2015-11-25 13:26:43 -0500 commented question OpenCV stops working well. Thank you very much for your interest boaz001 I want to say that it's like a loop. It never ends. It remains frozen. Another example, the next script never ends. The image is not generated. import numpy as np import cv2 import Image, ImageTk img1 = cv2.imread('Webcam.png') img2 = cv2.imread('Webcam2.png') mascara=img1.copy() cv2.absdiff(img1,img2,difference) mascara_arr = Image.fromarray(difference) mascara_arr.save('difference.png')  I want to stress that the script worked well, before. For the installation I follow this: https://help.ubuntu.com/community/OpenCV and everything seemed right. 2015-11-23 18:40:09 -0500 asked a question OpenCV stops working well. Hello. I had installed opencv me and everything worked fine until a few days ago. The problem I have is that there are things in opencv that work well and others not. I'm trying to explain with an example. if I do with python: import cv2 img_01 = cv2.imread ('Webcam_panel.png', 0)  All goes well. but if I do such a simple script like (this script worked well before, it should not have any errors): import cv2 img_01 = cv2.imread ('Webcam_panel.png', 0) print img_01.shape for c in range (20):     adapt_g = cv2.adaptiveThreshold (img_01, 255, cv2.ADAPTIVE_THRESH_GAUSSIAN_C, \                                     cv2.THRESH_BINARY_INV, 11, c)     c print     fn = 'adapt_g_' + '{: 02d}'. format (c) + '.png'     cv2.imwrite (fn, adapt_g)  Does not work and is thought for a long time .. (not show any error) And this happens with other scripts that I had and now this scripts doesn't work. I reinstalled opencv and has not fixed the error. (But not uninstall the previous opencv because I dont know how I have to do it with ubuntu) I'm working with ubuntu 14.04 + 2.7 + opencv python 3.0.0 Any idea to solve the problem? Sorry for my poor english. Thank You in Advance!