3D reconstruction (SFM) with multi-lens camera system (instead of pinhole camera model)

asked 2017-09-01 06:24:13 -0600

mirnyy
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updated 2017-09-01 06:25:01 -0600

3D reconstruction (especially SFM algorithms) are often related with pinhole camera models.
The state-of-the-art of these SFM techniques is to look where the rays of 2D-3D correspondences in two different cameras intersect in object space.
This enforces that the camera model is a pinhole model (where the 2D-3D ray is just a straight line).

But often in real world there are multiple lens system used, where you can't really figure out the ray of 2D-3D correspondence.

My question is: How does the SFM technique works with such multiple lens camera systems?

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answered 2017-09-01 18:53:00 -0600

Tetragramm

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Most lens systems can be well approximated by a pinhole camera + distortion. Which, of course, produces straight lines that work perfectly well with SfM models.

More Detail:

While it requires an approximation, in SfM, the user mostly doesn't care about the exact physical location of the cameras. So while the notional pinhole is not exactly aligned with the physical camera, the approximation produces the same rays as the true lenses. Thus, you still get the same 2D-3D correspondences and the same resulting structure.