Vander Lugt Filter Optimization For The Metrology In Industrial And Scientific Research

Holographic metrology of the cavitation bubble field has being successfully applied for the inter alia determination of its statistical properties.Bubble diameter's spatial distri-bution is deduced through measurements of each bubble diameter in the reconstructed field. Data reduction procedure is seriously tedious when the inspected volume and its cross-section is in a realistic range usually seen even in the smallest hydrodinamic tunnels.For the development of a hybrid Opto-Digital set-up, which distinguishes bubbles of a specific size from others, and from other particles in the inspected volume, it is of major importance to synthesize the appropriate SMF (Spatialy Matched Filter) for the FPC (Fourier Plane Corrlator). The large dynamical range of the bubble signal spectrum and the limited dynamical range cf photoemulsion combines into a weighting function by which the signal spectrum is multiplied in the holographically synthesized SMF. This weighting function is, to some extent, controlled by the selection of exposure and photo-processing parameters. The coherent optical correlation technique is used for the investigation and measurement of surface wear. Tappet's head surface wear from an IC (Internal Combustion) engine exhibits exponential decay of the optical cross-correlation of its initial and intermittent phases, in relation to the number of wear cycles. The Fourier spectrum of tappet surface shows in addition to a very pronounced DC component, an even spatial distribution.Nevertheless,the weighting function inherent to SMF synthesis must be controlled. Dimensional and statistical metrology of the granular structure of the photosphere of the solar disc is performed fast and easy through optical Fourier analysis. Through appropriate synthesis of optimally weighted SMF, temporal behaviour and decay half-times of the solar granular structure are obtained. In order to achieve acceptable control of the weighted SMF through the holographic procedure, a detailed theoretical and experimental analysis is carried out and empirical models are established for the FPC signal analysis based on the Vander Lugt filter.