aye

import cv2 as cv
import numpy as np

img = cv.imread('stop.png')  # ,cv.IMREAD_GRAYSCALE)
frame = cv.resize(img, (600, 600), interpolation=cv.INTER_AREA)
hsv = cv.cvtColor(frame, cv.COLOR_BGR2HSV)
hsv = cv.blur(hsv, (5, 5))
mask = cv.inRange(hsv, (0, 7, 0), (255, 255, 190))

contours_info = cv.findContours(mask, cv.RETR_TREE, cv.CHAIN_APPROX_NONE)
contours = contours_info[1]

if contours:
    contours = sorted(contours, key=cv.contourArea, reverse=True)
    cv.drawContours(frame, contours, 0, (255, 255, 0), 3)
    (x, y, w, h) = cv.boundingRect(contours[0])
    cv.rectangle(frame, (x, y), (x + w, y + h), (0, 255, 255), 2)

cv.imshow("Contours", frame)

while (True):
    if cv.waitKey() != 0:
        break
cv.destroyAllWindows()