The first objective of this research is to improve radio astronomy images of extended sources by Kalman filtering the atmospherically induced phase fluctuations in the spatial frequency domain. Models for the atmospheric-phase noise for each antenna pair are obtained with times series analysis. A model for the radio source is obtained from the CLEAN components by transforming them to the spatial frequency domain, putting them in the same time-baseline order as the data, and modeling these series. Both models are placed in the Kalman filter and then the data are subsequently filtered. The Kalman filter will discriminate between the wanted and unwanted signals, thereby producing a less corrupted data set which is ready for mapping. The second objective is to reduce the noise in the images by segmenting the image into statistically stationary segments, modeling the signal and the noise in the segments, and Kalman filtering each segment. New work in this area will be the incorporation of improved information; the signal and noise processes in the filter modes. One example is the inclusion of colored noise. This will reduce the background noise and will reduce the noise in the weak-signal portion of the astronomical object.
