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VSBATTLE WIKI REVISION: PERCEPTION BLITZING

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Arnoldstone18

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I had a small discussion with Agnaa, DMUA, and Armorchompy to see why certain ways of calcing speed blitzing speed feats or speed blitzing time frames were unusable. I realized that virtually most, if not all, ways of calcing speed blitzing feats were not quite valid. We even have sections that forbid the use of time frames from sources where humans have perceived extremely fast objects.

So I was forced to find a new way.

Now the new method I came up with is starting to get used for speed blitzing calcs so I want all of us to discuss the guidelines on how to properly use this method




For those who aren’t knowledgeable on how the eye works and its limitations on what we perceive when it comes to speed here is an explanation.




How do we see?
The eyes are the main organs that receive light and allow us to see. When light enters our eyes, it is converted into electrical signals. These signals then travel through different parts of our brain, and eventually reach the primary visual cortex (an area in the brain), which helps us make sense of what we see.

What are the speed limits of what we see?
Under normal conditions, our vision has certain limitations that can change depending on different conditions and circumstances. To understand these limitations, researchers conduct experiments under controlled conditions, often involving flickering lights.

When a light flickers very quickly, there is a minimum speed at which we no longer perceive the flickering and the light looks steady instead. This specific minimum flickering speed is called the critical flicker fusion frequency (cFFF) or Flicker Fusion Threshold (FFT). At this point, our eye receptors can't detect the individual changes in what we see anymore. Instead, they merge together, creating a steady signal that our brain interprets as continuous light.

What Does Flickering Lights Have To Do With Perceiving Motion?
People with higher Flicker Fusion thresholds (the ability to no longer see high speed flickering in flickering lights but instead see them as steady light) tend to have better accuracy in what they perceive in general. In other words, people who can see fast “flickering lights” at a higher speed than others, can see fast moving objects at a higher speed than others. [1]

This concept is also applied to TVs, cinemas, and other similar forms of media. That’s why frame-by-frame viewing needs to happen at frequencies close to the limit at which we can perceive “flickering lights” so we can view motion on TV fluidly. At a higher speed than our limit, things would look like they’re skipping frames. Animals that have better vision than humans need to “see fast flickering lights” better to survive in the wild. According to this study, Birds that have a great ability to see “flicker lights” can see fast-moving objects better than humans, especially when these objects could potentially collide with them in the air. [2]





If you want a deeper meaning on how the brain perceives light and what perception blitzing speeds would look like in the brain. See below, otherwise skip to the next point.

Intro

We need light to see. Light bounces off things and goes into our eyes. The retina in the back of our eye collects these things. (The Fovea is a part of the retina that collects colors.)

All that light that’s bouncing off of the moving/stationary things we are looking at is turned into electrical signals that go to the back of our brain. That place in the back of our brains is called the visual cortex. The first neurons in that part of the brain that collect the information is called V1 neurons. Their only job is to react to the light and edges. Anything involving light. Which means flickering light or changes of light in the environment (Changes of light can happen when something moves, so if a red light bouncing off a moving car moves to the left, we would know it moves to the left when it collects the info of light traveling across. In other words, it knows the direction of light bouncing off moving things). Then all that light goes from the V1 neurons from our retina, then it goes to all the other neurons (MT/V5, MST, 7a, all that stuff) that all specialize in motion (basically these neurons answer the following questions is this moving? Is this stationary? Where exactly is it moving? What is it doing? What does it look like when it’s moving? What should I do?), identifying what we are looking at (Wtf is this?), and so on. All of this does not matter because they all depend on the very first neurons to work well (the light detecting and light changing neurons, also known as “flickering lights” neurons). That’s why scientists use experiments that involve flickering lights, because they want to see the limits of this first set of neurons, NOT the following sets of neurons that deal with motion and all that stuff. Because all those other neurons rely on the first ones for perception [3][5]. So if things move so fast that they can’t be seen, it’s because the first set of neurons h don’t have enough light information to send off to other neurons which are used for reaction. The other sets of neurons are based on reactions.

Things can flicker or move at such high speeds that the primary visual cortex (V1) becomes unable to detect the rapid changes in light. Instead, the V1 simply presents the most recent, fully processed information as more light enters the eye. This phenomenon explains why afterimages and other fast-motion-vision-related illusions occur. As the visual system struggles to keep up with the rapid changes, it relies on the last processed image, creating the illusion of persistence and the blending of moving objects into the background, appearing invisible.

In summary, as things move, light changes; as things flicker, light changes. Our brain can only know what is moving if it can detect changing light in the first place. That’s why scientists use flickering lights to determine this, cuz flickering lights and moving objects are essentially just changing lights to first areas of our brain’s visual cortex.




So What is Flicker Fusion Threshold That Represents The Perception Blitzing Speed?


