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New Horizons II (1 Viewer)
- Thread starter Omid
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Sterngucker
Well-known member
LOL ... easier said than done with this out-of-print volume. But I shall see what I can find.
PS. Found it.
elkcub
Silicon Valley, California
This book chapter, composed by experimental psychologist James J. Gibson in the early 1970s, summarized his later views about "direct visual perception" and clarifies/corrects some of his earlier writings. One may or may not agree with him, but his arguments are very well founded, beautifully expressed, and at the same time quite entertaining. 
There's a reason why he was a member of the US National Academy of Sciences.
Ed
There's a reason why he was a member of the US National Academy of Sciences.
Ed
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Sterngucker
Well-known member
2002 Nöe, A. & Thompson, E. (eds) - Vision and Mind: Selected Readings in the Philosophy of Perception, chpt. 5This book chapter, composed by experimental psychologist James J. Gibson in the early 1970s, summarized his later views about "direct visual perception" and clarifies/corrects some of his earlier writings. One may or may not agree with him, but his arguments are very well founded, beautifully expressed, and at the same time quite entertaining.
There's a reason why he was a member of the US National Academy of Sciences.
Ed
Omid
Well-known member
The Structure, Function and Evolution of Human Retina
Here is an interesting lecture by Prof. Trevor Lamb (Australian National University) on the structure, function and evolution of the retina:
Some notable moments from the video: At 4:12 he explains that the retina is actually inside-out meaning that light has to pass through the entire thickness of the retina before reaching the photoreceptor cells. This is what I described in post #239 above. At 19:50 he mentions that retina is part of the brain. This is a very interesting and deep fact: retina does not send raw "image pixel" information to the brain, it is part of the brain. Several key visual processing functions are performed at the retina.
Most remarkably, Prof. Lamb explains (starting at 21:20 in the video) that cones are the primordial visual receptors. Cone receptors have been with us from the beginning while rods (which mediate scotopic surround vision as I explained in a previous post) were added later in the course of evolution. This fact has profound implications on who we are as species: Our ancestors must have been day-time hunters (a relatively rare thing in the animal kingdom. Most other large predators are nocturnal hunters). The ability to see our surroundings has been added later so our ancestors could walk or seek shelter at night.
Such a remarkable scientific lecture has gained only 2000 views in 10 years! Were it about a third-rate teenage celebrity showing off her new tattoo, it would have got 2 million views in 10 days
Here is an interesting lecture by Prof. Trevor Lamb (Australian National University) on the structure, function and evolution of the retina:
Some notable moments from the video: At 4:12 he explains that the retina is actually inside-out meaning that light has to pass through the entire thickness of the retina before reaching the photoreceptor cells. This is what I described in post #239 above. At 19:50 he mentions that retina is part of the brain. This is a very interesting and deep fact: retina does not send raw "image pixel" information to the brain, it is part of the brain. Several key visual processing functions are performed at the retina.
Most remarkably, Prof. Lamb explains (starting at 21:20 in the video) that cones are the primordial visual receptors. Cone receptors have been with us from the beginning while rods (which mediate scotopic surround vision as I explained in a previous post) were added later in the course of evolution. This fact has profound implications on who we are as species: Our ancestors must have been day-time hunters (a relatively rare thing in the animal kingdom. Most other large predators are nocturnal hunters). The ability to see our surroundings has been added later so our ancestors could walk or seek shelter at night.
Such a remarkable scientific lecture has gained only 2000 views in 10 years! Were it about a third-rate teenage celebrity showing off her new tattoo, it would have got 2 million views in 10 days
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Sterngucker
Well-known member
What if that is actually to protect the highly sensitive photoreceptor cells from too much light. Maybe Mother Nature discovered the negative side of sunlight (UV-A/B) long before it entered current discourse on skin cancer etc.
