**Review of Pupil**

Pupil is an accessible, affordable and extensible open source platform for ubiquitous eye-tracking and gaze-based interaction. Pupil's advantages are:

1. Light-weight eye tracking headset
2. an open source software framework for mobile eye tracking
3. A graphical user interface to playback and visualize video and gaze data. 
4. High-resolution scene and eye cameras for monocular and binocular gaze estimation.
5. Software and GUI are platform-independent and include state-of-the-art algorithms for real-time pupil detection and tracking, calibration, and accurate gaze estimation. 

After doing a performance evaluation it was shown that Pupil can provide an average gaze estimation accuracy of 0.6 degree of visual angle (0.08 degree precision) with a processing pipeline latency of only 0.045 seconds.


In order to know what someone is looking at, we must to establish a mapping between pupil and gaze positions. This is what we call calibration. The following pictures will show us the process in using Pupil hardware and software for gaze-tracking.

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**Pic.1 Positioning of the headset and adjusting the direction of the gaze**

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**Pic.2 A correct way of looking at the camera and three following incorrect was of doing that**

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[[Image(p4.png,30%)]]

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