我使用pip安装了matplotlib lib，但是当我运行这段代码时，它给了我这个错误：

shar@shar-Lenovo-G50-30 ~ $ python3 opencv.py
Traceback (most recent call last):
  File "opencv.py", line 3, in <module>
    from matplotlib import pyplot as plt
ImportError: cannot import name 'pyplot'

我的代码是：

import numpy as np
import cv2
from matplotlib import pyplot as plt

img1 = cv2.imread('/home/shar/home.jpg',0)  # queryImage
img2 = cv2.imread('/home/shar/home2.jpg',0) # trainImage

# Initiate SIFT detector
orb = cv2.ORB()

# find the keypoints and descriptors with SIFT
kp1, des1 = orb.detectAndCompute(img1,None)
kp2, des2 = orb.detectAndCompute(img2,None)
# create BFMatcher object
bf = cv2.BFMatcher(cv2.NORM_HAMMING, crossCheck=True)

# Match descriptors.
matches = bf.match(des1,des2)

# Sort them in the order of their distance.
matches = sorted(matches, key = lambda x:x.distance)

# Draw first 10 matches.
img3 = cv2.drawMatches(img1,kp1,img2,kp2,matches[:10], flags=2)

plt.imshow(img3),plt.show()

我也尝试从源代码安装matplotlib，但仍然给我错误。