MINIATURIZED OPTICAL SENSOR FOR MECHANICAL TESTING ININDUSTRIAL ENVIRONMENT

摘要

Optical methods are of great interest for quantitativeshape and deformation measurements as well as forNondestructive Testing (NDT) of spacecraft structuresand materials due to their advantageous properties withrespect to other methods. Because of their non-contactdata acquisition principle and high sensitivity thesemethods are well suited for testing of criticalcomponents such as satellite tanks.In this paper a novel compact sensor based on digitalholography is presented. The entire sensor including thedigital holographic interferometer with a CCD-camerais placed at the end of a flexible endoscope. Thisenables measurements in cavities and, due to theflexible endoscope, even behind edges.The diameter of the entire sensor is less than 10 mm.The system enables interferometric measurements witha speed of five reconstructions per second and it can beused outside of the laboratory in a harsh industrialenvironment. Shape measurements are performed withtwo wavelength contouring, while the deformation ismeasured with digital holographic interferometry. Toobtain full 3D-data in displacement measurements theobject can be illuminated sequentially from threedifferent illumination directions.Several application examples show the feasibility of thisuser-friendly and compact system to measure shape anddeformations of technical objects.