O.V.Verkhodanov, V.S.Shergin, V.N.Chernenkov, B.L.Erukhimov,
V.L.Gorokhov
SAO,Russia
For some problems of the radio astronomy the knowledge about the background around the sources is very important. The use of standard procedures as splines or fitting with a sample of curves very often can not help us in this situation.
Non-linear and non-parametric algorithms for data averaging, smoothing and clipping in the flexible astronomical data processing system are proposed. Algorithms are based on the robust methods and non-linear filters using iterational approach to smoothing and clipping. The algorithm use several start parameters: dispersion of noise, interval of smoothing, number of iterations, type of smoothing curve. It permits keeping a useful signal practically without changes inside of the given interval, but accurately calculates the background.
On the base of robust procedures the detector of faint sources is proposed also. This detector is based on the ratio of two statistics, characterizing the noise and signal, in the given interval.
These methods allow us to accelerate the process the data reduction and to improve the signal/noise ratio.
Examples of operation of these algorithms are shown. Corresponding pictures are presented.