Usama S. Mohammed

Highly scalable hybrid image coding scheme

This paper describes a highly scalable hybrid image coding scheme (HS-HIC). The proposed hybrid coding scheme combines simply modification of the data in the wavelet domain and the high performance of the set partitioning in hierarchical trees (SPIHT) coding. The modification of the subband image data is done based on the transformation of the high-frequency subband (details) in the wavelet domain. It is based on linear modification of 9-subband image data within three-layer in the wavelet domain. Except the image data in LL3, all other image data will be linearly modified based on the discrete Fourier transform (DFT) components. The modification process provides a new subband image data containing almost the same information as the original one but having a smaller frequency spectrum. The modified data is then located in the corresponding position and the simple SPIHT coder followed by adaptive arithmetic coder is applied on the resulting hierarchical representation to generate the symbol stream. Simulation results demonstrate that, with small addition in the computational complexity of the coding process, the PSNR performance of the proposed algorithm is much higher than that of the SPIHT test coder and some of famous image coding techniques.

A Fast Iterative Blind image restoration algorithm

Successful blind image deconvolution algorithms require the exact estimation of the Point Spread Function size, PSF. In the absence of any priori information about the imagery system and the true image, this estimation is normally done by trial and error experimentation, until an acceptable restored image quality is obtained. This paper, presents an exact estimation of the PSF size that yields the optimum restored image quality. The paper also describes a least squares PSF estimation, instead of the slow iterative update, that is commonly used in Iterative Blind Deconvolution software, IBD. Moreover, a technique is also proposed to improve the sharpness of the deconvolved images, by constrained maximization of the detail wavelet-coefficient entropies. Several simulations are given to verify these results.

A new total variation based image denoising and deblurring technique

This paper, describes a new total variation based de-noising scheme. The proposed technique optimally finds the threshold level of the noisy image wavelet decomposition that minimizes the energy of the error between the restored and the noisy image. The minimization algorithm is regularized by including 1st as well as 2nd order derivatives effects of the noisy image, into the minimization scheme. Next, the problem of blind deconvolution of noisy images is addressed. First, the order of the blurring Point Spread Function (PSF), is accurately estimated using a de-noised version of the noisy blurred image. Then, the deconvolution algorithm is modified by including the effects of the 1st as well as 2nd order derivatives of the blurred noisy images into the image update algorithm. Simulation results have shown significant performance improvements of the proposed schemes in both de-noising as well as deblurring noisy image.

A B_Spline Based Image Compression and Watermarking Technique

A fast computationally efficient method is proposed for computing the non real time response of non-causal digital systems. This method is then used for the computation of B_Spline signal decomposition. Next, it is shown that when this pre-transformed B_Spline based technique is used in image compression using bit rates of the order 1.0 bits/pixel or less, it performs better than known coding schemes like JPEG2K and SPIHT in spite of using far less amount of data. Moreover, this scheme is also used in digital image watermarking. Comparisons with vector quantization based watermarking schemes show that the proposed method yields a higher watermarked PSNR. Security of the watermarking image can be increased by varying the order of the B_Spline function used, as well as the decimation ratio M. Illustrative examples are given.

C23. An enhanced fast Iterative Blind Deconvolution algorithm for noiseless and noisy images

Successful blind image deconvolution algorithms require the exact estimation of the Point Spread Function size, PSF. In the absence of any priori information about the imagery system and the true image, this estimation is normally done by trial and error experimentation, until an acceptable restored image quality is obtained. This paper, presents an exact estimation of the PSF size, for both noisy and noiseless images. It is based on evaluating the detail energy of the wave packet decomposition of the blurred image. The minimum detail energy occurs at the optimum PSF size. Having accurately estimated the PSF, the paper also proposes a fast double updating algorithm for improving the quality of the restored image, by the least squares minimization of a system of linear equations describing some peak error deviations derived from the blurred image. Extension to the noisy case has also been investigated. Simulation results of several examples are verified.