Scientists determine this by figuring out the frequency our brain gives ups on detecting rapidly changing light and fuses the light into one (often the cause of afterimages when things move extremely fast). They do this through experiments that involve showing people flickering lights and speeding it up till the flickering fuses to become one single image of light. At this speed, the brain literally can’t detect changes in light. This is why when characters move at this speed, the brain won’t detect the changing positions of light bouncing off them at different points in space.

So in other words, the minimum speeds that surpass the limits of our vision is called Critical Fusion Threshold, which is also called Flicker Fusion Threshold. That speed is measured in Frequency Hertz. [4]

There are many experiments to find this speed. The most widely accepted being between 50 to 90 Hz like you see in the OP. [6][7] however since things have edges, DarkGarth has proposed that we use 500Hz (1/500th of a second for speed blitzing calcs) based on experiments (see below for more).

These are for Characters who are FTE to the point they appear invisible or cause visual illusions depending on how they move while moving faster than the eye's visual processing.













Dark Garth's Proposal

Having looked through the thread and the sourced information thoroughly, I would be comfortable with this standard. That being said, I don't believe we can afford to brush off the results of the Davis et al. article mentioned earlier in the thread. Despite the previous articles implying a 50-90Hz (20-11.1ms) threshold, this particular article suggests that visual flickers can be observed at as much as 500Hz (2ms). As mentioned earlier, this is in part due to saccades - saccades are a natural aspect of our vision, and even occur to some extent while we are visually fixated on a subject, so we would expect to see them influence our perception in a natural environment. Furthermore, the article sheds light regarding the variables that influence this perception:

"We presented users with a modulated light source, and asked them to determine the level of ambient illumination under which flicker was just noticeable. We performed experiments both with spatially uniform light resembling most prior studies on the critical flicker fusion rate, as well as with a spatially varying image as would be common on display devices such as TVs and computer screens... In our experiments, uniform modulated light was produced by a DLP projector and consists of a solid “bright” frame followed by a solid “black” frame. The high spatial frequency image is first “bright on the left half of the frame and black on the right”, and then inverted. We observed the effect described in this paper whenever we displayed an image containing an edge and its inverse in rapid succession. The effect was even stronger with more complex content that contained more edges, such as that in natural images. We chose a simple image with a single edge to allow our experimental condition to be as repeatable as possible... When the modulated light source is spatially uniform, we obtain a contrast sensitivity curve that matches that reported in most textbooks and articles. Sensitivity drops to zero near 65 Hz. However, when the modulated light source contains a spatial high frequency edge, all viewers saw flicker artifacts over 200 Hz and several viewers reported visibility of flicker artifacts at over 800 Hz. For the median viewer, flicker artifacts disappear only over 500 Hz, many times the commonly reported flicker fusion rate."

To broadly summarise, then, flicker becomes more noticeable at higher frequencies when the shapes depicted are more complex and contain more edges, capping out at around 800Hz for a simple image with a single edge, and with a median of 500Hz. The problem that this article identifies with previous research on the topic is that we only find the 50-90Hz rate described by many previous articles when we use a spatially uniform source without a defined edge, such as a pulsating light fixture, and that the frequency at which we can detect flickers is significantly higher for the kinds of more complex, defined shapes we would observe in a natural environment.

While I would like to focus primarily on the objective evidence here, and not simply an unverifiable anecdote, I would also like to mention in passing that most people (including me) who have seen displays with variable refresh rates (i.e.: monitors that can go between 60-120Hz) can see the difference in image changes - there are some monitors that go upwards of 300Hz, and while the jumps are known to have diminishing returns, the differences produced are still noticeable.

If we're going to use this standard as a baseline for calculating feats in the future, we need to acknowledge the evidence that our ability to perceive differences in visual stimuli are much higher in natural circumstances than they are when observing spatially uniform stimuli. As a hypothetical example: if Person A was looking at Person B, and Person B travelled fast enough to vanish/appear somewhere else via speed alone, then the fact that Person B is a more complex shape with a defined edge (try picking someone up with that line) would suggest Person A's ability to detect changes in Person B's position should be far better attuned than it would be for a spatially uniform pulsating light. For that feat, I would suggest then that a 500Hz baseline is more congruent with the evidence.
Guidelines
  • The observer's eyes must meet specific visual criteria. They should be able to focus clearly on the object before making any observations. Note that the flicker fusion threshold is dependent on the Field of View (FOV), with the optimal FOV being the center of view.
  • The flicker fusion threshold is influenced by the brightness intensity of the surroundings. Observations of feats in extremely dim or overly bright environments are not suitable for this method.
  • These guidelines are applicable only to observers with human eyes. For animals, specific studies detail the flicker fusion thresholds for various species. However, the range of studied animals is limited, and findings might not apply universally.
  • The object under observation should be unique. Duplications can distort frequency, creating illusions of speed.
  • Small or distant objects are challenging to monitor consistently. They are not recommended for reliable speed calculations.
  • Techniques that induce afterimages or illusions are not acceptable. There should be concrete evidence that any perceived speed or disappearance of the object is due to its actual speed. If there's any ambiguity, an alternative standard should be considered.
  • Any character with a perception speed differing from human standards is excluded, as this can result in skewed speed values.




