Table of contents:
2023 Author: Alfred Shackley | [email protected]. Last modified: 2023-05-21 13:14
FPS - Frames per Second - translated from English means the number of frames per second. The emergence and development of television inevitably raised the question - how many frames per second does the human eye perceive? The quality of any video you watch depends on the correct answer.
A little about the structure of the eye
The retina of the eye consists of a kind of rods and cones, which perceive information in different ways, but combine it into a single whole.
The rods almost do not feel color differences, but they are able to quickly catch the change in the image. From this point of view, the fps of the sticks is pretty high.
Cones, on the other hand, are excellent at distinguishing colors, but they do so at lower fps than rods.
Together, the rods and cones make up the photoreceptors of the eye, which are responsible for the integrity of the viewed image.
The task of calculating the maximum fps perceived by the human eye is complicated by the uneven distribution of photoreceptors on the retina. In the center, the number of different receptors is approximately the same, but closer to the edges of the retina, rods predominate.
This structure has a logical rationale from the point of view of nature. Even in those days, when it was necessary to constantly hunt in order to get food, a person had to be able to catch movement well with peripheral vision. For this, the fps of the eye along the edges of the retina is naturally increased by nature.
If we take direct gaze into account, then only the total fps of the photoreceptors located in the center of the retina will matter.
Early research findings
Dozens of scientists have studied this issue over the years. As a result, the minimum, maximum, and average fps values, which are normally perceived by the human eye, were displayed.
The structure of the human eye is such that it is "programmed" to see not individual frames, but the whole picture. That is, even if you show a person 1 frame per second for a long period of time, he will perceive not individual images, but the general picture of movement.
However, this fps is quite low and creates a persistent feeling of discomfort. Filmmakers came to this conclusion even in the days of silent cinema. It was then that the frame rate per second was 16. If you compare silent films with modern films, you will see a clear difference - there will be a feeling of slow motion.
In modern paintings, the global standard of 24 frames per second is recognized. This is fps, in which the human eye sees the big picture in quite comfortable conditions. But is this the limit?
Modern fps values
It would seem that if 24 frames per second is enough for the eye, then is there any practical sense to achieve more? It turns out there is. Today, every computer owner who has played a dynamic game at least once can be convinced of this.
With fps equal to 24, the human eye sees not only the overall picture on the monitor screen, but also individual frames.
This is where the game developers had to work hard to figure out which values are optimal in this context.
More recent research has shown that the human eye sees and perceives images at up to 60 frames per second!
In this case, all movements on the monitor screen are the smoothest and most realistic.
As you know, most scientists are people who do not stop at the achieved results and conduct more and more new tests and experiments. Scientists researching the capabilities of the human eye are no exception.
The tests are carried out as follows: a group of people is asked to view several videos with different frame rates. In some of them, frames with a defect are added at different intervals - they depict something superfluous that does not fit into the overall picture. For example, a group of subjects was shown a video supplemented by a flying object.
More than half of the participants in the experiment were able to notice this object. Such a result would not have caused surprise, if not for one "but" - video fps was 220 frames per second! And, although no one was able to see what exactly was depicted, the fact itself cannot be denied - the human eye can notice a separate image at a speed of 220 frames per second.
It turns out that in the days of the first films, cinema projectors were equipped with a manual speed stabilizer. A specially trained person turned the handle of such a cinema projector, and it was on him that the frame rate in the film depended.
If initially the speed was 16 frames, then then people began to arbitrarily change it depending on the behavior of the public. When showing a comedy image and high activity of viewers, fps was increased to 20-30.
But this also entailed negative consequences. During the end of the First World War, theater owners needed higher profits and played films at high speeds, reducing the total duration of one session and increasing the number of sessions. This led to the fact that some paintings were simply not perceived by the human eye. As a result, some governments have passed laws that limit the maximum frame rate.
In practice, increasing the fps value helps to "smooth" the image - to create the effect of incessant motion.
The relevance of the selection of values is determined by the purpose of applying the smoothing effect.
- Cinema. For watching videos of standard formats, the most comfortable fps is considered to be 24 frames per second - this is the speed offered by cinemas, amateur video recordings and modern cartoons;
- IMAX format. This is a new widescreen cinema that can be found in large cities. At this stage in the development of cinematography, it creates the maximum effect of immersion in virtual reality. It can only be enhanced by 3D-capable screens. Although the standard frame rate is fine for such systems, the latest films for such screens are created at fps equal to 48 frames per second;
- Computer games. To achieve maximum reality, the images use the standard frequency of 50 frames per second. Depending on the speed of the Internet connection, the load on the servers, as well as a number of other factors, this frequency can change both up and down.
The use of high frequencies at this stage of the development of technology simply does not make sense, although from time to time it is practiced by specialists in various fields.