Showing papers by "José A. Ferrari published in 2014"
TL;DR: This work presents a systematic algebraic approach for generating general PS algorithms with N arbitrarily spaced phase-steps, which present advantages (e.g., the PS error can be avoided) over known algorithms that assume equally spacedphase-steps.
Abstract: Phase-shifting (PS) is an important technique for phase retrieval in interferometry (and three-dimensional profiling by fringe projection) that requires a series of intensity measurements with known phase-steps. Usual PS algorithms are based on the assumption that the phase-steps are evenly spaced. In practice, however, this assumption is often not satisfied exactly, which leads to errors in the recovered phase. In this work we present a systematic algebraic approach for generating general PS algorithms with N arbitrarily spaced phase-steps, which present advantages (e.g., the PS error can be avoided) over known algorithms that assume equally spaced phase-steps. Simulations are presented.
19 citations
TL;DR: In this paper, a differential three-dimensional shape profiling method based on the combination of orthogonal fringe projection is presented. But this method is not suitable for 3D shape profiling.
14 citations
TL;DR: In this article, the authors demonstrate that this expression for the TIE solution holds when intensity and phase gradients are parallel (or null), but in general the usually accepted solution is not correct.
12 citations
01 Oct 2014
TL;DR: This work proposes a novel approach that consists in acquiring the scene under the projection of structured light (plus the natural ambient illumination), which allows to obtain the depth gradient map using a simple processing step with very low hardware requirements.
Abstract: In this work we will show that it is possible to perform three-dimensional (3D) analysis and extract features without performing a 3D surface reconstruction. We propose a novel approach that consists in acquiring the scene under the projection of structured light (plus the natural ambient illumination), which allows us to obtain the depth gradient map using a simple processing step with very low hardware requirements.
6 citations
2 citations
TL;DR: In this paper, the authors describe a nulling interferometer that consists of two arms in one collimated beam, and the two arms interfere with the help of a single beam-splitter cube.
Abstract: Nulling interferometry is a technique for darkening the field generated by a star rel- ative to its surroundings by destructive interference. We describe a nulling interferometer incor- porating a single beam-splitter (BS) cube. The device resembles a two-arm interferometer in which the arms are together in one collimated beam, and the two beam halves interfere with the help of the BS cube. By introducing an extra π∕2-phase difference between the two beam halves, it is possible to achieve destructive interference of the star with itself, while the off-axis image of the planet remains unchanged. An experimental setup is constructed to demonstrate the nulling features of this interferometer. A star and a planet solar system are simu- lated to prove its performance. © 2014 Society of Photo-Optical Instrumentation Engineers (SPIE) (DOI: 10.1117/1.JRS.8.084996)
1 citations