Therefore, I propose using 1/500s for perception blitzing calcs rather than s reaction time blitzing calcs.


Agree: DarkDragonMedeus (Recent; 1/500s), DarkGarth (Expert; 1/500s), LephyrTheRevanchist (Recent; 1/500s), Dalesean (Recent; 1/500s)
Neutral: DMUA (skeptical, albeit hasn't followed the thread much)
Disagree: DontTalk (outdated; 4 weeks), Flashylights (outdated; 4 weeks)

Due to the inability to gather input from staff members for one reason or another. This thread is considered accepted.
 
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See last thread on the topic.
But long story short, a moving object isn't a flickering light and human vision treats it different.
 
Needed a while to find it.

But, like, to add on a really simple argument: The method you suggest is that every feat beyond vision must happen in 1/70th of a second. However, it can easily be demonstrated that you can also perpetually outdo vision via speed without ever leaving the field of vision. Just look into a fast spinning fan blade. Not only do those typically not rotate once in 1/70th of a second, but you can stare at them as long as you like while they stay in your FOV. Yet they are invisible regardless (well, if you have the right fan, I guess).
 
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Therefore, a timeframe of approximately 1/70th of a second is suitable for conducting speed blitzing calculations where the observer is in an
Funny enough I know a character with 1/75th of a second for his reaction speed
 
But long story short, a moving object isn't a flickering light and human vision treats it different.

Well yeah.. It’s not about the flickering light tho. This thread is actually about the retina’s temporal resolution. The way to find that is via… flickering lights.




The eye captures a series of individual images, commonly referred to as frames, in a second. Our brain processes these frames and integrates them with contextual information to construct our visual perception of the world.

In the experiment, when a light is flickering, said images are images of the light off and other images of the light on that our brain translates to “flickering light”. There is a point where the images can’t even be captured at all and the light “stops flickering” and is left on. The flickering is so fast that our brain just merges it into a continuous perception of “this light is on”.

Stuff we see is technically 50-90 images every second that our brain puts together and add it’s magic to perceive motion. But there is a point where the brain can’t even perceive anything moving… it can’t even get enough information from the retina to create a blur effect… all due to our physiological limitations and that’s determined by Flicker Fusion Threshold*. Said character has to move within a timeframe between 1/50th to 1/90th of a second to accomplish this feat and vanish from perception. Hence why I proposed 1/70th of a second since it’s the average.

*Edit
 
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But, like, to add on a really simple argument: The method you suggest is that every feat beyond vision must happen in 1/70th of a second. However, it can easily be demonstrated that you can also perpetually outdo vision via speed without ever leaving the field of vision. Just look into a fast spinning fan blade. Not only do those typically not rotate once in 1/70th of a second, but you can stare at them as long as you like while they stay in your FOV. Yet they are invisible regardless (well, if you have the right fan, I guess).

Oh shit I missed this edit. Sorry for the multi-posting.

The brain still adds blur into fast moving blades,

Heck, the blades’ spin don’t even disappear but appear in a “solid state” due to an optical illusion.

Blades never truly become invisible. Unless I’m missing something. However they probably go from “solid” to “invisible” if they rotate once every 1/50th to 1/90th of a second.
 
Pretty much a repeat of last thread, but fine.
The eye captures a series of individual images, commonly referred to as frames, in a second.
Pretty sure they don't. Eyes aren't cameras. Pretty sure the cells just deliver a continuous untacted flow of input.

Our brain processes these frames and integrates them with contextual information to construct our visual perception of the world.

In the experiment, when a light is flickering, said images are images of the light off and other images of the light on that our brain translates to “flickering light”. There is a point where the images can’t even be captured at all and the light “stops flickering” and is left on. The flickering is so fast that our brain just merges it into a continuous perception of “this light is on”.

Stuff we see is technically 50-90 images every second that our brain puts together and add it’s magic to perceive motion. But there is a point where the brain can’t even perceive anything moving… it can’t even get enough information from the retina to create a blur effect… all due to our physiological limitations and that’s determined by Flicker Fusion Threshold*. Said character has to move within a timeframe between 1/50th to 1/90th of a second to accomplish this feat and vanish from perception. Hence why I proposed 1/70th of a second since it’s the average.

