Detect Holes, Ends And Beginnings Of A Line Using Opencv?

I'm trying to create a Python script that detects holes, ends and beginnings of a line. I thought that openCV would be great to achieve this. So for example everything starts with

Solution 1:

I added a func getLandmarks() it returns all the wholes. So here I assume that it will be counted as a hole if there are 2 corners in a radius of 30 pix

ifabs(x1-x2)<=30andabs(y1-y2)<=30:

This line defines the range.

import cv2
import numpy as np

def getLandmarks(corners):
    holes=[]
    for i in range(0,len(corners)):
        for j in range(i+1,len(corners)):
            x1,y1=corners[i].ravel()
            x2,y2=corners[j].ravel()
            if abs(x1-x2)<=30 and abs(y1-y2)<=30:
                holes.append((int((x1+x2)/2),int((y1+y2)/2)))
    return holes

# lodes in img

img = cv2.imread('img.png', cv2.IMREAD_COLOR)
img_gray = cv2.cvtColor(img, cv2.COLOR_RGB2GRAY)

corners = cv2.goodFeaturesToTrack(img_gray, 200, 0.05, 10)

holes=getLandmarks(corners)
print len(holes)
for corner in holes:
    cv2.circle(img, (corner), 7, (255,255,0), -1)

cv2.imshow('img',img)
cv2.waitKey(0)

output

Now for the Start and end You can easily sort the corners in either X(if the Path is along left to right) or Y(If the path is along top to down) and the min and max will be your start and end!