"They were a double pair of Joo Janta 200 Super-Chromatic Peril Sensitive Sunglasses, which had been specially designed to help people develop a relaxed attitude to danger. At the first hint of trouble they turn totally black and thus prevent you from seeing anything that might alarm you."
- Douglas Adams, The Restaurant at the End of the Universe
Killer-app for wearable-computing? Once a beach-head is secured, can add HUD, games, telephony, movies...
I was concerned that the geometry calculation requires your pupil to be at a precisely known location, but in practice, if it was off, you'd just adjust the sunglasses (and maybe the temples can be made so that you feel their position). You'd calibrate them when you first use them. Of course, the black-spot can be made a little overlarge, for margin of error.
Larry Niven (surely not the only one) mentioned this idea in Grendel (in the Neutron Star collection), a 1968 shortstory, which included [MINOR SPOILER] an update on the old fighter-pilot tactic of attacking out of the sun - which with these sunglasses, is hidden by the black-spot.
I think you'd be surprised what a small variation there would be on pupil location given a mounting point like a nose and a pair of ears. I'm guessing the standard deviation for normal people would be very small, and a fudge factor added to the blackout spot would cover 95% of the population. This could also be also catered for by a range of say, 3 sizes, narrow, wide and normal. George Bush gets a narrow, Uma Thurman gets a wide. It would be a snap to try on each size and work out which one was best.
My comment was mainly about when glasses shift slightly on your face, especially moving down the bridge. For conventional sunglasses, a small change in location has little effect, but for these, even a millimeter could correspond to over 10 pixels (depending on the dpi).
The pane is very close to the eye, so small changes are amplified if lines are extended outward into the scene being viewed.
Actually, to be more accurate, it wouldn't depend on the location of the pupil, but on the center of the eye (because the geometry is that when the eye looks in different directions, it rotates about this center). The pupil moves quite a lot, as you glance left and right.
Yes, you're right. So effectively the black spot is going to be of a sufficient size to create a shaded area over 95% of the area that the pupil is likely to be at any one time.
That's going to be difficult without having internally looking cameras that monitor the pupil.
I don't think that's necessary - when the pupil moves, the whole eyeball rotates, but the light still passes through the center of the eyeball. So we can just that center in our geometry calculations. http://en.wikipedia.org/wiki/Human_eye#Extraocular_muscles
Possibly, we might want to track the pupil size, but it seems reasonable to assume it is always small, since glare is only an issue in bright light. Although, once the glare is hidden, the pupil would dilate slightly, so it's probably best to use that pupil size in the calculations.
If we wanted to cover the whole retina (not just the fovea), we'd need a much bigger blackspot. Actually, the ideal is not to have a sharply delineated spot, but a gradient, corresponding to the sensitivity of retina that it falls upon.
Can the add a feature that will turn the entire field of view black when you are in danger? This would be awesome as I would like a more relaxed attitude to danger.
Sunglasses are cool, but I think with two layers of LCD polarized light you might be able to create an entire window that blocks the sun from reaching anywhere in the room directly.
The first sheet is polarized at 0 degrees and the second sheet is polarized at 90. When both sheets are on the window is black. When you draw a certain tiled pattern on the two sheets though, I hypothesize that you can mostly block the sun from any angle and let most of the ambient light in.
The only way I know how to solve this problem is w/ evolutionary algorithms, which might be well suited. I think someone here might have some mathematical insight into this though, so I'm putting it out there.
-- update --
OK so we need four sheets of LCDs, with each of the window layers having 2 LCD sheets each. Any light that goes through either layer is filtered with some pattern of 0' or 90' pixels.
Any random pattern, as long as the two layers have inverted pixels, will block the sun completely. Ambient light is allowed in at 50% brightness. So there you go.
Two complementary sheets of any black/white Pattern should suffice. With some space between. That would get you 25% of ambient and zero from one specific direction. Make the inside of the outer layer and the outdid of the inner layer reflective and you could approach 37%. Spacing can be very close, but requires a smaller feature size. Regular patterns will cause moire patterns.