*Edit
As you say, our brain does a lot of post-processing. The image we see alone of made up of not just one "frame", but of several frames that our eyes take in slightly different spots together.
So you can't just assume that the eyes will process a movement (which will happen outside the focussed spot) the same way it does a light shined directly into the eye.
The brain could easily post-process something out even if the photoreceptor cells percieve it, but whether it does so would depend on circumstances. For determining whether a light flickers, the brain only has to determine if some change in brightness happens, which is way different from whether it makes you perceive movement which involves way more varied input.

In fact, think of a camera's flash. Those can easily be in the range of about 1/300th or 1/1000th of a second, yet you would never miss them. That's because, despite being short, they produce a strong signal.
What does that tell us? Well, that perception of something way below flickering range is possible, as it's not as simple. Clearly this number needs to vary by how bright the object in question is. So with a test that uses light shone into eyes...

It's also obvious that, for example, size needs to be a factor. A small object is easier to lose sight of. We can all tell that much from experience when that annoying tiny fruit fly vanishes from vision as soon as you stop focussing on it for a moment.

And not just that. It also stands to reason that speed, or precisely visual angle covered per time, needs to be a factor. Our brain will obviously register a tiny movement in 1/70s of a second, while a large movement not so much. Like, the density of light that reaches each photoreceptor cell in the eye decreases the faster the movement is, essentially lowering the percentage of that light reaching that cell when compared to light from other sources.
Or consider this: Obviously there would be a difference between passing through the same spot many times a second and passing through lots of different spots just once in the same timeframe.

You also ignored that I already gave you an obviously troublesome counter-example: A spinning fan. The rotation speed of a fan is 1300 to 2100 RPM. I can tell from experience that the rotor blades of a fan (or at least their outer edges) become practically invisible in some fans. (Would love to show a video, but I am on holidays so I don't have my fan at hand... not that a video would proof much due to the fps of cameras)
2100 RPM is 1 rotation every 1/35th of a second. Pretty much half of your suggested value. That means, the fan blade passes through the same spot 35 times a second, yet it's still not visible no matter how long I stare. In fact, a fan has 3 identical blades, meaning actually 105 blades pass through that spot each second without being seen. Or in other words, the brain decides to not make those visible, despite one being present three times more often and in total 3 times longer than what was already half your value.
So we can conclude that it doesn't work like that by practical experiment.


Basically, movement is not flickering and you shouldn't expect our brain to deal with it the same way. A flicker test is not a suitable experiment to actually determine the value we are looking for. For that, you would need an experiment that deals with seeing movement under specific conditions.

Oh shit I missed this edit. Sorry for the multi-postings.

The brain still adds blur into fast moving blades,
Not in my fan.

Heck, the blades’ spin don’t even disappear but appear in a “solid state” due to an optical illusion.
Pretty sure that's exclusively a thing for cameras which happens due to fps. Fairly sure eyes don't do that? Like, never observed that.

Blades never truly become invisible. Unless I’m missing something. However they probably go from “solid” to “invisible” if they rotate once every 1/50th to 1/90th of a second.
Not from my observation, sorry.
 
Actually, did some looking up on that optical illusion.

I.e. the Wagon-wheel effect. As it turns out, it can happen after all. So I give you that point. Even if only at specific frequencies.
However, if you look at wikipedia, you will also see that science is not sure why. With there being evidence against the whole "frame" idea of vision.

Basically, the thing you are trying to proof here turns out to be an unresolved problem in science. Meaning, there can't be a conclusion to this.

Edit: Also turns out I'm not the only one to percieve fan blades as practically invisible. Like, it's probably an extension of the "smudging" of colors as it rotates, with the smudging at some point becoming so strong that it just blends into the background. In fact, IIRC the effect is less when I focus on an area behind the blades, which is kinda another point on the topic of focus being important. We have two eyes that focus on the objects we want to see well, both in terms of direction and distance.
However, a smudging kind of thing also immediately tells us that doing that over a greater area will have better results. I.e. if the fan didn't rotate but bounced all over the place at the same rate, the effect should be stronger, as then it would smudge over greater area.
 
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The flicker fusion threshold refers to the maximum speed at which visual stimuli can be perceived by the human eye. It occurs when a blinking light flashes so rapidly that it appears continuous, even though it is actually blinking. The blinking happens at such a high frequency that it becomes undetectable to the retina. Typically, the average human eye's threshold falls between 50 to 90 hertz depending on the intensity of light and contrast, indicating that a light flashing between 50 to 90 times per second will appear as if it has stopped flickering and remains continuously on. If the flashing rate is slower than this range, the flickering will be noticeable. This means that any events occurring within this timeframe cannot be captured by the retina.

