Imaging With Nature

Collection by Igorcarron

Using a lake as a mirror

Imaging With Nature: Wet Salt Lakes.

Yesterday, Imaging With Nature used the Moon as a reflector, today here is interesting Imaging With Nature example because the PSF is close to the identity "when covered with water, the Salar becomes one of the largest mirrors on Earth."( From Wikipedia ) additional mesmerizing photos can be found here. Credit: Ezequiel Cabrera; Liked this entry ? subscribe to Nuit Blanche's feed, there's more where that came from. You can also subscribe to Nuit Blanche by Email, explore the Big Picture in…

Planet sized reflectors (here the Moon)

These Technologies Do Not Exist: Planet Sized Sensors

About a year ago, I mentioned the possible utilization of the Moon as a way of imaging the Earth. Let me be more precise: Five hundred years ago, Leonardo explained what the Earthshine was in the Codex Leicester (Sheet 2A, folio 2r), i.e. it is a reflection of the Earth on the Moon. While this is great news for astrophysicist that are testing their theories on how they can detect exo-planets [2], this Earth reflection should also be seen as a great opportunity for imaging Earth. The test…

using galaxies as lenses

CS / Imaging With Nature: A Galaxy Wide Single Pixel Camera

Following up on this entry, I went about and went looking for information. From this site here is description of gravitational lensing: Gravitational lenses produce different shaped images depending on the shape of the lensing body. If the lens is spherical then the image appears as an Einstein ring (in other words as a ring of light) (top); if the lens is elongated then the image is an Einstein cross (it appears split into four distinct images) (middle), and if the lens is a galaxy cluster…

Turbulence aided imaging

CS / Imaging With Nature: Is Turbulence Ripe for Compressive Imaging ?

Echoing yesterday's use of a target to evaluate a turbulence field in (CS / Imaging With Nature: Turbulence Aided Lucky Imaging), one element of importance is to understand the type of sparsity that can be found in that field. If sparsity or approximate sparsity is not there, then compressive sensing can be of no use to determine the transfer function of interest. As it so happens, turbulence, a much studied subject [1], clearly show some sparsity in computations: The different eddies follow…

Using Clouds for Images

Imaging with Nature

The reason Russia has so much expertise in space (they flew several space stations) stems from the cold war era. During that time, the Russians had Salyut space stations manned with cosmonauts where cameras would fill half of the space station. The reason they had to man the cameras is that the earth is always covered with clouds and the Russians did not have much computing power to process away images with clouds. I talked about this in the following entry: Competing with the human element…

computations performed using the Moon as an incoherent detector

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 here, here 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…

Using clouds for structured lighting

CS: Imaging heavens and earth

You do remember the PACS camera that is on-board Herschel and for which some compressed sensing encoding have been tried (I still have not heard of the results). Anyway, that camera was used to image the encounter between the EPOXI spacecraft and Hartley-2. talk about a sparse scene ! The small dot is the EPOXI spacecraft. You probably recall the Integral Pixel Camera, well on of the authors, Nathan Jacobs, just came out with an instance of Imaging With Nature in: Using Cloud Shadows to…

Lucky Imaging

CS / Imaging With Nature: Turbulence Aided Lucky Imaging

While lucky Imaging is traditionally dedicated to astronomy, some other folks are using it to perform imaging on the ground. While the main idea is to get better images by using the magnifying capabilities of turbulence, one could probably reverse the problem by using a known target and evaluate the turbulence field. As I mentioned before, lucky imaging and gravitational lenses share similarities.

deblurring (turbulence or gravity)

Imaging With Nature: Some thoughts on deblurring.

Deblurring is somehow very close to calibration because it is sometimes equivalent to blind deconvolution. The interesting aspect of this procedure are the seemingly different routes used to perform the same task. In [1], Yu Mao and Jerome Gilles use a regularization method (nonlocal Total Variation) while Jerome Gilles and Stanley Osher [2] use a turbulence model to perform that deconvolution. Florent Couzinie-Devy, Julien Mairal, Francis Bach, Jean Ponce [3] build a dictionary from…

using seas as recording channels

CS: Is HIFT an instance of Imaging With Nature ? The data is available.

I know... I know, all of you are dying to see part II of this entry on Compressed Sensing or Inpainting ? Part I but this will have to wait as there is something more inspirational today. After talking to Raj Rao last week at the Random Matrix conference, I went ahead and asked Brian Dushaw about having access to the data of the Heard Island Feasibility Test. Brian got back to me with the following today: Hi Igor, The Heard Island data are on line now - you can find these data here…

Using the moon as a reflector

Imaging with Nature (part 2)

In the comment section of the previous entry, Laurent Jacques highlighted the fact that if one were to use clouds as a mechanism for performing imaging, one would need to figure out the cloud Point Spread Function (PSF). He is totally right. As in the Random Lens Imager case, the calibration step is essential to determine the point spread function (PSF). Hence the cloud PSF calibration needs to happen very fast indeed. Compressive Sensing gives a way of reducing the number of trials needed…