Watermarking by histogram specification

摘要: The paper investigates the use of image histograms as watermarks. First, problem exact histogram specification is addressed and a method for specification, consistent with human perception brightness, developed. Next, two watermarking techniques based on are proposed. first one directly considers Thus, particular assigned watermark images further transformed to have exactly histogram. Since quite large variations in not perceived by humans, an unlimited number invisible watermarks can be defined which appear visually non-distorted. Besides, selecting uniform histogram, only uniquely marked but also enhanced. second approach conserves, each image, its original procedure consists transforms: transform followed inverse recover recovery after exact, error obtained consecutive transforms used track watermark.© (1999) COPYRIGHT SPIE--The International Society Optical Engineering. Downloading abstract permitted personal only.