Let's consider the average of the range of frequencies of the human flicker fusion threshold between 50-90Hz, which is 70Hz. On average, any events happening between the first and second images without background visual changes captured by the eye will go undetected. Therefore, a timeframe of approximately 1/70th of a second is suitable for an average observer.
This isn't how vision works. The human eye doesn't operate within a paradigm of frames per second.

 
Yeah I had a vague recollection of the stuff DT's bringing up, but didn't actually go through the effort to mention it on the stuff that's been calced already
 
This isn't how vision works. The human eye doesn't operate within a paradigm of frames per second.


This is the problem I have with picking out specific parts of an entire argument.

I am aware that the eyes are not literally cameras and do not literally operate frame by frame. I only used that to better explain frequency of information that’s sent to the brain. And you would’ve probably known this had you responded to the entire argument.

The retina collects a continuous stream of light information, forms an image (please by image I mean processed information in the form of neural signal) and sends it to the brain through the optical nerve for interpretation.

DT is aware of what I mean judging by his reply with (“frames”). Which I will respond to soon.
 
I believe this is a topic best left for @Agnaa to handle.
I currently have 34 threads in my "to-evaluate" backlog, I've added this to the list, and will get to it eventually.

Until then, refer to my prior comments on this topic.
 
Pretty sure they don't. Eyes aren't cameras. Pretty sure the cells just deliver a continuous untacted flow of input.

Yes


As you say, our brain does a lot of post-processing. The image we see alone of made up of not just one "frame", but of several frames that our eyes take in slightly different spots together.

Yes




So you can't just assume that the eyes will process a movement (which will happen outside the focussed spot) the same way it does a light shined directly into the eye.

Okay so there are stages of processes the eye has to undergo.

Certain neurons in the visual system are specialized to detect sudden changes in luminance, and they play a fundamental role in the initial stages of processing visual motion. These neurons are part of a hierarchical system that progressively analyzes direction, speed, and overall motion velocities. So like… together, these processes contribute to our perception of objects in motion.

Hence why Flicker Fusion Frequency (FFF) is important for identifying moving objects too since that studies the literal first stage of perception — rapid changes in luminance. The other stages happen in and around that same timeframe of 1/50th to 1/90th of a second.

Oh and the study linked in the OP also implies FFT is important for animals to identify approaching targets fast enough.


In fact, think of a camera's flash. Those can easily be in the range of about 1/300th or 1/1000th of a second, yet you would never miss them. That's because, despite being short, they produce a strong signal.
What does that tell us? Well, that perception of something way below flickering range is possible, as it's not as simple. Clearly this number needs to vary by how bright the object in question is. So with a test that uses light shone into eyes...

Holy shit, nobody is partaking in a FFT experiment or even engaging in combat in a seizure inducing flash intensity akin to a camera’s flash. Using this method is against the guidelines to use this method anyway.

So while you’re right, it’s difficult to see in general much less see who is trying to blitz you. Extremely lit areas are just as bad as extremely dimly lit areas, and even as bad as your next point about small size being easy to lose track of t


It's also obvious that, for example, size needs to be a factor. A small object is easier to lose sight of. We can all tell that much from experience when that annoying tiny fruit fly vanishes from vision as soon as you stop focussing on it for a moment.

Yes, things that are easy to lose track of don’t count (I should add this to the guidelines, I was hoping someone would think of more guidelines for proper usage of this so thanks)
And not just that. It also stands to reason that speed, or precisely visual angle covered per time, needs to be a factor. Our brain will obviously register a tiny movement in 1/70s of a second, while a large movement not so much. Like, the density of light that reaches each photoreceptor cell in the eye decreases the faster the movement is, essentially lowering the percentage of that light reaching that cell when compared to light from other sources.
Or consider this: Obviously there would be a difference between passing through the same spot many times a second and passing through lots of different spots just once in the same timeframe.

The small movements detections probably being more detectable than larger movements are as a result of involuntary eye movements called saccades. Which brings me back to the research I told you I was eyeing earlier in this thread. That research tries to invoke saccades by incorporating high frequency edges to their experiment but let’s not digress to that yet.

Regardless of how the motion is depicted, less density of light bouncing from the object into the fovea would be limited due to its sheer uniform speed in the timeframe I suggested. Keep in mind the first thing the eye does to perceive motion is to actually track changes in luminus before anything else. So if tracking the sudden changes in luminance of an object can’t even happen then motion can’t even be tracked at all.


