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Related: I've jokingly said that I'm going to create a "glasses app" where you tell it your prescription number and it warps the camera's image so that you see

Related: I've jokingly said that I'm going to create a "glasses app" where you tell it your prescription number and it warps the camera's image so that you see it properly. I don't think it would be very practical, especially since I think it would be hard to make it work without dictating the exact distance from phone screen to eye and from camera to object being viewed. But it would be cool.

dakami 16y ago
Is this a really bad problem?
stoney 16y ago
I'm not sure what you mean here - is it a camera app to bring stuff into focus or is it a warped screen image to bring your phone into focus? If it's the first one then I don't think the distance from camera to object is a problem - cameras can already focus on arbitrary objects, so you can get a clear image of the target on the phone easily enough. The hard part is from phone to eye, which I'm not sure is even possible? Can you create a distorted image that looks right when viewed from a certain point by someone who's short/long sighted? I suspect you can't do it with today's displays - I think you'd need to be able to emit different images at different angles (since the angle between each pixel and my retina will be different and you don't know in advance where my eye will be relative to the screen). If your eyes have different prescriptions it's not going to work, but maybe you could set it up for one eye and just close the other (but then maybe it would be easier to hold the phone closer to/further from your face). I wish I could remember enough about optics to figure this out!
- jackowayed 16y ago
  I am saying the former. Yeah, I guess you're right that camera-to-object distance wouldn't matter. And you're right that two eyes would be a problem. Even if they have the same prescription, I think the fact that the angle from the left eye to the screen and from the right eye to the screen would be different. It seems like a monocole should be doable, at least if I dictate that they center the phone in front of their eye and the distance from their eye to the screen. But I don't know much about optics either.
  - stoney 16y ago
    I'm not sure that the refraction of a lens is mathematically invertible/reversible? As I understand it, the problem with my eye is that my lens doesn't focus a point light source (e.g. a pixel) onto a point on my retina - one consequence of which is that the point source gets smeared out over a larger area (also I have astigmatism which means my eyes aren't perfectly spherical so colours get messed up, but lets ignore that!). You can't fix that smearing by warping the shape of the image, but maybe you could adjust the brightness of the adjacent pixels to cancel out the smeared out bit - I guess by making the adjacent pixels a little darker than they should be. I don't know if that's a solvable set of equations. If I flip my glasses over and look through the lens backwards, my vision doesn't get twice as bad - it's actually better than no glasses at all. Not sure what that tells you other than optics is very confusing to me.

dakami 16y ago

Is this a really bad problem?

stoney 16y ago

I'm not sure what you mean here - is it a camera app to bring stuff into focus or is it a warped screen image to bring your phone into focus? If it's the first one then I don't think the distance from camera to object is a problem - cameras can already focus on arbitrary objects, so you can get a clear image of the target on the phone easily enough. The hard part is from phone to eye, which I'm not sure is even possible? Can you create a distorted image that looks right when viewed from a certain point by someone who's short/long sighted? I suspect you can't do it with today's displays - I think you'd need to be able to emit different images at different angles (since the angle between each pixel and my retina will be different and you don't know in advance where my eye will be relative to the screen). If your eyes have different prescriptions it's not going to work, but maybe you could set it up for one eye and just close the other (but then maybe it would be easier to hold the phone closer to/further from your face). I wish I could remember enough about optics to figure this out!

jackowayed 16y ago
I am saying the former. Yeah, I guess you're right that camera-to-object distance wouldn't matter. And you're right that two eyes would be a problem. Even if they have the same prescription, I think the fact that the angle from the left eye to the screen and from the right eye to the screen would be different. It seems like a monocole should be doable, at least if I dictate that they center the phone in front of their eye and the distance from their eye to the screen. But I don't know much about optics either.
- stoney 16y ago
  I'm not sure that the refraction of a lens is mathematically invertible/reversible? As I understand it, the problem with my eye is that my lens doesn't focus a point light source (e.g. a pixel) onto a point on my retina - one consequence of which is that the point source gets smeared out over a larger area (also I have astigmatism which means my eyes aren't perfectly spherical so colours get messed up, but lets ignore that!). You can't fix that smearing by warping the shape of the image, but maybe you could adjust the brightness of the adjacent pixels to cancel out the smeared out bit - I guess by making the adjacent pixels a little darker than they should be. I don't know if that's a solvable set of equations. If I flip my glasses over and look through the lens backwards, my vision doesn't get twice as bad - it's actually better than no glasses at all. Not sure what that tells you other than optics is very confusing to me.