如何解决此类错误“ValueError: setting an array element with a sequence”？

Question

我正在使用 k-means 对包含 66 个字体图像的图像进行聚类。 对于每张图像，我们使用投影在前 40 个主成分上的系数作为特征向量。 这个图像聚类项目来自《Programming Computer Vision with Python》一书。

但它发生了“TypeError：只有 size-1 arrays 可以转换为 Python 标量

上述异常是以下异常的直接原因：

回溯（最后一次调用）：文件“**/demo1.py”，第 16 行，在 immatrix = array([array(Image.open(im)).flatten() for im in imlist], 'f') ValueError：使用序列设置数组元素。 "

代码如下：

# -*- coding: utf-8 -*-
from PCV.tools import imtools
import pickle
from scipy import *
from pylab import *
from PIL import Image
from scipy.cluster.vq import *
from PCV.tools import pca

# Uses sparse pca codepath.
imlist = imtools.get_imlist('./a_selected_thumbs/')

im = array(Image.open(imlist[0]))  # open one image to get the size
m, n = im.shape[:2]  # get the size of the images
imnbr = len(imlist)  # get the number of images
print("The number of images is %d" % imnbr)

# Create matrix to store all flattened images
immatrix = array([array(Image.open(imname)).flatten() for imname in imlist], 'f')

# PCA
V, S, immean = pca.pca(immatrix)

#f = open('./a_pca_modes.pkl', 'wb')
f = open('./a_pca_modes.pkl', 'wb')
pickle.dump(immean,f)
pickle.dump(V,f)
f.close()


# get list of images
imlist = imtools.get_imlist('./a_selected_thumbs/')
imnbr = len(imlist)

# load model file
with open('./a_pca_modes.pkl','rb') as f:
    immean = pickle.load(f)
    V = pickle.load(f)
# create matrix to store all flattened images
immatrix = array([array(Image.open(im)).flatten() for im in imlist],'f')

# project on the 40 first PCs
immean = immean.flatten()
projected = array([dot(V[:40],immatrix[i]-immean) for i in range(imnbr)])

# k-means
projected = whiten(projected)
centroids,distortion = kmeans(projected,4)
code,distance = vq(projected,centroids)

# plot clusters
for k in range(4):
    ind = where(code==k)[0]
    figure()
    gray()
    for i in range(minimum(len(ind),40)):
        subplot(4,10,i+1)
        imshow(immatrix[ind[i]].reshape((25,25)))
        axis('off')
show()

是因为图片的大小吗？ 如果我把图片改成自己的（500 300，图片大小不一样），会报上面的错误，而书自带的图片数据（25 25像素）不会报错。