opencv的二值化0

import cv2
import numpy as np
from matplotlib import pyplot as plt
img = cv2.imread('thresh.png',0)
# 中值滤波
img = cv2.medianBlur(img,5)
ret,th1 = cv2.threshold(img,127,255,cv2.THRESH_BINARY)
#11 为 Block size, 2 为 C 值
th2 = cv2.adaptiveThreshold(img,255,cv2.ADAPTIVE_THRESH_MEAN_C,cv2.THRESH_BINARY,11,2)
th3 = cv2.adaptiveThreshold(img,255,cv2.ADAPTIVE_THRESH_GAUSSIAN_C,
                            cv2.THRESH_BINARY,11,2)
titles = ['Original Image', 'Global Thresholding (v = 127)',
          'Adaptive Mean Thresholding', 'Adaptive Gaussian Thresholding']
images = [img, th1, th2, th3]
for i in range(4):
  plt.subplot(2,2,i+1),plt.imshow(images[i],'gray')
  plt.title(titles[i])
  plt.xticks([]),plt.yticks([])
plt.show()