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• Multiple Optical Coherence Tomography (OCT) scanned sequences. • The procedure consists in a registration, an average and a filtering of the above OCT images (for this last step the Sampling Kantorovich (SK) algorithm has been used). • The retinal network has been detected by the application of an hybrid segmentation procedure (introduced in the present paper) based on classical Otsu and Phansalkar methods. The aim of this article is to provide an improvement in the reconstruction and visualization of retinal superficial capillary plexus and choriocapillaris images from healthy subjects. The implemented method uses multiple Optical Coherence Tomography (OCT) scanned sequences, performs a registration, an average and a filtering on them using for this last step the Sampling Kantorovich operator (SK). The resulting images are then analyzed with some well known methods in literature to quantitatively evaluate the improvement achieved by the proposed technique. Also fluoroangiography and histological images are introduced as reference to support the reliability and the goodness of the results. [ABSTRACT FROM AUTHOR]

A large class of multivariate quasi-projection operators is studied. These operators are sampling-type expansions ∑ k ∈ Z d c k (f) ψ (A j · − k) , where A is a matrix and the coefficients c k (f) are associated with a tempered distribution ψ ˜. Error estimates in L p -norm, 2 ≤ p < ∞, are obtained under the so-called weak compatibility conditions for ψ ˜ and ψ , and the Strang-Fix conditions for ψ. Approximation order depends on the smoothness of f and on the order of the compatibility and the Strang-Fix conditions. A number of examples aimed at engineering applications are provided. A special attention is payed to the quasi-projection operators associated with differential-difference expansions. Applications to solving some differential-difference equations are presented. [ABSTRACT FROM AUTHOR]