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A dual adaptive watermarking scheme in contourlet domain for DICOM images.

Rahimi F, Rabbani H - Biomed Eng Online (2011)

Bottom Line: Our results show that watermarked images in contourlet domain have greater robustness against attacks than wavelet domain.In addition, the qualitative analysis of our method shows it has good invisibility.The embedded watermark bits can be extracted without the original image, the proposed method has high PSNR and SSIM, and the watermarked image has high transparency and can still conform to the DICOM format.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Biomedical Engineering, Isfahan University of Medical Sciences, Isfahan, Iran.

ABSTRACT

Background: Nowadays, medical imaging equipments produce digital form of medical images. In a modern health care environment, new systems such as PACS (picture archiving and communication systems), use the digital form of medical image too. The digital form of medical images has lots of advantages over its analog form such as ease in storage and transmission. Medical images in digital form must be stored in a secured environment to preserve patient privacy. It is also important to detect modifications on the image. These objectives are obtained by watermarking in medical image.

Methods: In this paper, we present a dual and oblivious (blind) watermarking scheme in the contourlet domain. Because of importance of ROI (region of interest) in interpretation by medical doctors rather than RONI (region of non-interest), we propose an adaptive dual watermarking scheme with different embedding strength in ROI and RONI. We embed watermark bits in singular value vectors of the embedded blocks within lowpass subband in contourlet domain.

Results: The values of PSNR (peak signal-to-noise ratio) and SSIM (structural similarity measure) index of ROI for proposed DICOM (digital imaging and communications in medicine) images in this paper are respectively larger than 64 and 0.997. These values confirm that our algorithm has good transparency. Because of different embedding strength, BER (bit error rate) values of signature watermark are less than BER values of caption watermark. Our results show that watermarked images in contourlet domain have greater robustness against attacks than wavelet domain. In addition, the qualitative analysis of our method shows it has good invisibility.

Conclusions: The proposed contourlet-based watermarking algorithm in this paper uses an automatically selection for ROI and embeds the watermark in the singular values of contourlet subbands that makes the algorithm more efficient, and robust against noise attacks than other transform domains. The embedded watermark bits can be extracted without the original image, the proposed method has high PSNR and SSIM, and the watermarked image has high transparency and can still conform to the DICOM format.

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Related in: MedlinePlus

The contourlet transform of a CT brain image.
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Related In: Results  -  Collection

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Figure 2: The contourlet transform of a CT brain image.

Mentions: The contourlet transform [21], as introduced by Minh Do and Martin Vetterli, is a new image decomposition scheme, which provides a flexible multiresolution representation for two dimensional signals. It makes use of the Laplacian pyramid decomposition (LPD) for the multiresolution representation of the image. In the contourlet transform, the Laplacian pyramid decomposes an image into a low frequency subband and a high frequency subband. After this, a directional decomposition is performed on every band-pass image using directional filter banks (DFB). The contourlet transform is unequaled since the number of directional bands could be indicated by the user at any resolution. Finally, the image is represented as a set of directional subbands at multiple scales. Discrete countourlet transform is able to capture the directional edges and contours superior to discrete wavelet transform. The schematics structure of contourlet transform [22] and an example of contourlet decomposition of a CT brain image are illustrated in Figure 1 and 2 respectively.


A dual adaptive watermarking scheme in contourlet domain for DICOM images.

Rahimi F, Rabbani H - Biomed Eng Online (2011)

The contourlet transform of a CT brain image.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3142237&req=5

Figure 2: The contourlet transform of a CT brain image.
Mentions: The contourlet transform [21], as introduced by Minh Do and Martin Vetterli, is a new image decomposition scheme, which provides a flexible multiresolution representation for two dimensional signals. It makes use of the Laplacian pyramid decomposition (LPD) for the multiresolution representation of the image. In the contourlet transform, the Laplacian pyramid decomposes an image into a low frequency subband and a high frequency subband. After this, a directional decomposition is performed on every band-pass image using directional filter banks (DFB). The contourlet transform is unequaled since the number of directional bands could be indicated by the user at any resolution. Finally, the image is represented as a set of directional subbands at multiple scales. Discrete countourlet transform is able to capture the directional edges and contours superior to discrete wavelet transform. The schematics structure of contourlet transform [22] and an example of contourlet decomposition of a CT brain image are illustrated in Figure 1 and 2 respectively.

Bottom Line: Our results show that watermarked images in contourlet domain have greater robustness against attacks than wavelet domain.In addition, the qualitative analysis of our method shows it has good invisibility.The embedded watermark bits can be extracted without the original image, the proposed method has high PSNR and SSIM, and the watermarked image has high transparency and can still conform to the DICOM format.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Biomedical Engineering, Isfahan University of Medical Sciences, Isfahan, Iran.

ABSTRACT

Background: Nowadays, medical imaging equipments produce digital form of medical images. In a modern health care environment, new systems such as PACS (picture archiving and communication systems), use the digital form of medical image too. The digital form of medical images has lots of advantages over its analog form such as ease in storage and transmission. Medical images in digital form must be stored in a secured environment to preserve patient privacy. It is also important to detect modifications on the image. These objectives are obtained by watermarking in medical image.

Methods: In this paper, we present a dual and oblivious (blind) watermarking scheme in the contourlet domain. Because of importance of ROI (region of interest) in interpretation by medical doctors rather than RONI (region of non-interest), we propose an adaptive dual watermarking scheme with different embedding strength in ROI and RONI. We embed watermark bits in singular value vectors of the embedded blocks within lowpass subband in contourlet domain.

Results: The values of PSNR (peak signal-to-noise ratio) and SSIM (structural similarity measure) index of ROI for proposed DICOM (digital imaging and communications in medicine) images in this paper are respectively larger than 64 and 0.997. These values confirm that our algorithm has good transparency. Because of different embedding strength, BER (bit error rate) values of signature watermark are less than BER values of caption watermark. Our results show that watermarked images in contourlet domain have greater robustness against attacks than wavelet domain. In addition, the qualitative analysis of our method shows it has good invisibility.

Conclusions: The proposed contourlet-based watermarking algorithm in this paper uses an automatically selection for ROI and embeds the watermark in the singular values of contourlet subbands that makes the algorithm more efficient, and robust against noise attacks than other transform domains. The embedded watermark bits can be extracted without the original image, the proposed method has high PSNR and SSIM, and the watermarked image has high transparency and can still conform to the DICOM format.

Show MeSH
Related in: MedlinePlus