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Medical Forum / General / Vision / May 2008Computer displays that correct vision possible?
Imagine using a laptop without having to wear corrective eyeglasses. I know that 3D displays exist that don't require special glasses. So maybe this is possible as well? Amir > Imagine using a laptop without having to wear corrective > eyeglasses. [quoted text clipped - 4 lines] > > Amir What sort of 3D displays do you mean? Like, holographic technology? I was looking at holographic technology on the net so it's already been made but it still needs to be developed and refined and stuff until it can enter the mainstream market. So probably there is a long way to go. Right now the coolest thing out is OLED, organic light emitting diode. Have you heard of that? It's so thin! I want to buy a TV built with that but they are really expensive. Totally next gen though! Imagine just sticking it to the wall like you would with any poster or painting. Except... it moves! Kind of like the pictures in Harry Potter. > Imagine using a laptop without having to wear corrective > eyeglasses. Quite impossible. Since laptops were invented by people who need both corrective eyeglasses and corrective batteries. > I know that 3D displays exist that don't require special glasses. > > So maybe this is possible as well? > > Amir On 3 May, 15:01, "zzbun...@netscape.net" <zzbun...@netscape.net> wrote: > > Imagine using a laptop without having to wear corrective > > eyeglasses. > > Quite impossible. Since laptops were invented by > people who need both corrective eyeglasses and > corrective batteries. Well, owing to the amount of minute electronics and silicon chips and what not that go into a laptop and are needed to be handled with extreme and fine care, I quite doubt that the people who invented them would wear corrective lenses. It's more likely that they have very good eyesight indeed. > On 3 May, 15:01, "zzbun...@netscape.net" <zzbun...@netscape.net> > wrote: [quoted text clipped - 13 lines] > would wear corrective lenses. It's more likely that they have very > good eyesight indeed. Well, just about everybody with good eyes starts that way with computers. Until you start running into 16-hour eye strain and jerks with lasers and tickets to the Met. Which is why the people who understand computer networks invented robots, mini-cams, ipods, USB, gps, PV cells, fiber optics, Optical Computers, 7-11, internet, backspin, realprint, and Cruise Missiles for the tax-em-til-they-drop Fascist cranks. > Imagine using a laptop without having to wear corrective > eyeglasses. [quoted text clipped - 4 lines] > > Amir I don't think so... People who need glasses don't have a problem seeing things at the wrong distance - so correcting the apparent distance using a 3D effect doesn't help. On May 3, 9:59 am, "CWatters" <colin.watt...@NOturnersoakSPAM.plus.com> wrote: > "Amir Michail" <amich...@gmail.com> wrote in message > [quoted text clipped - 12 lines] > things at the wrong distance - so correcting the apparent distance using a > 3D effect doesn't help. Beg pardon? I am "nearsighted". Guess what the term means. Mark L. Fergerson On 5 May, 04:10, "n...@bid.nes" <Alien8...@gmail.com> wrote: > On May 3, 9:59 am, "CWatters" > [quoted text clipped - 19 lines] > > Mark L. Fergerson "Near-sighted" refers to the ocular defect where there is trouble in distance viewing, however I think what the earlier poster was pointing out is that having a 3D model would be no different than the normal flat screen, "2D screen" that we have of today. For example, using a 3D model to mitigate the effect of distance bluriness would be no more effective than simply bringing one's face closer to the conventional type screen in order to see objects clearly. The thing I am curious about here though is precisely what kind of 3D technology the original poster was hypothesizing should be utilized for this idea? In sci.physics Zetsu <absolutelyinvincible@hotmail.com> wrote: > On 5 May, 04:10, "n...@bid.nes" <Alien8...@gmail.com> wrote: > > On May 3, 9:59 am, "CWatters" [quoted text clipped - 20 lines] > > > > Mark L. Fergerson > "Near-sighted" refers to the ocular defect where there is trouble in > distance viewing, however I think what the earlier poster was pointing [quoted text clipped - 5 lines] > about here though is precisely what kind of 3D technology the original > poster was hypothesizing should be utilized for this idea? Vision problems are a result of the eye's lens being unable to focus an image on the retina. There is nothing that can be done about that other than to put a corrective lens (called glasses) in the system. Arm waving about "apparent distance" is babble unless there is a separate lens involved.  