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1. Shape From Sky: Polarimetric Normal Recovery Under the Sky

   Ichikawa, T. ( June 2021 , IEEE Conference on Computer Vision and Pattern Recognition)

   The sky exhibits a unique spatial polarization pattern by scattering the unpolarized sun light. Just like insects use this unique angular pattern to navigate, we use it to map pixels to directions on the sky. That is, we show that the unique polarization pattern encoded in the polarimetric appearance of an object captured under the sky can be decoded to reveal the surface normal at each pixel. We derive a polarimetric reflection model of a diffuse plus mirror surface lit by the sun and a clear sky. This model is used to recover the per-pixel surface normal of an object from a single polarimetric image or from multiple polarimetric images captured under the sky at different times of the day. We experimentally evaluate the accuracy of our shape-from-sky method on a number of real objects of different surface compositions. The results clearly show that this passive approach to fine-geometry recovery that fully leverages the unique illumination made by nature is a viable option for 3D sensing. With the advent of quad-Bayer polarization chips, we believe the implications of our method span a wide range of domains.
2. Improved modeling of cloudy-sky actinic flux using satellite cloud retrievals: Cloudy-Sky Actinic Flux

   https://doi.org/10.1002/2016GL071892  

   Ryu, Young-Hee ; Hodzic, Alma ; Descombes, Gael ; Hall, Samuel ; Minnis, Patrick ; Spangenberg, Douglas ; Ullmann, Kirk ; Madronich, Sasha ( February 2017 , Geophysical Research Letters)
3. The C-Band All-Sky Survey (C-BASS): template fitting of diffuse galactic microwave emission in the northern sky

   https://doi.org/10.1093/mnras/stac1210  

   Harper, S. E. ; Dickinson, C. ; Barr, A. ; Cepeda-Arroita, R. ; Grumitt, R. D. P. ; Heilgendorff, H. M. ; Jew, L. ; Jonas, J. L. ; Jones, M. E. ; Leahy, J. P. ; et al ( May 2022 , Monthly Notices of the Royal Astronomical Society)

   The C-Band All-Sky Survey (C-BASS) has observed the Galaxy at 4.76 GHz with an angular resolution of 0${_{.}^{\circ}}$73 full-width half-maximum, and detected Galactic synchrotron emission with high signal-to-noise ratio over the entire northern sky (δ > −15○). We present the results of a spatial correlation analysis of Galactic foregrounds at mid-to-high (b > 10○) Galactic latitudes using a preliminary version of the C-BASS intensity map. We jointly fit for synchrotron, dust, and free–free components between 20 and 1000 GHz and look for differences in the Galactic synchrotron spectrum, and the emissivity of anomalous microwave emission (AME) when using either the C-BASS map or the 408-MHz all-sky map to trace synchrotron emission. We find marginal evidence for a steepening (<Δβ> = −0.06 ± 0.02) of the Galactic synchrotron spectrum at high frequencies resulting in a mean spectral index of <β> = −3.10 ± 0.02 over 4.76–22.8 GHz. Further, we find that the synchrotron emission can be well modelled by a single power law up to a few tens of GHz. Due to this, we find that the AME emissivity is not sensitive to changing the synchrotron tracer from the 408-MHz map to the 4.76-GHz map. We interpret this as strong evidence for the origin of AME beingmore »spinning dust emission.

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4. Towards a Connected Sky: Performance of Beamforming with Down-tilted Antennas for Ground and UAV User Co-existence

   https://doi.org/10.1109/LCOMM.2019.2927452  

   Amer, Ramy ; Saad, Walid ; Marchetti, Nicola ( January 2019 , IEEE Communications Letters)
5. Caching in the Sky: Proactive Deployment of Cache-Enabled Unmanned Aerial Vehicles for Optimized Quality-of-Experience

   https://doi.org/10.1109/JSAC.2017.2680898  

   Chen, Mingzhe ; Mozaffari, Mohammad ; Saad, Walid ; Yin, Changchuan ; Debbah, Merouane ; Hong, Choong Seon ( May 2017 , IEEE Journal on Selected Areas in Communications)