Measurement of Surface-Displacements Normal to Line of Sight by Holo-Moiré Interferometry

Abstract

This paper describes a new technique called “Holo-moiré interferometry” which combines the moiré and holographic techniques so that full-field measurement of the displacements normal to the line of sight is achieved. The method is particularly useful in measuring in-plane displacements; a type of measurement for which the conventional moiré technique is too insensitive, and for which holographic interferometry requires pointwise separation of displacement components from a multiple-hologram scheme. Holo-moiré interferometry overcomes the major limitations of both. An example which compares experimental with analytical predictions is presented. The limitations of the scheme are discussed.