Abstract: A moire interferometer is presented which was specially designed for the study of middle ear mechanics. The apparatus is based on phase shift projection moire interferometry, and allows full field quantitative measurement of the shape and deformation of three- dimensional surfaces. Phase shifting and grating noise removal is obtained by piezo-actuated movements of the gratings in the projection and the viewing optical path, respectively. Object shape is then calculated from the recordings of four phase shift moire topograms. The angle between projection and viewing direction is very small, so that observation of the eardrum is possible with minimal shadow problems caused by the bony structures in the vicinity of the eardrum. Measurements obtained on a calibration object and on in-vitro middle ear preparations are presented.!6
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