An effective blind watermark algorithm based on DCT

Using the information hiding technology is to be more and more important in the multimedia network transmission, but what is used in the commercial image copyright protection mainly is the digital watermark technology. Realizing the digital watermark can use the digital watermark technology based on picturepsilas transform, which does DCT transform to the picture. It converts the host image block to the matrix, selects the partial frequency component from the transformed matrix DCT coefficient, converts the watermark to the matrix, then embeds the watermark in the host image, which obtain watermark image by IDCT transform. Extracting the watermark use the reverse process of embedding watermark.