Showing papers by "Philips published in 2001"

Advances in sensitivity encoding with arbitrary k-space trajectories.

Abstract: New, efficient reconstruction procedures are proposed for sensitivity encoding (SENSE) with arbitrary k-space trajectories. The presented methods combine gridding principles with so-called conjugate-gradient iteration. In this fashion, the bulk of the work of reconstruction can be performed by fast Fourier transform (FFT), reducing the complexity of data processing to the same order of magnitude as in conventional gridding reconstruction. Using the proposed method, SENSE becomes practical with nonstandard k-space trajectories, enabling considerable scan time reduction with respect to mere gradient encoding. This is illustrated by imaging simulations with spiral, radial, and random k-space patterns. Simulations were also used for investigating the convergence behavior of the proposed algorithm and its dependence on the factor by which gradient encoding is reduced. The in vivo feasibility of non-Cartesian SENSE imaging with iterative reconstruction is demonstrated by examples of brain and cardiac imaging using spiral trajectories. In brain imaging with six receiver coils, the number of spiral interleaves was reduced by factors ranging from 2 to 6. In cardiac real-time imaging with four coils, spiral SENSE permitted reducing the scan time per image from 112 ms to 56 ms, thus doubling the frame-rate. Magn Reson Med 46:638–651, 2001. © 2001 Wiley-Liss, Inc.

Coronary Magnetic Resonance Angiography for the Detection of Coronary Stenoses

Abstract: Background An accurate, noninvasive technique for the diagnosis of coronary disease would be an important advance. We investigated the accuracy of coronary magnetic resonance angiography among patients with suspected coronary disease in a prospective, multicenter study. Methods Coronary magnetic resonance angiography was performed during free breathing in 109 patients before elective x-ray coronary angiography, and the results of the two diagnostic procedures were compared. Results A total of 636 of 759 proximal and middle segments of coronary arteries (84 percent) were interpretable on magnetic resonance angiography. In these segments, 78 (83 percent) of 94 clinically significant lesions (those with a ≥50 percent reduction in diameter on x-ray angiography) were also detected by magnetic resonance angiography. Overall, coronary magnetic resonance angiography had an accuracy of 72 percent (95 percent confidence interval, 63 to 81 percent) in diagnosing coronary artery disease. The sensitivity, specificity,...

Universal lighting network methods and systems

Abstract: The present invention relates to smart lighting devices bearing processors, and networks comprising smart lighting devices, capable of providing illumination, and detecting stimuli with sensors and/or sending signals. Sensors and emitters can, in some embodiments, be removed and added in a modular fashion. Smart lighting devices and smart lighting networks can be used for communication purposes, building automation, systems monitoring, and a variety of other functions.

Association Between Hospital and Surgeon Procedure Volume and Outcomes of Total Hip Replacement in the United States Medicare Population

Abstract: Background: The mortality and complication rates of many surgical procedures are inversely related to hospital procedure volume. The objective of this study was to determine whether the volumes of primary and revision total hip replacements performed at hospitals and by surgeons are associated with rates of mortality and complications. Methods: We analyzed claims data of Medicare recipients who underwent elective primary total hip replacement (58,521 procedures) or revision total hip replacement (12,956 procedures) between July 1995 and June 1996. We assessed the relationship between surgeon and hospital procedure volume and mortality, dislocation, deep infection, and pulmonary embolus in the first ninety days postoperatively. Analyses were adjusted for age, gender, arthritis diagnosis, comorbid conditions, and income. Analyses of hospital volume were adjusted for surgeon volume, and analyses of surgeon volume were adjusted for hospital volume. Results: Twelve percent of all primary total hip replacements and 49% of all revisions were performed in centers in which ten or fewer of these procedures were carried out in the Medicare population annually. In addition, 52% of the primary total hip replacements and 77% of the revisions were performed by surgeons who carried out ten or fewer of these procedures annually. Patients treated with primary total hip replacement in hospitals in which more than 100 of the procedures were performed per year had a lower risk of death than those treated with primary replacement in hospitals in which ten or fewer procedures were performed per year (mortality rate, 0.7% compared with 1.3%; adjusted odds ratio, 0.58; 95% confidence interval, 0.38, 0.89). Patients treated with primary total hip replacement by surgeons who performed more than fifty of those procedures in Medicare beneficiaries per year had a lower risk of dislocation than those who were treated by surgeons who performed five or fewer of the procedures per year (dislocation rate, 1.5% compared with 4.2%; adjusted odds ratio, 0.49; 95% confidence interval, 0.34, 0.69). Patients who had revision total hip replacement done by surgeons who performed more than ten such procedures per year had a lower rate of mortality than patients who were treated by surgeons who performed three or fewer of the procedures per year (mortality rate, 1.5% compared with 3.1%; adjusted odds ratio, 0.65; 95% confidence interval, 0.44, 0.96). Conclusions: Patients treated at hospitals and by surgeons with higher annual caseloads of primary and revision total hip replacement had lower rates of mortality and of selected complications. These analyses of Medicare claims are limited by a lack of key clinical information such as operative details and preoperative functional status.

