Three-dimensional profiling with binary fringes using phase-shifting interferometry algorithms

Abstract

Three-dimensional shape measurements by sinusoidal fringe projection using phase-shifting interferometry algorithms are distorted by the nonlinear response in intensity of commercial video projectors and digital cameras. To solve the problem, we present a method that consists in projecting and acquiring a temporal sequence of strictly binary patterns, whose (adequately weighted) average leads to a sinusoidal fringe pattern with the required number of bits. Since binary patterns consist of "ones" and "zeros"--and no half-tones are involved--the nonlinear response of the projector and the camera will not play a role, and a nearly unit contrast gray-level sinusoidal fringe pattern is obtained. Validation experiments are presented.

Three-dimensional profilometry with nearly focused binary phase-shifting algorithms

“…However, their influence is minimized when the fringe stripe is narrow because of the discrete fringe generation nature. Ayubi et al proposed another method that uses separate binary images to represent each bit in an 8 bit grayscale sinusoidal pattern [7]. However, it requires at least eight images to generate each high-quality sinusoidal one, which reduces the measurement speed by 1=8.…”

Wrapping-free phase retrieval with applications to interferometry, 3D-shape profiling, and deflectometry

“…We utilized an experimental setup for fringe projection and acquisition similar to that described in [30]. Figure 1 shows four sinusoidal fringe patterns (I 1 ; …I 4 ), with a fringe shift of π∕2 between consecutive steps, projected on a mask.…”

Nonlinearity response correction in phase-shifting deflectometry

“…They show plateaus near the threshold and saturated intensity levels, which cannot be adequately described by a simple power law. Ayubi et al proposed a method to remove nonlinear response using binary patterns [20]. This approach has the advantage of not requiring calibration or compensation of the nonlinear response of the system, which could change over time.…”