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Conference on Mobile Multimedia/image processing for Military and Security applications

作者： Cherukuri, Ravindranath C. Agaian, Sos. S. Univ Texas Mobile Multimedia Signal Proc Lab 1 UTSA Circle San Antonio TX 78249 USA

ISBN: (纸本)9780819467010

Cellular communications constitute a significant portion of the global telecommunications market. Therefore, the need for secured communication over a mobile platform has increased exponentially. Steganography is an art of hiding critical data into an innocuous signal, which provide answers to the above needs. The JPEG is one of commonly used format for storing and transmitting images on the web. In addition, the pictures captured using mobile cameras are in mostly in JPEG format. In this article, we introduce a switching theory based steganographic system for JPEG images which is applicable for mobile and computer platforms. The proposed algorithm uses the fact that energy distribution among the quantized AC coefficients varies from block to block and coefficient to coefficient. Existing approaches are effective with a part of these coefficients but when employed over all the coefficients they show there ineffectiveness. Therefore, we propose an approach that works each set of AC coefficients with different frame work thus enhancing the performance of the approach. The proposed system offers a high capacity and embedding efficiency simultaneously withstanding to simple statistical attacks. In addition, the embedded information could be retrieved without prior knowledge of the cover image. Based on simulation results, the proposed method demonstrates an improved embedding capacity over existing algorithms while maintaining a high embedding efficiency and preserving the statistics of the JPEG image after hiding information.

关键词： steganography covert communication data hiding switching theory JPEG

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Design of multichannel filter banks for subband coding of audio signals using multirate signal processing techniques

Design of multichannel filter banks for subband coding of au...

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Conference on Mathematics of Data/image Pattern Recongnition, Compression, Coding, and Encryption x, with applications

作者： Goel, Aditya Deemed Univ MANIT Dept Elect & Commun Engn Bhopal 462007 India

ISBN: (纸本)9780819468482

This paper presents a design technique for multi channel filter banks for subband coding of audio signal. In sub-band coding, the speech is first split into frequency bands using a bank of bandpass filters. The individual band pass signals are then decimated by a factor 'N' and encoded for transmission. A filter bank is a collection of bandpass filters, all processing the same input signal. The important parameters in sub-band coders are the number of frequency bands and the frequency range of the system, and the sub - band coding technique. The total number of filters required are 2N. The sub-band signals can be reconstructed perfectly with linear- phase FIR filters. The filter bank is designed so as to overcome the effect of non-ideal transition-band and stop-bands filtering. With real-world filters, the non-zero signal energy in the transition and stop bands is reflected back into the pass-band during the interpolation process at the receiver causing aliasing. This aliasing is canceled in the filter bank during reconstruction of the signal. Ibis paper deals with the designing of 8 band filter banks and coding the subband signals at various bit rates using DPCM technique. In this we used a sampling rate of 44. 1 Khz. The first two bands are coded at 8 bits/sample, next three bands are coded at 4bits/sample and last 3 bands are coded at 2 bits /sample. Lower frequency spectrum is encoded at higher bit rate, as more energy is concentrated in the lower range. Simulated results using MATLAB Software shows that a compression ratio of 3.76:1 is achieved with perceptual quality. Beyond this we find that the signal quality degraded to reasonable extent, which is not recommended. There has to be a tradeoff between the compression ratio and Quality of transmitted signal.

关键词： multirate technique filter banks subband coding

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Data processing and image reconstruction methods for pixel detectors

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NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 2007年第1期576卷 223-234页

作者： Jakubek, Jan Czech Tech Univ Inst Expt & Appl Phys CZ-12800 Prague 2 Czech Republic

Semiconductor single-particle-counting pixel detectors offer many advantages for radiation imaging: high detection efficiency, energy discrimination, noiseless digital integration (counting), high frame rate and virtually unlimited dynamic range. All these properties allow to achieve high quality images. Examples of transmission images and 3D tomographic reconstruction using x-rays and slow neutrons are presented demonstrating effects that can affect the quality of images. A number of obstacles can limit detector performance if not handled. The pixel detector is in fact an array of individual detectors (pixels), each of them has its own efficiency, energy calibration and also noise. The common effort is to make all these parameters uniform for all pixels. However, an ideal uniformity can be never reached. Moreover, it is often seen that the signal in one pixel affects neighboring pixels due to various reasons (charge sharing, crosstalk, etc.). All such effects have to be taken into account during data processing to avoid false data interpretation. The main intention of this contribution is to summarize techniques of data processing and image correction to eliminate residual drawbacks of pixel detectors. It is shown how to extend these methods to handle further physical effects such as hardening of the beam and edge enhancement by deflection. Besides, more advanced methods of data processing such as tomographic 3D reconstruction are discussed. All methods are demonstrated on real experiments from biology and material science performed mostly with the Medipix2 pixel device. A brief view to the future of pixel detectors and their applications also including spectroscopy and particle tracking is given too. (c) 2007 Elsevier B.V. All rights reserved.

