"Truth is in the eye of the beholder", said Plato. Oculometry, or eye-tracking, offers an excuse to take this maxim literally. Our eye movements, our "gaze strategies", reveal our cognitive processes. Analyzing users' eye behaviors thus enables us to understand them from a new perspective, and to use the gaze as a new interaction channel, taking the load off conventional channels. The gaze can then be used as a new channel of interaction with the outside world.
Unlike a camera, our eyes only have a clear image on a very small cone. As a result, we constantly move our eyes from one point of interest to another. Eye-tracking is a technique to detect the focus of a user's eyes. Mainly used as a marketing and ergonomic analysis tool, it is also used for interaction, which allows to control the computer... in the blink of an eye.
There are two main applications of eye-tracking: the analysis of ocular behaviors and gaze-based interaction.
The gaze is an unconscious modality that reflects our cognitive processes. Our gaze can be attracted by the environment (a movement, a bright color) or guided by our objectives (where are my keys?). Gaze analysis is thus widely used in marketing and ergonomics, but it also makes it possible to study and document the gaze strategies of expert operators, thus facilitating the transfer of expertise, training, and evaluation.
As an interaction modality, gaze tracking can be used to validate operational processes (e.g., semi-automatic validation of visual control points), and can be used as a natural complementary interaction for specific situations (e.g., automatic scrolling of a document, display of additional information of a viewed element).
These eye trackers come in the form of bars to be fixed under the screen. After a quick configuration and calibration (only a few seconds), they allow you to analyze gaze behavior on a stimulus presented on the screen, or to control your application by looking at it.
These eye trackers are integrated to glasses, which allows to realize field studies. Explanation and transfer of expertise, professional performance, study of gaze strategies in dynamic situations (such as driving) are all cases of use where these eye-trackers have their place.
In our opinion, eye-tracking is nothing less than the next revolution in virtual reality. In addition to the analysis on 3D models, eye-tracking transforms the interaction in virtual reality, making it immediate and intuitive. The icing on the cake is that eye-tracking also allows to drastically reduce the computing costs related to virtual reality.
In addition to marketing and usability studies, the analysis of eye movements and gaze behavior offers a real interest in terms of expert skills transfer and performance evaluation. Indeed, expertise is characterized, among other things, in the difficulty of explaining certain behaviors that have become automatic.
By recording and analyzing the visual activity of an expert in his/her field, one can identify specific behaviors and strategies acquired over the years in the performance of various tasks. These strategies can then be understood, documented and used as skill transfer and training tool. Similarly, by measuring the eye behavior of a novice, it becomes possible to identify potential flaws in the performance of tasks, and thus optimize handling procedures.
Gaze interaction, on the other hand, can be a means of reducing cognitive load on users/operators during complex manipulations: for instance, automatic scrolling in a webpage or document, displaying additional information about an element when looking at it, or adaptating the interface to the point of focus. But the gaze, used here as a complementary modality, can also be the main interaction modality, for example in the validation of a visual inspection rountine in a maintenance task, by automatically checking if all the control points have been covered.
The choice of eye tracker is important for a good integration of this technology. But above all, a rigorous analysis methodology is necessary to achieve reliable results. Eye tracking is not the answer to everything; but well implemented, this technique can provide solid, actionable and both qualitative and quantitative conclusions.
Eye tracking is also emerging in the industry as an interaction modality and is proving to be extremely promising as a complement to more traditional inputs (keyboard/mouse, touch).
Eye tracking technology has recently been natively integrated into virtual reality headsets. This innovation opens up immense possibilities, both in terms of behavioural analysis and gaze-based interaction.
The analysis of gaze direction and eye movements in virtual reality allows to conduct behavioural studies within digital models, instead of real environments or mockups. This facilitates for example benchmarking and analysis already in the design phase: usability evaluation of a new workstation, new shelving arrangement, clarity of an architecture... etc.
Interaction prompted by gaze within virtual reality opens a whole new field of possibilities. Knowing what someone is looking at gives us their center interest at that time; using the gaze direction to trigger actions thus makes for a more fluid and natural interaction with the environment.
In this project realized with TotalEnergies, we used eye tracking to improve the navigability of a specialized geological study software used by experts in this field.
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