Improvement in Phase Analysis using Spatio-Temporal Images for Soret Coefficient Measurements

Abstract

The Soret-Facet Mission was conducted in microgravity to measure the Soret coefficient S(sub T) using a two-wavelength Mach-Zehnder Interferometer (2-MZI). Interferometer analysis generally uses procedures like fringe tracing (thinning method) that impede processing speed and accuracy. In the present study, an automated phase analysis using spatio-temporal images was developed based on the simple conversion of intensity 𝐼(𝑡) into phase 𝜙(𝑡). This automatically analyzes steps, starting with obtaining the spatio-temporal images of moving interference fringes to calculating phase change Δ𝜙(𝑡). It dramatically improved processing speed and larger analyzing areas compared to the thinning method. Applying filters and a threshold to the fringes using suitable conditions-which the method determined automatically and quickly-was confirmed to be efficient for the correct unwrapping of phase.