3D reconstruction of an image based on depth of intensity levels? Is there anyway of segmenting objects based on how far they are from the viewer?

Can color values assess this sort of a thing for us?
How will intensity levels help in determining how far the object is from the viewer?



Another image:
This is an extremely difficult task, one which is a very active line of research. I've managed to find a semi-recent paper on the subject. I won't go into the details, but here's a few things that this paper found that can be used.


Textures: If you see a given texture, they can help you figure out how far something is away. The wood texture here would be quite ideal for this.
Fixed object sizes: Identify common objects, see how large they are, and use them to help with depth analysis. The phone book, soda bottle, etc should work well with this.
Focus: If you know how the picture was take, focus can help you identify ranges.
Shadows- If you know where the light was coming from, shadows can help you identify how tall objects are, and thus how far they are away.