title: Finding the center line and center point of rectangular region
body: <p>I ran the following code to create a rectangle contour:</p>
  
  <pre><code>#import the necessary packages
  import argparse
  import imutils
  import cv2
  import numpy as np
  
  # construct the argument parse and parse the arguments
  ap = argparse.ArgumentParser()
  ap.add_argument("-i", "--image", required=True,
                  help="path to the input image")
  args = vars(ap.parse_args())
  
  # load the image, convert it to grayscale, blur it slightly, and threshold it
  image = cv2.imread(args["image"])
  gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
  gray = cv2.GaussianBlur(gray, (5, 5), 0)
  
  # threshold the image, then perform a series of erosions + dilations to remove any small regions of noise
  thresh = cv2.threshold(gray, 45, 255, cv2.THRESH_BINARY)[1]
  thresh = cv2.erode(thresh, None, iterations=2)
  thresh = cv2.dilate(thresh, None, iterations=2)
  
  contours, hierarchy = cv2.findContours(thresh,cv2.RETR_TREE,cv2.CHAIN_APPROX_SIMPLE)
  
  # Find the index of the largest contour
  areas = [cv2.contourArea(c) for c in contours]
  max_index = np.argmax(areas)
  cnt=contours[max_index]
  
  x,y,w,h = cv2.boundingRect(cnt)
  cv2.rectangle(image,(x,y),(x+w,y+h),(0,255,0),2)
  
  # show the output image
  cv2.imshow("Image", image)
  cv2.waitKey(0)
  </code></pre>
  
  <p>I would like to find the center line and center point of the rectangular contour. Please advise.</p>