Abstract:

This paper proposes a technique of image content authentication based on the Laplacian pyramid to verifythe authenticity of image content. First , the image is decomposed into Laplacian pyramid before the transformation.Next , the smooth and detailed properties of the original image are analyzed according to the Laplacian pyramid , andthe properties are classified and encoded to get the corresponding characteristic values. Then , the signature derivedfrom the encrypted characteristic values is embedded in the original image as a watermark. After the reception , thecharacteristic values of the received image are compared with the watermark drawn out from the image , and the algorithmautomatically identifies whether the content is tampered by means of morphologic filtration. The informationof tampered location is presented at the same time. Experimental results show that the proposed authentication algorithmcan effectively detect the event and location when the original image content is tampered , and can toleratesome distortions produced by compression , filtration and noise degradation.

Key words: digital watermark, image authentication, Laplacian pyramid, digital signature, morphology