실시간 영상 대신 촬영한 영상 불러오는 코드. 가로세로줄 뜸

import cv2
import numpy as np

cap = cv2.VideoCapture("Rack.mp4")

while True:
    ret, frame = cap.read()
    if ret is False:
        break
    
    roi = frame[100: 795, 537: 1416]
    rows, cols, _ = roi.shape
    
    gray_roi = cv2.cvtColor(roi, cv2.COLOR_BGR2GRAY)
    gray_roi = cv2.GaussianBlur(gray_roi, (7, 7), 0)
    
    _, threshold = cv2.threshold(gray_roi, 5, 255, cv2.THRESH_BINARY_INV)
    _, contours, _ = cv2.findContours(threshold, cv2.RETR_TREE, cv2.CHAIN_APPROX_SIMPLE)
    contours = sorted(contours, key=lambda x: cv2.contourArea(x), reverse=True)
    
    for cnt in contours:
        (x, y, w, h) = cv2.boundingRect(cnt)
        cv2.drawContours(roi, [cnt], -1, (0, 0, 255), 3)
        cv2.rectangle(roi, (x, y), (x + w, y + h), (255, 0, 0), 2)
        cv2.line(roi, (x + int(w/2), 0), (x + int(w/2), rows), (0, 255, 0), 2)
        cv2.line(roi, (0, y + int(h/2)), (cols, y + int(h/2)), (0, 255, 0), 2)
        break
    
    cv2.imshow("Threshold", threshold)
    cv2.imshow("gray roi", gray_roi)
    cv2.imshow("Roi", roi)
    key = cv2.waitKey(30)
    if key == 27:
        break
cv2.destroyAllWindows()