Robust watermark technology based on scrambling and multi-embedding
Nie Du-xian · Jisuanji gongcheng · 2005
A watermark algorithm was improved in embedding and extracting. One watermark pixel was embedded many times into DC, mid-frequency and low-frequency coefficients of the same DCT block. What it dose was not averaging watermark values extracted from one block, but applied a self-studying method to get the last watermark. The watermark system is more preferable.