Phase-shifting (PS) is a well-established technique for phase retrieval in interferometry that requires a series of intensity measurements with known or unknown phase-steps. The objective of this work is determinate a tunable PS algorithm that minimize the error in the reconstructed phase when the images have additive random noise and the phase-step was determined with certain error. Simulations to show the performance of the algorithm will be presented.
Phase-shifting (PS) is a well-established technique for phase retrieval in interferometry that requires a series of intensity measurements with known or unknown phase-steps. Contrast information is useful for evaluating the quality of the collected data. The objective of this work is determinate an algorithm to calculate the contrast function in the case of arbitrarily spaced phase steps.
Phase-shifting is a well-known technique for phase retrieval that requires a series of intensity measurements with
certain phase-steps. Additive noise is one of the most important source of errors in interferometry. In this
work we present a systematic algebraic approach for the generation of self-tunable phase shifting algorithms that
minimize the propagation of additive noise.
Phase-shifting is a well-known technique for phase retrieval that requires a series of intensity measurements with certain phase-steps. Harmonics and linear phase-shift errors are the main source of errors in interferometry. In this work we present a systematic algebraic approach for the generation of phase-shifting algorithms(for interferograms with arbitrarily phase-steps) insensitive to harmonics and linear phase-shift errors.
We present optical methods for edge enhancement in color images using optical derivative operations (first order
derivative and Laplacian operator). The proposed methods is based on the polarization properties of liquid-crystal
displays (LCD) and on the capacity of digital micro mirror devices to generate a (positive) copy of the digital image used
as input, and simultaneously a complementary color replica of it. In the proposed optical setup the negative and positive
replicas are at the same time imagined across a plane. First we analyzed the case when the negative replica has a lateral
differential displacement relative to the original one; an image with enhanced first derivatives along a specific direction
is obtained. In the case when the negative replica is low-pass filtered, one obtains the Laplacian of the original image.
Unlike Fourier, our proposal works with incoherent illumination and does not require precise alignment, and thus, it
could be a useful tool for edge extraction/enhancement in large images in real-time applications. Validation experiments
We present a three-dimensional (3-D) shape profiling method that involves the projection of two shifted strictly binary (square wave) fringe patterns, whose adequately weighted average allows to synthesize a sawtooth pattern. We demonstrate that the deformed fringes (after unwrapping) provide an intensity pattern proportional to the depth profile of the surface. The proposed technique overcomes the nonlinear response (i.e., the "gamma problem") of digital cameras and commercial video projectors without previous calibration. The two binary patterns can be encoded in the color components of a single color image, which allows a reliable 3-D profiling surface reconstruction at large time-rates. Validation experiments are presented.