Imshow error in opencv

cv2.error: OpenCV(4.5.2-pre) /home/pi/opencv/modules/highgui/src/window.cpp:404: error: (-215:Assertion failed) size.width>0 && size.height>0 in function ‘imshow’
hatası alıyorum çözüm yolu önerileriniz var mıdır?

YOUR INPUT IS EMPTY / INVALID !!

(and python users never expect that, you have to check the output from imread() or capture.read(), and python users never do that…)