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Management of pediatric radiation dose using GE's Revolution digital radiography systems

PEDIATRIC RADIOLOGY 2004年第Sup3期34卷 S215-S220页

作者： Jabri, KN Uppaluri, R xue, P GE Healthcare Waukesha WI 53188 USA

Digital flat-panel x-ray detectors offer excellent image quality and dose efficiency in addition to clinical productivity, connectivity, and adaptability to advanced clinical applications. GE's Revolution systems provide two modes of exposure control for setting the dose operating point, fixed time and automatic exposure control, the latter of which maintains high image signal-to-noise ratio for the given technique settings. In addition to enhancing detail contrast and compressing the dynamic range, postprocessing automatically determines the best window level and width for display, taking into account the dose at which the image was acquired. Several studies have examined the reduction in patient dose achievable with Revolution systems as compared to competing technologies, and results indicate significant dose savings with equivalent or superior image quality. For pediatric exams, pediatric default techniques provide for a lower patient dose as compared to adult techniques. Therefore, GE's Revolution systems can achieve a high image quality-to-dose ratio for pediatric imaging using the combined advantages of dose-efficient detection, advanced postprocessing, and independently adjustable pediatric techniques.

关键词： digital radiography pediatric radiography pediatric dose low-dose processing image quality

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Design of IIR orthogonal wavelet filter banks using lifting scheme

Design of IIR orthogonal wavelet filter banks using lifting ...

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IEEE International Conference on image processing

作者： x. Zhang W. Wang T. Yoshikawa Y. Takei Information and Communication Engineering The University of Electro-Communications Chofu-shi Tokyo Japan Department of Electrical Engineering Nagaoka Nagaoka University of Technology Niigata Japan

The lifting scheme is well-known to be an efficient tool for constructing second generation wavelets and is often used to design a class of biorthogonal wavelet filter banks. For its efficiency, the lifting implementation has been also adopted in the international standard JPEG2000. It is known that the orthogonality of wavelets is an important property for many applications. This paper presents how to implement two band IIR orthogonal wavelet filter banks according to the lifting scheme. It is shown that a class of IIR orthogonal wavelet filter banks can be realized by using allpass filters in the lifting steps. Thus, the proposed filter banks have approximate linear phase responses. Finally, the proposed IIR orthogonal wavelet filter banks are applied to image lossless compression and the coding performance is investigated.

关键词： Channel bank filters Filter bank Finite impulse response filter IIR filters image coding Wavelet transforms Transfer functions Design engineering Performance loss signal processing

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Transcranial ultrasonography system aided by fuzzy model

Transcranial ultrasonography system aided by fuzzy model

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image processing, Biomedicine, Multimedia, Financial Engineering and Manufacturing - International Forum on Multimedia image processing, IFMIP - Sixth Biannual World Automation Congress, WAC 2004

作者： Hata, Yutaka Kobashi, Syoji Kondo, Katsuya Ishikawa, Osamu Kitamura, Yuri Yanagida, Toshio Graduate School of Engineering University of Hyogo Japan Ishikawa Hospital Japan Graduate School of Medicine Osaka University Japan

ISBN: (纸本)188933524X

In conventional transcranial sonography system for human, available window of skull in adults is limited to the temporal bone. Visualization of an int4racranial tissue from all angles can support to diagnose the brain disease with high accuracy. However, no transcranial sonography system has been developed. This paper describes transeranial ultrasonography system based on anatomical knowledge. Generally, it is difficult to visualize intracranial tissues from frontal bone because of large attenuation in skull. To overcome this difficulty, we employ fuzzy signal processing and human brain anatomical model. In our system, we can successfully extract the skull and the brain surface for human. As u result, our method could visualize two-dimensional skull and brain surface.

关键词： Ultrasonic applications

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Elimination of artifacts in encrypted binary images by modified digital halftoning techniques

Elimination of artifacts in encrypted binary images by modif...

