Thresholding

import cv2
import matplotlib.pyplot as plt

def main():
    
    path = "D:\\image_processing_files\\Dataset\\"

    imgpath1 =  path + "gray21.512.tiff"
    img = cv2.imread(imgpath1, 1)
    th = 127
    max_value = 255
    ret,o1 = cv2.threshold(img,th,max_value,cv2.THRESH_BINARY)
    ret,o2 = cv2.threshold(img,th,max_value,cv2.THRESH_BINARY_INV)
    ret,o3 = cv2.threshold(img,th,max_value,cv2.THRESH_TOZERO)
    ret,o4 = cv2.threshold(img,th,max_value,cv2.THRESH_TOZERO_INV)
    ret,o5 = cv2.threshold(img,th,max_value,cv2.THRESH_TRUNC)
    
    output = [img,o1,o2,o3,o4,o5]
    titles = ['Original_image','Bin','Bin_inv',
             'Zero','Zero_inv','Trunc']
    for i in range(6):
        plt.subplot(2,3,i+1)
        plt.imshow(output[i])
        plt.title(titles[i])
        plt.xticks([])
        plt.yticks([])

    plt.show()  

if __name__ == "__main__":
    main()