Ahhh ... free humans exercising their rights on an intellectual basis too. Trump/Johnson voters have to be bred somewhere.Such a remarkable scientific lecture has got only 2000 views in 10 years! Were it about a 3rd rate teenage celebrity showing off her new tattoo, it would have got 2 million views in 10 days
tenex
reality-based
Then why would they have needed to be so sensitive? What I learned from the Lamb video is that photoreceptors consume lots of energy, because they maintain an internal current all the time and detect light by interruptions that temporarily shut it down. "They're the most energy-intensive tissue in the body." So maybe they need to be at the back of the retina, close to blood vessels?
"Unconscious inference" does seem to suggest a kind of processing that Gibson thinks isn't there... but how would he know? Where's the evidence? Whatever is going on, it certainly requires lots of learning in infancy.
But I really think some kind of shallow game is being played here with words like "image", because of course we form an image or model of our environment. Gibson (in the chapter Ed just posted) just calls it something like "surface layout" instead, reserving the word "image" for something two-dimensional that would require further interpretation.
What sort of science is psychology, if one can make an entire career out of the suggestion that the eye may not merely transmit an image to the brain, using arguments of this quality (p.89):
"Direct perception of a retinal image implies an eye inside the head, in the brain, with which to look at the image. But there is no little man anywhere in the brain who can do this."
Not only is this a ridiculous straw-man argument, it's what science (or rather "natural philosophy") sounded like centuries ago, in the day of Descartes and his critics. We've moved on since then.
I agree, but it wasn't Gibson or psychologists who established this.
This is completely absurd. Except owls, all the large predators that come immediately to my mind are daytime hunters. Many vertebrates aren't predators at all. Even primates generally aren't, and until quite recently (evolutionarily speaking) neither were "we".
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Sterngucker
Well-known member
They would need to be so sensitive in order to be highly functional in VISIBLE light. However, burns from UV light are not conducive to sharp vision.
Sorry about my typo.
I will look at Prof.Lamb's video.
From my point of view, my eyes are as they are.
I have tried to protect them as best as I can.
I am not really concerned as to how they got to where they are.
Mainly, I am an observer and have tried to develop methods to improve my visual performance.
We have developed ways of vastly improving our sight without re-inventing our eyes.
Firstly, eye glasses from about the year 1200, possibly earlier.
Then telescopes from the 1500s about.
Now we have image intensifiers, thermal imagers, digital imagers, stacking tens of thousands of video images etc.
A 14 inch telescope now equals the Palomar 200 inch telescope in the 1950s.
Vision is highly complex and different researchers approach the subject differently.
The are probably all correct, and also all incorrect at the same time.
Persons right at the cutting edge quite readily admit to me that they know very little about the subject.
It is fine to discuss the subject at length, but don't expect any definite conclusions that will actually turn out to be incorrect a hundred years from now.
Happy New Year to everyone.
Stay safe.
Regards,
B.
From my point of view, my eyes are as they are.
I have tried to protect them as best as I can.
I am not really concerned as to how they got to where they are.
Mainly, I am an observer and have tried to develop methods to improve my visual performance.
We have developed ways of vastly improving our sight without re-inventing our eyes.
Firstly, eye glasses from about the year 1200, possibly earlier.
Then telescopes from the 1500s about.
Now we have image intensifiers, thermal imagers, digital imagers, stacking tens of thousands of video images etc.
A 14 inch telescope now equals the Palomar 200 inch telescope in the 1950s.
Vision is highly complex and different researchers approach the subject differently.
The are probably all correct, and also all incorrect at the same time.
Persons right at the cutting edge quite readily admit to me that they know very little about the subject.
It is fine to discuss the subject at length, but don't expect any definite conclusions that will actually turn out to be incorrect a hundred years from now.
Happy New Year to everyone.
Stay safe.
Regards,
B.
elkcub
Silicon Valley, California
elkcub
Silicon Valley, California
Omid
Well-known member
Human vision is nearly entirely mediated by cones
Here is a paper by Prof. T Lamb which describes the difference between cone vision and rod vision in human eye. As the paper clearly explains, our functional vision is almost always mediated by cones. Rods activate under extreme low light to provide situational awareness which is crucial for stabilizing our upright body posture and self-orientation as we walk about in nature. This is done mostly unconsciously using information from peripheral regions of out field of view.
