Structure
The human eye perceives visual information using the cones and rods that make up the retina. These cones and rods perceive video in different ways, but have the ability to combine disparate information into a single picture. Rods do not detect color differences, but are able to detect changing images. Cones, on the other hand, are excellent at distinguishing colors. In general, the combination of cones and rods are the photoreceptors of the human eye, responsible for making the image being viewed look holistic.
How many frames per second does a person see? This is a common question. On the retina of the eyes, photoreceptors are located relatively unevenly; in the center there are approximately the same number of them, but closer to the edge of the retina, rods make up the majority. It is this structure of the eye that has a very logical explanation from the point of view of nature. In those days, when a person hunted a mammoth, his peripheral vision had to be adapted to catch the slightest movement on the right or left side. Otherwise, having missed everything in the world, he risked remaining hungry, or even dead, so this eye structure is the most natural. Thus, the structure of the human eye is such that it sees not individual frames, as in a storyboard for a cartoon, but a set of pictures as a whole.
The mechanism of human video perception
The human eye begins to identify the change of still pictures per second as intermittent movement when their number reaches 12. When the frequency moves into the range of 18-26 frames/sec, the viewer observes a moving scene and perceives it as video . If the FPS value is low, then the animation looks uneven, and if it is too high, the effect of hyper-realism appears.
What are utilities and what are they for?
One of the main components of creating realistic video is motion blur . When we observe objects around us, we miss the detail when they move quickly. In other words, we do not have enough time to perceive complete visual information and visual acuity is lost. In cinema, this effect is achieved by blurring, which occurs naturally when changing frames. But if the FPS level is too high, then this effect disappears, and the observer sees a hyper-realistic picture. This prevents him from believing what is happening on the screen.
How many frames per second does the human eye see?
If you show a person one frame per second over a long period of time, over time he will begin to perceive not the individual images, but the overall pattern of movement. However, demonstrating a video image at such a rhythm is uncomfortable for a person. Back in the days of silent films, the frame rate reached 16 per second. When comparing silent film footage and modern films, one is left with the feeling that they were filmed in slow motion in the early 20th century. When watching, you just want to hurry up the on-screen characters a little. The current standard for shooting is 24 frames per second. This is the frequency that is comfortable for human vision. But is this the limit, what is beyond this range?
Now you know how many frames per second a person sees.
How often does the human eye actually see?
The human visual organs are not an artificial device. Therefore, no scientist can accurately determine how many frames per second the human eye perceives. For each individual, the data varies depending on the degree of development of the brain and eyeballs, the speed of nerve impulse transmission, and visual acuity.
In fact, the human organs of vision do not see alternating frames, but the whole picture. The eyes perceive frames only when watching a movie. The surrounding reality is seen by a person as follows:
- as a result of changing the image during movement, it does not matter to a person how many frames per second are formed, the image for him will not change;
- the eyes perceive objects better if they move quickly and sharply;
- If there is a moving object in front of a person’s eyes, then the more frames per second, the better the perception.
It is because of the above factors that we can say that a person sees a picture with an FPS much higher than 24 frames per second. How clearly moving objects are displayed in the human brain depends on the health of the visual organs. If the acuity of perception decreases, the picture will be blurry. With 100% vision, a movie containing not 24, but 60, 100 FPS will be much better for a person.
Not only the number of frames per second affects, but also the following factors:
- frame change amplitude;
- sharpness from the transition to different colors;
- the time required for one frame.
You can glue 100 dissimilar frames together and flip through them quickly. The person will feel discomfort at this time, since the above parameters are not met. An unpleasant sensation is formed due to the fact that the human visual organs try to perceive each frame separately, since they are not interconnected. The subject's eyes and head hurt. If a person has epilepsy, a seizure will begin.
It has been revealed that a person is able to clearly perceive 120-150 frames per second. The number may increase, but the perception will deteriorate. This means that up to 150 frames a person recognizes the image perfectly.
If they increase, it causes discomfort in the eyes and discomfort. It is believed that with a high frame rate, a large number of pictures are shown in one second, the human eye recognizes them smoothly. But even if he doesn’t see the frame change, the brain still perceives it.
If you increase the frame rate, what will happen?
