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Diffused lighting camouflage was a form of active camouflage using counter-illumination to match the background, prototyped by the Royal Canadian Navy during World War II. The concept was to project light on to the sides of a ship so as to make its brightness match its background. For this purpose, projectors were mounted on temporary supports attached to the hull. The prototype was developed to include automatic control of brightness using a photocell. The prototyped concept was never put into production. The Canadian ideas were however adapted by the US Air Force in its Yehudi lights project. ==Concept== Diffused lighting camouflage was explored by the Royal Canadian Navy (RCN) and tested at sea on corvettes during World War II, and later in the armed forces of the UK and the US. An equivalent strategy, known to zoologists as counter-illumination, is used by many marine organisms, notably cephalopods including the Midwater Squid, ''Abralia veranyi''. The underside is covered with small photophores, organs that produce light. The squid varies the intensity of the light according to the brightness of the sea surface far above, providing effective camouflage by diffusely lighting out the animal's shadow. In 1940, a Canadian professor at McGill University,〔R.C. Fetherstonhaugh, R.C., 1947, pages 337-341.〕 Edmund Godfrey Burr, serendipitously stumbled on the principle of counterillumination, or as he called it "diffused-lighting camouflage".〔Burr, 1947, pages 45-54.〕〔Burr, 1948, pages 19-35.〕 Burr had been tasked by Canada's National Research Council (NRC) to evaluate night observation instruments. With these, he found that aircraft flying without navigation lights remained readily visible as silhouettes against the night sky, which was never completely black. Burr wondered if he could camouflage planes by somehow reducing this difference in brightness. One night in December 1940, Burr saw a plane coming in to land over snow suddenly vanish: light reflected from the snow had illuminated the underside of the plane just enough to cancel out the difference in brightness, camouflaging the plane perfectly. Burr informed the NRC, who told the RCN. They realized that the technique could help to hide ships from German submarines in the Battle of the Atlantic. Before the introduction of centimetre radar, submarines with their small profile could see convoy ships before they were themselves seen. Diffused lighting camouflage might, the RCN believed, redress the balance.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「diffused lighting camouflage」の詳細全文を読む スポンサード リンク
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