[Python] FInding a centerline of a contour?

I want to draw the centerline of a contour I made for the cable in the middle of the video I linked at the bottom. I also want to document the points of the centerline drawn in an array. How do I do this?

This is my code:

import cv2
from PIL import Image
from function import get_limits, get_limits_black
import numpy as np

black = [0,0,0]
cap = cv2.VideoCapture("/Users/samayjain/PycharmProjects/PythonProject/2025-06-07 11-24-40 Side.mp4")

while True:
ret, frame = cap.read()
roi = frame[0:1500, 0:1400]
hsvImage = cv2.cvtColor(roi, cv2.COLOR_BGR2HSV)
lowerBlack, upperBlack = get_limits_black(color=black)
mask_black = cv2.inRange(hsvImage, lowerBlack, upperBlack)

contours, _ = cv2.findContours(mask_black, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
i = 0
max_width = 0
index = 0
c_x,c_y,c_w,c_h= 0,0,0,0
for contour in contours:
min_area = 1000
if cv2.contourArea(contour) > min_area:
x, y, w, h = cv2.boundingRect(contour)
if x + w > max_width:
index = i
max_width = x + w
c_x,c_y,c_w,c_h=x,y,w,h
M = cv2.moments(contour)
if M["m00"] != 0:
centroid_x = int(M["m10"] / M["m00"])
centroid_y = int(M["m01"] / M["m00"])
i += 1
cv2.rectangle(frame, (c_x, c_y), (c_x + c_w, c_y + c_h), (0, 255, 0), 2)
cv2.drawContours(frame, contours, index, (0, 255, 0), 2)

cv2.circle(frame, (centroid_x, centroid_y), 10, (0, 0, 255), -1)
cv2.imshow("Original Frame with Contours", frame)
if cv2.waitKey(1) & 0xFF == ord('q'):
break

cap.release()
cv2.destroyAllWindows()


This is part of the video when I run the code: https://somup.com/cTijVkLRr7

This is the original video: https://youtu.be/Mx3RXRGzu4Q

Thanks for the help.

I tried dividing the amount of points of the contour in two and then addressing one half to the upper_limit list which was the top part of the contour and the other half to the lower_limit list which was the bottom part of the contour. Then I would create a new array called average_points which took the x values of the upper limit and then took the average of the y values of the upper and lower limit. After I created a line which was extremely inaccurate and was not even complete. This did not work because in actuality at different times of the video, either the upper or lower part had more points than the other since it is uneven due to constant movement of the cable. What I hoped to do is create a midline of the contour that ran through the middle of the contour.

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