Plastic transistors in active-matrix displays

Abstract: The handling of grey levels by these large displays paves the way for electronic paper. The main advantages of using soluble semiconductive polymers in microelectronic devices are ease of processing1,2,3 and mechanical flexibility4. Here we describe an active-matrix display with 64 × 64 pixels, each driven by a thin-film transistor with a solution-processed polymer semiconductor. In a significant step towards low-cost flexible displays, this polymer-dispersed liquid-crystal arrangement gives a reflective, low-power display with paper-like contrast, which can handle 256 grey levels while being refreshed at video speed.

The MPEG-4 fine-grained scalable video coding method for multimedia streaming over IP

Abstract: Real-time streaming of audiovisual content over the Internet is emerging as an important technology area in multimedia communications. Due to the wide variation of available bandwidth over Internet sessions, there is a need for scalable video coding methods and (corresponding) flexible streaming approaches that are capable of adapting to changing network conditions in real time. In this paper, we describe a new scalable video-coding framework that has been adopted recently by the MPEG-4 video standard. This new MPEG-4 video approach, which is known as Fine-Granular-Scalability (FGS), consists of a rich set of video coding tools that support quality (i.e., SNR), temporal, and hybrid temporal-SNR scalabilities. Moreover, one of the desired features of the MPEG-J FGS method is its simplicity and flexibility in supporting unicast and multicast streaming applications over IF.

Multiclass linear dimension reduction by weighted pairwise Fisher criteria

Abstract: We derive a class of computationally inexpensive linear dimension reduction criteria by introducing a weighted variant of the well-known K-class Fisher criterion associated with linear discriminant analysis (LDA). It can be seen that LDA weights contributions of individual class pairs according to the Euclidean distance of the respective class means. We generalize upon LDA by introducing a different weighting function.

Landmark-based elastic registration using approximating thin-plate splines

Abstract: The authors consider elastic image registration based on a set of corresponding anatomical point landmarks and approximating thin-plate splines. This approach is an extension of the original interpolating thin-plate spline approach and allows to take into account landmark localization errors. The extension is important for clinical applications since landmark extraction is always prone to error. The authors' approach is based on a minimizing functional and can cope with isotropic as well as anisotropic landmark errors. In particular, in the latter case it is possible to include different types of landmarks, e.g., unique point landmarks as well as arbitrary edge points. Also, the scheme is general with respect to the image dimension and the order of smoothness of the underlying functional. Optimal affine transformations as well as interpolating thin-plate splines are special cases of this scheme. To localize landmarks the authors use a semi-automatic approach which is based on three-dimensional (3-D) differential operators. Experimental results are presented for two-dimensional as well as 3-D tomographic images of the human brain.

