contours

import cv2
import numpy as np


cap = cv2.VideoCapture('.\\Resource\\red.avi')

while cap.isOpened():
    ret,frame = cap.read()
    hsv = cv2.cvtColor(frame, cv2.COLOR_BGR2HSV)
    lower_hsv = np.array([0, 43, 46])                                      
    high_hsv = np.array([50, 255, 255])
    mask = cv2.inRange(hsv, lowerb = lower_hsv, upperb = high_hsv)
    kernel = np.ones((5,5), np.uint8)
    closing = cv2.morphologyEx(mask, cv2.MORPH_CLOSE, kernel)
    opening = cv2.morphologyEx(closing, cv2.MORPH_OPEN, kernel)
    # Preprocess

    contours, hierarchy = cv2.findContours(opening,cv2.RETR_CCOMP, cv2.CHAIN_APPROX_SIMPLE)
    area = 0
    for cnt in contours:
        # find bounding box coordinates
        x, y, w, h = cv2.boundingRect(cnt)
        rect = cv2.rectangle(opening, (x, y), (x+w, y+h), (0, 255, 0), 2)
        # find minimum area
        rect = cv2.minAreaRect(cnt)
        # calculate coordinates of the minimum area rectangle
        x_m, y_m = rect[0]
        w_m, h_m = rect[1]
        Area = w_m * h_m

        if Area > 5000:
            box = cv2.boxPoints(rect)
            # normalize coordinates to integers
            box = np.int0(box)
            # draw contours
            img_s = cv2.drawContours(frame, [box], -1, (0, 255, 0), 3)

    cv2.imshow('video', img_s)
    print (area)
    c = cv2.waitKey(1)
    if c == 27:
        break

cap.release()
cv2.destroyAllWindows()