| Summary: | 碩士 === 中華大學 === 電機工程學系碩士班 === 99 === In today’s world, digital media, audio, video and image can be easily shared by the computer network. The digital watermark is an important copyright enforcement scheme that protects and copyright ownership.
In this study, based on the properties of the Human Visual System (HVS), the Quantization Index Modulation (QIM) method is used to embed the watermark without degrading the visual quality. The JND(Just Noticeable Distortion), the tolerance of changes of scales of a image, in spatial domain, DCT domain(Watson’s model) and DWT domain(PWM) are discussed. Applying Harr DWT, the high efficient computation scheme for spatial domain JND is proposed. Furthermore, the compromise between imperceptibility and robustness, in terms of the quantization step, of watermark is built.
Finally, the simulation results are used to verify the usefulness of this study.
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