DISPLACEMENT MEASUREMENTS BY VIDEOGRAMMETRY

摘要

Cost and time reduction in control operations, large-scale three dimensional measurements, high accuracyin hazardous environment and immediate results aretoday the industrial requirements. One deformationmeasurement method, which takes up this challenge, isthe videogrammetry. The use of digital camera and theimprovements of software methods by means ofmathematical statistics, automated detection andmeasurement of location of target points allows now toperform measurements in a short time and with highaccuracy for sophisticated test setups. The techniquerelies on triangulation. A targeted object isphotographed under different angles and themeasurement of the target points on each image allowsto determine the coordinates of these points bytriangulation.Intespace defines, prepares and carries outenvironmental testing (mechanical, thermal, electrical,electromagnetic) for all industrial sectors: spacesystems, automotive, electronics, etc. Videogrammetryis used for different applications. This technique hasbeen used to check the planeity of a vibration tableafter a maintenance operation for example. The methodis used mainly for thermoelastic strain measurementsas it allows to check the mathematical predictions ofthermal deformations directly by testing. Facilitieshave been developed in two thermal vacuum chambersand allow today to measure specimens of differentsizes and different shapes with an accuracy better than10 μm per meter of specimen. Tests have beenperformed for example on an optical bench assembly inaluminium, on different simple and dual-griddedantennas and on antenna towers.