Tukey’s robust M-estimator for phase demodulation of interferograms with nonuniform shifts

Abstract

In this paper, we introduce an iterative scheme for phase demodulation of interferograms with nonuniformly spaced phase shifts. Our proposal consists of two stages: first, the phase map is obtained through a least squares fitting; second, the phase steps are retrieved using a statistical robust estimator. In particular, we use Tukey’s biweighted M-estimator because it can cope with both noisy data and outliers in comparison with the ordinary least squares estimator. Furthermore, we provide the frequency description of the algorithm and the phase demodulation allowing us to analyze the procedure and estimation according to the frequency transfer function (FTF) formalism for phase-shifting algorithms. Results show that our method can accurately retrieve the phase map and phase shifts, and it converges by the 10th iteration.

Nationality as an Influential Variable with Regard to the Social Skills and Academic Success of Immigrant Students

“…In the case of R2 Adjusted = 0.787, this indicates that the SSSYI measures 78.7% of social skills as a function of the nationality, place of residence, gender and age variables. The results showed that RMSE was = 0.712, indicating that the model fit scores below 0.712 correctly as, according to some studies, this indicates that the adjustment is adequate [141] (Table 6). In order to verify which of the variables (nationality, place of residence, gender or age) was the one that had the most weight in the research and, therefore, was the greatest predictor of social skills, a comparison of competing model coefficients was calculated.…”