Different Forensic Watermarking Technologies and Their Uses
There are now many different types of digital watermarking techniques used for a host of applications. Read this post to know some popular types of watermarking techniques and their common uses.
Digital watermarking is the process of embedding information into digital content, including video, audio, and images with the help of specific algorithms. The embedded data can be visible or invisible and can only be extracted with the help of appropriate algorithms.
While watermarks are of many different types, and there are multiple ways to differentiate them, categorisation based on a domain is the most common. Based on the domain, the watermarks can be categorised into spatial domain watermarks and frequency domain watermarks. Let us have a detailed look at what these watermarks are and their sub-categories.
Frequency Domain Watermarks
The frequency-domain watermarks are watermarks that are embedded into a particular spectral coefficient of the image. These watermarks are very popular as HVS (Human Visual System) characteristics are better captured with the help of spectral coefficients.
Based on the algorithm used for embedding these watermarks, they can be further divided into:
- Discrete Cosine Transforms (DCT)
With the help of DCT algorithms, data is represented in frequency space and not in amplitude space. As compared to spatial domain watermarks, DCT watermarking is known to be more efficient and robust.
- Discrete Wavelet Transforms (DWT)
In DWT watermarks, small waves, known as wavelets, are used for image transformation. With the help of DWT algorithms, an image is decomposed into sub-image with independent frequencies and varying spatial domain.
- Discrete Fourier Transforms (DFT)
With DFT, the continuous function of an image is transformed into frequency components. Unlike DCT, which is weak against geometric attacks, DFT is known to be highly efficient. As a matter of fact, DFT is invariant to RST (Rotation, Scaling, and Translation).
Spatial Domain Watermarks
With the help of spatial domain watermarks, an image is manipulated with the help of an object represented in space. These watermarks load raw data directly into the image pixels and can also be applied with the help of colour separation.
Some common types of spatial watermarks are as follows-
- Least Significant Bit
As the name suggests, LSB watermarks are embedded into the least significant bit of the image. While LSB watermarks can be easily implemented, they are not known to be very efficient against common attacks.
- Additive Watermarking
This is the most common method used for embedding a spatial watermark into digital content. In additive watermarking, a random pseudo-noise pattern signal like floating-point numbers or integers are added to image pixels. They also have a key for watermark detection.
Common Applications of Digital Watermarks
Some of the most common uses of watermarks are as follows-
- Content Authentication
Digital watermarks are now commonly used for detecting modifications in the content. For instance, in case of an image, the characteristics like edges can be embedded with watermark and can then be compared with a modified image to know the difference.
- Prevent Illegal Recording of Movies and Live Content
Movies theatres and live streaming platforms now also use watermarks, which can help the studios and platform owners to know where and when the movie/live content was recorded. Even when a video is in a pre-release stage, it features an operator mark to prevent leaks.
- OTT Platforms
Even the premium content on OTT platforms now have watermarks to track illegal downloading and sharing of their content. With the help of the data embedded in the content, the owners and distributors can also know when and where the content leak took place.
Similarly, there are other uses of forensic watermarking like audience monitoring, user tracking, package identification, medical applications, and more.
Tracking Misuse of Content with Digital Watermarking
With consumers switching to the internet for their entertainment needs, each piece of original content is worth protecting.
If you are a content creator or distributor, try to know more about the benefits of digital watermarking as it can help you protect your content and prevent its misuse. You can also consider the modern SaaS-based watermarking services that are easy to adopt and more affordable than traditional solutions.
