opencv的二值化0

import cv2import numpy as npfrom matplotlib import pyplot as pltimg = 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()