Özet:

As information technology is fast developing, it brings great convenience to our everyday life. However, hackers may also access confidential data illegally and easily from computers over the Internet. Therefore, how to protect property rights against infringement is an essential issue. Digital watermarking is a method that adds personal information to an intellectual property to protect one's ownership rights. Should the intellectual property be disputed, the owner can retrieve the watermark and prove ownership rights. Based on the principles of visual cryptography and the law of large numbers, our study generates shares by comparing pseudorandomly selected value pairs during the processes of embedding and verifying the hidden watermark. The wavelet transformation coefficients of the LL$_{3}$ region are used as the sample population. Experimental results indicate that our method has good robustness against darkening, lightening, blurring, sharpening, noising, distortion, jitter, JPEG, and cropping attacks. There are 3 advantages to our method: 1) robustness is retained when the protected image suffers from attacks; 2) unexpanded shares are created to reduce the size of every share; 3) the embedded watermark is decoded by the human visual system during the verification process.

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