In [1]:

    

import cv2


    

In [2]:

    

im = cv2.imread('data/src/lena_square_half.png')


    

In [3]:

    

th, im_th = cv2.threshold(im, 128, 255, cv2.THRESH_BINARY)


    

In [4]:

    

print(th)


    

    




128.0

In [5]:

    

cv2.imwrite('data/dst/opencv_th.jpg', im_th)


    

    
Out[5]:





True

In [6]:

    

th, im_th_tz = cv2.threshold(im, 128, 255, cv2.THRESH_TOZERO)


    

In [7]:

    

print(th)


    

    




128.0

In [8]:

    

cv2.imwrite('data/dst/opencv_th_tz.jpg', im_th_tz)


    

    
Out[8]:





True

In [9]:

    

# th, im_th_otsu = cv2.threshold(im, 128, 192, cv2.THRESH_OTSU)
# error: OpenCV(4.2.0) /tmp/opencv-20200105-17262-cwpzm4/opencv-4.2.0/modules/imgproc/src/thresh.cpp:1529: error: (-215:Assertion failed) src.type() == CV_8UC1 in function 'threshold'


    

In [10]:

    

im_gray = cv2.cvtColor(im, cv2.COLOR_BGR2GRAY)


    

In [11]:

    

th, im_gray_th_otsu = cv2.threshold(im_gray, 128, 192, cv2.THRESH_OTSU)


    

In [12]:

    

print(th)


    

    




117.0

In [13]:

    

cv2.imwrite('data/dst/opencv_th_otsu.jpg', im_gray_th_otsu)


    

    
Out[13]:





True