python - Filling edges using flood fill not working properly

Question

I am using openCV in python to detect cracks in concrete. I am able to use canny edge detection to detect cracks. Next, I need to fill the edges. I used floodfill operation of openCV but some of the gaps are filled whereas some are not filled. The image on the left is the input image whereas that on the right is the floodfilled image. I am guessing this is because my edges have breaks at points. How do i solve this ? My code for floodfilling:

im_th1 = imginput
im_floodfill = im_th1.copy()
# Mask used to flood filling.
# Notice the size needs to be 2 pixels than the image.
h, w = im_th1.shape[:2]
mask = np.zeros((h + 2, w + 2), np.uint8)

# Floodfill from point (0, 0)
cv2.floodFill(im_floodfill, mask, (5, 5), 255);

# Invert floodfilled image
im_floodfill_inv = cv2.bitwise_not(im_floodfill)

# Combine the two images to get the foreground.
im_out = im_th1 | im_floodfill_inv
cv2.imshow("Foreground", im_out)
cv2.waitKey(0)

Answer 1

I found the solution to what i was looking for. Posting it here as it might come of use to others. After some research on the internet, it was just 2 lines of codes as suggested in this : How to complete/close a contour in python opencv?

The code that worked for me is :

kernel = cv2.getStructuringElement(cv2.MORPH_ELLIPSE, (9, 9))
dilated = cv2.dilate(image, kernel)
eroded=cv2.erode(dilated,kernel)

The result is in the image attached that shows before and after results.