Ayman Haggag

Progressive Encryption and Controlled Access Scheme for JPEG 2000 Encoded Images

In this paper we propose a progressive encryption and controlled access scheme for JPEG 2000 encoded images. Our scheme applies SNOW 2 stream cipher to JPEG 2000 codestreams in a way that preserves most of the inherent flexibility of JPEG 2000 encoded images and enables untrusted intermediate network transcoders to downstream an encrypted JPEG 2000 image without access to decryption keys. Our scheme can also control access to various image resolutions or quality layers, by granting users different levels of access, using different decryption keys. Our scheme preservers most of the inherent flexibility, scalability, and transcodability of encrypted JPEG 2000 images and also preserves end-to-end security.

Robust Watermarking in The DCT Domain Using Dual detection

In this paper, the discrete cosine transform domain (DCT domain) watermarking technique for copyright protection of still digital images is analyze and new watermarking method with dual detection is proposed. The DCT is applied in blocks of 8 times 8 pixels as in the JPEG algorithm. Previous DCT domain watermarking schemes proved to be very resilient against many attacks except for the geometric attack, especially rotation. Thus, these problems were tackled in our research to be overcome by using dual detection, which uses an equivalent form of the spatial version of the watermark embedded in the DCT domain as detection technique. In order to test the robustness of the algorithms, simple attacks such as filtering, JPEG compression, rotation, resizing and cropping were exploited

Simple adaptive control for SISO nonlinear systems using multiple neural networks

This paper presents a method of continuous-time simple adaptive control (SAC) using multiple neural networks for a single-input single-output (SISO) nonlinear systems with unknown parameters and dynamics, bounded-input bounded- output, and bounded nonlinearities. The control input is given by the sum of the output of the simple adaptive controller and the sum of the outputs of the parallel small-scale neural networks. The parallel small-scale neural networks are used to compensate the nonlinearity of plant dynamics that is not taken into consideration in the usual SAC. The role of the parallel small- scale neural networks is to construct a linearized model by minimizing the output error caused by nonlinearities in the control systems. Finally, the stability analysis of the proposed method is carried out, and the effectiveness of this method is confirmed through computer simulations.

An Adaptive Sliding Mode Control Using Simple Adaptive Control for A Class of SISO Nonlinear Systems with Bounded-Input Bounded-Output and Bounded Nonlinearity

Sliding mode control (SMC) has a strong capability in controlling nonlinear systems with uncertainties. However, SMC requires thorough knowledge of the controlled plant parameters and dynamics that is difficult to be obtained or may be unknown, which causes difficulties in calculating the equivalent control law of SMC. To overcome this problem, this paper proposes an adaptive SMC using simple adaptive control (SAC) developed for a class of single-input single-output (SISO) nonlinear systems with unknown parameters and dynamics, bounded-input bounded-output (BIBO), and bounded nonlinearity. The role of SAC is to construct an equivalent control input of adaptive SMC. To construct a corrective control input, this paper applies the sign function with a modified sliding surface. Finally, the stability analysis of the proposed method is carried out, and the effectiveness of this method is confirmed through computer simulations

Sliding mode control using neural networks for SISO nonlinear systems

Sliding mode control (SMC) has a strong capability of controlling nonlinear systems with uncertainties. However, the discontinuous control signal causes the significant problem of chattering. Furthermore, it requires thorough knowledge of the parameters and dynamics of the controlled plant, which are difficult to be obtained or may be unknown, to calculate the equivalent control law of SMC. In this paper, a combination of SMC and neural network (NN) is proposed. The weights of NN are adjusted using a backpropagation algorithm. To construct corrective control law of SMC for overcoming the chattering problem, a new and simple approach using a simplified distance function with a modified sliding surface is utilized. Thus, the chattering is eliminated and the performance of SMC is improved. Finally, a brief stability analysis of the proposed method is carried out, and the effectiveness of this method is confirmed through computer simulations.

Adaptive Motion Estimation Block Matching Algorithms for Video Coding

In most block-based video coding systems, the fast block matching algorithms (BMAs) use the origin as the initial search center, which may not track the motion very well. To improve the accuracy of the fast BMAs, a new adaptive motion tracking search algorithm is proposed in this paper. Based on the spatial correlation of motion blocks, a predicted starting search point, which reflects the motion trend of the current block, is adaptively chosen. It does not have the problem of being trapped by local minimum, and is characterized by finding the majority motion vector in one step. When compared with six other block-based search algorithms including the full-search and three-step-search, the new algorithm has an average PSNR very close to that of full search, yet an average search time faster than the three step-search

Scalable Authentication and Nonrepudiation Technique for JPEG 2000 Images Using JPSEC Protection Tools

In this paper, we first briefly discuss the newly emerging Secured JPEG (JPSEC) standard for security services for JPEG 2000 compressed images. We then propose our novel approach for applying authentication to JPEG 2000 images in a scalable manner. Our authentication technique can be used for source authentication, nonrepudiation and integrity verification for the received possibly transcoded JPEG 2000 images in such a way that it is possible to authenticate different resolutions or different qualities extracted or received from a JPEG 2000 encoded image. Three different implementation methods for our authentication technique are presented. Packet-Based Authentication involves using the MD5 hashing algorithm for calculating the hash value for each individual packet in the JPEG 2000 codestream. Hash values are truncated to a specified length to reduce the overhead in storage space, concatenated into a single string, and then signed using the RSA algorithm and the authors private key for repudiation prevention. Resolution-Based Authentication and Quality-Based Authentication methods involve generating a single hash value from all contiguous packets from each entire resolution or each entire quality layer, respectively. Our algorithms maintain most of the inherent flexibility and scalability of JPEG 2000 compressed images. The resultant secured codestream is still JPEG 2000 compliant and compatible with JPEG 2000 compliant decoders. Also, our algorithms are compatible with the Public Key Infrastructure (PKI) for preventing signing repudiation from the sender and are implemented using the new JPSEC standard for security signaling.

Interactive Secure Dissemination of Medical Images Using JPEG 2000

The increase in the number of medical exams, the need to store images resulting for those exams at a very high quality, and the introduction of teleradiology result in an overwhelm increase in storage and distribution costs of medical images. In this paper we propose a method using JPEG 2000 in the lossless or near lossless modes to encode medical images, in order to reduce image storage costs and in the same time store a very high image quality needed for medical applications. We use JPEG 2000 interactive protocols (JPIP) to allow interactive access to medical images in a way that minimizes the transmission bit rate by first displaying a reduced resolution or quality of the image, then allowing lossless display of regions of interest interactively specified by the image viewer. Our method secures medical images by applying JPEG 2000 specific security tools and is implemented in a way compliant to DICOM standard to ensure interoperability. Simulations and results verify the efficiency of the proposed method.