The extraction of information from laser anemometry data
Abstract
A method for extracting the maximum amount of information about the velocity distribution from photoncorrelation anemometry data is described. The method involves the use of the eigenfunctions and eigenvalues of the continuous 'impulse' (single velocity) response function for the apparatus and explicit formulae for these are given. The effects of discrete data points and truncation are considered. In this situation the problem is not properly defined without an a priori 'model' for the solution. Given such a model, the maximum information should be extracted by mapping it onto the space of eigenfunctions and optimising the parameters in this basis. However, numerical complexity has prevented this from being carried out yet. In certain situations, the difficulties caused by discrete data may be overcome to a good approximation by the use of Bspline functions. This technique is described here. The need to measure instrumental parameters such as beam radius, visibility and background is discussed.
 Publication:

Physica Scripta
 Pub Date:
 April 1979
 Bibcode:
 1979PhyS...19..412M
 Keywords:

 Data Processing;
 Eigenvectors;
 Information Retrieval;
 Laser Anemometers;
 Velocity Distribution;
 Approximation;
 Autocorrelation;
 Discrete Functions;
 Fourier Transformation;
 Least Squares Method;
 Photon Beams;
 Instrumentation and Photography