Problem Statement

1. Problem Statement

In past visual perception experiments when recording how the eye responds to a stimulus the camera has always been off center while the stimulus has been directly in front of the subject.  Not only does this make it harder to track the pupil, and thus the rest of the eye but this skewed perspective can also lead to inaccuracies in the final results from the data.  We propose that by placing a camera directly behind the stimulus, directly in front of the subjects, using a one-way mirror, the eye tracking data will be much more accurate and make tracking eye movements substantially easier.

2. Problem Objectives

In order to obtain the most accurate results there are many measures that need to be taken into account. Primarily the camera must have a way to see exactly when the stimulus takes place during the experiment. This can be accomplished in many ways, like a LED light that flashes in time with the stimulus on an external monitor that is connected to the processor. Secondly, the timecode for each frame taken by the camera needs to be sent a microprocessor, such as an Arduino or Raspberry Pi. One potential source for error that needs to be accounted for is the refresh rate of the iPad that will be used as an external display.  For example, if the camera we use to capture eye data films at 240 Hz, and the iPad’s refresh rate is 60 Hz then it will take 4 frames for a new slide to be presented to the subject.