DCT-Based Digital Watermarking Graduation Thesis with Algorithm Implementation Analysis

This paper presents a graduation thesis focusing on DCT-based digital watermarking technology. Through in-depth research, the study proposes three main approaches: low-frequency DCT watermarking algorithms, mid-frequency DCT watermarking algorithms, and adaptive video watermarking schemes based on DCT transformation. The low-frequency watermarking algorithm targets applications requiring high image quality preservation, typically implemented by embedding watermark data in DC coefficients through quantization index modulation. The mid-frequency approach suits scenarios with moderate image quality requirements, where watermark insertion in AC coefficients balances robustness and visual quality using block-based DCT decomposition. The adaptive video watermarking scheme dynamically adjusts embedding parameters according to video characteristics like motion intensity and texture complexity, employing frame-level DCT analysis and temporal synchronization mechanisms. Overall, DCT-based digital watermarking demonstrates broad application prospects in information security, and this research provides valuable references through practical algorithm implementations and performance evaluations using common programming frameworks.