I am quite near-sighted, so this question came to me while I was doing an emergency repair on my eyeglasses and waiting for the fumes from the super-glue to subside.
Without the correction of my glasses, everything is about the same level of “blur”. I suppose my question would apply to any blurry vision, but it is my particular example that interests me.
Is it possible, through the graphics abilities of a computer and special software, to be able to display text or photos on the screen and manipulate the image to where it appears to be in focus to the near-sighted person WITHOUT their glasses on?
Of course, it would have to have parameters put into it initially, and be variable to match the level of prescription correction, but assuming both eyes needed the same correction, could a computer adjust its screen so that a person could see it clearly without their glasses on?
It’s not as exotic, as personalized, or as experimental as the display Omar Little linked to, but you can buy off-the-shelf readers intended for people with macular degeneration. It’s basically a camera and a monitor that simply magnifies what you’re reading. Even myopic people (like me) can read print and see images if they’re enlarged. That’s the whole point of Large Print books.
Here’s one:
http://www.magnisight.com/
Heck, you can buy one of those “microscopes” you can clip to the camera on your cell phone and use its display for magnified reading.
No. What makes the images blurry to you is that the light from one area of your screen hits a larger area of your retina than it “should”. There’s no way to counteract that by manipulating the image shown on the screen.
The typical “this is how near sightedness works” image shows how this works, but it usually just uses a single point to show an example of how the light moves. To really grasp how not possible it is to just do something to the image you have to remember that the effect applies to every single point in your field of view.
Actually there is and recently read a article about it I believe on cNet. But it already exists in a different form, those magic eye pictures where you have to look into the picture to get the image, you are shifting your focal point also which means you can do so on a display screen.
I’d be interested to read such an article, but if you think magic eye pictures involve changing your focus I think you’ve misunderstood the article as well.
Unless you want to see a blur, magic eye picture viewing involves changing the direction of your eyes, but you need the lense to focus at the same distance.
The technology still requires an aligned pinhole mask for the screen.
naita is right in that there is nothing you can do for an ordinary 2D display device. However, if you add some means for the pixel color to be angle-dependent, it becomes possible. Your link shows a pinhole mask–each hole has one of several independent pixels behind it depending on what angle you look at it from. Another possibility would be an array of microlenses.
A “perfect” version of this would give every pixel on the screen its own high-resolution 2D array: instead of (to pick round numbers) a 1000x1000 display, you would have a 1000x1000x1000x1000 display. Another name for this is a lightfield display, and it means that you are controlling the light for every possible vector that passes through a given point.
A generalized lightfield display allows perfect holograms. A minor side effect is that you could use the hologram to display a 2D surface at whatever virtual distance you wanted, whether very close (for nearsightedness) or at infinity (for farsightedness).