My raspberry pi camera does not return frames to opencv

Question

I have a raspberry pi camera module 3 connected to raspberry pi. It is connected properly, since libcamera-still -o test.jpg works as intended. But when I try to capture a stream of frames, I get this error message error: (-215:Assertion failed) size.width>0 && size.height>0 in function 'imshow'.

My code looks like this:

cap = cv2.VideoCpture(0)

while True:
   _, image = cap.read()
   cv2,imshow("video stream", image)
   if(cv2.waitkey(1) == ord("q")):
      break

cap.release()
cv2.destroyAllWindows()

I have tried what this post says: opencv - unable to capture frame from camera on raspberry pi but it did not help.

Answer 1

So, the solution that worked for me looks kinda like this(I am using picamera2 to capture the camera frames and cv2 to show those frames in a window):

import cv2
from picamera2 import Picamera2

picam2 = Picamera2()
picam2.start()
while True:
    image = picam2.capture_array()
    cv2.imshow("Frame", image)
    if(cv2.waitKey(1) == ord("q")):
        cv2.imwrite("test_frame.png", image)
        break

cv2.destroyAllWindows()

Install Picamera2 using:

python3 -m pip install Picamera2