ppc@ufoctf: maze writeup

solve.py

import cv2
import numpy as np

print('Enter the .jpg or .png filename of maze image')
filename = str(raw_input())

maze = cv2.imread(filename)

grayscale = cv2.cvtColor(maze, cv2.COLOR_BGR2GRAY)

ret, threshold = cv2.threshold(grayscale, 127, 255, cv2.THRESH_BINARY_INV)

contours, hierarchy = cv2.findContours(threshold, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_NONE)
cv2.drawContours(threshold, contours, 0, (255, 255, 255), -1)

ret, threshold = cv2.threshold(threshold, 240, 255, cv2.THRESH_BINARY)

mask = np.ones((16, 16), np.uint8)
dilation_result = cv2.dilate(threshold, mask, iterations = 1)

erosion_result = cv2.erode(dilation_result, mask, iterations = 1)

difference = cv2.absdiff(dilation_result, erosion_result)

b, g, r = cv2.split(maze)

inverse_mask = cv2.bitwise_not(difference)
line = cv2.bitwise_and(g, g, mask = inverse_mask)

result = cv2.merge((b, line, r))

cv2.imshow('solved maze', result)
cv2.imwrite('solved.png', result)

cv2.waitKey(0)
cv2.destoyAllWindows()