Browsing by Subject "Spectral imaging"

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    ItemOpen Access
    All-chalcogenide glass omnidirectional photonic band gap variable infrared filters
    (AIP Publishing, 2009) Kondakci, H. E.; Yaman, M.; Koylu, O.; Dana, A.; Bayındır, Mehmet
    We report on the design, fabrication, and characterization of spatially variable infrared photonic band gap filter that consists of thermally evaporated, high refractive indexcontrast, amorphous chalcogenide glass multilayers. Due to graded thickness structure, the filter exhibits a position dependent stop band and a cavity mode ranging from 1.8 to 3.4 μm3.4 μmwavelengths. Reflection measurements on the variable filter agree well with theoretical calculations. These results pave the way to low-loss infrared mirrors, filters, spectral imaging, and miniaturized spectrometers at infrared region.
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    ItemOpen Access
    Effect of different sparsity priors on compressive photon-sieve spectral imaging
    (IEEE, 2018) Kar, O. F.; Oktem, F. S.; Kamaci, U.; Akyön, Fatih ÇaĞatay
    Compressive spectral imaging is a rapidly growing area yielding higher performance novel spectral imagers than conventional ones. Inspired by compressed sensing theory, compressive spectral imagers aim to reconstruct the spectral images from compressive measurements using sparse signal recovery algorithms. In this paper, first, the image formation model and a sparsity-based reconstruction approach are presented for compressive photon-sieve spectral imager. Then the reconstruction performance of the approach is analyzed using different sparsity priors. In the system, a coded aperture is used for modulation and a photon-sieve for dispersion. In the measurements, coded and blurred images of spectral bands are superimposed. Simulation results show promising image reconstruction performance from these compressive measurements.