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5th Conference on Optical Security and Counterfeit Deterrence Techniques

作者： Wang, HC Sung, JH Chen, YH Natl Taiwan Normal Univ Coll Technol Dept Graph Arts & Commun Taipei 106 Taiwan

ISBN: (纸本)0819452130

An anti-counterfeiting feature, latent image, has been widely applied for banknotes and security documents. The hidden pattern of denomination by intaglio printing process can be observed by viewing the bill at certain angles of elevation. While designing the latent image, a continuous-tone cover image and a binary figurative pattern are used. The continuous tone image is halftoned by horizontal and vertical line screen, respectively. The binary figurative pattern then serves as a mask to render the corresponding area of horizontal and vertical line screen on the figurative region and background region, respectively. These procedures can be done by many available commercial softwares. However, there are various artifacts such as gaps in the junctions of horizontal and vertical screen lines, discontinuous screen lines and the white or black artifacts on the edges of the latent image. The retouching of the resulting latent image needs to be carefully and skillfully handled. In this research, we developed an automatic process to generate the artifact-free latent image inside a cover image by modified digital halftoning techniques. The methods we applied include: (1) To design new 8x8 threshold matrices in order to make a perfect joint of the horizontal and vertical screen lines. (2) To use the linear scaling adjustment to enhance the cover image not resulting discontinuous line. (3) To register the 8x8-based figurative pattern to the 8x8 threshold matrix and to avoid the visual artifacts. For latent image detection, a frequency domain treatment by FFT (Fast Fourier Transformation) and inverse-FFT is used to extract the encrypted image. This is especially useful for machine-readable applications. The results show that the developed process in this research does has the ability to automatically generate the desired latent image without any artifact. It also saves the costly retouching in the existing process. A frequency domain detection method is applied to extract late

关键词： anti-counterfeiting digital image processing amplitude modulation signal processing watermarking

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Detection of linear features in synthetic-aperture radar images by use of the localized Radon transform and prior information

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APPLIED OPTICS 2004年第2期43卷 264-273页

作者： Onana, V Trouvé, E Mauris, G Rudant, JP Tonyé, E Ecole Polytech Yaounde Lab Elect & Traitement Signal Yaounde Cameroon Univ Marne la Vallee Inst Francilien Geosci Lab Geomat F-77454 Marne La Vallee 2 France Univ Savoie Ecole Super Ingn Annecy Lab Informat Syst Traitement Informat & Connaissa F-74016 Annecy France

A new linear-features detection method is proposed for extracting straight edges and lines in synthetic-aperture radar images. This method is based on the localized Radon transform, which produces geometrical integrals along straight lines. In the transformed domain, linear features have a specific signature: They appear as strongly contrasted structures, which are easier to extract with the conventional ratio edge detector. The proposed method is dedicated to applications such as geographical map updating for which prior information (approximate length and orientation of features) is available. Experimental results show the method's robustness with respect to poor radiometric contrast and hidden parts and its complementarity to conventional pixel-by-pixel approaches. (C) 2004 Optical Society of America.

关键词： Edge detection image processing Imaging noise Optical sensing Spatial resolution Synthetic aperture radar

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Non-redundant, linear-phase, semi-orthogonal, directional complex wavelets [image/video processing applications]

Non-redundant, linear-phase, semi-orthogonal, directional co...

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International Conference on Acoustics, Speech, and signal processing (ICASSP)

作者： F.C.A. Fernandes M.B. Wakin R.G. Baraniuk DSPS Research and Development Center Texas Instruments Inc. Dallas TX USA Department of Electrical and Computer Engineering Rice University Houston TX USA

The directionality and phase information provided by nonredundant complex wavelet transforms (NCWTs) provide significant potential benefits for image/video processing and compression applications. However, because existing NCWTs are created by downsampling filtered wavelet coefficients, the finest scale of these transforms has a resolution 4/spl times/ lower than the real input signal. In this paper, we propose a linear-phase, semi-orthogonal, directional NCWT design using a novel triband filter bank. At the finest scale, the resulting transform has a resolution 3/spl times/ lower than the real input signal. We provide a design example to demonstrate three important properties for image/video processing applications: directionality, magnitude coherency, and phase coherency.

关键词： Wavelet transforms Filter bank Solid modeling signal resolution Hidden Markov models Wavelet coefficients Instruments Video compression Information filtering Information filters

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Detection of buildings through automatic extraction of shadows in Ikonos imagery

Detection of buildings through automatic extraction of shado...

