python opencv 二值化 计算白色像素点的实例

#! /usr/bin/env python# -*- coding: utf-8 -*-import cv2import numpy as npfrom PIL import Imagearea = 0def ostu(img):  global area  image=cv2.cvtColor(img, cv2.COLOR_BGR2GRAY) # 转灰度  blur = cv2.GaussianBlur(image,(5,5),0) # 阈值一定要设为 0 ！高斯模糊  ret3,th3 = cv2.threshold(blur,0,255,cv2.THRESH_BINARY+cv2.THRESH_OTSU) # 二值化 0 = black ; 1 = white  # cv2.imshow('image', th3)  # a = cv2.waitKey(0)  # print a  height, width = th3.shape  for i in range(height):    for j in range(width):      if th3[i, j] == 255:        area += 1  return area