find intersection point of two lines drawn using houghlines opencv

Question

How can I get the intersection points of lines down using opencv Hough lines algorithm?

Here is my code:

import cv2
import numpy as np
import imutils         


        

Answer 1

Here I have processed my image with some methods;

1.Grayscale

2.Either bitwise conversion or edge detection, it depends on the image I guess,here I have gone with bitwise conversion. First carrying out all detected line into a list.

listOflines = cv2.HoughLines(mask_inv,1,np.pi/180,200)

We will be getting values of 'rho' and 'theta', What I am doing is here creating two empty list one for vertical lines one for the horizontal lines,and appending the values of both lines in respective list.

rowsValue = []
columnValue = []

Here is the logic for vertical and horizontal lines.

for line in listOflines:
if line[0][1] == 0:
    columnValue.append(line[0][0])
else:
    rowsValue.append(line[0][0])

Now the important part is here, When every line passing through and intersecting one another it is intersecting that line on a particular pixel value. And we have that pixel value in terms of 'rho'.

Now lets create tuples to pass as a co-ordinate into 'cv2' function i.e. in the form of (x,y).

tupsList = [(r,c) for r in rowsValue for c in columnValue]
for tups in tupsList:
     cv2.circle(image, tups, 1,(0,0,255), 2)
cv2.imshow('image',image)
cv2.waitKey(0)
cv2.destroyAllWindows()

Thats It!! Now here the images before and after.

Original Image

Intersection Image