cv2.imshow() function is opening a window that always says not responding - python opencv

Question

I am trying to run a very simple program. To open and jpg file and display it using the opencv library for python. Initially it all worked fine but now it just opens a window which doesn't show the image but says 'not responding'. I need to go to the task manager and close it!

from numpy import *
import matplotlib as plt
import cv2

img = cv2.imread('amandapeet.jpg')
print img.shape

cv2.imshow('Amanda', img)

http://stackoverflow.com/questions/6116564/destroywindow-does-not-close-window-on-mac-using-python-and-opencv — electron1979, Jul 28 '15 at 13:27

score 122 · Accepted Answer · answered Mar 09 '14 at 01:25

122

You missed one more line:

cv2.waitKey(0)

Then the window shows the image until you press any key on keyboard. Or you can pass as following:

cv2.waitKey(1000)
cv2.destroyAllWindows()

Here, window shows image for 1000 ms, or 1 second. After that, the window would disappear itself. But in some cases, it won't. So you can forcefully destroy it using cv2.destroyAllWindows()

Please read more tutorials first : http://docs.opencv.org/trunk/doc/py_tutorials/py_tutorials.html

answered Mar 09 '14 at 01:25

Abid Rahman K

51,886
31
146
157

2

Initially it worked even without cv2.waitKey(0). It showed up the window. But then now it showing up the window but says its not responding. And after I added the cv2.waitKey(0), it is displaying the image in the window but the window still says not responding. Though all this happens in many runs – vicky Mar 09 '14 at 02:24
1

Which version of OpenCV do you use? Which OS? – Abid Rahman K Mar 09 '14 at 02:54
Windows 8 i think it is version 2.4.6 of opencv – vicky Mar 09 '14 at 16:29
Note that pressing any key closes the window and exits the program (or displays the next image) but closing the window by e.g. clicking on the "x" of the window does not end the program or display the next image. – xuiqzy Jan 07 '22 at 20:17
this answer work for me – Nuwan Chamikara Mar 23 '22 at 05:32
All links are dead – Reinderien Sep 24 '22 at 16:00

score 30 · Answer 2 · answered Apr 29 '18 at 22:01

30

None of the answers here worked in MacOS. The following works:

Just add a cv2.waitKey(1) after cv2.destroyAllWindows().

Example:

import cv2
image = cv2.imread('my_image.jpg')
cv2.imshow('HSV image', hsv_image); cv2.waitKey(0); cv2.destroyAllWindows(); cv2.waitKey(1)

answered Apr 29 '18 at 22:01

Julio Batista Silva

1,861
19
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This was very helpful! it took me a minute to realize that the cv2 window opened as inactive, and I had to go and make the window active before the key would close it. – uhoh Nov 27 '19 at 03:46
2

This works for me too! The image first shown as not responding, now it's closed after hitting a key. It took me forever to find out your solution. Thank you. – Huyen Apr 13 '20 at 10:30
This does not work for me. Nothing has ever worked. I have half given up trying to learn python because it is JUST no consistent in its usage and is incredibly difficult to sort minor steps unlike R – Anurag N. Sharma Apr 13 '22 at 10:44

score 13 · Answer 3 · answered Sep 15 '19 at 14:15

The solution that worked for me: Switch from inline graphics to auto. It worked both in Spyder and in Jupyter notebooks.

To change Spyder setting: Go to Tools > Preferences > IPhyton console > Graphics > Backend: Automatic (Change backend from Inline to Automatic)
To change Notebook setting: Enter command:

%matplotlib auto

Some background for my case (for those who may be quick to judge):

It used to work fine: I could open an image, it would load, and it would be responsive (doesn't say "Not responding", can close, focus, etc.) Then I installed some packages and ran some demo notebooks that apparently messed up some settings (Spyder open files were reset too).

I tried adding waitKey(1) (and 0, 30, 1000, etc values too). It made the image load, at least. But the image frame was "Not Responding": didn't refresh, couldn't close, didn't come to top, etc. Had to close using cv2.destroyAllWindows().

Note that everything worked fine during the duration of waitKey. I put this in a loop that shows the same image in the same named window and waits for a few seconds. During the loop everything works fine. As soon as the loop ends, the image window is "Not responding" (which looks like a GUI thread issue). I tried using cv2.startWindowThread(), and didn't make any difference.

Finally, changing from Inline graphics to Auto brought everything back to order.

