Mohamed Salim Bouhlel

New scheme of digital watermarking using an adaptive embedding strength applied on multiresolution filed by 9/7 wavelet

Digital image watermarking is still a new field for research. In fact, digital watermarking is the best tool for the copyright protection and the authentication of the digital data. Researches are interested in the tradeoff that exists between the insertion capacity, the imperceptibility, and the robustness. The embedding function has a great influence on these characteristics. Channel coding techniques are used to reduce the error probability of the hidden watermark. On the other hand, the watermark strength is adapted according to human visual perception. In this article, we present a new scheme to achieve the embedding function in the framework of a robust and nonblind watermarking in multiresolution field by 9/7 wavelet of Daubechies. Indeed, we replace the constant embedding strength by a variable coefficient based on the logarithmic function. This coefficient is adaptive according to the magnitude of the wavelet transform magnitude that will be watermarked. This adaptive scheme reduces the computational error and enhances the robustness and the imperceptibility. Experimental results are presented to show that our scheme gives a better correlation and an improved PSNR. They demonstrate that the detection is enhanced.

Medical Image Compression Approach Based on Image Resizing, Digital Watermarking and Lossless Compression

The computerization of images have been important for different medical applications. Nevertheless, the huge volume of medical images can rapidly saturate transmission especially in telemedicine field and may encumber storage systems in case of local saving. Data compression represents the most used solution to deal with this problem. Indeed, it can minimize the data space and may reduce both the time of data transfer and bandwidth consumption. In this context, we have proposed new approaches, which combined image reduction and expansion techniques, digital watermarking and lossless compression standards such as JPEG-LS (JLS) and TIFF formats. We named these compression methods wREPro.TIFF (watermarked Reduction/Expansion Protocol combined with TIFF format) and wREPro.JLS (wREPro combined with JPEG-LS format). The results of comparative experiments show that we have provided significant improvements over the well-known JPEG image compression standard. Indeed, our proposed compression algorithms have ensured a better preservation of the image quality notably for high compression ratios.

A New Image Quality Metric using System Visual Human Characteristics

Several human visual system (HVS) based quality metrics have been developed in recent years to measure the quality distortions caused by digital image coding techniques. Because of the complicated nature of the HVS characteristics, these metrics do not provide acceptable correlation with perceptual evaluations of the distortion. Recent studies by the Visual Quality Experts Group (VQEG) also show that the current HVS-based techniques do not provide a clear advantage over a mathematically defined technique such as mean square error (MSE). Therefore, this paper proposes a new quality metric based on the dynamic characteristics and on the just-noticeable-difference threshold characteristics introduced by Webers law: the relative weighted Peak to Signal Noise Ratio. Our experiments on various image distortion types indicate that our metric performs significantly better than the widely used distortion metric Mean Squared Error. We should that the rwPSNR correlates with human perception of image quality.

Interactive Multiresolution Visualization of 3D mesh

Multiresolution visualization and interactive of three- dimensional mesh becomes a very active topic in recent years, which makes a state of art rich that it devoted this article. With the rapid development has seen computer graphics, three-dimensional objects become widely used in daily life. Given the large size of the mesh, it becomes very difficult to load them all into memory and transmit them on the internet. The segmentation techniques and multiresolution compression are used to reply these requirements. Indeed, in this paper, it proposed a new approach to multiresolution visualization based on a combination of segmentation and multiresolution mesh compression. For this, it proposed a new segmentation method that benefits the organization of faces of the mesh followed by a progressive local compression of regions of mesh to ensure the refinement local of the three-dimensional object. Keywordsmesh, Interactive visualization, 3D segmentation, Multiresolution compression, Refinement local, Selective visualization.

Contour-based surface modeling and analysis of microtomographic trabecular bone images

Bone quality is an important factor of bone strength. Osteoporosis is a disease characterized by longitudinal changes in 3-D trabecular bone structure, such as decreased trabecular thickness. With the purpose of identifying parameters indicate the quality of bone micro-architecture, a strategy are developed, using High Resolution Micro-Computed Tomography (μCT) images. The main idea is the use of the morphological operator and the watershed algorithm in order to separate at each slice the bone phase from the marrow phase. As well, we make use of basic morphological transforms for eliminating artifacts and aliasing from obtained contours. Three dimensional reconstructions of samples were created by stacking all the 2D obtained boundary top of each other. The zero iso-surface embedded in the computed volume in order to localize vertices from successive slices. A mesh that approximates the zero isosurface is then extracted from the resulting volume. Quantization transforms the trabecular bone structure in a set of numerical parameters that can directly gives a valid and reliable diagnosis histologist.

An Empirical Evaluation of MoonTouch: A Soft Keyboard for Visually Impaired People

This article presents a new text entry method for Visually Impaired people called MoonTouch. This method uses an enhanced version of the Moon system to help and assist visually impaired people to enter text into their touchscreen devices using simple gestures. A clinical tests of the method with a population of visually impaired participants showed that MoonTouch was perceived well by the users and presented a good learning curve.

Trabecular Bone Image Segmentation Using Wavelet and Marker-Controlled Watershed Transformation

This paper presents a new strategy for the segmentation of trabecular bone image. This kind of image is acquired with microcomputed tomography (micro-CT) to assess bone microarchitecture based chiefly on bone mineral density (BMD) measurements to improve fracture risk prediction. Disease osteoporosis can be predicted from features of CT image where a bone region may consist of several disjoint pieces. It relies on a multiresolution representation of the image by the wavelet transform to compute the multiscale morphological gradient. The coefficients of detail found at the different scales are used to determine the markers and homogeneous regions that are extracted with the watershed algorithm. The method reduces the tendency of the watershed algorithm to oversegment and results in closed homogeneous regions. The performance of the proposed segmentation scheme is presented via experimental results obtained with a broad series of images.

Control technique for a photovoltaic system with a Power grid connection

The paper presents a control technique of a photovoltaic power system connected the Power grid. The electric system includes a PV module, a DC/DC converter and a DC/AC converter to release the grid connection. A maximum-power-point-tracking (MPPT) technique is used to drive the DC/DC converter and a hysteresis technique is used to drive the DC/AC converter. These techniques ensure the PV optimum Power extraction. Matlab/Simulink environment and ISIS simulator are used to implement the system. From intensive simulation the system is tested and his accuracy is validated.

A comprehensive leap motion database for hand gesture recognition

The touchless interaction has received considerable attention in recent years with benefit of removing the burden of physical contact. The recent introduction of novel acquisition devices, like the leap motion controller, allows obtaining a very informative description of the hand pose and motion that can be exploited for accurate gesture recognition. In this work, we present an interactive application with gestural hand control using leap motion for medical visualization, focusing on the satisfaction of the user as an important component in the composition of a new specific database. In this paper, we propose a 3D dynamic gesture recognition approach explicitly targeted to leap motion data. Spatial feature descriptors based on the positions of fingertips and palm center are extracted and fed into a support vector machine classifier in order to recognize the performed gestures. The experimental results show the effectiveness of the suggested approach in the recognition of the modeled gestures with a high accuracy rate of about 81%.

Combining top-hat, Thresholding and watershed transformation for 3D Inverse Synthetic Aperture Radar Images segmentation

Segmentation is a critical step, preliminary to High-level processing such as classification, detection and object extraction from radar images. It provides an easier way to extract information in automatic target recognition (ATR) fields. However, extracting the shape of the target from this kind of images is very difficult task, so this paper presents a new approach for Radar image segmentation and how to be able to extract target shape from 3D Inverse Synthetic Aperture Radar (ISAR) Images by combining mathematical morphology watershed and thresholding methods with top-hat transformation.