Phase-shift extraction from twice-normalized light intensity changes recorded with random phase shifts

• Published in: Optical review (Tokyo, Japan) Vol. 21; no. 5; pp. 522 - 525
• Main Authors: Adachi, Masaaki, Sunada, Satoshi
• Format: Journal Article
• Language: English
• Published: Japan The Optical Society of Japan 03-10-2014
• Subjects: Atomic; Lasers; Microwaves; Molecular; Optical and Plasma Physics; Optical Devices; Optics; Photonics; Physics; Physics and Astronomy; Quantum Optics; Regular Papers; RF and Optical Engineering; phase shift; random phase shifts; interferometry; phase extraction; vertical vibration
• ISSN: 1340-6000; 1349-9432
• DOI: 10.1007/s10043-014-0082-1

A simple phase-shift extraction algorithm is proposed for interferograms recorded with random phase shifts that vary over at least 2
π
. The phase-shift-dependent changes in the intensity at two pixels having different phases, selected from one frame, are taken out and normalized. The sum and difference of the two normalized changes are calculated, and both the changes are normalized again along the phase shifts. The normalized sum and difference become the cosine and sine of a term including the random phase shift, respectively. Thereby, the phase shifts are extracted from both twice-normalized intensity changes. An experiment using an interference microscope equipped with a piezoelectric-transducer positioner of an objective lens is conducted to estimate the validity of the algorithm. The algorithm is verified to have satisfactory results when the multiple interferograms used have a sample size of more than 15 frames recorded with random phase shifts.