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SUMMARY:Lippmann Photography: The Art and Science of Multispectral Imagery
  - Professor Martin Vetterli (Ecole Polytechnique Fédérale de Lausanne)
DTSTART:20241030T140000Z
DTEND:20241030T150000Z
UID:TALK222127@talks.cam.ac.uk
CONTACT:Kimberly Cole
DESCRIPTION:We explored the earliest example of multispectral imaging\, de
 veloped in the late 19th century by Gabriel Lippmann\, who received the 19
 08 Nobel Prize in Physics. Unlike standard trichromacy\, Lippmann photogra
 phy relies on an interferential process that records the entire colour spe
 ctrum. Producing and viewing Lippmann plates is complex and challenging\, 
 therefore Lippmann photography remains a rare curiosity. \n\nWe first cons
 idered producing faithful digital copies of Lippmann photographs\, requiri
 ng high-dimensional multispectral acquisition. This led to a precise mathe
 matical modelling of the two key aspects in Lippmann photography: the way 
 in which standing waves are recorded in the light-sensitive medium\, and t
 he way in which these waves are reproduced when white light excites the re
 corded interference patterns. A physical model combined with mathematical 
 analysis provided us with a new and much more complete understanding of th
 e Lippmann process\, which was verified by experimental acquisitions and b
 y analysing the resulting plates via X-ray imaging and tomography. Some ph
 enomena\, absent from previous analyses\, can be explained and verified wi
 th this new model. In particular\, the folk theorem of perfect colour repr
 oduction by Lippmann photography was shown to be just that\, a folk theore
 m.\n\nWe also designed a “digital” Lippmann camera that mimics the acq
 uisition process carried out by the original analogue Lippmann method. Thi
 s is an alternative multispectral camera based on interferometry\, and ill
 ustrates interesting trade-offs between number of channels\, number of pix
 els\, and exposure time.\n\nWe then considered the idea of reproducing the
  Lippmann recording process using femto-second lasers on an appropriate su
 bstrate. Printing in three-dimensions and with a full spectrum could lead 
 to new high density permanent storage methods\, a technology of great inte
 rest given the explosion of digital data.
LOCATION:Department of Engineering - LT2
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