N. Mettripun

Publications (2)0 Total impact

• Conference Proceeding: Method of rearranging watermarked pixels for printed and scanned watermarked documents

  N. Mettripun, R. Lhawchaiyapurk, T. Amornraksa
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  ABSTRACT: In this paper, we consider the problem of extracting the embedded watermark from the printed and scanned watermarked images. Since in a practical situation, the parameters settings in the printing and scanning processes between users are different, recovering the embedded watermark from the watermarked paper, after being scanned back to the computer, is difficult and contains high amount of errors. We hence propose a method of rearranging the printed and scanned watermarked pixels to implement with the pixel-wise based digital watermarking in order to improve the accuracy of the extracted watermark. The proposed method is simple, low complex, and possible for practical watermarking applications. With our proposed method, the watermarked paper can now be scanned back in various resolutions with small inclined angles. The experimental results show the improved performance in term of NC obtained from our method, compared to the lower accuracy from the previous method.
  Communications and Information Technologies (ISCIT), 2010 International Symposium on; 11/2010
• Conference Proceeding: Improved performance of image watermarking by removing luminance bias in YCBCR channel

  N. Mettripun, K. Surachat, R. Lhawchaiyapurk, T. Amornraksar
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  ABSTRACT: A digital watermarking for color image based on the modification of image pixels is considered in this paper. Its performance is analyzed and the weaknesses in the watermark embedding and extraction processes are addressed. Based on our analysis, two methods are proposed to improve the watermark embedding and extraction performance. First, the watermark signal is embedded in the chrominance channel. Second, the bias caused by the luminance component in the extraction process is removed. By applying our approach in the above watermark scheme, the impressive improvements in term of PSNR and NC are obtained, and verified by the experimental results. Its performance is also compared to the previous watermarking methods. We finally evaluate the robustness of our watermarking method against various common image processing based attacks.
  Electrical Engineering/Electronics Computer Telecommunications and Information Technology (ECTI-CON), 2010 International Conference on; 06/2010