For some time now there have been devices called “Eye trackers”, which literally allow us to move the mouse cursor on the screen with just our gaze . In this article we are going to tell you how the eye tracking technology behind this works, and how thanks to this they have made it possible for people with disabilities to use a PC in an almost normal way.
For many years, technologies of all kinds have been developed so that people with cognitive and / or physical disabilities can use computers normally, living fuller and more independent lives thanks to technology. One of them is called eye tracking, and it allows these people to be able to use a computer without the need for a keyboard and mouse, controlling everything with their eyes. Do you want to know how this technology works? Then keep reading because we are going to explain everything to you.
What is eye tracking technology and how does it work?
This technology consists of a receiver / emitter that is placed on the monitor (or on the table as long as it is exactly facing the user) that emits an infrared light, which is reflected in the eyes of the user who is using the PC. Using a series of cameras configured to focus on the user’s eyes, reflections of infrared light are detected and, through filtering and a series of calculations, the tracker identifies where the user is looking and moves the mouse cursor accordingly.
With this we can move the mouse cursor just by looking at the area where we want, but how do you click? There are three ways to do this when using the gaze, and the available method will depend on the application being used, but also on the capabilities of the user:
- Blink : You can use the blink to click, but it is not the best way since doing so loses the focus of where you are looking.
- Dwell : the eyes are focused on a specific area for a specified time (milliseconds usually, although this is configurable), and then the system detects it and the click is performed.
- Pushbutton : if the user is able to control a pushbutton (for example with the index finger of one hand), it can also be configured to act as a click. It is in fact the simplest and non-intrusive way to do it, but as we have mentioned before it will depend on the capabilities of the user.
Eye tracking technology needs calibration
Not all users have eyes with the same shape and of course color, and that is why at the beginning it is necessary to calibrate the eye tracking technology so that it works in the best possible way.
During calibration, the eye tracker measures how infrared light is reflected in the user’s eyes by following a point, video, or other graphic element that moves across the screen; This data is combined with a 3D model of the human eye and together provide the best possible eye tracking experience.
A breakthrough for people with disabilities
Thanks to the 3D human eye model combined with scanning the user’s eye for better precision, these eye trackers allow you to move your head freely, meaning you don’t have to be staring at the screen for them to work properly anymore. that each time they are scanning the eyes to see where the user is looking. This is particularly beneficial for people who cannot control head movement, such as those with cerebral palsy or ALS, who may have to constantly adjust their posture.
In addition, these devices work with almost everyone and not necessarily only for people with disabilities. To achieve precise tracking, the sensor only needs to find the user’s pupils (and in fact it works in a similar way to how cameras eliminate the red-eye effect automatically). Actually, what helps eye tracking to determine where the user is looking is the relationship between the pupils and the flashes or reflections of infrared light, so anyone who has both eyes and can move them can use it without problems.
