TY - GEN
T1 - Improved DM-QIM Watermarking Scheme for PDF Document
AU - Kuribayashi, Minoru
AU - Wong, Kok Sheik
N1 - Funding Information:
Acknowledgment. This research has been partially supported by the Kayamori Foundation of Information Science Advancement and JSPS KAKENHI Grant Number 19K22846.
Publisher Copyright:
© 2020, Springer Nature Switzerland AG.
PY - 2020
Y1 - 2020
N2 - In any application of watermarking, the selection of feature vectors from a given multimedia content is important from the perspective of robustness and security. In the case of PDF document, the spaces between words and characters are commonly utilized for embedding watermark in the conventional schemes. Instead of modifying the space values directly, researchers proposed to manipulate the frequency components of the space values by using the quantization index modulation (QIM) watermarking method. The QIM method is further combined with dither modulation (DM) to enhance secrecy of watermark. In this paper, we improve the imperceptibility of watermarked PDF document by investigating into the DM operation. The proposed method selects the best secret key among some candidates which minimizes the degradation caused by embedding watermark. Information about the selected key is also embedded as side information so that the embedded watermark can be extracted without referring to the original PDF document. The degree of distortion caused by watermark embedding is quantitatively measured in our experiment. It is verified that the gain in terms of signal-to-noise ratio in the proposed method is increased with the number of secret key candidates.
AB - In any application of watermarking, the selection of feature vectors from a given multimedia content is important from the perspective of robustness and security. In the case of PDF document, the spaces between words and characters are commonly utilized for embedding watermark in the conventional schemes. Instead of modifying the space values directly, researchers proposed to manipulate the frequency components of the space values by using the quantization index modulation (QIM) watermarking method. The QIM method is further combined with dither modulation (DM) to enhance secrecy of watermark. In this paper, we improve the imperceptibility of watermarked PDF document by investigating into the DM operation. The proposed method selects the best secret key among some candidates which minimizes the degradation caused by embedding watermark. Information about the selected key is also embedded as side information so that the embedded watermark can be extracted without referring to the original PDF document. The degree of distortion caused by watermark embedding is quantitatively measured in our experiment. It is verified that the gain in terms of signal-to-noise ratio in the proposed method is increased with the number of secret key candidates.
KW - Dither modulation
KW - PDF document
KW - Quantization index modulation
KW - Watermark
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U2 - 10.1007/978-3-030-43575-2_14
DO - 10.1007/978-3-030-43575-2_14
M3 - Conference contribution
AN - SCOPUS:85083692399
SN - 9783030435745
T3 - Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
SP - 171
EP - 183
BT - Digital Forensics and Watermarking - 18th International Workshop, IWDW 2019, Revised Selected Papers
A2 - Wang, Hongxia
A2 - Zhao, Xianfeng
A2 - Shi, Yunqing
A2 - Kim, Hyoung Joong
A2 - Piva, Alessandro
PB - Springer
T2 - 18th International Workshop on Digital Forensics and Watermarking, IWDW 2019
Y2 - 2 November 2019 through 4 November 2019
ER -