ABSTRACT
Objective To propose a double watermarking algorithm based on contourlet transform and speckle detection to automatically select the region of interest(ROI)for solving the problems of copyright infringement and malicious destruction of CT and MRI images.Methods The method used speckle detection and singular value decomposition to select the most relevant location in the low frequency domain of the medical image contourlet wave as the ROI,generated a zero-watermarked image in ROI for protecting image integrity,and embed the ROI zero-watermark and the copyright watermark together in the region of non-interest.Results Compared with other double watermarking algorithms,the double watermarking algorithm could greatly improve the invisibility of the carrier image after the attack.The double watermarked images had a structure similarity index measure higher than 94%.Conclusion The proposed double watermarking algorithm incorporating speckle detection and contourlet transform has better robustness against conventional attacks and geometric attacks,and significantly improves the visual quality of carrier images.
ABSTRACT
Objects:To investigate the current situation of counselors'implementation and their attitude to informed consent in Beijing.Methods:Eleven counselors who worked in Beijing were interviewed,the average of their working years was (7.4 ± 4.4).A semi-structured interview was used to learn about their practicing processes in and viewpoints on informed consent,and their interview transcripts were analyzed through qualitative method.Results:The results could be categorized into four categories,including the content of informed consent,the influential factors of informed consent,problems and confusions,and the significance of informed consent.The crucial role of informed consent in psychotherapy was generally recognized by counselors,and they could obey the related rules as well.The therapists had some confusion and problems about informed consent,such as the form and length,the consent for special population and online consultation.Conclusion:Basically,the counselors in Beijing could comply with the ethical standards of informed consent.However,they also suggest that certain limitations of these rules should be noticed.