When we look at something (i.e. pay attention consciously), our vision is mediated by a small central part of the retina called the fovea which is populated entirely by cones. That's why we are functionally blind at night although we can still see our surroundings. Scotopic vision has nothing to do with focused frontal vision.
Here is a paper by Prof. T Lamb which describes the difference between cone vision and rod vision in human eye. As the paper clearly explains, our functional vision is almost always mediated by cones. Rods activate under extreme low light to provide situational awareness which is crucial for stabilizing our upright body posture and self-orientation as we walk about in nature. This is done mostly unconsciously using information from peripheral regions of out field of view.
When we look at something (i.e. pay attention consciously), our vision is mediated by a small central part of the retina called the fovea which is populated entirely by cones. That's why we are functionally blind at night although we can still see our surroundings. Scotopic vision has nothing to do with focused frontal vision.
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elkcub
Silicon Valley, California
The fascinating 2015 Lamb article that Omid posted (#254) goes a long way to explain the evolutionary development of our visual system, which according to him began ~ 500 Mya. This greatly predated the evolution of mammals that the Nature article referred to, which was ~ 66 Mya.
What does your anger about the imputed destructiveness of sapiens have to do with the subject of this thread?
Ed
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tenex
reality-based
What the general tone and quality of this discussion has suggested to me for some time now is that it is not really about science at all. Shall we inquire what is going on instead? Let's consider a little thought experiment.
If relativity (for example) had been mentioned and someone said they didn't really see the point, I would start explaining and illustrating the theory and what it means, how certain experimental results had created nagging problems for classical physics, how new observations have since continued to confirm the theory, and answering any specific questions, and so on. And we would have fun doing it, because it's elegant and beautiful, and our ability to discover and understand it is also beautiful. And one can get a good sense of all this (and why one doesn't simply "agree or disagree" with Einstein) even without understanding every detail of the math, which I have to say is a good deal more difficult than anything we're encountering here.
If instead I started making cryptic remarks like "there's a reason why Einstein was a member of the academy of sciences", and talking about how "entertaining" relativity is, and kept posting papers (half a century old!) that said pretty much the same thing as the last ones, and telling you to "take your time" learning to appreciate them, and tossing out random bits of information of dubious relevance, and repeating myself instead of answering direct questions... the result would be less pretty, and you might start wondering what was wrong with me. And if you encountered a second person in the same thread doing the same thing, you might begin to have the same suspicion not only of them too but perhaps of Einstein as well, and theoretical physics as a field, that it must be some sort of pseudoscientific, even obscurantist, cult. Except that doesn't happen, does it.
So if anything significant has actually come of Gibson's "ecological optics" in recent years, now would be a really good time to mention it and demonstrate your understanding of and ability to explain it.
If relativity (for example) had been mentioned and someone said they didn't really see the point, I would start explaining and illustrating the theory and what it means, how certain experimental results had created nagging problems for classical physics, how new observations have since continued to confirm the theory, and answering any specific questions, and so on. And we would have fun doing it, because it's elegant and beautiful, and our ability to discover and understand it is also beautiful. And one can get a good sense of all this (and why one doesn't simply "agree or disagree" with Einstein) even without understanding every detail of the math, which I have to say is a good deal more difficult than anything we're encountering here.
If instead I started making cryptic remarks like "there's a reason why Einstein was a member of the academy of sciences", and talking about how "entertaining" relativity is, and kept posting papers (half a century old!) that said pretty much the same thing as the last ones, and telling you to "take your time" learning to appreciate them, and tossing out random bits of information of dubious relevance, and repeating myself instead of answering direct questions... the result would be less pretty, and you might start wondering what was wrong with me. And if you encountered a second person in the same thread doing the same thing, you might begin to have the same suspicion not only of them too but perhaps of Einstein as well, and theoretical physics as a field, that it must be some sort of pseudoscientific, even obscurantist, cult. Except that doesn't happen, does it.
