Multi-Scale Image Analysis Applied to Radioastronomical Interferometric Data

Abstract

Multi-Scale image analysis is specially suited to detect objects in deep wide field radio astronomical images obtained through interferometric aperture synthesis techniques. These images are usually complex and show a diversity of objects that can be characterized at different scales. In this context wavelet decomposition can be a tool to detect and separate the components of the image. However, the presence of very bright sources produce polluting artifacts in the planes of the wavelet decomposition that difficult the analysis. To overcome this problem we propose a hybrid method where in a first stage bright sources are detected through thresholding techniques and a image that does not contain them is created. In a second stage wavelet decomposition is applied to this residual image in order to detect fainter sources. We show the validity of the method using a previously catalogued image.