adaptive_thresholding.py

# Code from
# https://opencv-python-tutroals.readthedocs.io/en/latest/py_tutorials/py_imgproc/py_thresholding/py_thresholding.html

import cv2
from matplotlib import pyplot as plt

img = cv2.imread('radar.png', 0)
img = cv2.medianBlur(img, 5)

print(img.shape)

ret, th1 = cv2.threshold(img, 40, 255, cv2.THRESH_TOZERO)
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 = 40)',
          '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()