Hussain Nyeem | Queensland University of Technology (original) (raw)

Papers by Hussain Nyeem

Despite significant improvements in capacity-distortion performance, a computationally efficient ... more Despite significant improvements in capacity-distortion performance, a computationally efficient
capacity control is still lacking in the recent watermarking schemes. In this paper, we propose
an efficient capacity control framework to substantiate the notion of watermarking capacity control to
be the process of maintaining “acceptable” distortion and running time, while attaining the required capacity.
The necessary analysis and experimental results on the capacity control are reported to address
practical aspects of the watermarking capacity problem, in dynamic (size) payload embedding.

ABSTRACT Background: As the increasing adoption of information technology continues to offer bett... more ABSTRACT Background: As the increasing adoption of information technology continues to offer better distant medical services, the distribution of, and remote access to digital medical images over public networks continues to grow significantly. Such use of medical images raises serious concerns for their continuous security protection, which digital watermarking has shown great potential to address.

Methods: We present a content-independent embedding scheme for medical image watermarking. We observe that the perceptual content of medical images varies widely with their modalities. Recent medical image watermarking schemes are image-content dependent and thus they may suffer from inconsistent embedding capacity and visual artefacts. To attain the image content-independent embedding property, we generalise RONI (region of non-interest, to the medical professionals) selection process and use it for embedding by utilising RONI's least significant bit-planes. The proposed scheme thus avoids the need for RONI segmentation that incurs capacity and computational overheads.

Results: Our experimental results demonstrate that the proposed embedding scheme performs consistently over a dataset of 370 medical images including their 7 different modalities [1] . Experimental results also verify how the state-of-the-art reversible schemes can have an inconsistent performance for different modalities of medical images. Our scheme has MSSIM (Mean Structural SIMilarity) larger than 0.999 with a deterministically adaptable embedding capacity.

Conclusions: Our proposed image-content independent embedding scheme is modality-wise consistent, and maintains a good image quality of RONI while keeping all other pixels in the image untouched. Thus, with an appropriate watermarking framework (i.e., with the considerations of watermark generation, embedding and detection functions), our proposed scheme can be viable for the multi-modality medical image applications and distant medical services such as teleradiology and eHealth.

The research presented in this thesis revolves around the digital watermarking and its applicatio... more The research presented in this thesis revolves around the digital watermarking and its application to medical images. Digital watermarking is an evolving technology, which has great promise for addressing multimedia information security. Digital medical images, on the other hand, are the outcome of the advanced imaging technology that has enabled modern health care to seamlessly offer many distant medical services. Thereby, with the remote access and distribution, medical images are subject to many complex and new legal and ethical issues. Under this circumstance, while the security need of the medical images is critical, the conventional tools seem to fall short of providing necessary protection. Digital watermarking has thus been studied to address this problem for this research.
Several research gaps have been identified. They are: (i) requirements for the watermarking of medical images are not well defined; (ii) there is no known construction of a complete or formal watermarking model that helps identify and evaluate the state-of-the-art watermarking scheme for an application; (iii) watermarking properties are not well defined and some of them (e.g., robustness, security) are naturally misinterpreted in practice; (iv) security levels of existing watermarking schemes are mostly unknown; and (iv) there is no watermark embedding scheme available which is equally suitable for various medical image modalities.
This research has started with a comprehensive literature review on digital watermarking schemes and their applications to medical images. A general watermarking model for digital image applications has then been developed and a set of fundamental watermarking properties (e.g., perceptual similarity, robustness, etc.) has been defined. Models for a set of expected attacks in digital image application scenarios have been developed using the proposed watermarking model. The current state of watermarking security has been reviewed and the need for complete security analysis of watermarking schemes has been identified. To this, three new counterfeiting attack models have been developed and validated for some image authentication schemes. Thereby, the watermarking based self-authentication schemes have been shown to violate the systematic definition of security.
For defending against the counterfeiting weaknesses and proposed attacks, a set of fundamental requirements has been determined and a tentative construction of a self-authentication scheme is proposed. Considering that construction, a novel medical image embedding scheme is developed that avoids the limitations of existing schemes. A watermarking capacity control framework is developed and validated using the asymptotic analysis. Experimental results demonstrate that the proposed scheme has higher capacity-distortion performance and more efficient capacity control ability than some prominent existing schemes. Being irreversible and general RONI (region of non-interest) based, the proposed scheme would help provide continuous security protection and minimize legal-ethical impacts, and thereby could be commercially viable in the future for different medical image applications.
This research advances knowledge in the area of digital image watermarking and its applications. Developing a formal model and defining fundamental parameters and possible attacks presented in this thesis, are the first steps toward a unified and intuitive watermarking theory. The developed model would allow a unified treatment of all practically meaningful variants of digital image watermarking schemes. The developed new attack models and their uses in rigorously analysing security of watermarking schemes can be used as principles to determine the security levels of watermarking schemes. The proposed watermarking scheme for medical images and its validation create knowledge of an efficient embedding approach, which can be used for different applications such as content authentication, tampering detection and localization, and annotation. Further, the generalized notion of watermarking capacity control and the use of asymptotic analysis for studying computational aspects of watermarking schemes would create a new era in watermarking research.
In summary, the findings, theoretical development and analyses, and experimental evidence of this research represent a comprehensive source of information, which can be assimilated and disseminated towards standardizing future research in the formal modelling, complete security analysis and computational aspects, of watermarking schemes.

