4 ms·

I assure you it is semi opaque. A one way mirror is a primitive example of this. You can make the reflection increasingly transparent but it will be tinted up u

I assure you it is semi opaque. A one way mirror is a primitive example of this. You can make the reflection increasingly transparent but it will be tinted up until the point it doesn't reflect anything. It may not be noticeably visible to the human eye under most lighting conditions, though.

godelski 3y ago
>> but the example on the CES floor does not have an __apparent__ tint. > I assure you it is semi opaque > It may not be __noticeably visible__ to the human eye under most lighting conditions, though. I'm not sure you two are disagreeing. Seems like you're just reinforcing their point. I mean if someone said glass is opaque and their evidence is that you can't see through glass and your evidence is to point at UV light... well... you'd be technically correct but you're talking from a different ballpark.
- xyzzy_plugh 3y ago
  Typically people can see better in the dark than imaging sensors can (only considering visible spectrum here), especially small sensors. If you redirect the light somewhere, what would you see? How much light would you need to divert? If the image is grayscale and has very high gain/noise/ISO, then I imagine with a low enough frame rate you could avoid noticable tinting. You would likely still notice the tint in comparison to regular glass, I'm too lazy to do the napkin math though. Practically speaking, I would expect it to be strictly more noticeable than glass for holographic projection. If true, it's likely noticeable. But the eye is fickle. You don't notice the tint of, say, a car window when you've been inside for a bit. Or sunglasses. Here's an arbitrary Google search result for in-glass HUDs: https://www.lumineq.com/applications/automotive https://www.lumineq.com/applications/automotive They state their glass is 70% transparent. That's definitely noticeably opaque.
  - godelski 3y ago
    > in the dark I don't think how you framed this is accurate. The quality is a function of the pixel size and of course the exposure time. I mean those are the two main variables that control how much light hits the sensor, but we'd have to get into sensitivity to make direct comparisons (human eyes are VERY sensitive and some evidence that the average eye is sensitive to a single photon, but you're not going to see well with that and this is besides the point). Definitely not a straight forward calculation and I'm feeling too lazy to go grab my optics books. But guesstimating here, there should be enough light considering you can see light and distortions when looking at the side of a pane. So I'd lean on it being more about the quality of the signal. Which glass is highly structured but I'm assuming that this type of glass has some unique optical properties to specifically make the side panels have higher quality signals. My understanding is that they are projecting from the side, so that's what I'm inferring from -- basically just reverse the photon direction through the medium and I don't have reason to believe that quality is directionally dependent (should I?). My whole spitballing is dependent on this understanding. > it's likely noticeable. Well one user said they didn't notice it. > They state their glass is 70% transparent. That's definitely noticeably opaque. That's not uncommon for Low-E glass, so maybe not very noticeable, especially in many different environments. But yeah, I think if you compared side by side you'd notice. I think we're just using different criteria and we probably decently align? Idk, I am mostly thinking aloud here, so I do want to portray that I don't have high confidence here. It's been 10 years since I've been in an optics lab lol. But I've built microphones with really weak signals before and they are useful. Distorted, but useful. (Definitely not fun being forced to run experiments at 3am and find out someone is walking around on the other side of the building...) So I can't see why this couldn't (theoretically) be similarly done for a window? I definitely don't think this would work with a typical pane of glass, especially considering how they're cut, but this does seem like specialty glass specifically built for directing photons directed from an edge to the pane face. Any idea if it can only display to one face? (I'm sure you can invert img but projection face probably matters for a camera?)

godelski 3y ago

>> but the example on the CES floor does not have an __apparent__ tint. > I assure you it is semi opaque > It may not be __noticeably visible__ to the human eye under most lighting conditions, though. I'm not sure you two are disagreeing. Seems like you're just reinforcing their point. I mean if someone said glass is opaque and their evidence is that you can't see through glass and your evidence is to point at UV light... well... you'd be technically correct but you're talking from a different ballpark.

xyzzy_plugh 3y ago
Typically people can see better in the dark than imaging sensors can (only considering visible spectrum here), especially small sensors. If you redirect the light somewhere, what would you see? How much light would you need to divert? If the image is grayscale and has very high gain/noise/ISO, then I imagine with a low enough frame rate you could avoid noticable tinting. You would likely still notice the tint in comparison to regular glass, I'm too lazy to do the napkin math though. Practically speaking, I would expect it to be strictly more noticeable than glass for holographic projection. If true, it's likely noticeable. But the eye is fickle. You don't notice the tint of, say, a car window when you've been inside for a bit. Or sunglasses. Here's an arbitrary Google search result for in-glass HUDs: https://www.lumineq.com/applications/automotive https://www.lumineq.com/applications/automotive They state their glass is 70% transparent. That's definitely noticeably opaque.
- godelski 3y ago
  > in the dark I don't think how you framed this is accurate. The quality is a function of the pixel size and of course the exposure time. I mean those are the two main variables that control how much light hits the sensor, but we'd have to get into sensitivity to make direct comparisons (human eyes are VERY sensitive and some evidence that the average eye is sensitive to a single photon, but you're not going to see well with that and this is besides the point). Definitely not a straight forward calculation and I'm feeling too lazy to go grab my optics books. But guesstimating here, there should be enough light considering you can see light and distortions when looking at the side of a pane. So I'd lean on it being more about the quality of the signal. Which glass is highly structured but I'm assuming that this type of glass has some unique optical properties to specifically make the side panels have higher quality signals. My understanding is that they are projecting from the side, so that's what I'm inferring from -- basically just reverse the photon direction through the medium and I don't have reason to believe that quality is directionally dependent (should I?). My whole spitballing is dependent on this understanding. > it's likely noticeable. Well one user said they didn't notice it. > They state their glass is 70% transparent. That's definitely noticeably opaque. That's not uncommon for Low-E glass, so maybe not very noticeable, especially in many different environments. But yeah, I think if you compared side by side you'd notice. I think we're just using different criteria and we probably decently align? Idk, I am mostly thinking aloud here, so I do want to portray that I don't have high confidence here. It's been 10 years since I've been in an optics lab lol. But I've built microphones with really weak signals before and they are useful. Distorted, but useful. (Definitely not fun being forced to run experiments at 3am and find out someone is walking around on the other side of the building...) So I can't see why this couldn't (theoretically) be similarly done for a window? I definitely don't think this would work with a typical pane of glass, especially considering how they're cut, but this does seem like specialty glass specifically built for directing photons directed from an edge to the pane face. Any idea if it can only display to one face? (I'm sure you can invert img but projection face probably matters for a camera?)