Wavelet Transform-Based Watermarking Algorithm

A wavelet transform-based watermarking algorithm that enables blind detection while effectively resisting common geometric attacks. This algorithm embeds watermark information into images through multi-level discrete wavelet decomposition (DWT), typically selecting mid-frequency sub-bands (like HL and LH) for embedding to balance robustness and imperceptibility. The implementation involves modifying wavelet coefficients using quantization index modulation (QIM) or additive embedding schemes, ensuring the watermark survives operations like rotation, scaling, and cropping. The blind detection mechanism operates without original image reference by employing correlation analysis or statistical detection on extracted coefficients. With high robustness and stealth characteristics, the watermark remains imperceptible while protecting image copyright and integrity. This algorithm demonstrates broad application prospects in digital image security, particularly for copyright protection systems requiring geometric attack resistance.