1,801 research outputs found
Logarithmic mathematical morphology: a new framework adaptive to illumination changes
A new set of mathematical morphology (MM) operators adaptive to illumination
changes caused by variation of exposure time or light intensity is defined
thanks to the Logarithmic Image Processing (LIP) model. This model based on the
physics of acquisition is consistent with human vision. The fundamental
operators, the logarithmic-dilation and the logarithmic-erosion, are defined
with the LIP-addition of a structuring function. The combination of these two
adjunct operators gives morphological filters, namely the logarithmic-opening
and closing, useful for pattern recognition. The mathematical relation existing
between ``classical'' dilation and erosion and their logarithmic-versions is
established facilitating their implementation. Results on simulated and real
images show that logarithmic-MM is more efficient on low-contrasted information
than ``classical'' MM
Electron correlation in FeSe superconductor studied by bulk-sensitive photoemission spectroscopy
We have investigated the electronic structures of recently discovered
superconductor FeSe by soft-x-ray and hard-x-ray photoemission spectroscopy
with high bulk sensitivity. The large Fe 3d spectral weight is located in the
vicinity of the Fermi level (EF), which is demonstrated to be a coherent
quasi-particle peak. Compared with the results of the band structure
calculation with local-density approximation, Fe 3d band narrowing and the
energy shift of the band toward EF are found, suggesting an importance of the
electron correlation effect in FeSe. The self energy correction provides the
larger mass enhancement value (Z^-1=3.6) than in Fe-As superconductors and
enables us to separate a incoherent part from the spectrum. These features are
quite consistent with the results of recent dynamical mean-field calculations,
in which the incoherent part is attributed to the lower Hubbard band.Comment: 8 pages, 5 figures, 1 talbl
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