Nowadays, fringe projection profilometry is widely used in optical three-dimensional (3D) measurement. However, due to distortion, epipolar constraints are inaccurate for use in correspondence matching of a projector. This results in low accuracy of final 3D reconstruction. To address the issue, two simple and effective methods for undistorted correspondence matching are proposed in this paper. The first removes distortion from projector correspondences using double epipolar constraints; the second pre-distorts the fringe images for projection, thus the projected fringes become naturally undistorted. Comparative experiments are implemented, in a measurement volume of (50 × 30 × 8) mm. The results show that typical mean reconstruction errors of the two methods drop to 32.9% and 27.6% from that of an existing method based on single epipolar-constraint undistortion.

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