It is related to measures based upon spectral techniques such as autocorrelation and Fourier transform. This Gaussian form is assumed in deriving the functional form of the autocorrelation. MUSIC estimates the frequency content of a signal or autocorrelation matrix using an eigenspace method. The linear autocorrelation of an MLS approximates a Kronecker delta. The latter is a well-known statistic that accounts for the Global spatial autocorrelation. Alignment methods use image registration algorithms, such as autocorrelation methods to correct these errors. Multi-dimensional autocorrelation is defined similarly. Thermal generation produces Poissonian statistics with an impulse function autocorrelation, and afterpulsing produces non-Poissonian statistics. For the other periods one cannot reject the null hypothesis of no autocorrelation. A process called autocorrelation was used for this analysis. An alternative formulation is in terms of the autocorrelation function. The most important use of the autocorrelation function is its use for size determination. The phase shift is found by taking the autocorrelation between echoes from two consecutive firings. In the bottom plot is the autocorrelation on the same data. Different fields of study define autocorrelation differently, and not all of these definitions are equivalent.