Method for evaluating interferograms and interferometer therefor

US5357341A · kind A · utility

Assignee

• Carl Zeiss Stiftung · DE

Inventors

• Michael Kuchel · Oberkochen, DE
• Karl-Heinz Schuster · Oberkochen, DE
• Klaus Freischlad · Aalen, DE

Key dates

• Filing date: Jul 13, 1992
• Grant date: Oct 18, 1994
• Expiry date: Jul 13, 2012

Classification

• Technology area (CPC G): Physics
• CPC primary: G01B2290/70
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

The invention relates to an evaluation method for interferograms and an interferometer corresponding thereto with which tile influence of coherent noise is reduced with simultaneously high interference contrast. Several phase maps are computed from interferograms which are recorded with coherent light. The interferogram components of the test object and the interferogram components of the coherent noise are displaced relative to each other in the camera plane between recording the interferograms. The influence of the coherent noise is suppressed by subsequently averaging the phase maps.