This will not "block the sun from any angle". Not unless you make it block all light from any angle. If I'm understanding your proposal, what it will do if it works is to block all light that enters the window perpendicularly (and at certain other angles), whether it comes from the sun or not; but if you happen not to be looking straight at the window, there's no guarantee that the sun will be blocked. And if you are looking straight at the window, you won't see anything.
There's nothing magical about sunlight that will enable you to block it while letting in other light from the same direction. And light from the sun could reach the window at a wide range of different directions.
(If you somehow contrive to have the sun always in the same direction -- say you're in a spaceship and it keeps a consistent orientation relative to the sun -- then this kind of thing could work. Not so feasible here on earth, though.)
I don't think that will work the way you intend. Direct sunlight is (on average) unpolarized. Polarized lenses only block glare off, for example, the surface of a body of water, because reflection affects polarization. (http://en.wikipedia.org/wiki/Specular_reflection). If the design blocks direct sunlight via polarization, it must necessarily block ambient light to a similar degree.
layer 1 polarizes all light in the '+' direction or the '-' direction. layer 2 does the same, but is the inverse of layer 1.
Notice that ambient light can pass through at an angle because the light didn't pass through both polarization directions. I think jws is saying 25% of ambient light passes through because the polarization step takes 50%, but half the ambient directions are blocked off completely (say by the moire patterns) so that makes 25% of ambient light.
That still won't work the way I think you intend. This will block light that enters perpendicularly, while passing some of the light that enters at an angle. The problem is that light entering at an angle is not aimed at your pupils. Allowing ambient light to pass at an angle only lights up your eye socket, while blocking everything (sun and ambient) that was bound to fall anywhere you could detect it.
"an angle" refers to any angle other than the angle directly from the sun.
when you look outside the window, any sunlight that enters your eyes from the angle of the sun is the sun because the sun is so far away. this is why we have well defined shadows.
any light that comes at an angle is all the light that did not come directly from the sun. light coming at an angle is directly aimed at your pupils if you're looking at the source.
what you said, the only way it's true, is if you're always looking directly at the sun.
>"an angle" refers to any angle other than the angle directly from the sun.
So do these conceptual glasses have a way to find the direction of the sun, and adjust the moire patterns in real time? Based on the description, it sounded like it would always block rays normal to the plane of the lens, while allowing rays to pass through at any other angle. Rays from the sun will only rarely be normal to the lens, and so they will only rarely be blocked, without an active adjustment to change the "rejection angle." Short of that, I don't follow how the glasses can "tell" sunlight from ambient light, and I don't think it can be done without active logic.
I wasn't talking about the glasses but rather a new window system for homes. But yeah, the windows in my idea would require adjustment based on the time.
Welders might buy this - they already have auto-darkening helmets, they might be interested in something that darkened only part of the field of vision.
Of course you would have to be very careful on the design, since a failure would be very hazardous.
Exactly what I thought. A welder helmet is large enough to easily fit the electronics inside, plus as a professional product the price point may be somewhat less sensitive. Would make sense as a first, preliminary product.
Yeah, it's not the visible spectrum that's harmful to your eyes. If you filter out all of the harmful frequencies entirely, you can selectively filter the visible spectrum for convenience while retaining a non-disastrous failure mode.
Every evening commute I dream of this as the tall SUVs and pickups beam their headlights of death into my fully dark adapted eyes. I was thinking windshield, but sunglasses might work too.
How about red lensed goggles? That'd preserve dark adaptation.
I've thought about this also. The increasingly bright headlights are probably counterproductive in a public safety, tragedy-of-the-commons sense. Your bright lights help you see a little better, but other drivers can see worse, because of your lights.
I can see this as a great feature for a car windshield. Why bother even wearing glasses when the LCD windshield can block out the sun while it gives you a HUD.
LCD windshields seem like something that would be regulated to oblivion (what happens if a bug, unlucky particle strike, vulnerability, etc.) causes your entire windshield to become opaque?) That said, in a world tolerant of reasonable amounts of risk I agree.
(Almost) All car failures are perfectly safe if you assume they occur when the user is otherwise safe. It's the failures that occur in conjunction with other failures and run you out of safety margin you have to worry about.
