Method of and apparatus for double-exposure holographic interferometry

US4428675A · kind A · utility

Assignee

• The United States of America as represented by the Administrator of the National Aeronautics and Space Administration · US

Inventor

• William K. Witherow · Huntsville, US

Key dates

• Filing date: Jun 17, 1981
• Grant date: Jan 31, 1984
• Expiry date: Jun 17, 2001

Classification

• Technology area (CPC G): Physics
• CPC primary: G01B9/021
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Double-exposure holographic interferometry is carried out using first and second lasers (11), (12) responsive to respective applied firing signals for producing respective pulsed output beams. An optical system is provided oriented such that the output beams of the lasers produce coinciding scene (20) and reference (21) beams. An initiator circuit (30) generates and applies a firing signal to the first laser (11); and a timer/firing device (31), responsive to the generation of a firing signal by the initiator circuit (30), generates and applies a firing signal to the second laser (12) a predetermined period of time later.