I am using this code to remove the lines from the following image:

I don't know the reason, but it gives me as output ZeroDivisionError: division by zero error on line 34 - x0, x1, y0, y1 = (0, im_wb.shape[1], sum(y0_list)/len(y0_list), sum(y1_list)/len(y1_list)).

What's the reason ? How can I fix it ?

import cv2
import numpy as npimg = cv2.imread('lines.png',0)# Applies threshold and inverts the image colors
(thresh, im_bw) = cv2.threshold(img, 128, 255, cv2.THRESH_BINARY | cv2.THRESH_OTSU)
im_wb = (255-im_bw)# Line parameters
minLineLength = 100
maxLineGap = 10
color = 255
size = 1# Substracts the black line
lines = cv2.HoughLinesP(im_wb,1,np.pi/180,minLineLength,maxLineGap)[0]# Makes a list of the y's located at position x0 and x1
y0_list = []
y1_list = []
for x0,y0,x1,y1 in lines:if x0 == 0:y0_list.append(y0)if x1 == im_wb.shape[1]:y1_list.append(y1)# Calculates line thickness and its half
thick = max(len(y0_list), len(y1_list))
hthick = int(thick/2)# Initial and ending point of the full line
x0, x1, y0, y1 = (0, im_wb.shape[1], sum(y0_list)/len(y0_list), sum(y1_list)/len(y1_list))# Iterates all x's and prints makes a vertical line with the desired thickness
# when the point is surrounded by white pixels
for x in range(x1):y = int(x*(y1-y0)/x1) + y0if im_wb[y+hthick+1, x] == 0 and im_wb[y-hthick-1, x] == 0:cv2.line(img,(x,y-hthick),(x,y+hthick),colour,size)cv2.imshow('clean', img)
cv2.waitKey(0)

The question reffers to this other one: Python: How to OCR characters crossed by a horizontal line

Well the cause of the error is that the length is 0 of either y0_list or y1_list (or both). Since you initialize them in this for loop :

for x0,y0,x1,y1 in lines:if x0 == 0:y0_list.append(y0)if x1 == im_wb.shape[1]:y1_list.append(y1)

You can narrow your error down to either lines not having the expected values or your 2 if statements being faulty. I believe the problem is caused by the latter but the easiest check you can do is print out lines and check manually if your if statements would be triggered.