INTEGRITY CHECKING PROCESS OF IMAGE USING REVERSIBLE WATERMARKING PROCESS TECJNIQUE

摘要

PURPOSE: An integrity authentication method of an image which uses a reversible watermarking technology is provided to authenticate integrity without damage to picture quality by applying a watermarking algorithm to a JPEG image compression format. CONSTITUTION: A quantization DCT coefficient is restored by extracting an authentication code from the restored watermarking quantization DCT coefficient. An original image is restored through the inverse quantization of the restored quantization DCT coefficient, inverse DCT, and color space variation. The authentication code is regenerated from the restored original image. The integrity of the image is confirmed by comparing the extracted authentication code with the regenerated authentication code. [Reference numerals] (AA) Compression process with loss; (BB) Image divided into a 16 x 16 block unit; (CC) Convert into an YCbCr to an RGB color domain; (DD) Divide an 8 x 8 block unit, Descrete cosine convert; (EE) DCT coefficient quantization; (FF) Restored RGB; (GG) Restore YCbCr to RGB; (HH) Inverse DCT; (II) Inverse quantization; (JJ) Quantization DCT coefficient; (KK) Down-sample a 16 x 16 block into an 8 x 8; (LL) Gray scale each channel with the average value; (MM) 8 x 8 feature block; (NN) Select 8 coefficients and insert into the 16 x 16 block; (OO) Quantization; (PP) Feature block DCT coefficient; (QQ) Water mark inserted quantization DCT coefficient; (RR) Water mark inserting process; (SS) Water mark inserted JPEG image; (TT) Entropy coding; (UU) Compression process without loss