The Evaluation Of A Random Sampling Error On The Polynomial Fit Of Subaperture Test Data

The interpretation of interferometric test data frequently involves fitting sampled data points to some set of polynomials and the removal of a reference wavefront. Random uncorrelated sampling errors introduces inaccuracies into the polynomial fit. This process is complicated when testing a large component with multiple non-overlapping apertures by the need to reconstruct the total surface shape from the related subaperture data sets. This paper examines the error introduced into the polynomial fit by random uncorrelated sampling errors. The error, expressed as an rms value, is represented as a projection onto the reference and total polynomial spaces.