The use of a phase-modulated reference wave for the electronic heterodyne recording and processing of a hologram is described. Heterodyne recording is used to eliminate the self-interference terms of a hologram and to create a Leith-Upatnieks hologram with coaxial object and reference waves. Phase modulation is also shown to be the foundation of a multiple-view hologram system. When combined with hologram scale transformations, heterodyne recording is the key to general optical processing. Spatial filtering is treated as an example.
The use of a Nd:YAG laser to record holographic motion pictures of time-varying reflecting objects and time-varying phase objects is discussed. Sample frames from both types of holographic motion pictures are presented. The holographic system discussed is intended for three-dimensional flow visualization of the time-varying flows that occur in jet-engine components.
SummaryA theory to determine the properties of a fluid from measurements of its projection was developed and tested. Viewing cones as small as 10° were evaluated, with the only assumption being that the property was space limited . The res ul ts of applying the theory to numerical and actual interferog rams of a spherical discontinuity of refractive index are presented. This theory wa developed to te t the practicality and limits of using three-dimensional computed tomography in interna l fl uid dynamics.
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