You also ignored that I already gave you an obviously troublesome counter-example: A spinning fan. The rotation speed of a fan is 1300 to 2100 RPM. I can tell from experience that the rotor blades of a fan (or at least their outer edges) become practically invisible in some fans. (Would love to show a video, but I am on holidays so I don't have my fan at hand... not that a video would proof much due to the fps of cameras)
2100 RPM is 1 rotation every 1/35th of a second. Pretty much half of your suggested value. That means, the fan blade passes through the same spot 35 times a second, yet it's still not visible no matter how long I stare. In fact, a fan has 3 identical blades, meaning actually 105 blades pass through that spot each second without being seen. Or in other words, the brain decides to not make those visible, despite one being present three times more often and in total 3 times longer than what was already half your value.
So we can conclude that it doesn't work like that by practical experiment.

And I told you the blades are visible in the form of a blur at that speed. This thread is discussing speeds that the brain can’t even perceive/process at all.

If you can’t even see a blur in a fan of 1300 RPM to 2100 RPM then I must have superhuman eyes even tho Im legally blind in my left eye 😃. I’ve asked the girl I was dating she says she can’t see the blades of a standing fan at its highest but she can see the blur and tell it’s still there. (A blur is still information the eye captures, seeing only blurs doesn’t mean the blades are completely invisible). Also I just noticed you said “at least the outer edges” the blur is still there just barely cuz I can see the color difference between the black edges and my white wall.

Have you seen an industrial fans? They move around 3000 RPM, those fan blades are completely invisible to me (edges or not). Probably to anyone else for that matter.

Also keep in mind the brain only willingly removes the blade’s visibility if you are not focusing, which is against my suggested standards anyway. I can’t even see the edges of my fan unless I focus on it, same applies to my nose and my glasses.


Basically, movement is not flickering and you shouldn't expect our brain to deal with it the same way. A flicker test is not a suitable experiment to actually determine the value we are looking for. For that, you would need an experiment that deals with seeing movement under specific conditions.

While our brain processes flickering light and the initial step of perceiving motion (which involves sudden changes in light) similarly, it is important to note that they rely on the same neural network. However, the distinction lies in the fact that perceiving motion involves a multi-step process within the neural network. That’s why the flicker test is utilized in studies as one of the initial assessments to measure an animal's ability to visually detect motion, given typical environmental conditions and among other additional experiments for other motion step process. You get it right?
 
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I.e. the Wagon-wheel effect. As it turns out, it can happen after all. So I give you that point. Even if only at specific frequencies.
However, if you look at wikipedia, you will also see that science is not sure why. With there being evidence against the whole "frame" idea of vision.

Basically, the thing you are trying to proof here turns out to be an unresolved problem in science. Meaning, there can't be a conclusion to this

Interesting, looking into it


Edit: Also turns out I'm not the only one to percieve fan blades as practically invisible. Like, it's probably an extension of the "smudging" of colors as it rotates, with the smudging at some point becoming so strong that it just blends into the background. In fact, IIRC the effect is less when I focus on an area behind the blades, which is kinda another point on the topic of focus being important. We have two eyes that focus on the objects we want to see well, both in terms of direction and distance.
However, a smudging kind of thing also immediately tells us that doing that over a greater area will have better results. I.e. if the fan didn't rotate but bounced all over the place at the same rate, the effect should be stronger, as then it would smudge over greater are

Yes focus is part of the proposed guidelines too. If you come into an agreement with flicker fusion being relevant, please work with me to set up guidelines where using 1/70s timeframe (and/or saccades related timeframes) are usable.

Also I’m a bit unsure what you mean about the background blending, you mean the blur effect? Yeah that too count as info the retina processes. Industrial Fans between 50-90htz I can’t see the blades anymore, not even a blur.
 
Actually, did some looking up on that optical illusion.

I.e. the Wagon-wheel effect. As it turns out, it can happen after all. So I give you that point. Even if only at specific frequencies.
However, if you look at wikipedia, you will also see that science is not sure why. With there being evidence against the whole "frame" idea of vision.

Basically, the thing you are trying to proof here turns out to be an unresolved problem in science. Meaning, there can't be a conclusion to this.

Okay so I looked into it, after sleeping

I realize that the concept of objects blending into the background at high speeds kinda aligns with my initial point about objects moving so fast at specific frequencies that they become invisible (with the one adjustment to my argument being the fact that it’s still motion blur but the frequency is so high that the blur blends into the back-ground to the point the brain loses track of it or causes persistence in vision). It appears that the notion of “frames” isn't particularly significant in either theory, as both theories rely on the concept of frequency. but yeah like you said the science is still uncertain about the reason behind that decrease in visibility at certain high frequencies.

So what I aim to prove here is not an unresolved problem but rather how the flicker fusion frequency (FFF) is used to determine the limits of our visual processing systems. FFF is relevant in explaining positive afterimages and motion blurs, which are concepts related to blitz worthy fast-moving characters or events.

So please I need your help to make the proposed guidelines on how best to use 1/70s (or how best to use the range) as a time frame for speeding blitzing calcs better.
 