The term frame rate (fps) was first used by photographer Eadweard Muybridge. And since then, filmmakers have been tirelessly experimenting with this indicator. From the point of view of practicality, it may seem that it is unreasonable to change the number of frames per second, because a different number will not be visible to the human eye.
How many fps does the eye perceive? We know that 24. Does it make sense to change anything? It turns out that all these efforts are paying off. Modern gamers, and just people who use computers, can say this with confidence.
Scientific background
Scientists have proven that at a 24-fold frame rate, a person perceives not only the overall picture on the monitor, but also individual frames on a subconscious level. For game developers, this information became an incentive to conduct further research into the capabilities of the human visual organs. Amazingly, the human eye can perceive video at a speed of 60 frames per second or more. The ability to perceive more images increases when you concentrate on something. In this case, a person is able to perceive up to one hundred frames per second without losing the semantic thread of the video image. And in the case when attention is scattered, the speed of perception can drop to 10 frames per second.
When answering the question of how many fps the human eye sees, we can safely name the number 100.
Color perception
The psychology of color perception is the human ability to perceive, identify and name colors.
The perception of color depends on a complex of physiological, psychological, cultural and social factors. Initially, research on color perception was carried out within the framework of color science; Later, ethnographers, sociologists and psychologists joined the problem.
Visual receptors are rightfully considered “a part of the brain brought to the surface of the body.” Unconscious processing and correction of visual perception ensures the “correctness” of vision, and it is also the cause of “errors” when assessing color under certain conditions. Thus, eliminating the “background” illumination of the eye (for example, when looking at distant objects through a narrow tube) significantly changes the perception of the color of these objects.
Simultaneous examination of the same non-self-luminous objects or light sources by several observers with normal color vision, under the same viewing conditions, makes it possible to establish an unambiguous correspondence between the spectral composition of the compared radiations and the color sensations caused by them. This is what color measurements (colorimetry) are based on. This correspondence is unambiguous, but not one-to-one: the same color sensations can cause streams of radiation of different spectral composition (metamerism).
There are many definitions of color as a physical quantity. But even in the best of them, from a colorimetric point of view, the mention is often omitted that the indicated (not mutual) unambiguity is achieved only under standardized conditions of observation, lighting, etc., and the change in color perception when changing the intensity of radiation of the same spectral composition is not taken into account (Bezold-Brücke phenomenon), the so-called color adaptation of the eye, etc. Therefore, the variety of color sensations that arise under real lighting conditions, variations in the angular sizes of elements compared in color, their fixation on different parts of the retina, different psychophysiological states of the observer, etc., is always richer than the colorimetric color variety.
For example, in colorimetry some colors (such as orange or yellow) are defined equally, which in everyday life are perceived (depending on lightness) as brown, “chestnut”, brown, “chocolate”, “olive”, etc. In In one of the best attempts to define the concept of Color, which belongs to Erwin Schrödinger, difficulties are removed by the simple absence of indications of the dependence of color sensations on numerous specific conditions of observation. According to Schrödinger, Color is a property of the spectral composition of radiation, common to all radiation that is visually indistinguishable to humans. [6]
Due to the nature of the eye, light that causes the sensation of the same color (for example, white), that is, the same degree of excitation of three visual receptors, can have a different spectral composition. In most cases, a person does not notice this effect, as if “guessing” the color. This is because although the color temperature of different lighting may be the same, the spectra of natural and artificial light reflected by the same pigment can differ significantly and cause a different color sensation.
The human eye perceives many different shades, but there are “forbidden” colors that are inaccessible to it. An example is a color that plays with both yellow and blue tones at the same time. This happens because the perception of color in the human eye, like many other things in our body, is built on the principle of opposition. The retina of the eye has special opponent neurons: some of them are activated when we see the color red, and some of them are suppressed when we see the color green. The same thing happens with the yellow-blue pair. Thus, the colors in the pairs red-green and blue-yellow have opposite effects on the same neurons. When a source emits both colors in a pair, their effect on the neuron cancels out, and the person cannot see either color. Moreover, a person is not only unable to see these colors under normal circumstances, but also to imagine them.
