Restauracao de Radioimagens Solares (Solar Radioimage Restoration)

摘要

The general problem of image restoration is proposed, as well as a brief description of the methods to solve it. Then, this problem is placed in the context of radioastronomy images by considering the physical aspects of image formation. By using regression techniques for image restoration, computational results are presented. The ill-conditioning of this method due to the presence of additive noise in the image and computer round-off error is analyzed; the analysis of the condition number is also used as a tool to illustrate the ill-conditioning problem. Alternative methods are presented, such as inverse filtering, Fourier domain solution, etc., as well as their computational limitations. Restoration results through the use of regression techniques and the solution for the problem of oscillations due to ill-conditioning are discussed. Simulation results are presented where there exists control over the degradation process, and the proposed method is applied to real radioastronomy images. The problems of lack of knowledge of the degradation process and the computational effort for its solution by using regularization techniques are also indicated.