[jorvi]

I wonder if it would work to project a microdot pattern on those kind of objects..

Obviously you lose the ease-of-use of using your cellphone then, though.

[djmips]

That's kind of what the original Kinect depth camera did. It projected a known constellation of IR dots to help with the 3D reconstruction.

[fake-name]

The problem with that approach is that the microdot pattern has to be fixed. SFM type approaches work by doing feature matching between images to determine the correspondence between images. If the microdot pattern changes for each image, the correlation fails.

AIUI, the kinect and similar tools don't do SFM, but rather measure depth by looking at how the micro-dot pattern is distorted.