Photographer's personal watermark: photo by generally represents the photographer of the picture. It is a digital watermark. The process of digital watermarking is to embed some information in protected digital objects (such as still images, videos, audio, etc.), such as the author's serial number, company logo, meaningful text, etc. ) can prove copyright ownership or trace infringement. The photographer's watermark is used to prove the ownership of the picture and prevent it from being stolen by others. On the other hand, it can also improve the popularity of the author and his team.

Extended data

Basic characteristics of watermark

Proveability of watermark

Watermark should be able to provide complete and reliable evidence for the ownership of information products protected by copyright. Watermarking algorithm identifies the owner information embedded in the protected object (such as registered user number, product identification or meaningful words) and can extract it when necessary. Watermark can be used to judge whether the object is protected or not, and can monitor the spread, authenticity identification and illegal copy control of protected data.

This is actually the basic driving force for the development of watermarking technology, although from the current literature, there is relatively little research on it. As far as many existing algorithms are concerned, the attacker can completely destroy the watermark in the image, or copy a theoretically existing "original image", which makes the file owner unable to convincingly provide valid evidence of copyright ownership. Therefore, a good watermarking algorithm should be able to provide completely uncontroversial copyright proof, which requires a lot of work.

Imperceptibility of watermark

It is not easy to detect and contains two meanings. One is visual invisibility, that is, the image change caused by embedding watermark should be imperceptible to the observer's visual system. Ideally, the watermark image is exactly the same as the original image, which is the requirement that most watermarking algorithms should meet. On the other hand, the watermark cannot be recovered by statistical methods. For example, it is impossible to extract or determine the existence of watermarks for a large number of information products that have been processed by the same method and watermarking.

Watermark robustness

Robustness is very important for watermarking. Robustness is a technical term, which simply means that a digital watermark should be able to withstand a large number of different physical and geometric distortions, including intentional (such as malicious attacks) or unintentional (such as image compression, scanning and copying, noise pollution, size change, etc. After these operations, the robust watermarking algorithm should still be able to extract the embedded watermark from the watermark image or prove the existence of the watermark.

If you don't know all the relevant knowledge about watermarking, the copyright protection mark of data products should be difficult to forge. If the attacker tries to delete the watermark, it will lead to the complete destruction of multimedia products. Suppose a reader downloads the works published by the digital library on the Internet, prints them out and illegally distributes them in large quantities for profit, then in the case of physical distortion, the works containing watermarks should still provide sufficient copyright evidence.

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