old_contents: import sensor, time
  
  KEYPOINTS_THRESH=16
  MATCHING_THRESH=70
  NORMALIZED=False
  
  # Reset sensor
  sensor.reset()
  
  # Sensor settings
  sensor.set_contrast(1)
  sensor.set_gainceiling(16)
  sensor.set_framesize(sensor.QQVGA)
  sensor.set_pixformat(sensor.GRAYSCALE)
  
  # Skip a few frames to allow the sensor settle down
  # Note: This takes more time when exec from the IDE.
  for i in range(0, 10):
      img = sensor.snapshot()
  
  kpts1 = None
  while (kpts1 == None):
      img = sensor.snapshot()
      kpts1 = img.find_keypoints(threshold=KEYPOINTS_THRESH, normalized=NORMALIZED)
  
  print (kpts1)
  time.sleep(1000)
  
  def draw_cross(img, x, y, l):
      img.draw_line((x-l, y,   x+l, y))
      img.draw_line((x,   y-l, x,   y+l))
  
  clock = time.clock()
  while (True):
      clock.tick()
      img = sensor.snapshot()
      kpts2 = img.find_keypoints(threshold=KEYPOINTS_THRESH, normalized=NORMALIZED)
      if not kpts2:
          continue
  
      c=img.match_keypoints(kpts1, kpts2, MATCHING_THRESH)
      if (c):
          draw_cross(img, c[0],  c[1], 10)
          time.sleep(10)
      print (clock.fps())
  
new_contents: import sensor, time
  
  KEYPOINTS_THRESH=32
  MATCHING_THRESH=70
  NORMALIZED=False
  
  # Reset sensor
  sensor.reset()
  
  # Sensor settings
  sensor.set_contrast(1)
  sensor.set_gainceiling(16)
  sensor.set_framesize(sensor.QQVGA)
  sensor.set_pixformat(sensor.GRAYSCALE)
  
  # Skip a few frames to allow the sensor settle down
  # Note: This takes more time when exec from the IDE.
  for i in range(0, 10):
      img = sensor.snapshot()
  
  kpts1 = None
  while (kpts1 == None):
      img = sensor.snapshot()
      kpts1 = img.find_keypoints(threshold=KEYPOINTS_THRESH, normalized=NORMALIZED)
  
  print (kpts1)
  time.sleep(1000)
  
  def draw_cross(img, x, y, l):
      img.draw_line((x-l, y,   x+l, y))
      img.draw_line((x,   y-l, x,   y+l))
  
  clock = time.clock()
  while (True):
      clock.tick()
      img = sensor.snapshot()
      kpts2 = img.find_keypoints(threshold=KEYPOINTS_THRESH, normalized=NORMALIZED)
      if not kpts2:
          continue
  
      c=img.match_keypoints(kpts1, kpts2, MATCHING_THRESH)
      if (c):
          draw_cross(img, c[0],  c[1], 10)
          time.sleep(10)
      print (clock.fps())
  
subject: Increase keypoints threshold