METHOD FOR AUTHENTICATING AN IMAGE BY A BLOCK UNIT USING REVERSIBLE WATERMARKING BASED ON A PROGRESSIVE DIFFERENTIAL HISTOGRAM TO INCREASE AUTHENTICATION ACCURACY

摘要

PURPOSE: A method for authenticating an image by a block unit using reversible watermarking based on a progressive differential histogram is provided to divide original image data by a block unit to insert an authentication code to each block using a DCT(Discrete Cosine Transform) coefficient, thereby authenticating damage due to an attacker.;CONSTITUTION: Original image data are separated(S1). The separated original image data are divided by a block unit(S2). A feature value is extracted(S3). Each authentication code is matched with a corresponding divided block(S4). A progressive differential histogram for each divided block is formed(S5). A modified progressive differential histogram is generated by inserting the generated authentication code. A pixel value of each divided block is updated according to each channel(S6). Watermarking image data are obtained by remerging the channels(S7).;COPYRIGHT KIPO 2013;[Reference numerals] (AA) Start; (BB) End; (S1) Separating original image data into RGB color channels; (S2) Dividing the separated original image data by blocks; (S3) Extracting feature values by DCT and quantization about the divided blocks; (S4) Generating each authentication code by exclusive-OR operating the feature values with a private key; (S5) Forming progressive differential histogram about the divided blocks and inserting the authentication code to be corrected; (S6) Updating the pixel values of the divided blocks for each channel using the corrected progressive differential histogram; (S7) Recombining the RGB channels and obtaining water mark inserted marking-image data