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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 original (top row) and watermarked image (bottom row) in contourlet domain for several CT scans.
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Figure 11: The original (top row) and watermarked image (bottom row) in contourlet domain for several CT scans.

Mentions: To understand the effect of transform domain on our method, we select five CT images of that collection and perform the method on those in two domains contourlet and wavelet (decompose the host Image into two levels by means of Daubechies wavelet transform). For ROI watermarking in wavelet domain the basic quantization step are set to 8 and 6 for CT and MRI images respectively. For RONI embedding in wavelet domain, the basic quantization step achieved by lots of experiments are 260 and 202 for CT and MRI images respectively. Figure 11 shows these images (original) and watermarked images (in contourlet domain) together. This figure shows our method has good invisibility.


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

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

The original (top row) and watermarked image (bottom row) in contourlet domain for several CT scans.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 11: The original (top row) and watermarked image (bottom row) in contourlet domain for several CT scans.
Mentions: To understand the effect of transform domain on our method, we select five CT images of that collection and perform the method on those in two domains contourlet and wavelet (decompose the host Image into two levels by means of Daubechies wavelet transform). For ROI watermarking in wavelet domain the basic quantization step are set to 8 and 6 for CT and MRI images respectively. For RONI embedding in wavelet domain, the basic quantization step achieved by lots of experiments are 260 and 202 for CT and MRI images respectively. Figure 11 shows these images (original) and watermarked images (in contourlet domain) together. This figure shows our method has good invisibility.

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