//step1
Mat edges;
adaptiveThreshold(vertical, edges, 255, CV_ADAPTIVE_THRESH_MEAN_C, THRESH_BINARY, 3, -2);
imshow("edges", edges);
// Step 2
Mat kernel = Mat::ones(2, 2, CV_8UC1);
dilate(edges, edges, kernel);
imshow("dilate", edges);
// Step 3
Mat smooth;
vertical.copyTo(smooth);
// Step 4
blur(smooth, smooth, Size(2, 2));
// Step 5
smooth.copyTo(vertical, edges);
// Show final result
imshow("smooth", vertical);

#step1
edges = cv2.adaptiveThreshold(vertical,255,cv2.ADAPTIVE_THRESH_MEAN_C,cv2.THRESH_BINARY,3,-2)

#step2
kernel = np.ones((2, 2), dtype = "uint8")
dilated = cv2.dilate(edges, kernel)