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Tóm tắt

Digital watermarking techniques have being studied according to two trends: approach in!to the image space domain and the image frequency domain. In the second trend, the Discret Cosine Transform (DCT) and Discrete Wavelet Transform (DWT) are used popularly. In this paper, we present a new watermark scheme using two independent random number matrices to embed same watermark simultaneously in three bands LH, HL and HH. The watqrmarlextraction of this scheme does not require the original image as well as the original watermarkOur experiments showed that this new scheme allway remains the host image quality a acceptable level and the watermark is robust against almost attacks to watermarked images.