Spatial-temporal phase demodulation decoding superimposed ghost reflections in optical testing

Sotero Ordones, Jae Hyeung Park, Henry Quach, Daewook Kim, Heejoo Choi

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


We introduce a method of phase demodulation to distinguish the ghost reflection commonly observed in optical testing. The method digitally processes a sequence of fringe patterns to separate the reflections from the front and rear surfaces. First, we use a phase-shifting algorithm to compute an analytic signal with the two reflections coupled, and thenwe decouple them through a maximized spatial filtering. The process requires the acquisition of at least three fringe patterns, as well as fulfilling opposite signs for the magnifications of the two reflections. We demonstrate the decoding process through a real phase measuring deflectometry data processing example.

Original languageEnglish (US)
Pages (from-to)4135-4138
Number of pages4
JournalOptics letters
Issue number16
StatePublished - Aug 15 2022

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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