While formal definitions and security proofs are well established in some fields like cryptograph... more While formal definitions and security proofs are well established in some fields like cryptography and steganography, they are not as evident in digital watermarking research. A systematic development of
watermarking schemes is desirable, but at present, their development is usually informal, ad hoc, and omits the complete realization of application scenarios. This practice not only hinders the choice
and use of a suitable scheme for a watermarking application, but also leads to debate about the state-of-the-art for different watermarking applications. With a view to the systematic development of watermarking schemes, we present a formal generic model for digital image watermarking. Considering possible inputs, outputs, and component functions, the initial construction of a basic watermarking model is developed further to incorporate the use of keys. On the basis of our proposed model, fundamental watermarking properties are defined and their importance exemplified for different image applications. We also define a set of possible attacks using our model showing different winning scenarios depending on the adversary capabilities. It is envisaged that with a proper consideration of watermarking properties and adversary actions in different image applications,use of the proposed model would allow a unified treatment of all practically meaningful variants of watermarking schemes.

In most of the digital image watermarking schemes, it becomes a common practice to address securi... more In most of the digital image watermarking schemes, it becomes a common practice to address security in terms of robustness, which is basically a norm in cryptography. Such consideration in developing and evaluation of a watermarking scheme may severely affect the performance and render the scheme ultimately unusable. This paper provides an explicit theoretical analysis towards watermarking security and robustness in figuring out the exact problem status from the literature. With the necessary hypotheses and analyses from technical perspective, we demonstrate the fundamental realization of the problem. Finally, some necessary recommendations are made for complete assessment of watermarking security and robustness.

Teleradiology allows medical images to be transmitted over electronic networks for clinical inter... more Teleradiology allows medical images to be transmitted over electronic networks for clinical interpretation, and for improved healthcare access, delivery and standards. Although, such remote transmission of the images is raising various new and complex legal and ethical issues, including image retention and fraud, privacy, malpractice liability, etc., considerations of the security measures used in teleradiology remain unchanged. Addressing this problem naturally warrants investigations on the security measures for their relative functional limitations and for the scope of considering them further. In this paper, starting with various security and privacy standards, the security requirements of medical images as well as expected threats in teleradiology are reviewed. This will make it possible to determine the limitations of the conventional measures used against the expected threats. Further, we thoroughly study the utilization of digital watermarking for teleradiology. Following the key attributes and roles of various watermarking parameters, justification for watermarking over conventional security measures is made in terms of their various objectives, properties, and requirements. We also outline the main objectives of medical image watermarking for teleradiology, and provide recommendations on suitable watermarking techniques and their characterization.

We propose a computationally efficient image border pixel based watermark embedding scheme for me... more We propose a computationally efficient image border pixel based watermark embedding scheme for medical images. We considered the border pixels of a medical image as RONI (region of non-interest), since those pixels have no or little interest to doctors and medical professionals irrespective of the image modalities. Although RONI is used for embedding, our proposed scheme still keeps distortion at a minimum level in the embedding region using the optimum number of least significant bit-planes for the border pixels. All these not only ensure that a watermarked image is safe for diagnosis, but also help minimize the legal and ethical concerns of altering all pixels of medical images in any manner (e.g, reversible or irreversible). The proposed scheme avoids the need for RONI segmentation, which incurs capacity and computational overheads. The performance of the proposed scheme has been compared with a relevant scheme in terms of embedding capacity, image perceptual quality (measured by SSIM and PSNR), and computational efficiency. Our experimental results show that the proposed scheme is computationally efficient, offers an image-content-independent embedding capacity, and maintains a good image quality of RONI while keeping all other pixels in the image untouched.

In this paper, we present three counterfeiting attacks on the block-wise dependent fragile waterm... more In this paper, we present three counterfeiting attacks on the block-wise dependent fragile watermarking schemes. We consider vulnerabilities such as the exploitation of a weak correlation among block-wise dependent watermarks to modify valid watermarked images, where they could still be verified as authentic, though they are actually not. Experimental results successfully demonstrate the practicability and consequences of the proposed attacks for some relevant schemes. The development of the proposed attack models can be used as a means to systematically examine the security levels of similar watermarking schemes.

This paper presents a key based generic model for digital image watermarking. The model aims at a... more This paper presents a key based generic model for digital image watermarking. The model aims at addressing an identified gap in the literature by providing a basis for assessing different watermarking requirements in various digital image applications. We start with a formulation of a basic watermarking system, and define system inputs and outputs. We then proceed to incorporate the use of keys in the design of various system components. Using the model, we also define a few fundamental design and evaluation parameters. To demonstrate the significance of the proposed model, we provide an example of how it can be applied to formally define common attacks.