Saturday, October 29, 2011

Strike Number 5 in the "Technologies That Do Not Exist" Section

You always wonder when some of these things will show up ... if ever.. Daniel Reetz pointed me to this new preprint that instantiate item 5 in the These Technologies Do Not Exist section, i.e. Imaging Earth using the Moon (see herehere and here for some background on Nuit Blanche). The authors do even more and this is fantastic!

Here is the paper: Diffuse Reflectance Imaging with Astronomical Applications by Samuel W. Hasinoff, Anat Levin, Philip R. Goode, William T. Freeman. The abstract reads:

Diffuse objects generally tell us little about the surrounding lighting, since the radiance they reflect blurs together incident lighting from many directions. In this paper we discuss how occlusion geometry can help invert diffuse reflectance to recover lighting or surface albedo. Selfocclusion in the scene can be regarded as a form of coding, creating high frequencies that improve the conditioning of diffuse light transport. Our analysis builds on a basic observation that diffuse reflectors with sufficiently detailed geometry can fully resolve the incident lighting. Using a Bayesian framework, we propose a novel reconstruction method based on high-resolution photography, taking advantage of visibility changes near occlusion boundaries. We also explore the limits of single-pixel observations as the diffuse reflector (and potentially the lighting) vary over time. Diffuse reflectance imaging is particularly relevant for astronomy applications, where diffuse reflectors arise naturally but the incident lighting and camera position cannot be controlled. To test our approaches, we first study the feasibility of using the moon as a diffuse reflector to observe the earth as seen from space. Next we present a reconstruction of Mars using historical photometry measurements not previously used for this purpose. As our results suggest, diffuse reflectance imaging expands our notion of what can qualify as a camera.

Maybe it is time to update both the Imaging With Nature and the These Technologies Do Not Exist pages. Thanks Daniel.

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