Application of a multiscale maximum entropy image restoration algorithm to HXMT observations

Abstract

This paper introduces a multiscale maximum entropy (MSME) algorithm for image restoration of the Hard X-ray Modulation Telescope (HXMT), which is a collimated scan X-ray satellite mainly devoted to a sensitive all-sky survey and pointed observations in the 1-250 keV range. The novelty of the MSME method is to use wavelet decomposition and multiresolution support to control noise amplification at different scales. Our work is focused on the application and modification of this method to restore diffuse sources detected by HXMT scanning observations. An improved method, the ensemble multiscale maximum entropy (EMSME) algorithm, is proposed to alleviate the problem of mode mixing exiting in MSME. Simulations have been performed on the detection of the diffuse source Cen A by HXMT in all-sky survey mode. The results show that the MSME method is adapted to the deconvolution task of HXMT for diffuse source detection and the improved method could suppress noise and improve the correlation and signal-to-noise ratio, thus proving itself a better algorithm for image restoration. Through one all-sky survey, HXMT could reach a capacity of detecting a diffuse source with maximum differential flux of 0.5 mCrab.

Applying the Maximum Entropy Technique to the Gaussian Dispersion Plume Model

“…It should be noted that Maximum Entropy techniques have been applied to a wide variety of subjects. In physics, this technique has been used in particle physics to determine the quark distribution in pions [17], QCD calculations [18], in condensed matter physics applications such as solving certain mathematical techniques [19] and the modeling of Helium-4 [20]and in astronomy the principle has been used to aid in the reconstruction of x-ray images [21,22] and in the analysis of the mass-radius relationship of exo-planets [23], as well as providing a unified view of transport equations( ref our paper). In biology it has been used to analyse the structure of DNA [24][25][26], model species distributions [24,[27][28][29], and to study gene expression [30,31].…”