An digital image watermark algorithm is proposed based on the synergetic neural network

combined with encryption technique

to guarantee its robustness and security.The meaningful gray image is serially processed into watermark signal and embedded into the DC elements of the block DCT coefficient matrix of the host image.Watermark detection/extraction algorithm is realized by using synergetic neural network.The(network's) input is possible watermark signal and its output is the recognition result.The emulational experiments indicates that

the proposed algorithm can fulfill the watermark detection/extraction at one time after image processing

and identify the watermark owner which shows good performance.