{"id":21172,"date":"2019-05-14T09:03:59","date_gmt":"2019-05-14T07:03:59","guid":{"rendered":"https:\/\/test.srlabs.it\/le-metriche-delleye-tracking\/"},"modified":"2026-04-28T11:51:56","modified_gmt":"2026-04-28T09:51:56","slug":"le-metriche-delleye-tracking","status":"publish","type":"post","link":"https:\/\/www.srlabs.it\/en\/le-metriche-delleye-tracking\/","title":{"rendered":"Eye tracking metrics"},"content":{"rendered":"

There is an extreme variety of metrics used in the practical application of eye tracking<\/a>. Below, we examine the most commonly used ones.<\/p>\n<\/div>

Gaze points<\/h3><\/div>

Certainly the most important metrics for eye tracking. Gaze points constitute the basic unit of measurement: one gaze point is equivalent to a raw sample recorded by the tracker<\/strong>.<\/p>\n<\/div><\/div><\/div>

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heatmap<\/h3><\/div>

A heatmap is an overlaid visualization of the fixations that have occurred over time on a specific stimulus. They are generally displayed as an overlay of different color gradients on the image or the presented stimulus.<\/strong> The colors red, yellow, and green represent, in descending order, the quantity of fixations directed toward the various parts of the image.<\/p>\n<\/div><\/div><\/div>

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Fixations<\/h3><\/div>

If a gaze point is maintained for a certain amount of time, it becomes a fixation, a period during which the test subject’s eyes are locked onto a specific object.<\/p>\n<\/div>

Areas of interest (AOI)<\/h3><\/div>

Within a visual stimulus, it is possible to select one or more different regions<\/strong> (the AOIs) on which to concentrate the analysis, or to differentiate the metrics to be recorded in each. Although not strictly a metric itself, it defines the area based on which other metrics are calculated.<\/p>\n<\/div><\/div><\/div>

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Fixation sequences<\/h3><\/div>

By specifying the order and direction in which fixations occur, it is possible to see what first captured a test subject’s attention and the manner in which the stimulus was viewed.<\/p>\n<\/div>

Time to first fixation (tTFF)<\/h3><\/div>

This indicates the amount of time it takes a test subject (or all respondents, on average) to look at a specific AOI from the onset of the stimulus.
Similar to fixation sequences, the time between the start of the stimulus and the viewing of a defined region provides information on when a particular AOI is seen for the first time. This information can be valuable for evaluating what is expected (and what is not) within a scene.<\/p>\n<\/div><\/div><\/div><\/div><\/div>

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