Statistical analysis of a plate corrected for photographic noise.
Abstract
The paper describes a statistical analysis method for the correction, for photographic noise, of the spatial power spectrum of the density fluctuations of a photospheric solar granulation plate. It is assumed that the photographic noise is statistically independent of the signal. If this noise is ignored, any spatial frequency is overestimated. Increasing the size of the spot is inefficient, because, although the photographic noise is reduced at the highest frequencies, nothing is changed for all the lower frequencies of the signal. Signal/noise discrimination can be made using the difference in spread of the two spectra. The method requires the investigation of a zone of uniform density. The shape of the autocorrelation function of the photographic noise is obtained using an exploring spot small enough not to cut off too much of the high frequencies of the photographic noise. The plate is then investigated with the same exploring spot, and the subtraction of the photographic noise is made at the autocorrelation function.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- December 1974
- Bibcode:
- 1974A&A....37..105R
- Keywords:
-
- Noise Reduction;
- Photographic Plates;
- Random Noise;
- Solar Granulation;
- Statistical Analysis;
- Angular Resolution;
- Astronomical Photography;
- Autocorrelation;
- Density Distribution;
- High Resolution;
- Normal Density Functions;
- Photosphere;
- Signal To Noise Ratios;
- Astronomy