Sampling rate of eye gaze
The "sampling rate," one of the settings of an eye tracking device, is the number of data points that the device acquires in one second (Tobii website). The unit is Hertz (Hz), and products are available with sampling rates ranging from 30 to 1200 Hz. The higher the value, the more precisely eye movements are captured. The specific difference is that, for example, a low rate cannot detect blinks. The analyst needs to set a criterion and make a judgment such as "A certain number of data is flying at this moment, so it must be a blinking moment.
Another setting factor is the "frame rate," which is the number of still images projected on the screen per second by the device. The unit is fps (fps ; frames per second). Generally, 24 to 120 fps is used, and the higher the value, the smoother the moving image appears.
While machines have a fineness of time for acquiring and displaying data in this way, we investigated the fineness of time at which the human eye views images and scenery. Unlike machines, our eyes are not equipped with monitors, so I am not sure if this is something that can be quantitatively said in the first place.
The results show that the human eye can perceive 30-60 fps [1,2] per second and under certain conditions may be able to see details at rates faster than 90 Hz (← units here are in Hertz).
[1] Your Eyes vs. Frame Rates: What You Can (and Can’t) See - NAB Amplify (nabshow.com)
[2] The Number of Frames That Human Eyes Can See Per Second (caseguard.com)
[3] Recognition and Action in Intelligent Systems
They are quantifying human vision only by the number of rates on the device side. I didn't know that...
Incidentally, under certain experimental conditions, it is possible to visually track up to 500 Hz [4].
For competitive gaming, monitors with refresh rates above 60 fps are recommended, and it has been noted that the effect decreases above 144 fps [5]. However, beyond 144 fps, the difference is not so noticeable to most people.
The average rate of human vision in daily life is approximately 30 to 60 fps, with an upper limit around 144 fps. In addition to frame rate, various other factors such as visual acuity, age, gender, and environmental conditions have been reported to have a considerable effect on visual acuity.
Speaking of "Kanagawa Okinamiura," there is a common theory that the sampling rate of Katsushika Hokusai's eyes must have been terribly accurate, because the waves in this painting look like this when the camera shutter is released at 1/80000 second. This may mean that Hokusai saw the world differently from other people.
There is a common belief that Picasso also had a slightly unique way of seeing called "stereopsis. It is said that he was able to draw cubist paintings because he had a special way of seeing.
It seems that more and more discoveries will come out.
I was impressed as a child when I saw the moment of capturing the Milk Crown at about 0.002 second, but the level of "attosecond moment" is no longer the same.
