Slashdot Mirror
"Microsaccades" Help To Refresh Your Field of View
Ponca City, We love you writes with news of research from the Salk Institute into small, unconscious eye movements called "microsaccades," the purpose of which has been in question for many years. A recent study showed that those movements were essentially responsible for maintaining a coherent image for interpretation by the brain. They are also the cause of a famous optical illusion in which a still image appears to move.
'"Because images on the retina fade from view if they are perfectly stabilized, the active generation of fixational eye movements by the central nervous system allows these movements to constantly shift the scene ever so slightly, thus refreshing the images on our retina and preventing us from going 'blind,'" explains Hafed. "When images begin to fade, the uncertainty about where to look increases the fluctuations in superior colliculus activity, triggering a microsaccade," adds Krauzlis.'"
I remember reading about this back in the 90s...so what is new here?
There is nothing new here; this has been well known for decades. People with vision difficulties also move their eyes more than those with perfect vision, for the same reasons. This isn't news.
What? Nobody will believe it if it is on the internet. The internet is full of liars and pervaricators who tell the not truth ever. I think you would be better off eating tacoes. If my vagina was here it would be a hot rod of a wiz bang time! Hooray for the VAGUS NERVE!
I tested both illusions on the link provided in the summary and neither one had the effect on me that was claimed. What would that imply?
I tried them multiple times shifting my focus to different aspects of the image than directed just to see if it had any effect and it was no different.
You think that's the world, you're seeing? No, you're seeing a representation of it constructed by your mind. The only time you need to see something is when it's moving (or when you're moving in relation to it.) Otherwise it still looks pretty much like it did the last time you looked at it. On the other hand, if something is moving and your eye is damaged, or your brain wants more information about it, then it should need the information. Not that I know more about what this guy is talking about than he does or anything, but I guess what I'm clumsily doing is asking whether that's necessary for sight, or just a byproduct?
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
If you're really asking and just trolling, go see an eye doctor. Looks like you have yourself a serious eye infection there.
do a barrel roll
Can we finally get some specs on life, such as Refresh rate and resolution?
http://CryoLANparty.com/ A lan I'm staff on!
If you can perfectly relax your eyes you can watch the image fade. Color fades before lightness, and eventually the whole image is just noisy gray. It's easiest if there's nothing visually interesting in your field of vision so you don't accidentally look at something and move your eyes.
Yet again - conceptual confusions abound (in linked articles and comments). The brain does not 'interpret' anything. A person can 'interpret', a brain cannot.
Until now I couldn't quite explain it, say there was this tall blond passing by my eyes would continuesly wander.
Was it some large brunette it wouldn't happen but once only, even though I've always liked dark haired women best.
But this study finally explains it, the big broad doesn't get lost from vision as easily as the slim blonde!
Thanks for nature!
"The likes of Facebook and WhatsApp are free to those whose privacy is of zero value."
Finally, a viable excuse...
"Yes, I keep glancing at your tits. Nope, sorry, I'm afraid I can't stop unconscious eye movements"
Comment removed based on user account deletion
Simply enable vsync and triple buffering.
News for nerds, stuff that matters, replacement for a failing school system.
Slashdot, just like a good video streaming protocol, must send a background stream of image updates about science and knowledge, filling in all the missing pieces of static, known stuff for the lossy observers, while also trying to selectively send some content that is actually new and different.
All I can think of is DRAM. You need to keep refreshing the memory by re-addressing it and recharging the cells. By moving the eye, you are just refreshing the pixels.
I am also reminded by the probably nonsensical warning to "hold still" because the T-REX's vision was based on movement. It seems our vision is also based on movement, except we supply the movement with our eyes.
might this be the cause of those people who lose their sight after having especially traumatic experiences?
Yes but the real reason for microsaccades is that almost all the photoreceptors in the retina are designed to detect changes, such as the onset or offset of illumination. Unless there is change in the field of view, the sensors will not fire and the brain stops receiving visual signals. Indeed, retinal ganglion cells (RGC) use a center-surround arangement so that they can detect movement in many different directions. There must be a slight delay between the signals sent from the photoreceptors to the center and side cells in order for the RGC to fire. This is crucial for the detection of things like edges, lines, etc. The brain is primarily a massively parallel discrete signal processor. The precise timing of signals is crucial to its operation.
