Spatially Phase-Shifted Digital Speckle Pattern Interferometry (SPS-DSPI) and Cryogenic Structures: recent improvements

摘要

The Spatially Phase Shifted Digital Speckle Pattern Interferometer (SPS-DSPI) is a speckle pattern interferometer in which the four phase-shifted interferograms are captured simultaneously in a single image. Designed to measure thermal distortions of large matte-surfaced structures for the James Webb Space Telescope (JWST) program, this metrology instrument has been used in two major cryo-distortion tests. This report will describe how differences in the vibrational motions of the test objects necessitated changes in basic algorithms. The authors also report operational upgrades, quantification of uncertainty, and improvement of the software operability with a graphic interface. Results from the tests of the JWST test structures are discussed as illustration.