Depth from DeFocus of Structured Light

April 1, 1990


Bernd Girod, Stephen Scherock


We propose a new range sensing technique that uses defocus of structured light to measure depth. The technique is an extension of the original passive depth-from-defocus idea to an active, structured-light system. Depth from defocus of structured light has similar properties as structured light triangulation, but it avoids the "missing parts problem" and the "correspondence problem" by eliminating the parallax between the structured light source and the camera. We propose refinements to the technique, using either an anisotropic aperture or astigmatic optics for the light source. Both refinements use an isotropic structured light pattern and compare blur in two orthogonal directions. We point out different ways to remove the ambiguity between objects behind and in front of the plane of best focus.

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