Underwater target detection by imaging polarimetry
Résumé
Light comes to Earth from the sun unpolarized. But once it hits the atmosphere, gaseous molecules and other particulate matter wreak havoc, scattering sunlight in all directions and causing it to polarize. Some ocean-dwelling organisms have evolved the ability to sense and respond to polarized light. For example, octopi, mantis shrimp and some echinoderms (e.g., star fish, sea urchins, etc.) can detect polarized light in water, which helps them to navigate, detect prey and interpret intra-species communication signals. Researchers are working on developing novel instruments that are capable of determining polarization, mimicking the visual system of these creatures, said George Kattawar of Texas A&M University in College Station, U.S.A.
Ayman Alfalou of Institut Supérieur d’Électronique et du Numérique (ISEN) and Christian Brosseau of the University of Brest in France morphed JTC—originally used to improve image data encryption with partially polarized light input—into a new technique that has direct applicability to underwater imaging.