So what I aim to prove here is not an unresolved problem but rather how the flicker fusion frequency (FFF) is used to determine the limits of our visual processing systems
What he's saying is that this only occurs at specific frequencies, not at or above specific frequencies, and we don't know why that sometimes happens, but it's not a hard limit on human perception where anything in the field of vision for less time than that is simply not registered by the eye.
 
What he's saying is that this only occurs at specific frequencies, not at or above specific frequencies, and we don't know why that sometimes happens, but it's not a hard limit on human perception where anything in the field of vision for less time than that is simply not registered by the eye.

Under normal lighting conditions and with good vision, it is a “hard” limit on human perception. I say “hard” cuz everyone’s different but in a range of 50Hz to 90Hz.
 
It's a little weird. I mean while, yes, the human eye can stare at a fan (like, for example, a ceiling fan, which typically have lower speeds than even the lowest speed setting of a plug-in fan), at the same time, you couldn't really follow a fan's individual blade if you marked it with a red dot with a Crayola washable marker and watched it go. Ceiling fans go at around 200, maybe 300 revolutions a minute at best and yet mine's a blur when I look at it.

Really, it all depends on how far away something is. Maybe size if something's spinning. For example, Earth rotates at 1000 miles an hour, yet the sun hardly seems to move while Earth rotates. At the same time, you can probably see a car zip by perceivably fast if you watched one zip past you at 50 miles an hour. When you really think about it, giving faster-than-the-eye a speed figure is really a faulty practice as there is no single "faster-than-the-eye" speed.
 
It's a little weird. I mean while, yes, the human eye can stare at a fan (like, for example, a ceiling fan, which typically have lower speeds than even the lowest speed setting of a plug-in fan), at the same time, you couldn't really follow a fan's individual blade if you marked it with a red dot with a Crayola washable marker and watched it go. Ceiling fans go at around 200, maybe 300 revolutions a minute at best and yet mine's a blur when I look at it.

Motion blurs contain valuable information. If motion blur is clearly visible and distinguishable, it indicates that the observer has not reached their visual limit yet. However, it is unlikely that a ceiling fan alone will push one to that limit imo. Standing fans are closer to achieving this effect because they are generally way faster and they often appear as a solid disk fading into the background rather than a vivid and distinguishable motion blur to me. The former is a result of our limitations under normal light.

This limit of human perception occurs when the fan blur blends together to form a disk and into the background to become less visible. The frequency range at which this visual limit occurs for fans is typically between 50-90Hz.



To understand how fans reach this frequency faster, we need to consider the number of blades. For fans with a single blade, it needs to rotate at 50-90 revolutions per second (rps) for us to reach our limit. However, fans with two or more blades can create the illusion of movement at 50-90rps by moving at half the speed, i.e., 25-45rps. This is because two blades pass through the same exact spots, thus recreating the same visual effects as a single blade moving at higher speeds beyond our perception (50-90rps).

In the case of your fan with probs three or five blades, each blade needs to move at speeds ranging from 16.67-30rps or 10-18rps, respectively, to exceed your visual capabilities.



Really, it all depends on how far away something is. Maybe size if something's spinning. For example, Earth rotates at 1000 miles an hour, yet the sun hardly seems to move while Earth rotates. At the same time, you can probably see a car zip by perceivably fast if you watched one zip past you at 50 miles an hour. When you really think about it, giving faster-than-the-eye a speed figure is really a faulty practice as there is no single "faster-than-the-eye" speed.

This concept doesn’t depend on the distance of the observer relative to the object. Which is pretty cool to say the least. As long as the object is clear and isn’t small and hard to see due to its distance.

Also using the sun and the earth is WILD!!!

The sun actually takes A LITERAL DAY to us observers to move across the sky due to not just the earth’s rotation but it’s speed of revolution around the sun. 😭
 
Im still typing up the post. It’s pretty long but that’s cuz I needed to make it as simple as possible to understand.

I’m currently just adding sources to it and adding things that could help my points whenever I find something.
 
The eyes are the main organs that receive light and allow us to see. When light enters our eyes, it is converted into electrical signals. These signals then travel through different parts of our brain, and eventually reach the primary visual cortex (an area in the brain), which helps us make sense of what we see.

Under normal conditions, our vision has certain limitations that can change depending on different conditions and circumstances. To understand these limitations, researchers conduct experiments under controlled conditions, often involving flickering lights.

When a light flickers very quickly, there is a minimum speed at which we no longer perceive the flickering and the light looks steady instead. This specific minimum flickering speed is called the critical flicker fusion frequency (cFFF) or Flicker Fusion Threshold (FFT). At this point, our eye receptors can't detect the individual changes in what we see anymore. Instead, they merge together, creating a steady signal that our brain interprets as continuous light.

