The Importance Of Watermarking Process In Mother Night By Kurt Vonnegut
The extraction process, as a minimum, takes the watermarked image and the key as inputs. Depending on the specific watermarking method, the extraction may additionally take as input the original (unwatermarked) image and/or the watermark that is thought to be embedded in the image. The output of the extraction process varies, as well. Some watermarking systems extract the watermark and return it as an output, where others (most often those that take the watermark as an input to the extraction) will return a measure of confidence that the specified watermark is found in the image. The reasons for these different extraction methods will be explained later.
In addition to the generic embedding/extraction steps, watermarking systems have a number of characteristics that can be generically defined. The three most important of these characteristics are the watermark's robustness, payload, and level of perceptibility.
Robustness is simply the notion of how much can be done to the watermarked image in the form of attacks (deliberate and otherwise), such that the watermark can still successfully be extracted from that altered image. In general, a more robust watermark is preferred to one that is less so, but that is not always the …show more content…
Those three applications are copyright enforcement, image authentication, and fingerprinting.
The use of watermarks to ensure copyright enforcement, as has already been mentioned, is by far the largest motivation for watermarking today. Photographers, for instance, can embed some unique identifier (social security number, etc.) into each image that they capture in order to identify themselves as the owner of that image. Others attempting to use these images without the photographer's consent can subsequently be identified by extracting the watermark from the image(s) in question.
The proliferation of the Internet is the largest motivation for these types of watermarks, as images on the Internet are free to be taken and reused by others. It should be clear that the use of a watermark is not effective in, nor intended to prevent someone from reusing an image that is publicly available. Rather the watermark is used to identify the proper owner if and when there is a dispute between two people who claim ownership. Thus, in addition to being robust against common forms of image processing (cropping, rotating, etc.), watermarks containing copyright notices need to be able to identify the unique owner in the event of multiple watermarks. Additionally, since the same person may embed the same copyright notice