OpenCV function from outside while loop

Question

I have a OpenCV program written in python which tracks the position of a ball and uses a webcam as the input.
How would I now implement a function, that can get the position of the ball only when it's called (i.e. by a keyboard event).
The problem is that the OpenCV algorithm is running in a while loop which would have to be killed before I can call another function.
I'm still kinda new to python and therefore don't know whether or not this is a dumb question. Thanks in advance!

Ian Chu · Accepted Answer · 2021-01-22 15:13:30Z

1

Yep, it's doable! You can get keyboard input from cv2.waitKey(milliseconds).

import cv2

# make it brighter
def brighten(img):
    img[:,:,:] += 10;

# get image
img = cv2.imread("image.jpg");

# loop
done = False;
while not done:
    # do processing stuff

    # show image
    cv2.imshow("Image", img);
    key = cv2.waitKey(1);

    # check for keypresses
    done = key == ord('q'); # when q is pressed
    if key == ord('b'):
        brighten(img);

answered Jan 22, 2021 at 15:13

Ian Chu

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