Tomographic Reconstructions Using Map Algorithms-- Application to the SPIDR Mission.

Roy, D. N. ; Cook, T. A. ; Chakrabarti, S. ; Wilton, K.

Technical Information Center Oak Ridge Tennessee

关键词: Astronomy;    Tomography;    Spectra;    Entropy;    Algorithms;   

RP-ID  :  DE2005838183

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

The spectral image of an astronomical scene is reconstructed from noisy tomographic projections using maximum a posteriori (MAP) and filtered backprojection (FBP) algorithms. Both maximum entropy (ME) and Gibbs prior are used in the MAP reconstructions. The scene, which is a uniform background with a localized emissive source superimposed on it, is reconstructed for a broad range of source counts. The algorithms are compared regarding their ability to detect the source in the background. Detectability is defined in terms of a contrast-to-noise ratio (CNR) which is a Monte Carlo ensemble average of spatially averaged CNRs for the individual reconstructions. Overall, MAP was found to yield improved CNR relative to FBP. Moreover, as a function of the total source counts, the CNR varies distinctly different for source and background regions. This may be important in separating a weak source from the background.