This is why you put the LCD inside the windshield. This way, by the time the LCD takes damage the windshield is already shattered, and a shattered windshield is about as see-through as icebergs.
This is a good point. Really good ideas can overcome legislative and regulatory inertia, with enough money and time behind them, thank goodness.
My only devil's advocate point would be that drive-by-wire cars typically have mechanical failsafes that the average person is fairly comforted by. For example, many drive by wire systems have some springs that set the car to just above idle if the ECU gets confused. I guess the analog for a potentially opaque windshield is sticking your head out the window, though this may not be fast enough if you're on a windy mountain road, driving through construction, etc.
A liquid-crystal-less region at the bottom of the windshield may do the job, and still do all the information-displaying and sun-blocking you need.
I thought about a filter that would stick on your window, to block glare from your side mirrors.
Use two disks of polarized film. When the brightness off the mirror spikes, rotate one disk to reduce the amount of light transmitted. Once a sensor notes that the mirror is no longer reflecting someone's too-bright headlights, it would rotate the disk back to maximum light transmission.
The area involved could be pretty small, and most of the view through the window and mirror would be unaffected.
That is basically a crude description of how LCD displays work - polarized layers, one of which can be selectively rotated to control how much light comes through.
Right. I just figure a coupla pieces of polarized film would be cheaper, simpler, and more flexible (physically) than an LCD. (Since car interiors and glass tend towards curvy rather than flat, a flexible film would likely be more workable than an LCD panel.)
Great idea and all, but the frames are going to have to match the style of current glasses - without the electronics on the nosepiece. Otherwise, the cool factor of wearing glasses is lost, and he might as well sell the honky prototype.
I bet they can find a market even if they are ugly. Commuters won't care, they'll only be wearing them in the car anyways. There are a lot of people who keep a pair of ugly over-your-normal-glasses sunglasses in the car all the time.
I've wanted this for car windshields for a long time. Head tracking could aim the black dots, and you could even take out the glare of headlights (I hate headlights while driving. Especially those extra-bright ones.). Unlikely to ever happen, abso-positivelutely. But I can dream, can't I?
If you are overly concerned about avoiding cars via seeing their headlights perhaps you should try driving on the other side of the road, it's safer over there.
Curvy roads, and lack of light pollution in the sky, combined with probable sleep deprivation doesn't make for a good situation. Even if you stay on your side of the road, who says that other guy coming in your direction is doing as well?
Headlights in your face are not a very good way to keep track of traffic, neither is a complete absence of light where a car should be though. An optimal solution would probably be something that prevented getting blinded by oncoming headlights while still retaining enough visual cue to be able to perceive that a car is headed towards you and to track its position.
You could just dim the glare points so they aren't glary anymore, but you could still see the light sources. My car has an auto-dimming rear view mirror, which works very well. This dims the lights so you don't get glare (much of the glare at night is from cars behind) but you can still see the lights without problem. It's so natural you don't notice it happening. The same principle could be used.
I would see it as a thin film applied to the inside of the windscreen, or possibly some type of HUD optics.
Car makers can already track eyes, because the latest research is in tracking blink rates to detect fatigue.
I'd say this tech is feasible just needs the different disciplines brought together to make it work.
You can judge distance from individual, over-bright dots? It's a well-known extremely difficult task for humans.
You have no size to compare, because the glow is larger than the headlight itself. You have large distances, so your parallax is minimal, and isn't very accurate anyway. It's dark, so on highways you frequently don't have any known references to compare against (like road width or car size). The closest you get is the distance between headlights and occlusion, which is unknown on any random vehicle and on more widely-spaced vehicles.
When you drive in the dark, if there is no ambient lighting, all you can generally see of a car approaching or behind is its lights, and you can definitely judge distance from that. This is noticeable particularly on motorways - it's very hard when you start to drive but becomes quite natural after a time.
Fantastic! I always wanted a pair of glasses like this for a bunch of project ideas (heck, including this very idea). I wonder what the odds are they will be hackable for other purposes?
- Douglas Adams, The Restaurant at the End of the Universe