Factor analysis and deconvolution are commonly used tools in analysis of time activity analysis of biological organs in scintigraphic data. Typically, these are used independently such that the output of the former is taken as an input to the latter. Each method is thus unaware of the restrictions imposed by the other and fails to respect them. In this… (More)
Tomography is performed in 2 steps: 1st step = data acquisition (record of projections) The result is a set of angular projections. The set of projections of a single slice is called sinogram. 2nd step = image recontruction from projections There are 2 groups of reconstruction methods: analytic (e.g. FBP = filtered back projection) and iterative (e.g. ART =… (More)
Our aim was to estimate the volumes of homogeneous structures whose contrast / intensity was changing with time, using only few (here 4) projections of the structures. Each projection was recorded over a period of time and consisted of a sequence of images. The projections of the structures were first separated by factor analysis of the total projections.… (More)
Principal component analysis is a well developed and understood method of multivariate data processing. Its optimal performance requires knowledge of noise covariance that is not available in most applications. We suggest a method for estimation of noise covariance based on assumed smoothness of the estimated dynamics.