The EURion constellation (also known as Omron rings[1] or doughnuts[2]) is a pattern of symbols incorporated into a number of banknote designs worldwide since about 1996. It is added to help imaging software detect the presence of a banknote in a digital image. Such software can then block the user from reproducing banknotes to prevent counterfeiting using color photocopiers. Research shows that the EURion constellation is used for color photocopiers but probably not used in computer software.[3] However, there have been reported incidents where Adobe Photoshop doesn’t allow the editing of banknotes upon detection of the EURion constellation.[4]
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