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Conference on image and signal processing for Remote Sensing Ix

作者： González, JA Docampo, LG Guerrero, IC Univ Santiago de Compostela Escuela Politecn Super Lugo Depto Ingn Agroforestal Lugo 27002 Spain

ISBN: (纸本)0819451215

The extraction of man-made objects from remotely sensed imagery is a common application in remote sensing. Building detection is useful in territorial planning, mapping and Geographic Information Systems. Nevertheless these features are difficult to recognise in satellite data because of their variations in structure and size and especially because of the spatial resolution of the imagery. IRS panchromatic data, with 5,8 meters pixel size, was the higher spatial resolution sensor in civil applications until the Ikonos imageries distribution. Several approaches have been proposed for building detection in aerial images. Buildings cast a shadow in some direction and that is why many authors have employed shadows to detect constructions. Other authors use shadows to verify them, once they have been detected by some other techniques. This work focus on shadows detection probabilistic methods: it is found that digital supervised classification of the first principal component obtained from the application of a principal component analysis on the four channels of Ikonos allows identifying shadows and distinguishing them from other covers in the image. It is a fast and effective method and it can be implemented through tools available in commercial remote sensing software. This shadow detection system will provide cost -effectiveness in the inventorying of buildings, especially in areas of dispersed settlement, given that it significantly reduces fieldwork., and even can function as a support and test of the methods of automatic extraction of buildings from satellite images developed up to now.

关键词： building automatic detection shadow Ikonos principal component analysis image classification

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Time-frequency analysis for multi-channel color pattern recognition

Time-frequency analysis for multi-channel color pattern reco...

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2nd European Conference on Color in Graphics, Imaging, and Vision/6th International Symposium on Multispectral Color Science

作者： Lenz, R Hernández-Andrés, J Linkoping Univ Dept Sci & Technol SE-60174 Norrkoping Sweden

ISBN: (纸本)089208250X

Today almost all color images are captured by RGB cameras. They describe color information by three measurements only. This is too restrictive for many applications and alternative, multichannel color description techniques have thus received a lot of attention recently. In this paper we will describe some tools from time-frequency analysis and study if and how they can be used for multichannel color signal processing. We will mainly use these tools to study if they can be used to investigate problems involving scenes illuminated by different illumination sources.

关键词： Color image processing

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Advances in uncooled 1-mil pixel size focal plane products at DRS

Advances in uncooled 1-mil pixel size focal plane products a...

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Conference on Infrared Technology and applications xxx

作者： Howard, PE Clarke, JE Ionescu, AC Li, C Frankenberger, A DRS Technol Anaheim CA 92806 USA

ISBN: (纸本)0819453293

DRS has developed and demonstrated a family of miniaturized, low-power uncooled infrared focal plane camera products integrated with our 1-mil pixel size 640x480 and 320x240 uncooled infrared focal plane arrays (UIRFPA). The UIRFPA cameras operate from -40 degreesC to +55 degreesC without UIRFPA temperature regulation using our patented TCOMP sensor concept. Furthermore, they are software based, with significant memory and signal processing overcapacity, which supports significant camera setup reconfigurations without having to undergo camera firmware and hardware modifications. The elimination of the UIRFPA temperature regulation requirement results in reduced sensor power and prompt sensor turn-on. The new 320x240 camera weighs less than a quarter pound (including batteries and a 23mm. aperture F/1.2 optic), and dissipates approximately one watt when operated at a full 60Hz frame rate. The 640x480 camera dissipates about two watts when operated at a TV compatible 30 Hz frame rate. This paper describes the UIRFPA camera products, their features and capabilities, and their key performance characteristics. Illustrative examples of thermal image quality are also included.

关键词： Sensors Cameras Bolometers Electronics signal detection Video Infrared cameras Monte Carlo methods Resistance Thermography

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A novel SAR signal detection method based on spectrogram-radon transform and wavelet transform

A novel SAR signal detection method based on spectrogram-rad...

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Proceedings of the International Computer Congress 2004 on Wavelet Analysis and its applications, and Active Media Technology

作者： He, You Su, Feng Qu, Changwen xia, Mingge Res. Institute of Information Fusion Nav. Aero. Engineering Institute Yantai 264001 China

ISBN: (纸本)981238961X

In low signal-Noise Ratio (SNR) environment, it is difficult to detect linear FM signals effectively with Spectrogram-Radon transform. To improve the detecting performance, Wavelet transform is applied as a further processing step in this paper to eliminate the noise of the image obtained from Spectrogram-Radon transform. Simulation results demonstrate that it is effective to detect linear FM signals with the method proposed in this paper.

关键词： signal detection

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