A Generic Framework for Non-rigid Registration Based on Non-uniform Multi-level Free-Form Deformations

Abstract: This work presents a framework for non-rigid registration which extends and generalizes a previously developed technique by Rueckert et al. [1]. We combine multi-resolution optimization with free-form deformations (FFDs) based on multi-level B-splines to simulate a non-uniform control point distribution. We have applied this to a number of different medical registration tasks to demonstrate its wide applicability, including interventional MRI brain tissue deformation compensation, breathing motion compensation in liver MRI, intra-modality inter-modality registration of pre-operative brain MRI to CT electrode implant data, and inter-subject registration of brain MRI. Our results demonstrate that the new algorithm can successfully register images with an improved performance, while achieving a significant reduction in run-time.

Polyol-Mediated Preparation of Nanoscale Oxide Particles.

Abstract: Largely monodisperse, crystalline nanoscale oxide particles (for example, Cu2 O, TiO2 , Nb2 O5 ) are preparatively accessible with the polyol method. The colloidal suspensions of the particles thus obtained can be employed readily for the homogeneous coating of various substrates (for example, glass plates, Al2 O3 powder).

Fluid control in multichannel structures by electrocapillary pressure.

Abstract: We demonstrate control of fluid motion in three-dimensional structures with thousands of microchannels. Fluids are manipulated via an electrocapillary pressure, originating from electrostatic control of the solid/fluid interfacial tension in the microchannels. Reversible fluid displacement has been achieved for all channel orientations with respect to gravity. The velocities of several centimeters per second are nearly two orders of magnitude higher than the velocities demonstrated by other electrofluidic actuation principles.

Dynamic channel selection scheme for IEEE 802.11 WLANs

Abstract: Disclosed is a method and system for dynamically selecting a communication channel between an access point (AP) and a plurality of stations (STAs) in an IEEE 802.11 wireless local area network (WLAN). The method includes the steps of: determining whether a new channel between the AP and STAs within a particular basic service set (BSS) is needed; requesting a channel signal quality measure to some of the plurality of stations by the AP; reporting a channel signal quality report back to the AP based on a received signal strength indication (RSSI) and a packet error rate (PER) of all channels detected by the stations within the BSS; selecting a new channel based on the channel quality report for use in communication between the AP and the plurality of stations.

Ball throwing assistant

Abstract: A ball-throwing machine includes a camera connected to a computer vision unit and a microphone connected to a speech-processing unit. The computer vision unit processes images from the camera to determine a user's position, and to detect user gestures from a predetermined repertoire of gestures. The speech-processing unit recognizes user vocal commands from a predetermined repertoire of commands. A computer receives information from a control panel, from the computer vision unit, from the speech-processing unit, and from a file describing the ballistic properties of the ball to be thrown. The computer accordingly determines a ball trajectory according to the user's position and parameters indicated by a combination of control-panel settings, user gestures, and user vocal commands. The computer then adjusts the direction, elevation, ball speed, and ball spin to conform to the determined trajectory, and initiates throwing of a ball accordingly.

Dynamic pricing system

Abstract: The present invention provides a dynamic pricing system that generates pricing recommendations for each product in each market. In particular, the system normalizes historic pricing and sales data, and then analyzes this historic data using parameters describing the user's business objectives to produce a pricing list to achieve these objectives. The system uses historical market data to forecast expected sales according to a market segment, product type, and a range of future dates and to determine the effects of price changes on the forecasted future sales. The system further calculates unit costs for the product. The system then estimates profits from sales at different prices by using the sales forecasts, adjusting these sales forecasts for changes in prices, and the costs determinations. The system optionally optimizes prices given current and projected inventory constraints and generates alerts notices according to pre-set conditions.

RF-CMOS performance trends

Abstract: The impact of scaling on the analog performance of MOS devices at RF frequencies was studied. Trends in the RF performance of nominal gate length NMOS devices from 350-nm to 50-nm CMOS technologies are presented. Both experimental data and circuit simulations with an advanced validated compact model (MOS Model 11) have been used to evaluate the RF performance. RF performance metrics such as the cutoff frequency, maximum oscillation frequency, power gain, noise figure, linearity, and 1/f noise were included in the analysis. The focus of the study was on gate and drain bias conditions relevant for RF circuit design. A scaling methodology for RF-CMOS based on limited linearity degradation is proposed.

