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Google's New Camera App Simulates Shallow Depth of Field
New submitter katiewilliam (3621675) writes with a story at Hardware Zone about a new feature that Google's working on for Android phones' built-in cameras: the illusion of shallow depth of field in phone snapshots, which typically err on the side of too much in focus, rather than too little. Excerpting: "The Google Research Blog [note: here's a direct link] revealed that there's quite a fair bit of algorithms running to achieve this effect; to put it in a nutshell, computer vision algorithms create a 3D model of the world based on the shots you have taken, and estimate the depth to every point in the scene."
Depends what you mean by 3D modelling. Looking further at the article, it's a depth mapping technique for each pixel. Which is more analogous to DOOM than Quake. Remember those restrictions? No bridges in the map, no tables. Just a single height for the floor and a single height for the ceiling at any map position.
As the OP says it's 2.5D not 3D.
Consider this picture of a spider dining on its prey--possibly a cricket.
What's important? the spider, the web, the meal.
What's not important? the storm drain, the foliage
It's not completely successful, but both the foliage and the storm drain are out of focus, while the spider, the meal, and the web are in focus. The aperture control on a large sensor camera lets the photographer select where the blurriness ends, and where it begins. Generally, the longer the focal length of the lens, the more dramatic the effects of opening up the aperture. Since camera phones use short focal length lenses, the blurring effect is quite subtle, and is often insufficient to draw in the viewers eye.
In this particular case, it's a macro shot, so even a very narrow aperture (f/16) involves some blurriness. Quite often, macro-photographers use very narrow apertures-- f/16-f32, in an attempt to resolve all of the interesting aspects of their subjects.