How does eye tracking work

Dark pupil systems are more robust in varying light conditions and with participants with dark eyes and small pupils. They are also usually larger since the IR sources have to be physically separated from the camera.

This accounts for the elongated rectangular shape of many commercial eye tracking systems. This is a mechanism used for differentiating between eye movements and head movements. The human visual system uses both of these to acquire and track a visual target, but an eye tracking system that only sees the eye has to understand the difference. When the eye rotates, the pupil moves but the CR stays in place like a flashlight shining on a spinning ball.

When the head moves, however, both the pupil and CR move together. Gaze position is the primary indicator of human attention and a basis for subsequent analysis metrics dwell time, glance, area of interest, etc. Before calibration, gaze can be calculated in simple terms as:. For head-mounted systems, including eye tracking glasses and VR-integrated devices, CR tracking can not be used to determine head position since the IR source moves with the head in this case.

However, it is still done for slip compensation. This is a process to remove small movements between the eye tracking gear and the eye from the data. Visible light web camera systems have seen some use in recent years. However, these systems have some significant drawbacks in terms of accuracy and data quality.

This can be compensated for, to some extent, by increasing the total number of possible test participants. The problem with this approach is that tracking difficulty is not evenly distributed among test participants. These systems will often have trouble tracking the eyes of older participants, those with long eyelashes or eye makeup, people with glasses, etc, causing a significant selection bias problem in the resulting data.

Most modern eye tracking systems require relatively little setup. Thresholds for pupil and CR detection and artifact rejection are now automated and continuously adjusted. Eye tracking systems do a reasonably good job at adapting to different eye color, size, shape, and interpupillary distance. Eye tracking systems do require a calibration , which is a method of algorithmically associating the physical position of the eye with the point in space that the participant is looking at gaze.

This is because there are some variations in eye size, fovea position and general physiology that have to be accommodated for each individual. To a degree, gaze position is a function of the perception of the participant. A calibration typically involves the participant looking at fixed, known points in the visual field.

In VR applications , eye tracking can allow the respondent to control features by merely looking at a particular virtual button. All in all, if experiments need participants to respond in natural, dynamic surroundings, wearable eye tracker devices are the best solution. The difference between eye tracking and head tracking is simple. While both processes involve monitoring positions and movements, the former only tracks the eyes while the latter records only head activity.

When combined, the two technologies provide even more valuable data and create a rich user experience in applications like gaming. So far, the technology has been used to make tremendous advancements in cognitive science, neuromarketing, AI, workplace safety, and many other research and business fields of interest.

As predicted , eye tracking has already revolutionized the way humans communicate with devices and vice-versa. Yet, we still need to develop eye tracking technology so every standard consumer device will be equipped with it. Until then, it continues to assist academics, developers, and advertisers in gaining unparalleled insight into conscious and subconscious human behavior. As already mentioned, eye tracking has significant contributions to both qualitative and quantitative research.

In an academic context, the technology can be used as a tool for:. Eye tracking plays a major role in safety in the automotive industry. The technology can help detect if the driver is drowsy or distracted, and help prevent car accidents. By incorporating the technology into smart dashboards, features like augmented reality HUDs and virtual co-pilot become a central part of the driving experience.

Within the field of psychology, gaze tracking enables the study of cognitive processes. Examples include memory, problem-solving, language, decision-making, perception, and attention in general. For example, technology has helped researchers demonstrate the recognition and comprehension of complex emotions in adults with ASD.

As eye tracking technology facilitates the study of visual attention, it has become a useful tool for neuro marketers and advertisers on a broader scale. In both online and offline applications, gaze tracking helps determine what customers are naturally most interested in and what they might ignore altogether.

Furthermore, neuro marketers now use eye tracking and facial coding to measure emotions when exposed to multimedia stimuli. Foveated rendering, enveloping graphics, and extended gaze control are all cutting-edge features in the gaming industry that are possible through eye tracking. The user can explore the environment through their gaze and interact with various elements of the game just by looking at them.

Similarly, for several years now, individuals have been able to control televisions based on the same principles. Through eye tracking, people with disabilities can control computers and mobile devices and even create digital art.

Individuals who cannot move or speak can communicate with machines through eye movements. The technology has greatly improved accessibility and empowered disabled users to perform a variety of computer-related tasks. As a result, retailers can make notable improvements in terms of display, store, and packaging design, as well as layout and distribution. Without a doubt, the advantages of eye tracking technology are bountiful. As eye tracking continues to be a developing technology, there remains a multitude of challenges that need to be approached.

Conducting eye tracking studies and experiments have a learning curve. Explore Products. The basics. How it works. Eye tracking basics. Eye tracking for accessibility. Speech generation. Computer access. Environmental control. Increased engagement. How does eye tracking work?

The eye tracker sends out near infrared light. The light is reflected in your eyes. Through filtering and calculations, the eye tracker knows where you are looking.

See good calibration tips. The method available depends on the application you use as well as your abilities: Dwell : A click occurs after focusing your eyes on a specific area for a predetermined number of milliseconds.

Switch : Look where you want to click, and then press a switch to perform the click. Watch gaze interaction methods. Free head movement. An infrared light source and thus detection method is necessary as the accuracy of gaze direction measurement is dependent on a clear demarcation and detection of the pupil as well as the detection of corneal reflection. While there are many different eye trackers, there are two principal types: screen-based and glasses.

They are used across variety of fields and research areas, but how they are used and the data they provide as a result can differ. Screen-based devices require respondents to sit in front of a monitor and interact with screen-based content.

Although these devices track the eyes only within certain limits the so-called headbox , the freedom of movement is still sufficiently large for respondents to be relatively unrestricted at least in terms of a normal range of movement while watching screen-based stimuli. As the name implies, mobile devices are fitted near the eyes usually mounted onto eyeglass frames and allow respondents to move freely.

Clearly, this is a plus if your study design requires performing tasks in a natural environment. On the downside, the glasses could potentially shift during the recording if there is a large amount of movement such as within sports. Eye tracking devices are continuously being produced and launched onto the market. Amidst all the manufacturer specifications, it can be quite hard to keep an overview and evaluate which eye tracker is right for your research endeavor. Before your purchase, think about these key questions that can make or break your research:.

Even though they appear to be a good bargain and the ideal solution for smaller budget, the lack of a controlled light source along with a rather weak camera performance will render your data quality effectively useless.

Eye tracking is used across a range of different research fields, and for various different applications within the commercial realm too. Obtaining detailed information about where an individual or group of people look is useful in a range of contexts, from psychological research, to medical diagnosis, neuromarketing applications and beyond.

Understanding when and how people look is essential for understanding how attention is distributed. Eye tracking is widely used within psychological tests like the IAT implicit association test , Stroop Test , and the Iowa Gambling Task , as well as within gaze contingency paradigms. Studies have shown the potential predictive power of eye tracking in diagnosing autism , as well as other neurological disorders.

Future uses may see the application of eye tracking data in providing optimal patient care in healthcare settings.