A Comparison of DCT and DWT Block Based Watermarking on Medical Image Quality (original) (raw)
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Visual quality assessment of watermarked medical images
Medical Imaging 2007: Image Perception, Observer Performance, and Technology Assessment, 2007
Increasing transmission of medical images across multiple user systems raises concerns for image security. Hiding watermark information in medical image data files is one solution for enhancing security and privacy protection of data. Medical image watermarking however is not a widely studied area, due partially to speculations on loss in viewer performance caused by degradation of image information. Such concerns are addressed if the amount of information lost due to watermarking can be kept at minimal levels and below visual perception thresholds. This paper describes experiments where three alternative visual quality metrics were used to assess the degradation caused by watermarking medical images. Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) medical images were watermarked using different methods: Block based Discrete Cosine Transform (DCT) and Discrete Wavelet Transform (DWT) with various embedding strengths. The visual degradation of each watermarking parameter setting was assessed using Peak Signal-to-Noise Ratio (PSNR), Structural Similarity Measure (SSIM) and Steerable Visual Difference Predictor (SVDP) numerical metrics. The suitability of each of the three numerical metrics for medical image watermarking visual quality assessment is noted. In addition, subjective test results from human observers are used to suggest visual degradation thresholds.
Journal of Computer Science and Engineering, 2016
As security is very crucial in almost every sector of services nowadays, watermarking is more or less an important mechanism in securing vital information such as medical images. Water marking aimed at providing secure medical images through integrity verification, such that unauthorized person cannot be able to modify it. In a bid to find a secured watermarking technique which prevents a medical image from degradation, this research explores a mechanism known as Hybrid Transformed Watermarking. Two mechanisms are employed that include Discreet Cosine Transform (DCT) and Discreet Wavelet Transform (DWT). The two techniques were combined to transform a medical image with the intent of providing authenticity and integrity verification, the final result was an efficient watermarked imaged.
AN INVESTIGATION OF WATERMARKING MEDICAL IMAGES
This paper presents the results of watermarking selected various medical cover images with simple string of letters image (patients' medical data) using a combination of the Discrete Wavelet Transform (DWT) Discrete Cosine Transform (DCT) and singular value decomposition (SVD). The visual quality of the watermarked images (before and after attacks) was analyzed using PSNR and four visual quality metrics (WSNR, MSSIM, PSNR-HVS-M, and PSNR-HVS). The PSNR, PSNR-HVS-M, PSNR-HVS, and WSNR average values of the watermarked medical images before attacks were about the 32 db, 35 db, and 42 db, 40 db respectively; while the MSSM index indicated a similarity of more than 97% between the original and watermarked images. The metric values decreased significantly after attacking the images with various operations but the watermark image could be retrieved after almost all attacks. Thus, the initial results indicate that watermarking medical images with the patients' data does not significantly affect their visual quality and they still can be utilized for their medical purpose.
Securing Medical Images by Watermarking Using DWT-DCT-SVD
2014
Telemedicine is well known application where enormous amount of medical data need to be transferred securely over network and manipulate effectively. Security of digital data, especially medical images, becomes important for many reasons such as confidentiality, authentication and integrity. Digital watermarking has emerged as a advanced technology to enhance the security of digital images. The insertion of watermark in medical images can authenticate it and guarantee its integrity. The watermark must be generally hidden does not affect the quality of the medical image. In this paper, we propose blind watermarking based on Discrete Wavelet Transform (DWT), Discrete Cosine Transform (DCT) and Singular Value Decomposition (SVD), we compare the performance of this technique with watermarking based DWT and SVD. The proposed method DWT, DCT and SVD comparatively better than DWT and SVD method. Keywords— Digital Watermarking, Medical images, Discrete Wavelet Transform (DWT) Discrete Cosin...
Secure Watermarking Technique for Medical Images with Visual Evaluation
SSRN Electronic Journal, 2018
This paper presents a hybrid watermarking technique for medical images. The method uses a combination of three transforms: Discrete Wavelet Transform (DWT), Discrete Cosine Transform (DCT), and singular value decomposition (SVD). Then, the paper discusses the results of applying the combined method on different medical images from eight patients. The images were watermarked with a small watermark image representing the patients' medical data. The visual quality of the watermarked images (before and after attacks) was analyzed using five quality metrics: PSNR, WSNR, PSNR-HVS-M, PSNR-HVS, and MSSIM. The first four metrics' average values of the watermarked medical images before attacks were approximately 32 db, 35 db, 42 db, and 40 db respectively; while the MSSM index indicated a similarity between the original and watermarked images of more than 97%. However, the metric values decreased significantly after attacking the images with various operations even though the watermark image could be retrieved after almost all attacks. In brief, the initial results indicate that watermarking medical images with patients' data does not significantly affect their visual quality and they can still be used by medical staff.
Securing Medical Images by Watermarking Using DWT DCT and SVD
Telemedicine is well known application where enormous amount of medical data need to be transferred securely over network and manipulate effectively. Security of digital data, especially medical images, becomes important for many reasons such as confidentiality, authentication and integrity. Digital watermarking has emerged as a advanced technology to enhance the security of digital images. The insertion of watermark in medical images can authenticate it and guarantee its integrity. The watermark must be generally hidden does not affect the quality of the medical image. In this paper, we propose blind watermarking based on Discrete Wavelet Transform (DWT), Discrete Cosine Transform (DCT) and Singular Value Decomposition (SVD), we compare the performance of this technique with watermarking based DWT and SVD. The proposed method DWT, DCT and SVD comparatively better than DWT and SVD method.
