Invisible watermarking using Discrete Cosine Transform (DCT): A comprehensive exploration

Invisible watermarking is a technique used to protect digital media, like images and videos, by adding a secret mark (watermark) that cannot be seen. This helps prevent copying and ensures the content’s authenticity. One popular method for invisible watermarking is called Discrete Cosine Transform (DCT), which works by changing the image into a form where small changes can be made without affecting its quality. DCT focuses on the frequency of the image, which helps hide the watermark in a way that it’s not noticeable to the human eye. This technique is used in many areas like copyright protection and security. In this paper, we explain how DCT works, how to apply it using Python, and where it can be used. We also discuss the advantages and disadvantages of DCT-based watermarking compared to other methods, showing why it’s a strong choice for protecting digital content.