Jupyter kernel crashes when trying to display image with OpenCV

Question

I'm trying to run the example from here

import cv2

def viewImage(image):
    cv2.namedWindow('Display', cv2.WINDOW_NORMAL)
    cv2.imshow('Display', image)
    print('test')
    cv2.waitKey(0)
    cv2.destroyAllWindows()
def grayscale_17_levels (image):
    high = 255
    while(1):  
        low = high - 15
        col_to_be_changed_low = np.array([low])
        col_to_be_changed_high = np.array([high])
        curr_mask = cv2.inRange(gray, col_to_be_changed_low,col_to_be_changed_high)
        gray[curr_mask > 0] = (high)
        high -= 15
        if(low == 0 ):
            break

image = cv2.imread('ombre_circle.png')
viewImage(image)
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
grayscale_17_levels(gray)
viewImage(gray)

Whenever I run the code I get the error:

Kernel Restarting
The kernel for main.ipynb appears to have died. It will restart automatically.

I when I comment out these lines:

#cv2.namedWindow('Display', cv2.WINDOW_NORMAL)
#cv2.imshow('Display', image)

the core runs and prints out 'test' and I don't get an error.

I'm using:

Ubuntu-server 18.04
Jupyter lab 1.1.3
opencv-python 4.1.1.26

I run this on a server not on my local environment

I found a workaround for this issue by displaying it with Matplotlib:

def viewImage(image):
    plt.subplot(122)
    plt.title("RGB")
    plt.imshow(image)
    plt.show()

image = cv2.imread('img/ombre_circle.png')
viewImage(cv2.cvtColor(image, cv2.COLOR_BGR2RGB))

gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
grayscale_17_levels(gray)
viewImage3(cv2.cvtColor(gray, cv2.COLOR_GRAY2RGB))

However this doesn't solve the issue and takes extra transformations/code so I would like to find a solution to display with opencv.

X11 forwarding is enabled.

I tried opening an SSH connection with the -Y and -C flag (via this question) but this doesn't fix it.

Any ideas what could be the issue?

score 0 · Answer 1 · answered Jan 24 '20 at 14:35

0

IPython Github Issue

What I understand from the discussion is that it's a C-level linking or runtime error from the openCV code being run. I faced the same problem, got solved by using matplotlib SO jupyternb crash

answered Jan 24 '20 at 14:35

Aakash Gupta

716
6
11

score 0 · Answer 2 · answered Jul 21 '20 at 11:05

0

image=cv2.imread("the file")
cv2.imshow("test file", image)
cv2.waitKey(0)
cv2.destroyAllWindows()

answered Jul 21 '20 at 11:05

code-freeze

465
8
8

score 0 · Answer 3 · answered Jul 23 '21 at 15:55

0

I encountered similar issue when I'm loading large tiff files. Same code works for small tiff files. You can look at this post to compress your image then display.

answered Jul 23 '21 at 15:55

Chloe

71
1
7

score 0 · Answer 4 · edited Nov 06 '21 at 19:35

0

cv2.imshow() would cause Jupyter sessions to crash: this post of the issue.

As a substitution, please consider using from google.colab.patches import cv2_imshow on Google Colab.

edited Nov 06 '21 at 19:35

Cloud Cho

1,594
19
22

answered Nov 05 '21 at 19:16

Abraham Owodunni

11
3

Jupyter kernel crashes when trying to display image with OpenCV

4 Answers4