cv2 imshow displaying black images sometimes

asked 2020-07-11 15:21:09 -0600

cv-newbie
11 ●1

updated 2020-07-12 03:33:50 -0600

supra56

943 ●9 ●6

I am trying out cv2 on ubuntu 20.04, python 3.7. I have run the following script:

import cv2
img = cv2.imread('butterfly.jpg')
cv2.imshow('ImageWindow', img)
cv2.waitKey()

Sometimes I would get the lovely picture of the original butterfly image,

but sometimes I would get a small black window.

cv2error

The behavior is a bit random, and I am not sure what is causing this issue. Any help is appreciated, thanks!

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Comments

Add Index zero to cv2.waitKey(0)

Edit: I tested it on raspberry pi using linux w/out index. Actually, I don't know If this cv2.waitKey(0) work on UBUNTU

supra56 ( 2020-07-12 03:34:52 -0600 )edit

I haven't seen this before, you can try to run the following script under Windows, using IDE can help you see the cause of the error. Maybe it would be better if you read the image using absolute path.Like this:

import cv2
img = cv2.imread('D:/CODE/python/opencv/lena.jpg')
cv2.imshow('ImageWindow', img)
cv2.waitKey()

x1290148 ( 2020-07-17 05:38:21 -0600 )edit

Having the same trouble. It seems to display correct about 50% of the time. Using named windows doesn't seem to help. I know the image is being read correctly as it plots fine using matplotlib.

ETA: I went back a couple of revisions with the opencv library and it works fine now. I am using Kubuntu 20.04. Doesn't seem to be a widespread problem.

sam556 ( 2020-07-25 13:55:56 -0600 )edit

I am having the same problem, can you please guide me how you fixed that?

Dipansh ( 2020-07-30 08:53:09 -0600 )edit

I'm having the exact same problem... my machine is Ubuntu 18.04.4, using python 3.6.9, opencv version 4.3.0

eddie ( 2020-08-03 02:25:42 -0600 )edit

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