opencv otsu binarization not working I tried to apply opencv OTSU binarization on the following image, but it generate a black image. 



Here is the following python code:

import cv2

image = cv2.imread('test_otsu.png', 0)
ret, thresh = cv2.threshold(image, 0,250,cv2.THRESH_BINARY+cv2.THRESH_OTSU)
cv2.imwrite('temp.png', thresh)


Did I miss anything in my code? Please help me how to get correct binarization of the given image.
the problems seems to be with the white border of the image you are using. remove it manually and test again.