System to aid a driver to determine whether to change lanes

Abstract: A vehicular vision system to aid a driver of a vehicle to determine whether it is safe to change lanes includes a camera having a field of view such that the field of view corresponds to at least a portion of an area proximate the vehicle. The system also includes an object identifier electrically coupled to the camera, a distance determiner which determines a distance of the object which is in the field of the camera, and a display electrically coupled to the camera which displays an image generated by the camera and provides an indication of the type of object which is in the field of view of the camera and the distance of the object from the vehicle.

Packaged information systems

Abstract: An embodiment of this invention relates to an intelligent lighting device that can receive signals and change the illumination conditions as a result of the received signals. The lighting device can change hue, saturation, and brightness as a response to received signals. One example of using such a lighting device is to display particular colors as a response to certain events. Among others, embodiments may include vehicle lighting systems, an information cube, a back lighting system for a display panel, and an indicator of a condition of a package.

Method and apparatus for controlling a lighting system in response to an audio input

Abstract: Methods and apparatus for executing a lighting program to control a plurality of light emitting diodes (LEDs) in response to at least one characteristic of an audio input. In one embodiment, the audio input is digitally processed to determine the at least one characteristic. In other embodiments, control signals for the LEDs are generated in response to a timer and/or input from a user interface, as well as in response to the at least one characteristic of the audio input. In another embodiment, the control signals for the LEDs are generated by a same computer that processes the audio input to transmit signals to speakers to audibly play the audio input. In a further embodiment, a GUI is provided to assist in authoring the lighting program. In another embodiment, the audio signal is processed before being played back. In a further embodiment, the lighting program anticipates changes in the audio input.

Systems and methods for digital entertainment

Abstract: In computer games, there is typically a display that represents a view into a virtual world of some type. There is also typically a user in a real world environment that surrounds the display screen interacting with the virtual world. Disclosed herein are systems and methods for using lighting systems, in particular LED based lighting systems, to allow a user to receive information from the virtual world in coordination with, in addition to, and/or instead of the information received from the display.

Methods and apparatus for illumination of liquids

Abstract: Methods and apparatus for illumination of liquids in a variety of environments. In one example, multi-color LED-based light sources are employed to achieve a wide range of enhanced lighting effects in liquids. In another example, a pool or spa is illuminated by one or more multi-color light sources that may be employed as individually and independently controllable devices, or coupled together to form a networked lighting system to provide a variety of programmable and/or coordinated color illumination effects in the pool or spa environment.

Power supply for leds

Abstract: The power supply for LEDs of the present invention provides power to a variable number of LEDs wired in series or in parallel. The power supply uses current feedback to adjust power to the LEDs and provides protection against open circuits and circuit malfunctions. A current controller compares sensed current to a reference current and generates a feedback signal, which is processed by a power factor corrector to adjust the current flow through the transformer supplying current to the LEDs.

Three-dimensional lifting schemes for motion compensated video compression

Abstract: Three-dimensional wavelet decompositions are efficient tools for scalable video coding. We show a lifting formulation for these decompositions. The temporal wavelet transform is inherently nonlinear, due to the motion estimation step, and the lifting formalism allows us to provide several improvements to the scheme initially proposed by Choi and Woods: a better processing of the uncovered areas is proposed and an overlapped motion-compensated temporal filtering method is introduced in the multiresolution decomposition. As shown by simulations, the proposed method results in higher coding efficiency, while keeping the scalability functionalities.

Streaming video bookmarks

Abstract: A method, apparatus and systems for bookmarking an area of interest of stored video content is provided. As a viewer is watching a video and finds an area of interest, they can bookmark the particular segment of the video and then return to that segment with relative simplicity. This can be accomplished by pressing a button, clicking with a mouse or otherwise sending a signal to a device for marking a particular location of the video that is of interest. Frame identifiers can also be used to select a desired video from an index and to then retrieve the video from a medium containing multiple videos.