Digital Watermarking in Images Using Dct: Embedding, Extraction and Visual Quality Preservation

This paper presents an algorithm for embedding and extracting a digital watermark in an image using the Discrete Cosine Transform (DCT).The standard Lenna image was used as the test image, while the watermark was implemented in the form of a chessboard, defined within a simple matrix structure to facilitate implementation.The simulation of the process was carried out using MATLAB software support.This approach enables the visualization of the process, significantly simplifying the embedding and extraction of the digital watermark.In addition to its application in digital image protection, this model can serve as a foundation for analyzing the impact of various transmission channels on an image, such as atmospheric channels in wireless communications.Beyond the DCT, the proposed approach can also be adapted to other frequency domain transformations, such as the Discrete Fourier Transform (DFT) or the Discrete Wavelet Transform (DWT).