Documents / Report
This Defense Intelligence Reference Document, dated 2 March 2010 and produced by the Defense Intelligence Agency under its Advanced Aerospace Weapon System Applications (AAWSA) Program, is a technical survey of invisibility. It covers camouflage, including stealth aircraft and optical camouflage, then transparency, cloaking by coordinate transformation, metamaterials and non-Euclidean broadband cloaking. It concludes that perfect cloaking is impossible but imperfect microwave cloaks are within reach of present technology. Whether cloaking will work at visible wavelengths remains unclear.
“The Times”8 pages
UNCLASSIFIED//5O9 OFFICIO k YEE a••k>! Another recent example of camouflage is optical camouflage, developed by the University of Tokyo's Tachi Laboratory. Figure 2 shows an example of optical camouflage. A camera captures the background scene behind the person. The image is processed and projected onto the person via a semitransparent mirror. The person wears an "invisibility cloak" made of a retroreflective material that reflects light back in the direction whence it came, like cats-eye-reflectors do. As the cloak carries the projected image of the background, the person seems to disappear, but surely the equipment standing around the person is clearly visible. In addition, optical camouflage works only in one direction; seen from the side, the person is visible. Nevertheless, optical camouflage may become a useful tool in some situations where obstacles are in the way of sight- Figure 2. Optical Camouflage (Tachi Laboratory, for example in surgery, where the Tokyo) surgeon's hands and instruments may obstruct the view. Figure 3 shows how optical camouflage works. (41"'~* 1,,-..,,,'J .. , ... , ,..,,,, ~•~• _,,...... .,, ",h, , ..,.... ,, ....,,, ...... ,... I~ I It.off MNTO<1 .........., '"'"" •h• .~ ..... IZ)Compuu, f",, ........, ,, ...........1 --....... I""•• .,., thr ...... ,.,, ... I/ I (1 'I, 111c""'*'"" c..",..,.,<:1 ,.,.. ,.,,.,, ..... , ..... , ,t..- , ... ,,,,., The SecrN of Trana:parrnt Cloak Figure 3. The Secret Optical Camouflage (Tachi Laboratory, Tokyo) 2 UNCLASSIFIED/ ;CEiOAt OFFIQl.ltk Wlili &••t\f
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Report, from the dia collection. The PDF is mirrored here; the original link is under it. 29 pages are in the text index: search them above, or from the library's search.