SignatureJim Pennino Remove .spam.sux to reply. On May 5, 9:05 am, j...@specsol.spam.sux.com wrote: > In sci.physics Zetsu <absolutelyinvinci...@hotmail.com> wrote: > [quoted text clipped - 34 lines] > Vision problems are a result of the eye's lens being unable to focus > an image on the retina. Correct. I was sorely confused at C. Watters' phrasing: "People who need glasses don't have a problem seeing things at the wrong distance". > There is nothing that can be done about that other than to put a > corrective lens (called glasses) in the system. > > Arm waving about "apparent distance" is babble unless there is a > separate lens involved. I'm not entirely sure of that re: holography. As far as other so- called 3D display technologies (polarization, blink, etc.) are concerned I agree with you completely. However I know of no a priori reason a hologram cannot produce an image that my unaided eyes could see clearly (at a distance beyond my unaided maximum sharp focus distance) but "normal" eyes would see as blurred at the same distance. Not that I know that much about holograms (IOW I'm speaking from ignorance above). So, any holography experts available? A quick Google yields nothing relevant. Mark L. Fergerson In sci.physics nuny@bid.nes <Alien8752@gmail.com> wrote: > On May 5, 9:05 am, j...@specsol.spam.sux.com wrote: > > In sci.physics Zetsu <absolutelyinvinci...@hotmail.com> wrote: [quoted text clipped - 35 lines] > > Vision problems are a result of the eye's lens being unable to focus > > an image on the retina. > Correct. I was sorely confused at C. Watters' phrasing: "People who > need glasses don't have a problem seeing > things at the wrong distance". > > There is nothing that can be done about that other than to put a > > corrective lens (called glasses) in the system. > > > > Arm waving about "apparent distance" is babble unless there is a > > separate lens involved. > I'm not entirely sure of that re: holography. As far as other so- > called 3D display technologies (polarization, blink, etc.) are > concerned I agree with you completely. However I know of no a priori > reason a hologram cannot produce an image that my unaided eyes could > see clearly (at a distance beyond my unaided maximum sharp focus > distance) but "normal" eyes would see as blurred at the same distance. How about basic optics as a good reason? SignatureJim Pennino Remove .spam.sux to reply. <Snipola> >> an image on the retina. <Snipola> > I'm not entirely sure of that re: holography. I have no experience making holograms, and as such, I don't see why making a hologram "out of focus" in such a way that requires a lens to view that is equal to one's prescription wouldn't work. Actually, I think if you shot the image through your glasses would work. But as I said, I've never made a holo. Brian Signaturehttp://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism Seismic FAQ: http://www.skywise711.com/SeismicFAQ/SeismicFAQ.html Quake "predictions": http://www.skywise711.com/quakes/EQDB/index.html Sed quis custodiet ipsos Custodes? In sci.physics Skywise <into@oblivion.nothing.com> wrote: > <Snipola> > >> an image on the retina. > <Snipola> > > I'm not entirely sure of that re: holography. > I have no experience making holograms, and as such, I don't see > why making a hologram "out of focus" in such a way that requires > a lens to view that is equal to one's prescription wouldn't work. > Actually, I think if you shot the image through your glasses > would work. Neither will work. Visualize a spot just big enough to see. If the eye doesn't focus properly, the spot image spreads into a fuzzy ball on the retina. Spreading the original spot just makes the fuzzy ball image on the retina bigger. You can't make the spot smaller than just big enough to see. The ONLY way to bring the spot into focus is with another lens. This is basic optics. SignatureJim Pennino Remove .spam.sux to reply. > <Snipola> > >> an image on the retina. [quoted text clipped - 5 lines] > why making a hologram "out of focus" in such a way that requires > a lens to view that is equal to one's prescription wouldn't work. I do, and what you propose is simply impossible. There is no way to produce a hologram that is "out of focus". If you see an real object at arms length as fuzzy, you will see a hologram of that same object as fuzzy also. > Actually, I think if you shot the image through your glasses > would work. You normally don't shoot a hologram through a lens, and if you did, you end up with a hologram of a lens. The hologram of the lens would work just like the original, for other objects captured by the hologram. So, you could make a hologram of your eyeglasses in front of a book, and be able to read the book through the eyeglasses. However, someone with better vision would simply see the image as distorted by the lens, but not out of focus. And, it being a holgram, they could simply change their viewing angle and read the book over the eyeglasses. --Gene > In article <KHPTj.41565$2Y1.13...