Open Source Eye Tracking

Eye Tracking
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Cameras

The first thing about building an eye tracker is that you need the cameras to be as small as possible. This is because you will be carrying them around on your head. but to balance that, you need them to be good quality too. (mine were not that great in quality)

I had a couple of cheap CMOS spy cams in my junk pile from older projects, so I thought that they could be used again to test if I could actually get openEyes to work. The model of camera is identical to the one shown here:

spycam

Just like in the openEyes project, I used a pair of safety glasses with the lenses out to hold all this together.

Recording

The video needs to be in a digital format, so I used my video capture card for one camera, and a miniDV camcorder for the other (using aux input). After I was done recording, I transferred the video from the camcorder to the computer via the same video capture card.

After both cameras were recording, I used a camera flash to show a time of sync in each of the video streams. The light from the flash was visible in both the eye cam and scene cam.

Problems

There were 2 big problems with the hardware I used.

First, these cameras are very poor quality in all but the best lighting conditions, it was easy to focus the eye camera to a close range, however, it needed lighting to be able to allow the algorithm to work.

Second, the field of view of the scene camera is so small, it was easy to forget how much space is within camera range and allow to my gaze to leave that area. As this was a temporary hardware test, I didn't want to invest any money into new cameras or lenses. I mounted 2 laser pointers to highlight the field of view of the camera. one pointed at the top right corner, and the other at the bottom left. With those dots in place, I was able to see what the camera could see, and then keep my view within those limits.

If I build this in a more serious manner, I would try and use a wide angle lenses to allow the largest field of view for the camera. However I will have to be cautious as radial distortion may interfere with the algorithm.

Temporary Prototype

Please note that I do not have the original separate RAW video files of the EYE and SCENE streams. I regretfully thought they were unnecessary and deleted them shortly after creating this prototype. I have updated the downloads section to include the original files that I used to do this project. They are a re-creation of the original EYE and SCENE files using the jpgs that I still had, so the quality is lower than the originals, but should still work.