关键词： pixel detector image reconstruction tomography x-ray radiography neutron radiography phase contrast imaging

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New quality metrics for digital image resizing

New quality metrics for digital image resizing

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applications of Digital image processing xxx

作者： Kim, Hongseok Kumara, Soundar Dept. of Computer Sci. and Eng. Pennsylvania State Univ. University Park PA 16802 United States

ISBN: (纸本)9780819468444

Digital image rescaling by interpolation has been intensively researched over past decades, and still getting constant attention from many applications such as medical diagnosis, super-resolution, image blow-up, nano-manufacturing, etc. However, there are no consented metrics to objectively assess and compare the quality of resized images. Some existing measures such as peak-signal-to-noise ratio (PSNR) or mean-squared error (MSE), widely used in image restoration area, do not always coincide with the opinions from viewers. Enlarged digital images generally suffer from two major artifacts: blurring, zigzagging, and those undesirable effects especially around edges significantly degrade the overall perceptual image quality. We propose two new image quality metrics to measure the degree of the two major defects, and compare several existing interpolation methods using the proposed metrics. We also evaluate the validity of image quality metrics by comparing rank correlations.

关键词： image analysis

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Recent developments and future directions in hyperspectral data classification

Recent developments and future directions in hyperspectral d...

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Conference on image and signal processing for Remote Sensing xIII

作者： Plaza, Antonio J. Univ Extremadura Dept Technol Comp & commun E-10071 Caceres Spain

ISBN: (纸本)9780819469069

Imaging spectroscopy, also known as hyperspectral imaging, has been transformed in less than 30 years from being a sparse research tool into a commodity product available to a broad user community. As a result, there is an emerging need for standardized data processing techniques, able to take into account the special properties of hyperspectral data and to take advantage of latest-generation sensor instruments and computing environments. The goal of this paper is to provide a seminal view on recent advances in techniques for hyperspectral data classification. Our main focus is on the design of techniques able to deal with the high-dimensional nature of the data. and to integrate the spatial and spectral information. The performance of the proposed techniques is evaluated in different analysis scenarios, including land-cover classification, urban mapping and spectral unmixing. To satisfy time-critical constraints in many remote sensing applications, parallel implementations for some of the discussed algorithms are also developed. Combined, these parts provide a snapshot of the state-of-the-art in those areas, and offer a thoughtful perspective on the potential and emerging challenges in the design of robust hyperspectral data classification algorithms.

关键词： hyperspectral data classification mathematical morphology support vector machines intelligent training sample selection algorithms spectral mixture analysis parallel processing

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Fast super-resolution reconstructions of mobile video using warped transforms and adaptive thresholding

Fast super-resolution reconstructions of mobile video using ...

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Conference on applications of Digital image processing xxx

作者： Kanumuri, Sandeep Guleryuz, Onur G. Civanlar, M. Reha DoCoMo Commun Labs USA Inc Palo Alto CA 94304 USA

ISBN: (纸本)9780819468444

Multimedia services for mobile phones are becoming increasingly popular thanks to capabilities brought about by location awareness, customized programming, interactivity, and portability. With mounting attraction to these services there is desire to seamlessly expand the mobile multimedia experience to stationary environments where high-resolution displays can offer significantly better viewing conditions. In this paper, we propose a fast, high quality super-resolution algorithm that enables high resolution display of low-resolution video. The proposed algorithm, SWAT, accomplishes sparse reconstructions using directionally warped transforms and spatially adaptive thresholding. Comparisons are made with some existing techniques in terms of PSNR and visual quality. Simulation examples show that SWAT significantly outperforms these techniques while staying within a limited computational complexity envelope.

关键词： warped transforms sparse signal models sparse reconstructions adaptive thresholding iterated denoising shrinkage

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A multi-layer neural network and an adaptive linear combiner for on-line harmonic tracking

A multi-layer neural network and an adaptive linear combiner...

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IEEE International Symposium on Intelligent signal processing

作者： Zouidi, Abdelaziz Fnaiech, Farhat AL-Haddad, Kamal Univ Tunis Ecole Super Sci & Tech Tunis Equipe Rech Signal Image & Commande Intelligent S 5 Av Taha Hussein Tunis 1008 Tunisia CRC ECPE Ecole Technol Super Quebec City PQ H3C 1K3 Canada

ISBN: (纸本)9781424408290

Intelligent techniques of harmonic detection or estimation are nowadays of a great interest in power system applications, their ability to deal with high non-linearities attract researchers to investigate the performance of these methods mainly based on artificial intelligence namely using artificial neural networks. In the literature many harmonic detection or estimation methods were presented, in this paper we focus on a new idea to apply an adaptive linear neuron (ADALINE) and a multi-layer artificial neural net work (M-LANN) [5] to estimate the fundamental component and the total harmonic content of a distorted signal.

