gaze/fixation-dependent start of trial

Comments

• eduard

  November 2019

  Hi Louisa,

  I don't know this function and what it does. But if it is sampling gaze position, you have to record, I think (though not sure). I did something similar in the past, and my code was in between start and stop recording (pygaze plugins). So, I suppose your experiment gets stuck in that function, because it doesn't get any gaze information, but that is just a hunch. If you wish, I can also share the code that I used to ensure fixation prior to a trial.

  Eduard

  
• LouisaB

  November 2019 edited November 2019

  Thanks Eduard!

  Just moving my inline script doesn't work (the function fix_triggered_drift_correction is a pygaze function and gives an error when it is put after the start recording pygaze plugin).

  For now I have things working with a pygaze_drift_correct plugin before every trial, but it is more strict than I would like it to be. If you have code that allows one to specify how strict one wants to be to accept a certain eye position as sufficiently close to the fixation point, sharing it would be very helpful.

  Louisa
• eduard

  November 2019

  Hi Louisa,

  
  

  here the code I used, basically measuring the distance of the fixation to a reference location over some time.

  # check whether a fixation is on black ring in the beginning of the trial. Rather liberal
  # automatically continue unless no fixation occurred
  # dist() is a user-defined function measuring the euclidian distance between two dots 
  tw = clock.time()
  while dist((var.curfix_x+var.width*0.5,var.curfix_y+var.height*0.5),exp.pygaze_eyetracker.sample())>var.ROI:
     if clock.time()-tw >5000:
        var.accFix = 0
        warning_cv.show()
        clock.sleep(1000)
        break