8x8 Block-based Digital Watermark Embedding and Extraction Algorithm

This section discusses the working principles and practical significance of the 8x8 block-based digital watermark embedding and extraction algorithm. The algorithm employs discrete cosine transform (DCT) on 8x8 pixel blocks, where watermark data is embedded in mid-frequency coefficients to balance visibility and robustness. Key functions include block partitioning, DCT coefficient modification using quantization matrices, and inverse DCT transformation for watermark reconstruction. The implementation features adaptive thresholding for extraction and supports both binary and grayscale watermark patterns. Having undergone comprehensive debugging, the algorithm demonstrates reliable performance in various applications including image authentication and copyright protection with minimal perceptual impact. The code structure incorporates modular design with separate functions for embedding (embedWatermark) and extraction (extractWatermark), utilizing matrix operations for efficient block processing.