The problem with that solution is optical, I believe. It would work if you were able to put such a filter directly on your retina, but when you put it earlier in the path of the light, before images are focused, you cannot selectively block individual pixels as they appear on your retina. As a result, the dark spots will look blurry.
(Also, if the pixels are dense enough I imagine you'll get diffraction.)
Here's is Michael Abrash's better explanation:
>“But wait,” you say (as I did when I realized the problem), “you can just put an LCD screen with the same resolution on the outside of the glasses, and use it to block real-world pixels however you like.” That’s a clever idea, but it doesn’t work. You can’t focus on an LCD screen an inch away (and you wouldn’t want to, anyway, since everything interesting in the real world is more than an inch away), so a pixel at that distance would show up as a translucent blob several degrees across, just as a speck of dirt on your glasses shows up as a blurry circle, not a sharp point. It’s true that you can black out an area of the real world by occluding many pixels, but that black area will have a wide, fuzzy border trailing off around its edges. That could well be useful for improving contrast in specific regions of the screen (behind HUD elements, for example), but it’s of no use when trying to stencil a virtual object into the real world so it appears to fit seamlessly.
What about Near-Eye Light Field Displays[1][2]? From what I've seen those look to have promise in solving some focus problems and some of the problems with how cumbersome most VR/AR displays are. As a bonus, they can correct for prescriptions.
The answer is a higher resolution screen plus some clever adaptive optics and software. The problem is that even 8k screens do not come close to required resolution... And you also want fast refresh rate.
(Also, if the pixels are dense enough I imagine you'll get diffraction.)
Here's is Michael Abrash's better explanation:
>“But wait,” you say (as I did when I realized the problem), “you can just put an LCD screen with the same resolution on the outside of the glasses, and use it to block real-world pixels however you like.” That’s a clever idea, but it doesn’t work. You can’t focus on an LCD screen an inch away (and you wouldn’t want to, anyway, since everything interesting in the real world is more than an inch away), so a pixel at that distance would show up as a translucent blob several degrees across, just as a speck of dirt on your glasses shows up as a blurry circle, not a sharp point. It’s true that you can black out an area of the real world by occluding many pixels, but that black area will have a wide, fuzzy border trailing off around its edges. That could well be useful for improving contrast in specific regions of the screen (behind HUD elements, for example), but it’s of no use when trying to stencil a virtual object into the real world so it appears to fit seamlessly.
http://blogs.valvesoftware.com/abrash/why-you-wont-see-hard-...