A Watermarking System for Still Images based on JPEG compression Process

摘要

PURPOSE: A watermarking system for a still image based on JPEG compression algorithm is provided to insert watermarks into contents including still images, thereby preventing the contents from being stolen by an optional attacker. CONSTITUTION: A system extracts DC coefficient values from each block of DCT(Discrete Cosine Transform) images, and configures basic matrices. The system performs a shuffling process for each of components by using a PRNG(Pseudo Random Number Generator), and compares position-converted component values with average values of peripheral components. If the component values are bigger than the average values of the peripheral components, the system increases the component values by 1. The system watermarks a matrix consisting of 1 and 0, and uses the matrix when proving owner