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I am creating an alarm system that when you press t it turns on the alarm and if too much movement is detected it will sound an alarm. When I press t to activate the alarm it gives this error:

 frame_bw = cv2.cvtColor(frame = cv2.COLOR_BGR2GRAY)
cv2.error: OpenCV(4.6.0) :-1: error: (-5:Bad argument) in function 'cvtColor'
> Overload resolution failed:
>  - cvtColor() missing required argument 'src' (pos 1)
>  - cvtColor() missing required argument 'src' (pos 1)

Does anyone know what is happening?

here is my code:

import winsound
import threading
import cv2
import imutils

cap = cv2.VideoCapture(0, cv2.CAP_DSHOW)

cap.set(cv2.CAP_PROP_FRAME_WIDTH, 640)
cap.set(cv2.CAP_PROP_FRAME_WIDTH, 480)


_, start_frame = cap.read()
start_frame = imutils.resize(start_frame, width=500)
start_frame = cv2.cvtColor(start_frame , cv2.COLOR_BGR2GRAY)
start_frame = cv2.GaussianBlur(start_frame, (21, 21), 0)

alarm = False
alarm_mode = False
alarm_counter = 0

def beep_alarm():
    global alarm
    for _ in range(5):
        if not alarm_mode:
            break
        print("ALARM!")
        winsound.Beep(2500, 1000)
    alarm = False


while True:

    _, frame = cap.read()
    frame = imutils.resize(frame, width=500)

    if alarm_mode:
        frame_bw = cv2.cvtColor(frame = cv2.COLOR_BGR2GRAY)  
        frame_bw = cv2.GaussianBlur(frame_bw, (5, 5), 0)

        difference = cv2.absdiff(frame_bw, start_frame)
        threshold = cv2.threshold(difference, 25, 255, cv2.THRESH_BINARY)[1]
        start_frame = frame_bw

        if threshold.sum() > 300:
            alarm_counter +=1
        else:
            if alarm_counter > 0:
                alarm_counter -=1
        
        cv2.imshow("Cam", threshold)
    else:
        cv2.imshow("Cam", frame)

    if alarm_counter > 20:
        if not alarm:
            alarm = True
            threading.Thread(target=beep_alarm).start()

    key_pressed = cv2.waitKey(30)
    if key_pressed == ord("t"):
        alarm_mode = not alarm_mode
        alarm_counter = 0
    if key_pressed == ord("q"):
        alarm_mode = False
        break

cap.release()
cv2.destroyAllWindows()
Christoph Rackwitz
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Shaahid Patel
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  • Check to see if your frame grab actually has an image. Either view it or get its shape and print the shape. – fmw42 Nov 06 '22 at 16:56
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    `_, frame = cap.read()` -- when you ignore the status flag that `read()` returns, you're bound to run into those sorts of errors, since you end up calling other functions with an empty image, which in many cases is invalid. – Dan Mašek Nov 06 '22 at 18:00
  • @fmw42 sorry, how do you do this – Shaahid Patel Nov 06 '22 at 18:49
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    did you use Github Copilot without checking what code it generates for you? or did you not notice that `cvtColor` expects a `src` argument, not a `frame` argument? -- voting to close. it's a typo. -- previous comments mistake the error message. those assumptions can't be made yet. – Christoph Rackwitz Nov 06 '22 at 20:12

1 Answers1

2

Please check this line:

frame_bw = cv2.cvtColor(frame = cv2.COLOR_BGR2GRAY)

It should be:

frame_bw = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
Markus
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