opencv图像二值化 cv2.threshold: 阈值处理(cv2.threshold) 探究(图示+源码)

代码：

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

img = cv2.imread(r'C:\Users\HouLw\Desktop\cat.jpg', 0)

ret, thresh1 = cv2.threshold(img, 127, 255, cv2.THRESH_BINARY)
ret, thresh2 = cv2.threshold(img, 127, 255, cv2.THRESH_BINARY_INV)
ret, thresh3 = cv2.threshold(img, 127, 255, cv2.THRESH_TRUNC)
ret, thresh4 = cv2.threshold(img, 127, 255, cv2.THRESH_TOZERO)
ret, thresh5 = cv2.threshold(img, 127, 255, cv2.THRESH_TOZERO_INV)

titles = ['Original Image', 'BINARY', 'BINARY_INV', 'TRUNC', 'TOZERO', 'TOZERO_INV']
images = [img, thresh1, thresh2, thresh3, thresh4, thresh5]

for i in range(6):
    plt.subplot(2, 3, i + 1)
    plt.imshow(images[i], 'gray')
    plt.title(titles[i])
    plt.xticks([]), plt.yticks([])
plt.show()

阈值类型：

0表示cv2.THRESH_BINARY   
1表示cv2.THRESH_BINARY_INV
2表示cv2.THRESH_TRUNC
3表示cv2.THRESH_TOZERO
4表示cv2.THRESH_TOZERO_INV