experiment freezes during drift correct

Comments

• eduard

  October 2020

  Hi Figen,

  Unfortunately, I cannot help you (I don't have any eye tracker available), but to make sure that the problem is really related to the eye tracking part of your experiment, can you try to simplify it as much as possible? That is, remove items that are not necessary (i.e. sampler and media player). Does the experiment that still freezes on the drift correct?

  Eduard

  
• FKaraca

  October 2020

  Hi Eduard,

  
  

  Thanks for your reply. I simplified the experiment following your suggestions and it still freezes during drift-correct plugin. The other pygaze plugins run perfectly.

  
  

  Figen
• eduard

  November 2020

  Hi Figen,

  Thanks for trying. Unfortunately, without a (Tobii) eyetracker, I am at a loss here. Maybe @Edwin can help?

  Eduard

  
• Edwin

  November 2020 edited November 2020

  Hi Figen,

  Interesting problem; wouldn't really know how to solve it without more debugging access. Perhaps a simpler fix would be to simply put in your own drift check by using an inline_script. You would use this inline_script instead of a drift_correction, and the code in the Run Phase of the inline_script should look like this:

  
  

  # Set the fixation position. (Example is screen centre.)
  fix_pos = (int(var.get("width")/2), int(var.get("height")/2))
  # Set the maximum allowed distance (in pixels) between fixation target and fixation.
  max_dist = 60
  
  # Create a canvas instance.
  screen = Canvas()
  # Draw the fixation dot.
  screen["fix_dot"] = Circle(x=fix_pos[0], y=fix_pos[1], r=10, fill=True)
  
  # Create a keyboard instance.
  kb = Keyboard(timeout=None)
  # Create a synth instance.
  beep = Synth(freq=440, osc="sine", length=200)
  
  # Loop until the fixation is OK.
  fixation_confirmed = False
  while not fixation_confirmed:
  
      # Check if a key was pressed.
      key, press_time = kb.get_key()
  
      # If Escape was pressed, calibrate the tracker.
      if key.lower() in ["Esc", "Escape"]:
          fixation_confirmed = True
          pygaze_eyetracker.calibrate()
  
      # Do a fixation check.
      elif key.lower() == "space":
          # Get a sample from the eye tracker.
          gaze_pos = pygaze_eyetracker.sample()
          # Measure how far it is from the fixation.
          d = math.sqrt((gaze_pos[0] - fix_pos[0])**2 + (gaze_pos[1]-fix_pos[1])**2)
          # Confirm if the fixation is close enough.
          if d < max_distance:
              fixation_confirmed = True
          else:
              beep.play()
  
• FKaraca

  December 2020

  Dear Edwin,

  Using an inline_script for my own drift check is a great solution to my problem. However, when I tried to run the code you very generously provided, I came across this error:

  File "C:\Program Files (x86)\OpenSesame\lib\site-packages\libopensesame\inline_script.py", line 81, in prepare

    self.var.get(u'_run', _eval=False))

   File "C:\Program Files (x86)\OpenSesame\lib\site-packages\libopensesame\base_python_workspace.py", line 110, in _compile

    return compile(script, u'<string>', u'exec')

   Inline script, line 5

    ^

  SyntaxError: invalid syntax
• FKaraca

  December 2020

  Oh, never mind my previous comment. There were a couple invisible characters in the script, which caused the problem...

  Thank you again Edwin, for the idea and also for providing the script. For posterity, I used the below script to solve my drift-correct problem.

  # Create a canvas instance.
  screen = Canvas()
  
  # Draw the fixation dot.
  screen["fix_dot"] = FixDot()
  
  # Show the fixation dot.
  screen.show()
  
  # Loop until the fixation is OK.
  
  fixation_confirmed = False
  while not fixation_confirmed:
  
      fixation_confirmed = eyetracker.drift_correction(fix_triggered = True)