1. ECWAY TECHNOLOGIES
IEEE PROJECTS & SOFTWARE DEVELOPMENTS
OUR OFFICES @ CHENNAI / TRICHY / KARUR / ERODE / MADURAI / SALEM / COIMBATORE
BANGALORE / HYDRABAD
CELL: +91 98949 17187, +91 875487 1111 / 2111 / 3111 / 4111 / 5111 / 6111 / 8111
VISIT: www.ecwayprojects.com MAIL TO: ecwaytechnologies@gmail.com
HYPERSPECTRAL IMAGERY RESTORATION USING NONLOCAL SPECTRALSPATIAL STRUCTURED SPARSE REPRESENTATION WITH NOISE ESTIMATION
ABSTRACT:
Noise reduction is an active research area in image processing due to its importance in improving
the quality of image for object detection and classification. In this paper, we develop a sparse
representation based noise reduction method for hyperspectral imagery, which is dependent on
the assumption that the non-noise component in an observed signal can be sparsely decomposed
over a redundant dictionary while the noise component does not have this property. The main
contribution of the paper is in the introduction of nonlocal similarity and spectral-spatial
structure of hyperspectral imagery into sparse representation. Non-locality means the selfsimilarity of image, by which a whole image can be partitioned into some groups containing
similar patches. The similar patches in each group are sparsely represented with a shared subset
of atoms in a dictionary making true signal and noise more easily separated. Sparse
representation with spectral-spatial structure can exploit spectral and spatial joint correlations of
hyperspectral imagery by using 3-D blocks instead of 2-D patches for sparse coding, which also
makes true signal and noise more distinguished. Moreover, hyperspectral imagery has both
signal-independent and signal-dependent noises, so a mixed Poisson and Gaussian noise model is
used. In order to make sparse representation be insensitive to the various noise distribution in
different blocks, a variance-stabilizing transformation (VST) is used to make their variance
comparable. The advantages of the proposed methods are validated on both synthetic and real
hyperspectral remote sensing data sets.