@newsfe30.ams2>, > i...@oblivion.nothing.com says... [quoted text clipped - 13 lines] > > I do, Ah, good, someone who knows what they're talking about (as opposed to say, me). > and what you propose is simply impossible. There is no way to > produce a hologram that is "out of focus". If you see an real object at > arms length as fuzzy, you will see a hologram of that same object as > fuzzy also. Well yes, but that's not quite what I meant. > > Actually, I think if you shot the image through your glasses > > would work. > > You normally don't shoot a hologram through a lens, and if you did, you > end up with a hologram of a lens. The hologram of the lens would work > just like the original, for other objects captured by the hologram. I have read about holographic lenses (probably yet another subject) but have not had the opportunity to play with any. > So, you could make a hologram of your eyeglasses in front of a book, and > be able to read the book through the eyeglasses. However, someone with > better vision would simply see the image as distorted by the lens, but > not out of focus. And, it being a holgram, they could simply change > their viewing angle and read the book over the eyeglasses. Now we're sneaking up on what I had in mind. Is it possible to frame the hologram so that the eyeglass lens frame is out of the hologram frame; IOW you cannot tell by inspection that it was shot through the lens of my glasses- there is no available viewing angle that does not "see through" the lens? With an ordinary camera one would simply put the eyeglass lens up next to the camera lens but that probably won't work with holography. (Come to think of it one would use the converse of my prescription, yes/no? Did I mention this is way outside my area of expertise?) Also, what sort of distortion do you mean? When I hold my glasses away from my face and look through them, objects appear smaller than usual just like the infamous warning sticker on car mirrors (I am nearsighted) but not blurred at all until the lenses are about six inches away from my eyes which conveniently is about where I can barely begin to focus on the lenses themselves. Would there not be a range of viewing distances where I would, without my glasses, be better able to view the hologram than a person with normal vision viewing it at the same distance? Mark L. Fergerson On May 5, 3:23 pm, "n...@bid.nes" <Alien8...@gmail.com> wrote: > I'm not entirely sure of that re: holography. Oh, yes, holography would work, but I presume the OP isn't asking about technologies that don't yet exist; he is asking if the fact that certain types of 3D displays *already* exist would lead to something that would work, which is not the case. John Savard > On May 3, 9:59 am, "CWatters" > <colin.watt...@NOturnersoakSPAM.plus.com> wrote: [quoted text clipped - 19 lines] > > Mark L. Fergerson Nope. It means you have a problem focusing on distant objects. It doesn't mean obects appear to you to be at the wrong distance. Important difference. Holograms are all about reproducing an effect caused by stereoscopic vision - which needs two eyes. They make parts of the image appear nearer or further away by presenting each eye with a different image. If you only have one eye you can't see the 3D effect. Aside: If you only have one ey you can see _a_ 3D effect if you move your head or the hologram but that's a different 3D effect. In that case you are seeing something more akin to a sequence of 2D images. > Holograms are all about reproducing an effect caused by stereoscopic > vision - which needs two eyes. They make parts of the image appear nearer or > further away by presenting each eye with a different image. If you only have > one eye you can't see the 3D effect. Perhaps a bit nit-picky, but holograms aren't a "stereoscopic effect" in the sense that you purposely send two different images to each eye. Holograms reproduce the original wavefront that came from the object that the hologram was made from. If you have one eye, theoreticially you will