Enhanced Fourier-Hilbert-transform suppression for saturation-induced phase error in phase-shifting profilometry

Abstract

Intensity saturation tends to induce severe errors in high dynamic range three-dimensional measurements using structured-light techniques. This paper presents an enhanced Fourier-Hilbert-transform (EFHT) method to suppress the saturation-induced phase error in phase-shifting profilometry, by considering three types of residual errors: nonuniform-reflectivity error, phase-shift error, and fringe-edge error. Background normalization is first applied to the saturated fringe patterns to suppress the effect of the nonuniform reflectivity. A self-correction method is proposed to correct the large phase-shift error in the compensated phase. The self-corrected phase error is detected to assist in locating the fringe-edge area, within which the true phase is computed based on the sub-period phase error model. Experimental results demonstrated the effectiveness of the proposed method in suppressing the saturation-induced phase error and other three types of residual errors with fewer images.

Handheld structured light system for panoramic 3D measurement in mesoscale

“…Thus, based on equations ( 12) and ( 14), we can obtain: Theoretically, the periodic error caused by intensity saturation and gamma distortion can be simultaneously compensated by averaging the FF-based phase and the HT-based phase. However, the HT may introduce phase shifted error into HTbased wrapped phase Φ H , leading to the undesirable error correction and further cause significant jump errors after phase unwrapping [47]. Therefore, it is necessary to compensate the phase shifted points for Φ H before averaging them.…”

Three-dimensional measurement based on equal spacing binary fringe coding

“…However, errors may occur when applying this method to non-uniform reflectivity surfaces and edges. Therefore, Wan et al [17] proposed an enhanced FHT (EFHT) method, which can correct the phase shift error of the compensating phase obtained by FHT, but requires multiple iterations for calculation. In this paper, we project equally spaced binary stripes with intensity values of 0 and 255.…”