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 windo

Answer 1

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.

Answer 2

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()

Answer 3

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

Answer 4

I found that i had a breakpoint on the

cv2.waitkey()

funtion. removing that fixed the issue for me

Answer 5

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.

Answer 6

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