A fast ICA based Iterative Blind Deconvolution algorithm

Successful blind image deconvolution algorithms require the exact estimation of the Point Spread Function size, PSF. In the absence of any priori information about the imagery system and the true image, this estimation is normally done by trial and error experimentation, until an acceptable restored image quality is obtained. This paper, presents an exact estimation of the PSF size that yields the optimum restored image quality. The paper also describes a least squares PSF estimation, instead of the slowly iterative update, that is commonly used in Iterative Blind Deconvolution software, IBD. Moreover, a technique is also proposed to improve the sharpness of the de-convolved images using Independent Component Analysis techniques (ICA). Simulation examples are given to show that the proposed technique manages to accurately estimate the PSF size apart from competing very well with the existing approaches.

Nonblind and quasiblind natural preserve transform watermarking

This paper describes a new image watermarking technique based on the Natural Preserving Transform (NPT). The proposed watermarking scheme uses NPT to encode a gray scale watermarking logo image or text, into a host image at any location. NPT brings a unique feature which is uniformly distributing the logo across the host image in an imperceptible manner. The contribution of this paper lies is presenting two efficient nonblind and quasiblind watermark extraction techniques. In the quasiblind case, the extraction algorithm requires little information about the original image that is already conveyed by the watermarked image. Moreover, the proposed scheme does not introduce visual quality degradation into the host image while still being able to extract a logo with a relatively large amount of data. The performance and robustness of the proposed technique are tested by applying common image-processing operations such as cropping, noise degradation, and compression. A quantitative measure is proposed to objectify performance; under this measure, the proposed technique outperforms most of the recent techniques in most cases. We also implemented the proposed technique on a hardware platform, digital signal processor (DSK 6713). Results are illustrated to show the effectiveness of the proposed technique, in different noisy environments.

Parallel binary tree splitting protocol for tag anti-collision in RFID systems

This paper describes new tree based anti-collision algorithm for Radio Frequency Identification (RFID). The proposed algorithm is based on parallel binary splitting (PBS) technique to follow new identification path through the binary tree. The dialog between the reader and tags needs only one bit tag response followed by one bit reader reply (one-to-one bit dialog). The proposed scheme does not send restarting node position, from the tree leaves, after each tag identification. So, the number of transmitted bits is equal to twice the number of the binary tree nodes of the existing tags except the leaves nodes. Performed computer simulations have shown that the collision recovery scheme is very fast and simple. The simulation results shows that the proposed technique outperforms most of the recent techniques in most cases.

Enhanced MFSK spectral efficiency based on super-resolution spectral estimation

Single tone M-ary frequency shift keying (MFSK) enjoys constant envelop transmission at the expense of much lower spectral efficiency (SE). Many research efforts were given for enhancing the SE of MFSK. In this paper, SE of coherent single tone MFSK is improved by filling up the same allocated spectral band-width by larger number of uniformly spaced non-orthogonal tones. The main idea resides in two main points, first, regarding the detection task as an operation of super-resolution (SR) spectral line estimation, second, highlighting implicit sparsity construction of MFSK scheme. Compressive sensing (CS) based SR approaches are enabled for resolving activated atom from over-complete dictionary. Moreover, more general keying schemes can be performed on learned dictionary instead of the classical Fourier (sinusoidal) dictionary, where each atom may occupy the whole allocated spectrum instead of residing on a specific tone. This allows better diversity against narrow band interference and frequency selective fading channel under sever fading conditions but, on the cost of losing the constant envelop advantage.

Damping shift keying (Dsk): A new modulation space for single carrier communications

While the amplitude, frequency and phase, are the well-known carrier features that can be modulated according to digital data stream, there is still another unexploited sinusoidal feature. Sinusoidal damping factor is the suggested modulation technique that can be used in carrier communication. In this paper, damping shift keying (DSK) is proposed as a new modulation space that can be combined with conventional modulation techniques to increase the data rate per symbol. In addition to the complex amplitude modulation, the carrier can be modulated using multi-damping factors according to the data stream. Combination of DSK with quadrature amplitude modulation (QAM) increases the data rate of the so called Damped QAM (D-QAM). Simulation results measures the performance of the proposed D-4PSK (carrying 3 bits/symbol) against conventional QPSK (carrying 2 bits/symbol). The proposed scheme exhibits nearly the same bit-error-rate (BER) performance but with 50% increase in the data rate. Moreover, in this paper all-feature shift-keying (ALFSK) schemes will be defined which allows modulating of all sinusoidal features (amplitude, phase, frequency and damping factor) simultaneously.