You can see such colors only as part of a scientific experiment. For example, scientists Hewitt Crane and Thomas Piantanida from the Stanford Institute in California created special visual models in which stripes of “arguing” shades alternated, quickly replacing each other. These images, recorded by a special device at human eye level, were shown to dozens of volunteers. After the experiment, people claimed that at a certain moment the boundaries between the shades disappeared, merging into one color that they had never encountered before.
How is research carried out?
Experiments in the field of identifying the capabilities of the human visual organs are constantly being carried out, and scientists are not going to stop there. For example, they conduct the following testing: a control group of people watches the proposed videos at different frame rates. Frames with some kind of defect are inserted into certain fragments at different periods of time. They depict some kind of extra object that does not fit into the general outline. It could be a fast moving flying object. In all groups, more than 50% of subjects notice a flying object. This circumstance would not be so surprising if it were not for knowing that this video was shown at a frequency of 220 frames per second. Of course, no one was able to examine the image in detail, but even the fact that people were simply able to notice flickering on the screen at such a frame rate speaks for itself.
Many people are interested in how many frames per second a person sees. Let's look at more interesting details below.
About research
Scientists have conducted many studies on the topic of recognizing different numbers of frames that the human brain and visual organs perceive. Most often, experiments were carried out by advertisers, since they believed that a hidden frame would lead to a subconscious perception, which would force a person to buy a certain product:
- Different groups of people sat in front of the TV. They were provided with video material that contained defective frames depicting an object that was unnecessary for this movie. After watching it, most people said that they saw some strange flickering on the TV. This is quite interesting, since the FPS was beyond the number 220. That is, a person can recognize the number of frames much more than 24.
- Scientists have studied peripheral vision. It was found that it differs from direct vision in image frequency. Therefore, when creating helmets, they use values not of 30-60 Hertz, as for a TV, but higher – 90 Hertz.
- In the fifties of the last century, an American film was released in which the words “Eat popcorn, drink Coca-Cola” were inserted into many frames. This is how frames were embedded that were recognized only on an unconscious level. The marketing company that carried out this study said that sales of popcorn and Coca-Cola increased many times after that.
- In American television there was a study on the content of frame 25. In one popular American TV show, the words “Call Now” were inserted 350 times at high speed. But no one ever called. At the end of the TV show, the host said that the show contained a message and asked for the correct answer about the content. Many letters were sent, but none of them contained the correct answer.
American trading companies have developed many studies on the topic of 25 frames and the introduction of information into the subconscious area of the human brain. But none of the studies confirmed the veracity of this theory. However, in many countries advertising at the level of subconscious human activity has been prohibited. In the US, this method may result in the loss of your broadcast license.
Unexpected facts
Not everyone knows about this interesting fact: experiments with displaying video images at different frequencies began more than a hundred years ago in the era of silent films. To show the first films, film projectors were equipped with a manual speed control. That is, the film was shown at the speed with which the mechanic turned the handle, and he, in turn, was guided by the reaction of the audience. The original speed of silent film was 16 frames per second.
But when watching a comedy, when the audience was highly active, the speed was increased to 30 frames per second. But this ability to arbitrarily regulate the display speed could also have negative consequences. When the cinema owner wanted to earn more, he, accordingly, reduced the showing time of one session, but increased the number of sessions themselves. This led to the fact that the film production was not perceived by the human eye, and the viewer remained dissatisfied. As a result, in many countries, at the legislative level, the demonstration of films at an accelerated frequency was prohibited and the standard in accordance with which projectionists worked was determined. In general, why are fps and the human eye studied? Let's talk about it.
What is it for?
The practical benefit of these studies is as follows: increasing the speed at which frames flicker on the screen smooths out the image, creating the effect of continuous movement. For watching standard video, the most optimal speed is 24 frames per second, this is how we watch movies in cinemas. But the new IMAX widescreen format uses a frame rate of 48 frames per second. This creates the effect of immersion in virtual reality with maximum approximation to reality. This feeling can be further enhanced by the use of 3D technology. When creating computer games, developers use a cycle of 50 frames per second. This is done to achieve maximum realistic gaming reality. But Internet speed also plays a role here, so the frame rate can change down or up.
We looked at how many frames per second a person sees.