关键词： harmonic detection artificial intelligence artificial neural networks

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2007 9th International symposium on signal processing and its applications 12-15 February 2007 Sharjah - United Arab Emirates

2007 9th International symposium on signal processing and it...

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International Symposium on signal processing and Its applications (ISSPA)

The following topics are dealt with: UWB; multirate signal processing; wireless network scheduling; multichannel systems identification; time-frequency signals; LabVIEW; image analysis; adaptive networks; Arabic languages; MIMO; image coding; natural languages; speech processing; watermarking; biomedical signals; receivers; CDMA; multimedia signals; detection and estimation; machine vision; filters; wireless sensor networks; radar signals; data mining and visualization; cryptography; tracking; soft computing; array processing; bioinformatics; OFDM; wavelets; sampling.

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Comparison of PDE-based nonlinear diffusion approaches for image enhancement and denoising in optical coherence tomography

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IEEE TRANSACTIONS ON MEDICAL IMAGING 2007年第6期26卷 761-771页

作者： Salinas, Harry M. Fernandez, Delia Cabrera Mt Sinai Sch Med New York NY 10029 USA Univ Miami Miller Sch Med Dept Ophthalmol Bascom Palmer Eye Inst Miami FL 33136 USA

A comparison between two nonlinear diffusion methods for denoising OCT images is performed. Specifically, we compare and contrast the performance of the traditional nonlinear Perona-Malik filter with a complex diffusion filter that has been recently introduced by Gilboa et al.. The complex diffusion approach based on the generalization of the nonlinear scale space to the complex domain by combining the diffusion and the free Schrodinger equation is evaluated on synthetic images and also on representative OCT images at various noise levels. The performance improvement over the traditional nonlinear Perona-Malik filter is quantified in terms of noise suppression, image structural preservation and visual quality. An average signal-to-noise ratio (SNR) improvement of about 2.5 times and an average contrast to noise ratio (CNR) improvement of 49% was obtained while mean structure similarity (MSSIM) was practically not degraded after denoising. The nonlinear complex diffusion filtering can be applied with success to many OCT imaging applications. In summary, the numerical values of the image quality metrics along with the qualitative analysis results indicated the good feature preservation performance of the complex diffusion process, as desired for better diagnosis in medical imaging processing.

关键词： complex diffusion filter image enhancement optical coherence tomography segmentation speckle noise

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A design of real time image capturing and processing system using Texas instrument's processor

A design of real time image capturing and processing system ...

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Multimedia Systems and applications x

作者： Wee, Toon-Joo Chaisorn, Lekha Rahardja, Susanto Gan, Woon-Seng Institute for Infocomm Research Singapore 119613 Singapore School of EEE Nanyang Technology University Singapore 639798 Singapore

ISBN: (纸本)9780819469373

In this work, we developed and implemented an image capturing and processing system that equipped with capability of capturing images from an input video in real time. The input video can be a video from a PC, video camcorder or DVD player. We developed two modes of operation in the system. In the first mode, an input image from the PC is processed on the processing board (development platform with a digital signal processor) and is displayed on the PC. In the second mode, current captured image from the video camcorder (or from DVD player) is processed on the board but is displayed on the LCD monitor. The major difference between our system and other existing conventional systems is that image-processing functions are performed on the board instead of the PC (so that the functions can be used for further developments on the board). The user can control the operations of the board through the Graphic User Interface (GUI) provided on the PC. In order to have a smooth image data transfer between the PC and the board, we employed Real Time Data Transfer (RTDx™) technology to create a link between them. For image processing functions, we developed three main groups of function: (1) Point processing;(2) Filtering and;(3) 'Others'. Point processing includes rotation, negation and mirroring. Filter category provides median, adaptive, smooth and sharpen filtering in the time domain. In 'Others' category, auto-contrast adjustment, edge detection, segmentation and sepia color are provided, these functions either add effect on the image or enhance the image. We have developed and implemented our system using C/C# programming language on TMS320DM642 (or DM642) board from Texas Instruments (TI). The system was showcased in College of Engineering (CoE) exhibition 2006 at Nanyang Technological University (NTU) and have more than 40 users tried our system. It is demonstrated that our system is adequate for real time image capturing. Our system can be used or applied for application

关键词： Real time systems

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