still perceive similar depth in the hologram as you would viewing a real scene with one eye. Obviously with 2 eyes you have greater depth perception and the depth observed in the hologram will appear accordingly. In regards to the topic of trying to create a hologram that is "out of focus" for normal viewing but in focus for an uncorrected nearsighted person for example, this is only possible if you know ahead of time the distortion that your eye adds to the wavefront entering the eye and then somehow perturbing the hologram to create a distorted wavefront that when passed through the nearsighted eye creates the proper wavefront at the eye. I know of no mechanism available during the recording of a hologram that would be able to create such a distortion. It is probably feasible to calculate and then create a computer generated hologram that would distort the wavefront coming from a monitor such that when it entered your uncorrected eye the image appeared focus. I think a practical problem is that you would lose a significant amount of brightness because hologram diffraction efficiencies are usually low (meaning a lot of light will get thrown out of the "main beam" and not enter your eye). It also may only work over a small angle, meaning it would only appear in focus straight on and a few degrees to the left/right of straight on. | > Holograms are all about reproducing an effect caused by stereoscopic | > vision - which needs two eyes. They make parts of the image appear nearer or [quoted text clipped - 29 lines] | over a small angle, meaning it would only appear in focus straight on | and a few degrees to the left/right of straight on. It is changes in the small angle that leads to the mental perception of depth or "3D". In this image changing the point of view with just one eye is insufficient to detect 3D, simply because it is a photograph but it is sufficient for the real thing. http://hyperphysics.phy-astr.gsu.edu/hbase/geoopt/optpic/brokpen.jpg Also, because we cannot detect any 3D in the image, we conclude it is 2D and say words like "obviously". Stereoscopy has little to do with it. People will sit and stare for hours at a moving picture, a still image they only glance at. And not just people either, my cat will chase the red dot from my laser pointer for as long as I move it. Movement is the key. >> Holograms are all about reproducing an effect caused by stereoscopic >> vision - which needs two eyes. They make parts of the image appear nearer [quoted text clipped - 11 lines] > you have greater depth perception and the depth observed in the > hologram will appear accordingly. Agreed. > > Holograms are all about reproducing an effect caused by stereoscopic > > vision - which needs two eyes. They make parts of the image appear nearer or [quoted text clipped - 19 lines] > the recording of a hologram that would be able to create such a > distortion. That's why I suggested shooting a hologram through one of my eyeglass lenses (or its prescription's dual); the lens "encodes" exactly the relevant distortion, yes? > It is probably feasible to calculate and then create a computer > generated hologram that would distort the wavefront coming from a [quoted text clipped - 5 lines] > over a small angle, meaning it would only appear in focus straight on > and a few degrees to the left/right of straight on. One of the other posters suggested the technique might have security uses; just take off your glasses and you're the only one who can read what's on your monitor. The added angular limitations you describe would be a feature, not a bug. Mark L. Fergerson > That's why I suggested shooting a hologram through one of my > eyeglass lenses (or its prescription's dual); the lens "encodes" > exactly the relevant distortion, yes? But then viewing the hologram has to be that close to your eye. So you haven't achieved the goal of reproducing the wavefront exiting eyeglasses using a distant magical source. On May 9, 8:32 pm, "n...@bid.nes" <Alien8...