So if anything significant has actually come of Gibson's "ecological optics" in recent years, now would be a really good time to mention it and demonstrate your understanding of and ability to explain it.
elkcub
Silicon Valley, California
tenex, re post 257
On post #244 I attached a 13 pg. document entitled "A Theory of Direct Visual Perception," written by James Gibson. In it the author clearly and poinedly articulates the elements of his theory and how it differs in fundamental ways from standard reductionist thinking on the subject.
It's up to you to read and understand the document, it's not up to me or the OP to explain it to you, or to defend its scientific merit. If you don't see its applicability to the perceptions we have looking through binoculars, so be it. However, Julian Hochberg's obituary on post #252 well documents Gibson's eternal standing in the annals of scientific thought about human perception.
Any of this, of course, is perfectly open to query, discussion or disagreement, but you have chosen to spend your time attacking the OP and me for reasons that only you can understand. I for one won't be reading any more of your diatribes.
Ed
On post #244 I attached a 13 pg. document entitled "A Theory of Direct Visual Perception," written by James Gibson. In it the author clearly and poinedly articulates the elements of his theory and how it differs in fundamental ways from standard reductionist thinking on the subject.
It's up to you to read and understand the document, it's not up to me or the OP to explain it to you, or to defend its scientific merit. If you don't see its applicability to the perceptions we have looking through binoculars, so be it. However, Julian Hochberg's obituary on post #252 well documents Gibson's eternal standing in the annals of scientific thought about human perception.
Any of this, of course, is perfectly open to query, discussion or disagreement, but you have chosen to spend your time attacking the OP and me for reasons that only you can understand. I for one won't be reading any more of your diatribes.
Ed
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Omid
Well-known member
Human Vision vs Camera - Part I
The human eye is often compared to a camera and its performance is often described in photographic terms such as image resolution, modulation transfer function (MTF), depth of field, etc. Based on this view, it would have been ideal if out eyes possessed a lens as sharp as a Leica M-series lens and a retina as good as Fuji Velvia 50 film.
However, the human visual system functions in a manner which is more analogous to a Leica laser scanner than a Leica camera! A laser scanner such as the one shown below forms a 3-D model of the environment not by capturing an "image" but by conducting a series of laser scans that leads to a "point cloud" model of the environment. The human visual system does something very similar: the eye gaze seldom remains stationary or fixated at a point; it constantly moves around and looks at points of interest in the environment. The brain then forms a stable mental "3D CAD Model" of the environment from fragmented eye scans. The environment is perceived sequentially as in a Leica scanner not in one shot as in a Leica camera.
The human eye/brain is very remarkable in that it synthesizes a "stable", "constant" and "panoramic" perception of the environment from "highly variable", shaky" and "limited FOV" stream of retinal sensations. As we walk around, retinal images change drastically due to eye, head and body movements but our perception of the environment remains stable.
Look at a person as he walks towards you from a distance of 2m: does he look twice as tall when he gets to 1m distance? This phenomenon is known as "Size Constancy" in perception. Similarly, there is "color constancy" and "shape constancy". A camera image does not have size constancy: The image size changes proportional to the object distance (and based on the lens focal length).
In a camera image, certain objects or areas are recorded out of focus. In the perceived world constructed sequentially by the human visual system, everything is always in focus.
The human eye is often compared to a camera and its performance is often described in photographic terms such as image resolution, modulation transfer function (MTF), depth of field, etc. Based on this view, it would have been ideal if out eyes possessed a lens as sharp as a Leica M-series lens and a retina as good as Fuji Velvia 50 film.
