ellipsis (`...`), numpy.newaxis (`None`) and integer or boolean arrays are valid indices

Answer 1

因为ctr2是由np.dot返回的，所以它实际上是一个浮点数，尽管它看起来像一个int。尝试int(ctr2) + z_idx。