Watermark embedding and detction method for authentication and detection of manipulated position in digital video

摘要

PURPOSE: A watermark insertion/detection method for recognizing digital video authorizing and manipulating positions is provided to recognize authorization procedure and manipulation position by extracting authorization data inserted for video data in the raw format or MPEG-2 bit stream format. CONSTITUTION: A watermark insertion/detection method for recognizing digital video authorizing and manipulating positions includes determining whether a video data in the raw format is inputted(S100), converting the inputted video data to frequency domains proper for corresponding application(S101), and inserting authorization data by using a quantized coefficient value(S102). If a video data in the MPEG-2 bit stream is inputted(S103), a DCT coefficient value quantized by variable length decoding is recovered from the bit stream(S104). A hash function output value is obtained with a 128 bit length by using the quantized DCT coefficient value as an input value of the hash function(S105). Am LSB is extracted from the coefficient selected for video data authorization for generating a bit stream formed of the LSB(S106). LSB bit streams for the video data authorization is compressed without loss(S107). In a space reduced by the lossless compression is inserted information required for an output value of the hash function(S108). Change information of a DC coefficient is inserted into the LSB(S110). The LSB of the coefficient selected in the step S106 is converted to the LSB modified in the steps S108,S110(S111). Insertion of authorization data for all frames are determined by variable length decoding(S112,113). If so, video data in the compressed video bit streams format inserted with the authorization data is generated(S114).