Martinez-Conde still doesn't know exactly how microsaccades create the false perception of motion.
Aliasing at the retinal level ??
We are Turing O-Machines. The Oracle is out there.
What I find amazing is that no-one seems to have figured out that it also increases effectives resolution too. And is probably involved in focusing.
Coming soon - pyrogyra
Please post a video, or no free advise. (p.s. i am a doctor and I can help)
I kept seeing the phantom of the white background when I looked off the screen. It's like a watermark. Is that the illusion?
Michele Rucci's lab figured out a while back that microsaccades improve our perception of high spatial frequency stimuli.. here's the article.
Stabilized images on the retina fade. Microsaccades prevent it from happening. I actually think I read an article about this in Scientific American in the 1960s. Certainly I encountered it in a perceptual psychology course I took in the 1970s.
As for illusions like the Enigma illusion, we were told that caused by small eye movements, amplified by a moire effect between the image and the afterimage. Maybe that was only the professor's guess, and the new study did something to pin it down, but it's not a very new idea.
"How to Do Nothing," kids activities, back in print!
I read that as "microcascades" and was expecting to see headcrabs in TFA. I was sorely disappointed. :(
Homonyms are fun!
You're driving your car, but they're riding their bikes there.
I was 13, in the 7th grade at my school back in 1983 and I can clearly remember, as if it had happend today, the way our teacher described this phenomenon in biology and how the scientists examining it discovered the effects the prevention of these micromovements of the eye have on the visual perception of things. He also specifically described the blinding of the retina once an eyeball is held fix by small suction-cups.
Ever so often I encounter this, that things people have discovered decades or even a century or longer ago are rediscovered and sold as brand new insights into a specific field. Has any of you guys noticed the same thing? I'd suppose so. Strange isn't it? Does the scientific community need this sort of thing in order to 'stay important' - kinda like fashion fads reoccuring every 25 years or so?
We suffer more in our imagination than in reality. - Seneca
The article in Wired seems to be a 'dumbed down for public consumption' version of an article that appeared in Scientific American in August 2007. The original was authored by Dr Susana Martinez-Conde and Dr Stephen L Macknik, and referred to a study they had completed in 2006. There is a preview available here:
http://www.sciam.com/article.cfm?id=windows-on-the-mind
unfortunately one would have to pay for the whole article as they are a subscription magazine. But the proof is in the preview, and if anyone should want more, I would encourage them to go to their local library and find the magazine there. The article in Scientific American is much more educational.
-Magdalene --"there are 10 types of people in the world, those who read binary, and those who don't"
... at least in my field.
It's been awhile since it's come up but it takes 7 of those little vibrations (if memory serves- I can ask the expert) to register the j-curve for the minimum contrast detection in the standard observer.
Useful for image refresh calculations :)
into a negative term or is it still positive?
'Damn, whatever that guy gave me last week seems to be sponge-worthy, better go to the clinic'
'course, it'd go for guys too now...
'Damn girl, you're so hot you're Sponge-Worthy!'
Blindness can be induced by paralyzing the ocular muscles and immobilizing the head. This was done decades ago using curare. If the visual field remains constant, there is a loss of visual contrast until everything greys out. With practice this can be done by forcing the eyes to remain focused on a point. The visual system detects edges via saccades, movement or both, and fills in the remainder via a combination of detection and heuristic recognition. The process description and references are in Karl Pribram's book "Brain and Perception" (the same book erroneously blamed for the "holography" ridiculousity). We used a similar technique on rats in his lab to negate visual input while measuring whisker input, the bottom line of which was to show the calculation process in both to be very similar.
