Robust SVD-based calibration of active range sensors

Coordinate calibration is a critical step in reconstructing 3-D range images from 2-D camera images of structured light projections. Having accurate reconstruction yields accurate measurement of objects, assembly of multiple views of the same object from different directions and interlacing of multiple camera and projection field of views. We present a robust calibration algorithm, which combines a 3-D registration algorithm with structure light projections. The light projection is implemented with a spatial light modulator using an array of deformable mirrors. The approach uses 6 or more non-coplanar registration points on a physical calibration device. These points are in view to both the camera and projector. The camera and projector orientations are unknown. Singular value decomposition is applied to this data to estimate the perspective transformation parameters between 3-D world coordinate and 2-D camera coordinates. The same process is applied to find the transformation parameters between the projector coordinates and the world coordinates. From these two transformations we incorporate the lateral distortions produced by structured light projections and reconstruct manifolds that accurately represent the surfaces being measured. While sine wave projection is used in this study, the calibration and reconstruction methodology can be applied to a variety of structured light projection methods. Experimental results demonstrate the algorithm performance.