Finally! The command `%matplotlib auto` worked for me. I had tried everything else but python would always crash after I pressed a key to close the window. Thanks ! — Nawra C, Mar 17 '20 at 14:08

score 3 · Answer 4 · answered Jul 14 '17 at 14:24

3

I've been working with opencv 3.2 and matplotlib too recently and discovered (through trial and error of commenting out lines) that the import of pyplot from matplotlib has some sort of interference with the cv2.imshow() function. I'm not sure why or how it really works but in case anyone searches for this issue and comes across this old forum, this might help. I'm working to try to find a solution around this interference bu

answered Jul 14 '17 at 14:24

Madelyn A.

39
1

I found the `cv2.imshow()` doesn't actually display anything unless I have already tried to plot something using matplotlib, e.g. `plt.plot(x, y)`. I can image that doing so somehow configures a graphical back-end, but haven't found the true reason. I am working inside an iPython session (not a Jupyter notebook). – n1k31t4 Apr 12 '18 at 10:08

score 2 · Answer 5 · answered Jan 16 '19 at 09:24

I did also face the same issue. I am running through command line python prompt in centos 7 with the following code

>> import cv2, numpy as np
>> cap=cv2.VideoCapture(0)
>> img=cap.read()
>> cap.release()
>> cv2.imshow('image',img[1])
>> cv2.waitKey(0)
>> cv2.destroyAllWindows()
>> cv2.waitKey(1)

Even then the problem persisted and didn't solve. So I added

>> cv2.imshow('image',img[1])

Adding this did close the image window.Running the command again would create a new instance. Hope you can try if you still face any issues.

score 2 · Answer 6 · answered Jul 04 '19 at 10:29

The cv2.imshow() function always takes two more functions to load and close the image. These two functions are cv2.waitKey() and cv2.destroyAllWindows(). Inside the cv2.waitKey() function, you can provide any value to close the image and continue with further lines of code.

    # First line will provide resizing ability to the window
    cv.namedWindow('Amanda', cv.WINDOW_AUTOSIZE)

    # Show the image, note that the name of the output window must be same
    cv.imshow('Amanda', img)

    # T0 load and hold the image
    cv.waitKey(0)

    # To close the window after the required kill value was provided
    cv.destroyAllWindows()

Hoping that you will get the image in a separate window now.

Yes - very helpful. This answer made me realize that cv2.waitKey forces an update. So if you are in a loop, and writing images to the same window repeatedly (from a camera, say) then waitKey(1) will enable a 1 millisecond wait time, but force the update of the images. — JB2, Aug 26 '23 at 20:34

datmc · Answer 7 · 2022-07-12T06:26:28.490

2

I've installed opencv-contrib-python library instead of opencv-python and now cv2.imshow() function works as expected.

edited Jul 12 '22 at 06:26

answered Dec 27 '20 at 09:10

datmc

49
6

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the issue was a lack of `waitKey`, not an installation issue. – Christoph Rackwitz Jul 12 '22 at 10:54

score 1 · Answer 8 · answered Sep 26 '17 at 01:43

If you have used python notebooks then there is a problem in using cv2.waitKey(0) and cv2.destroyallwindows() in Unix based system to run a program of opencv.

I have an alternative method which would prevent from freezing your image

Steps: -Copy the code from python notebooks and create new filename.py and paste it - Open terminal - cd path/to/file - source activate VirtualEnvironment - python filename.py

This will run code directly from terminal. Hope this helps you. Example Link: https://youtu.be/8O-FW4Wm10s

score 0 · Answer 9 · answered Jul 28 '19 at 08:32

I was having this same error until I added the below lines of code. For the waitKey, you can input figures above 0(i.e 1, 100 and above). It serves as the delay time for the window and it is in milliseconds.

----> cv2 waitKey(0) ----> cv2 destroyAllWindows()

score 0 · Answer 10 · answered Apr 24 '20 at 11:10

0

I found that i had a breakpoint on the

cv2.waitkey()

funtion. removing that fixed the issue for me

answered Apr 24 '20 at 11:10

Zain Noman

11

Please clarify what you'd like to the existing answers. – Praveen Rai Apr 24 '20 at 20:54

score 0 · Answer 11 · answered Nov 07 '22 at 13:45

As I tried all solutions mentioned above, it works for displaying an image but in my case, I want to display the video not just the single image in the window, So to solve the problem added

k=cv2.waitkey(10)
if k == 27:
  break

after cv2.imshow('title',img)

cv2.imshow() function is opening a window that always says not responding - python opencv

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