@gmail.com> wrote: > That's why I suggested shooting a hologram through one of my > eyeglass lenses (or its prescription's dual); the lens "encodes" > exactly the relevant distortion, yes? No. You cannot change the reconstructed wavefront to accomodate an aberrated eye. You will create geometrical distortion in the reconstructed image. > You cannot change the reconstructed wavefront to accomodate an > aberrated eye. You will create geometrical distortion in the > reconstructed image. Geometrical distortion is trivial to compensate for. John Savard > > You cannot change the reconstructed wavefront to accomodate an > > aberrated eye. You will create geometrical distortion in the [quoted text clipped - 3 lines] > > John Savard I didn't say it wasn't. In article <f5527a1b-d89b-4767-bcbf-2bc88cadfe33@d1g2000hsg.googlegroups.com>, > Imagine using a laptop without having to wear corrective > eyeglasses. [quoted text clipped - 4 lines] > > Amir Glasses correct for a variety of conditions. So, if what you suggest were possible, your computer would have to be set according to your "prescription." And then it would be wrong for (almost) everyone else. In article <lybanon-76BC9C.14483804052008@earthlink.vsrv- sjc.supernews.net>, lybanon@earthlink.net says... > In article > <f5527a1b-d89b-4767-bcbf-2bc88cadfe33@d1g2000hsg.googlegroups.com>, [quoted text clipped - 11 lines] > were possible, your computer would have to be set according to your > "prescription." And then it would be wrong for (almost) everyone else. ...which, given the nosiness of other people, on planes and in coffee shops, would make it an asset. --Gene > So maybe this is possible as well? No. Corrective lenses must be near, or on (as in contact lenses) the eye. >> So maybe this is possible as well? > > No. Corrective lenses must be near, or on (as in contact lenses) the eye. That's a good point. > > So maybe this is possible as well? > > No. Corrective lenses must be near, or on (as in contact lenses) the eye. Actually, this isn't really an issue with a holographic display, but since holographic displays don't yet exist, the kind of 3D displays which do exist don't imply that any technology would exist that would help. In the case of a holographic display, able to create any arbitrary light wavefront, if the corrective lens has to be within 1 cm of the eye... then the only constraint is that the position of the head with respect to the laptop has to be controlled to a tolerance of 1 cm. Instead of bolting the laptop to one's head, it could even use infrared sensors to monitor the position of one's head! John Savard > Actually, this isn't really an issue with a holographic display, ... The question was whether it could be done with lenses. It's an old and worthwhile question. If eyeglasses make you see properly, then why can't we invert the system and put "object glasses" on things to make us myopes (or whatever your refractive error) see them properly without having to have apparatus on our heads. > > Actually, this isn't really an issue with a holographic display, ... > [quoted text clipped - 4 lines] > make us myopes (or whatever your refractive error) see them properly > without having to have apparatus on our heads. For the same reason that you can't use a hologram of a microscope lens to replace the lens. You can get correct reconstruction only at one field position and one set of conjugates. > For the same reason that you can't use a hologram of a microscope lens > to replace the lens. I don't follow that reasoning. We're postulating refractive optical elements, not holograms. > > Actually, this isn't really an issue with a holographic display, ... > > The question was whether it could be done with lenses. The question was whether it could be done with whatever technology is used to make 3D displays, at least as I understood it. It could not be done, for example, with vertical strips and slots, because that changes which eye an image goes to, not its distance for focusing. Holography is another technique used for 3D displays. Of course lenses could do it, just generate a real image floating in air a few inches from someone's eyes if that person is nearsighted. But a giant thick lens is not comparable to any technology used for 3D displays, so I didn't count the question as being about that as an alternative. John Savard > Of course lenses could do it, just generate a real image floating in > air a few inches from someone's eyes if that person is nearsighted. Of course! A 1X microscope objective with a two-foot aperture. You're a genius! > Imagine using a laptop without having to wear corrective > eyeglasses. > > I know that 3D displays exist that don't require special glasses. > > So maybe this is possible as well? If your eyes don't focus on the laptop surface, then each point of light on that surface is spread out over a larger area. Since the relative phase of light from different parts of that surface can't be controlled, destructive interference can't be created, so one can't put anything on the laptop screen that would be seen as less blurry than an ordinary sharp display; one can only make things worse. John Savard |
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