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Symposium on Microoptical Imaging and Projection (1)

Today, November 27th, the brand new Symposium on Microoptical Imaging and Projection started at the Fraunhofer Institute in Jena (Germany). Due to my late arrival at the Symposium and my lack of knowledge in projection, I only attended 7 talks, of which 5 were on imaging. Most of the imaging stuff today was about multi-aperture cameras. Unfortunately I have to report that not that much new stuff was presented in the first two talks. The presentations of Pelican Imaging (here given by Jacques Duparre) and the one from LinX Imaging (given by Ziv Attar) were repetitions of the ones I heard before. What I memorized from Ziv’s talk is the fact that a multi-aperture camera still has some challenging issues to solve. To name a few : manufacturability of the optics, packaging, sensor compatibility, image processing, lack of standards, processing power needed, and power consumption. After the talk, Ziv advised me to be positive, so here is a list of advantages of a multi-aperture camera : low height (Z dimension), zero colour cross-talk, simple colour filter technology, very simple colour correction matrix, depth sensing, extremely wide depth of focus, wide viewing angle, lack of auto-focusing system up to 10 M pixels, fully independent control of each camera in the array, wide dynamic range, … . Maybe I am still forgetting some.

Interesting was the work reported by Andreas Brueckner (Fraunhofer Institute, Jena). He presented a multi-aperture camera based on a regular 2D CMOS image sensor of 3M pixels provided with a dedicated lens array to make a multi-aperture camera out of it. Andreas presented also some images as well as numerical data. An engineer likes to see numbers (although Neil said “Numbers add up to nothing”). At the end of the talk, Andreas announced that they are working on a much higher resolution imager than the one used today.

Next was the talk of Edward Dowski (Ascentia Imaging, Boulder, CO), who is added a coding grid on top of the multi-aperture cameras, e.g. to depolarize the incoming light. Different apertures can be coded in a unique way relative to other channels in multi-aperture system. This enables in many applications the location estimation of general objects to sub-pixel precision.

The last multi-aperture solution was presented by Guillaume Druart (ONERA, Palaiseau, France) in which he is using the device for IR sensing ! A regular IR sensor is foreseen by an array of 4 x 4 lenslets, which allows the focal length of the individual lenslets to be 4 times less than a regular lens in front of the full resolution device. The lenslets are placed and/or designed such that the 16 sub-arrays do not “see” the same information. So out of the 16 low resolution images, a single high resolution end result is constructed. Nice video of moving image concluded the talk. See you tomorrow through a multi-aperture camera ?

Albert, 27-11-2012.

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