What Does Flickering Lights Have To Do With Perceiving Motion?

People with higher Flicker Fusion thresholds (the ability to no longer see high speed flickering in flickering lights but instead see them as steady light) tend to have better accuracy in what they perceive in general, and it's also linked to increased alertness and improved visual processing in the brain. In other words, people who can see fast “flickering lights” at a higher speed than others, can see fast moving objects at a higher speed than others. [1]

This concept is also applied to TVs, cinemas, and other similar forms of media. That’s why frame-by-frame viewing needs to happen at frequencies close to the limit at which we can perceive “flickering lights”. Animals that have better vision than humans need to “see fast flickering lights” better to survive in the wild. According to this study, Birds that have a great ability to see “flicker lights” can see fast-moving objects better than humans, especially when these objects could potentially collide with them in the air. [2]






Let’s look at the eye and the brain.

We need light to see. Light bounces off things and goes into our eyes. The retina in the back of our eye collects these things. (The Fovea is a part of the retina that collects colors.)

All that light that’s bouncing off of the moving/stationary things we are looking at is turned into electrical signals that go to the back of our brain. That place in the back of our brains is called the visual cortex. The first neurons in that part of the brain that collect the information is called V1 neurons. Their only job is to react to the light. Just light. Anything involving light. Which means flickering light or changes of light in the environment (Changes of light can happen when something moves, so if a red light moves to the left, we would know it moves to the left when it collects that info. In other words, it knows the direction of light bouncing off moving things. Don’t forget that all we see is light bouncing off of things). Then all that light goes from the V1 neurons to all the other neurons (MT/V5, MST, 7a, all that stuff) that all specialize in motion (is this moving? Is this stationary? Where exactly is it moving? What is it doing? What does it look like when it’s moving?), identifying what we are looking at (Wtf is this?), and so on. All of this does not matter because they all depend on the very first neurons to work well (the light detecting and light changing neurons, also known as “flickering lights” neurons). That’s why scientists use experiments that involve flickering lights, because they want to see the limits of this first set of neurons, NOT the following sets of neurons that deal with motion and all that stuff. Because all those other neurons rely on the first ones for perception. [3][5]

Things can flicker or move at such high speeds that the primary visual cortex (V1) becomes unable to detect the rapid changes in light. Instead, the V1 simply presents the most recent, fully processed information as more light enters the eye. This phenomenon explains why afterimages and other fast-motion-vision-related illusions occur. As the visual system struggles to keep up with the rapid changes, it relies on the last processed image, creating the illusion of persistence and the blending of moving objects into the background, appearing invisible.

In summary, as things move, light changes; as things flicker, light changes. Our brain can only know what is moving if it can detect changing light. That’s why scientists use flickering lights to determine this, cuz flickering lights and moving objects are essentially just changing lights to first areas where our brains collect these changing lights. Without detecting the changes itself, the rest of our motion sensitive brains are completely useless.




What is Flicker Fusion Threshold?



Scientists determine this by figuring out the frequency our brain gives ups on detecting rapidly changing light. They do this through experiments that involve showing people flickering lights and speeding it up till the flickering fuses to become one single image of light. At this speed, the brain literally can’t detect changes in light. That’s why when characters move at this speed, the brain won’t detect the changing positions of light bouncing off them at different points in space.

So in other words, the minimum speeds that surpass the limits of our vision is called Critical Fusion Threshold, which is also called Flicker Fusion Threshold. That speed is measured in Frequency Hertz. [4]

There are many experiments to find this speed. The most widely accepted being between 50 to 90 Hz like you see in the OP. [6][7]

Characters who are FTE to the point they appear invisible or cause visual illusions depending on how they move have to be moving faster than the eye's visual processing. In other words the character or thing is so fast that the brain just gives up detecting the object altogether. This means said character must be moving between 1/50th of a second to 1/90th of a second. Therefore, I propose 1/70s be used as the timeframe for FTE calcs at this level. If accepted I will continue to fine tune the guidelines to factor in less typical conditions for better use of this method.





TL;DR: Flicker fusion refers to the point at which a flickering light appears as a continuous stream to our eyes. It represents the limit at which our visual system can detect changes in light. People with higher flicker fusion thresholds can perceive fast-moving objects better. Scientists study this phenomenon because it reveals the limit of the initial light-detecting neurons (V1 neurons) in our brain. When light changes too rapidly, these neurons can't keep up, and our brain perceives a steady image in the form of afterimages or other visual illusions. The critical flicker fusion frequency (cFFF) or Flicker Fusion Threshold is the minimum speed at which things move beyond the limits of visual perception. Characters who can move faster than the ability the observer's visual system can detect them should be moving at least 1/50th to 1/90th of a second to appearing invisible by blending into the background or cause visual illusions.
 
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