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Multimed Tools Appl (2017) 76:65756594 DOI 10.1007/s11042-016-3332-3
Hwai-Tsu Hu1 & Ling-Yuan Hsu2
Received: 28 July 2015 /Revised: 3 January 2016 /Accepted: 2 February 2016 / Published online: 17 February 2016# Springer Science+Business Media New York 2016
Abstract In this paper the merits of block-based blind watermarking in a composite DWTDCT domain are explored. To improve the performance in robustness and imperceptibility, the quantization index modulation (QIM) applied to DWT-DCT coefficients has been formulated in an adaptive manner, where controlling parameters are designed to minimize the bit error rates of extracted watermarks subject to a quality criterion. The targeted coefficients are chosen based upon signal analysis in combination with additional consideration of human visual characteristics. To further enhance watermarking efficiency, two collective strategies are proposed. One takes advantage of multi-bit embedding and the other modifies the norm of a vector constituted by selected coefficients. Experimental results show that, in comparison with other DWT- and/or DCT-related watermarking methods, the proposed collective schemes achieve satisfactory improvements in robustness while the imperceptibility is properly maintained.
Keywords Block-based image watermarking . Discrete wavelet transform . Discrete cosine transform . Progressive quantization index modulation . Collective embedding strategy
1 Introduction
Due to the advance of information technology, the access, modification and redistribution of digital multimedia data are now much easier than before. While the protection of multimedia
* Hwai-Tsu Hu [email protected]
1 Department of Electronic Engineering, National I-Lan University, No. 1, Sec. 1, Shen-Lung Rd.,
Yi-Lan City, Yi-Lan, Taiwan 26041, Republic of China
2 Department of Information Management, St. Marys Junior College of Medicine, Nursing and Management, 100, Lane 265, Sansing Rd., Sec. 2, Sansing Township, Yi-Lan, Taiwan 26644, Republic of China
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6576 Multimed Tools Appl (2017) 76:65756594
content increasingly became an important issue, digital watermarking was proposed as a promising resolution to prevent intellectual property infringement. Watermarking techniques are intended to insert information into digital data without introducing perceptual changes and later extract the inserted information for a variety of purposes such as content authentication, integrity verification and secret communication.
There are four important concerns for digital watermarking, namely, imperceptibility, robustness, capacity and security [40]. Researchers have...