However, the human visual system functions in a manner which is more analogous to a Leica laser scanner than a Leica camera! A laser scanner such as the one shown below forms a 3-D model of the environment not by capturing an "image" but by conducting a series of laser scans that leads to a "point cloud" model of the environment. The human visual system does something very similar: the eye gaze seldom remains stationary or fixated at a point; it constantly moves around and looks at points of interest in the environment. The brain then forms a stable mental "3D CAD Model" of the environment from fragmented eye scans. The environment is perceived sequentially as in a Leica scanner not in one shot as in a Leica camera.
The human eye/brain is very remarkable in that it synthesizes a "stable", "constant" and "panoramic" perception of the environment from "highly variable", shaky" and "limited FOV" stream of retinal sensations. As we walk around, retinal images change drastically due to eye, head and body movements but our perception of the environment remains stable.
Look at a person as he walks towards you from a distance of 2m: does he look twice as tall when he gets to 1m distance? This phenomenon is known as "Size Constancy" in perception. Similarly, there is "color constancy" and "shape constancy". A camera image does not have size constancy: The image size changes proportional to the object distance (and based on the lens focal length).
In a camera image, certain objects or areas are recorded out of focus. In the perceived world constructed sequentially by the human visual system, everything is always in focus.
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I don't like personal unspecific sweeping attacks on Omid. Objective special criticism is perfectly fine. One compares the quality of the contributions of Omid with the alpha animals and writing maniacs often with opinions without for third comprehensible reasons, facts and experiences in posts.
The republication of older scientific contributions I find okay, how much money do modern professional textbooks cost? As a layman, I also only remember the big picture. If I read something several times, it stays in my memory and the probability increases that I have memorized the right thing. A professional discussion about newer findings in detailed questions is okay and highly interesting.
And hardly any scientist has no mistakes in his publications and new theories and findings. That's what peer reviews by other scientists are for. I ask to keep the discussion impersonal and purely technical. I would find it very sad if Omid would be scared away from the forum. So what, he is subject to an error. Friendly and factual hints are enough, an interesting discussion will arise. A factual discussion among scientists is the usual way of working, see peer reviews and other scientific methods.
en.wikipedia.org
An understandable and instructive thread by tenex on relativity theory would be interesting. I would be happy to read along.
A little suggestion to Omid, who invents: I would like to have a focus that is speed switchable. Minox already had something there, different mechanical transmission (focus speed) in the near and far range. I would like 2 speed levels manually selectable by me. My car has 6 automated gears in its transmission, "alpha bins" (or better high end binoculars) costs a lot and have complicated therefore fault prone focus system with combination of focus and dioptric compensation. Every cheap small car has manual selectable 4 forward gears and 1 reverse gear.
And I would like to have lS bins (10x30...32) with a mass of ~ 600 gramms with significant larger FoV as today on the market. My day dreams of bins.
The republication of older scientific contributions I find okay, how much money do modern professional textbooks cost? As a layman, I also only remember the big picture. If I read something several times, it stays in my memory and the probability increases that I have memorized the right thing. A professional discussion about newer findings in detailed questions is okay and highly interesting.
And hardly any scientist has no mistakes in his publications and new theories and findings. That's what peer reviews by other scientists are for. I ask to keep the discussion impersonal and purely technical. I would find it very sad if Omid would be scared away from the forum. So what, he is subject to an error. Friendly and factual hints are enough, an interesting discussion will arise. A factual discussion among scientists is the usual way of working, see peer reviews and other scientific methods.
Scientific method - Wikipedia
An understandable and instructive thread by tenex on relativity theory would be interesting. I would be happy to read along.
A little suggestion to Omid, who invents: I would like to have a focus that is speed switchable. Minox already had something there, different mechanical transmission (focus speed) in the near and far range. I would like 2 speed levels manually selectable by me. My car has 6 automated gears in its transmission, "alpha bins" (or better high end binoculars) costs a lot and have complicated therefore fault prone focus system with combination of focus and dioptric compensation. Every cheap small car has manual selectable 4 forward gears and 1 reverse gear.
And I would like to have lS bins (10x30...32) with a mass of ~ 600 gramms with significant larger FoV as today on the market. My day dreams of bins.
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