Coded aperture for projector and camera for robust 3D measurement

General active 3D measurement system using structured light is based on triangulation, which requires correspondence between projection pattern and camera observed pattern. Since both the projected pattern and the camera image should be in focus on the target, the condition makes a severe limitation on depth range of 3D measurement. In this paper, we propose a technique using coded aperture (CA) for projector and camera system to relax the limitation. In our method, Depth from Defocus (DfD) technique is used to resolve the de-focus of projected pattern. By allowing blurry pattern of projection, measurement range is extended compared to common structured light methods. Further, overlapped blur pattern can also be resolved with our technique.