Autocorrelation central hole estimate from the moments of the total number of counts: Application to overlapped photopulses.
In an experiment in which two or more photoevents arriving to the same pixel are considered as a single count, a one-pixel-sized central hole appears in the autocorrelation estimate. When the arriving photoevents are detected as extended spots, two different overlapped spots are usually considered as a single count. In this case, the central hole is widened by a few pixels. The autocorrelation central hole introduces high frequency noise in the power spectrum, so that the effective cut-off frequency is reduced. The speckle interferometry, based on the evaluation of the power spectrum, is therefore limited by this artifact. Recently, a simple method based on the statistical analysis of the total number of counts has been proposed to remove the hole in the clipped autocorrelation function. In this paper, we show that this technique can be easily extended to the more complex problem of overlapped detection. In order to study the method accuracy, theoretical expressions for both the statistical and the systematic errors have been developed. Finally, both the expressions for the autocorrelation hole area estimate and for its variance have been checked by applying the technique to series of simulated images.
Astronomy and Astrophysics Supplement Series
- Pub Date:
- November 1995
- INSTRUMENTATION: DETECTORS;
- METHODS: DATA ANALYSIS;
- METHODS: STATISTICAL