Robust Multiple Watermarking Technique for Medical Applications using DWT, DCT and SVD
Transactions on Machine Learning and Artificial Intelligence, 2017
The security of medical data plays an important role in preserving their integrity and confidentiality. This paper presents a robust multiple watermarking algorithm based on a combination of discrete wavelet transform (DWT), discrete cosine transform (DCT) and singular value decomposition (SVD). In this proposed method, we have inserted three watermark images (a patient image, a doctor image and a fingerprint of the patient) into a single cover medical image. In the insertion phase, the original image is decomposed into the third level of DWT, and then the DCT and SVD transforms are applied on the selected sub bands (HH1, HH2, and HH3). The first watermark goes through the same steps that the original image. Moreover, the second and the third watermarks are decomposed until the second level and the first level by DWT respectively and subsequently transformed by SVD. The singular values of the three watermarks are inserted into the singular values of the original image. The experimental results show that the proposed method gives better performance in terms of capacity, quality and robustness against various attacks compared to other reported techniques.
An efficient medical image watermarking scheme based on FDCuT–DCT
Engineering Science and Technology, an International Journal, 2017
In this paper, a blind medical image watermarking scheme based on Fast Discrete Curvelet Transform (FDCuT) and Discrete Cosine Transform (DCT) is proposed. FDCuT is applied on the medical image to get different frequency coefficients of its curvelet decomposition. On the high frequency curvelet coefficients of the medical image, block wise DCT is applied to get different frequency coefficients. Then mid band frequency coefficients of the medical image are modified by White Gaussian Noise (WGN) sequences according to watermark bit to get watermarked medical image. At extraction end, blind recovery of watermark data is performed by correlation of WGN sequences. The proposed scheme is tested for its effectiveness on various types of medical images such as X-ray, Ultrasound (US), Magnetic Resonant Imaging (MRI) and Computerized Tomography (CT). Result analysis shows that imperceptibility of watermarked medical image is better as PSNR is above 45 dB for all types of the medical images. In addition, the robustness of the scheme is better than an existing scheme for a similar set of medical images in terms of Normalized Correlation (NC). Experimental results show that scheme is robust to geometric attacks, signal processing attacks and JPEG compression attacks. An analysis is also carried out to verify the performance of the proposed scheme to support binary watermarks with different details in it: text and logos. Moreover, the proposed scheme resulted in zero false positive rate when tested on 100 nonwatermarked images.
A Robust Hybrid Watermarking Technique for Securing Medical Image
International Journal of Intelligent Engineering and Systems, 2018
In the aim to contribute to the security of medical image, we present a robust watermarking method which combines discrete wavelet transform (DWT), discrete cosine transform (DCT) and singular value decomposition (SVD). This approach is intended to insert an invisible image watermark in a medical image. The cover medical image is divided up into the third level of DWT coefficients and then is transformed by DCT and SVD. The same procedure is applied to the watermark image. The singular value of watermark is inserted into the singular value of the high-frequency sub bands of the third level DWT of the cover image. However, the insertion of the watermark in these areas makes it possible to reinforce the robustness of the system of watermarking without hindering the quality of the watermarked image. The performance of the proposed method was evaluated in term of invisibility by calculating the Peak Signal to Noise Ratio (PSNR) between the original and the watermarked image and in term of robustness by measuring the normalized correlation coefficient (NC) between the original watermark and the extracted watermark after applying attacks. The experimental results approve that our proposed hybrid algorithm gives an excellent compromise imperceptibility and robustness against several attacks such as Gaussian noise, Saltand-Pepper, Speckle noise, Average filter, Median filter, and Wiener filter compared with existing methods.
Multimedia Tools and Applications, 2016
In this paper, a blind image watermarking scheme based on discrete wavelet transform (DWT) and singular value decomposition (SVD) is proposed. In this scheme, DWT is applied on ROI (region of interest) of the medical image to get different frequency subbands of its wavelet decomposition. On the low frequency subband LL of the ROI, block-SVD is applied to get different singular matrices. A pair of elements with similar values is identified from the left singular value matrix of these selected blocks. The values of these pairs are modified using certain threshold to embed a bit of watermark content. Appropriate threshold is chosen to achieve the imperceptibility and robustness of medical image and watermark contents respectively. For authentication and identification of original medical image, one watermark image (logo) and other text watermark have been used. The watermark image provides authentication whereas the text data represents electronic patient record (EPR) for identification. At receiving end, blind recovery of both watermark contents is performed by a similar comparison scheme used during the embedding process. The proposed algorithm is applied on various groups of medical images like X-ray, CT scan and mammography. This scheme offers better visibility of watermarked image and recovery of watermark content due to DWT-SVD combination. Moreover, use of Hamming error correcting code (ECC) on EPR text bits reduces the BER and thus provides better recovery of EPR. The performance of proposed algorithm with EPR data coding by Hamming code is compared with the BCH error correcting code and it is found that later one perform better. A result analysis shows that imperceptibility of watermarked image is better as PSNR is above 43 dB and WPSNR is above 52 dB for all set of images. In addition, robustness of the scheme is better than existing scheme for similar set of medical images in terms of normalized correlation coefficient (NCC) and bit-error-rate (BER). An analysis is also carried out to verify the performance of the proposed scheme for different Multimed Tools Appl