Eye-tracking is a technology-based technique that can provide some unique insights into how our users interact with a software user interface. There certainly are a number of pros and cons to using eye-tracking. However, the best software designs often come from having a wide variety of research tools at our disposal.
Small-business practitioners who would like to conduct their own eye-tracking research often find the relatively high cost of the systems to be prohibitive. Prices in excess of twenty thousand dollars only fit the budgets of fairly large organizations. A more affordable solution – EyeGuide Eye Tracker – is now available from a company called Grinbath. Here is a quick look at what you can expect from this product.
EyeGuide comes with hardware and software components. A series of videos on the EyeGuide web site takes you through the process of connecting and calibrating the hardware. The eye rig consists of a headband attached to which is a battery pack, camera and an LED light source. A simple on/off switch is the only control on the headset.
Using a headset is a less than optimal way to gather eye-tracking data. It definitely adds a foreign element into the experiment and may be distracting to the test subject. Setting it up with each subject requires fitting and calibrating the unit while it is on their head. On the positive side, it makes the system very portable and probably contributed to its relatively inexpensive price.
The image from the headset is controlled by EyeGuide Capture software, available for PC and Mac. The Capture application is presented in a window with a live black and white viewer showing what the camera is picking up. The connection between the computer and the headset is through a USB radio transmitter that plugs into the computer.
It took me about 30 minutes of experimentation to figure out the best headset arrangement. The camera and LED should be positioned about two to three inches below the eye. When it is correctly positioned the Capture viewer shows a green circle lock on the pupil.
At first, I had some problems getting a clear signal from the camera. It turned out that the rat’s nest of devices, plugs, cables, and lights on my desk was causing the interference. The camera operates at 2.4 GHz, the same frequency as a lot of wireless devices. Everything cleared up when I ran the system from my laptop in a room with no other electronics.
The next step is to create a series of instructional steps for your experiment using the Capture software. These instructions are displayed to the test subject in sequential order after the test is started. A checkmark icon appears in the bottom corner of the test screen. When the subject completes a step, they click the icon to display the next instruction. The eye-tracking data is being recorded throughout the experiment.
A separate application, Analyze, is used to review your data. A tabbed interface gives you a number of ways to look at it. First, there is a real-time animation of the experiment – Replay – that uses a circle to represent the focus of the eye moving around the test screen. The Gaze Plot provides a more detailed animation drawing straight lines between major dwell points (shown below). The Reply and Gaze plots give you a good overall understanding of what attracted the attention of the test subject in the UI.
Three other plots – Heatmap, Bee Swarm, and Clusters – provide supplemental views of the data. All the map plots are controlled with Play/Pause buttons. It would be nice if the video progress bar could be clicked on to instantly jump back and forth in the video.
You can export any video or image frame of any recording. You can also get the gaze plot data in CSV format which shows you the pupil x and y coordinates at 50 times per second. If you want other data points, such as pupil diameter, you can use the API which also comes with the system.
The camera and camera arm are encased in plastic. It appears that it would be durable over time. My demo unit came with a AAA battery charger and I needed it. I forgot to turn off the unit and the batteries were dead when I got back to it the next day.
There are alternate LED attachments for different users and for replacements. A short LED is optimal for quick set up and calibration for users without glasses or obstructed pupils. The longer LEDs are intended for more flexibility, so that people with glasses or otherwise obstructed pupils can get proper lighting for a good lock and a good calibration.
The only part of the hardware I didn’t like is that the USB receiver has a wide body and took up two USB slots on my laptop. Also, with the quick battery drain I experienced, don’t forget to keep the charger handy.
The price is $2,495 USD for commercial customers, $2,295 USD for academics, government, and nonprofits. There is discounted pricing for multiple unit purchases.
All software upgrades are free, so any addition to future versions will be available to all customers with complete backwards compatibility. They promise customer support with a turnaround of one business day maximum via support forum, email (support.grinbath.com), and Skype.
In summary, this device provides a relatively affordable solution for organizations with limited budgets. The headset introduces an artificial experience into any experiment, but it makes the unit portable. It is pretty rugged and should work well on field trips. The Capture and Analyze software gives you all the data and quality you need for simple experiments. If you are looking to add eye-tracking to your software design and testing, this is a great value.
For more details, contact Jeremy Huston, EyeGuide™ Product Manager, Grinbath LLC, firstname.lastname@example.org, http://www.grinbath.com/eyeguide/