Comparison of real-time phase-reconstruction methods in temporal speckle-pattern interferometry

Abstract

Three real-time methods for object-phase recovery are implemented and compared in temporal speckle-pattern interferometry. Empirical mode and intrinsic time-scale decompositions are used and compared as real-time nonstationary and nonlinear filtering techniques for the extraction of the spatio-temporal evolution of the object phase. The proposed real-time methods avoid the application of the Hilbert transform and improve the accuracy of the measurement by filtering under-modulated pixels using Delaunay triangulation. The performance of the proposed methods is evaluated by comparing phase-recovery accuracy and computation time by means of numerical simulations and experimental data obtained from common and simultaneous π/2 phase-shifting heterodyne interferometry.

Comparative analysis of nanometric inspection methods in fringeless speckle pattern interferometry

“…As described in Ref. [33], this setup was used to acquire a sequence of images that contained information about the temporal evolution of the sample and a nonlinear decomposition framework allowed to recover the phase field evolution. In this work, we took advantage of the whole sequence by using the temporal mean value of intensity I t instead of I i for the PGLS normalization procedure.…”

Medición de desplazamientos nanométricos en polímeros piezoeléctricos usando método de descomposición en modos empíricos bivariados en patrones de speckle

“…Como se muestra en [22], para remover la influencia del término de modulación de intensidad de los interferogramas y obtener una mayor precisión, los interferómetros heterodinos de fase rotada en π/2 en simultáneo (SQHI de sus siglas en inglés) resultan muy convenientes. Asimismo, los resultados obtenidos en [19] muestran que es posible reducir aún más los niveles de ruido mediante la combinación de las técnicas SQHI y BivEMD.…”