The old SciAm article others mention was probably "What The Frog's Eye Tells The Frog's Brain", which describes that the frog detects motion by remaining still so that the visual field blanks, and waiting for motion to cross the visual field and so become visible. If the visual system was always detecting everything, it would run slower and the frog would be less able to react quickly and snatch the flying insect out of the air with its tongue.
The article summary is wrong in that saccades have been understood for years. TFA is a novel contribution in the sense that it describes the process of illusory motion. Yet this is not entirely novel since it is a variation of the spinning room illusion familiar to anyone who's tried to lay down after too much to drink, as well as the 'waterfall illusion' wherein things appear to be moving upward after having watched a waterfall for some time.
But the "maintaining a coherent image" stuff? 50 years old. Karl took the curare trip himself in the 50s. Luckily he had the foresight to use a ventilator also. Curare paralyzes the diaphragm as well.
"I may be synthetic, but I'm not stupid." -- Bishop 341-B
Actually, all that means is you read the inaccurate summary too well and didn't read the actual article carefully enough. (What's new here has nothing to do with anything you just said, and is not something anyone knew about back in 1983.)
What's new here has absolutely nothing to do with the fact that these movements occur, nor anything to do with their purpose, which has also been well understood for decades. What's new here is the pinpointing (or at least narrowing down) of the mechanism (or at least the area of the brain) that generates and controls these movements, and it's not where a lot of people thought it was.
I doubt a 7th grade class on the subject would have even touched on these details. Do you remember them discussing the various brain regions involved in the different parts of visual perception?
"Convictions are more dangerous enemies of truth than lies."
I focused on the dot without issue, but when the blue circle disappeared I found it harder to focus on the dot. Does anybody else experience this?
I had assumed that type of eye movement allowed the brain to apply a super-resolution filter. Since the eye has a limited number of rods and cones and the eyes lens isn't perfect, it would allow the brain take multiple images and average to get a more detailed image. http://en.wikipedia.org/wiki/Super-resolution
Though knowing what part of the brain is responsible for this feat is a great revelation, it has been known that eye movement helps us to filter the noise and false images generated by our all too imperfect visual system.
With movement our brain tests repeatedly our rods and cones to verify that what they see is actually in front of us and not due to various things like the blood flowing through our retina, or the attenuation of a single or group of rods or cones with respect to others. After such eye movements, if a rod or cone still registers the same value then the brain can filter it out as not being real, or at least part of a smooth blank space (which probably gets ignored as well).
I am wondering if this can be applied to modern cameras, which seem to have problems with image noise. Instead of employing small sensor movements to reduce camera shake, perhaps they could be used to move the sensor in a predetermined path, one in which the final image could be calculated from. It would seem that if such a calculation of the resultant image could be done, then a much better image could be the result.
That' anomaly of vision is exploited in the above painting.
Without looking at the paper in detail (things to do today, I'm afraid) I'd have to agree that this doesn't sound like anything new. I worked in video compression about, oh, ten years ago, and I remember it being explained to me as already fairly well established that:
1. The eye makes tiny, constant movements referred to as "tremor".
2. While the iris reacts to total constant light levels over time, the rods, cones, and optic nerve work to transfer transition data, primarily, to the visual cortex-- like other nerve activity, steady-state levels are of lesser importance than transitions, and seem to be processed slower.
3. If a sharp edge or feature is focused on the retina, tremor will cause rods and cones to move onto and off of that edge or feature, causing a sort of pulse train for the optic nerve and visual cortex.
4. This seems to account for things like conflicting results when early graphics researchers were trying to figure out the minimum acceptable frame rate for a flight simulator: We detect motion of edges and large objects at extremely high rates (I have heard 120-160 frames/sec equivalents), color (at all) at lower rates, texture features at even lower rates, and so on. This is why 24 frames per second can be either adequate or jarring, depending on what's in the scene and how things are moving.
One thing to share for sure, though: the physiology and related science of visual perception is absolutely, positively fascinating. Utterly rewarding stuff to read about-- you'll see it everywhere, once you learn some. Anybody the least bit interested in optics or graphics-- programmers, photographers, and videographers, sure, but even gamers-- should get a kick out of studying perception.