title: Improve HoughLines for horizontal lines detect (Python, OpenCV)
body: <p>I have this source image:</p>
  
  <p><a href="https://i.stack.imgur.com/ZLCEX.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ZLCEX.png" alt="src"></a></p>
  
  <p>My goal is to remove the bottom line while keep the letters/numbers untouched.</p>
  
  <p>This is the code I use:</p>
  
  <pre><code>import cv2
  import numpy as np
  
  img = cv2.imread('src.png')
  gray = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)
  
  edges = cv2.Canny(gray,100,200,apertureSize = 5)
  
  minLineLength = 0
  maxLineGap = 19
  lines = cv2.HoughLinesP(edges,1,np.pi/180,15,minLineLength,maxLineGap)
  for x in range(0, len(lines)):
      for x1,y1,x2,y2 in lines[x]:
          cv2.line(img,(x1,y1),(x2,y2),(255,255,255),2)
  
  cv2.imshow('hough',img)
  cv2.waitKey(0)
  </code></pre>
  
  <p>The best result I achieved by now is this:</p>
  
  <p><a href="https://i.stack.imgur.com/t3CLJ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/t3CLJ.png" alt="out"></a></p>
  
  <p>How can I improve it more, to clean the image as much as possible ?
  For example, all the debris all around the image, points and (still) lines under the words, how can I remove them ?</p>
  
  <p>Thank you.</p>
  
  <p>OT: is there a way to create a trackbar of this which change the parameters (apertureSize, minLineLength, maxLineGap, etc) to see results in real time ?</p>