Contours Image Find center line

I’m trying to find a centerline in that image, what should I do?
종이 - 복사본

what’s the meaning of ‘centerline’. If you want to detect straight lines, you can use Hough line transformation. OpenCV: Hough Transform

I would like to find the center line and the center of the corner as shown in the image.

Start with skeletonization (Skeletonization in Python using OpenCV | by Neeramitra Reddy | Analytics Vidhya | Medium), then simplify the polyline (OpenCV Contour Approximation - PyImageSearch).

be very careful with approxPolyDP. it does not maintain lines, it maintains corners. if the thinning/skeleton “rounds” the corner, you’ll get lines that lie off-center.

I’ve really got to implement something better than DP. commercial packages have some simple approaches that are easy to implement from nothing but looking at freely accessible advertising/sales brochures and docs.

Thank you for your help

Thank you for your help!